Final Report ERT 1342 · 2013-08-06 · Final Report ERT 1342 Client Contractor English Nature Hampshire and Isle of Wight Team 1 Southampton Road LYNDHURST Hants SO4 7BU ERT (Scotland)

Solent Intertidal Survey, August to September 2005

Contract no FIN/T05/02

Final Report

ERT 1342

Solent Intertidal Survey, August to September 2005

Contract no FIN/T05/02

Final Report

ERT 1342

Client Contractor English Nature Hampshire and Isle of Wight Team 1 Southampton Road LYNDHURST Hants SO4 7BU

ERT (Scotland) Ltd Research Park South Heriot-Watt University EDINBURGH EH14 4AP

Contact Contact Chris Pirie Dr Iain Dixon tel: 0131 449 5030 fax: 0131 449 5037 e-mail: [email protected]

The information contained in this document is confidential and proprietary. The contents must not be disclosed to any third party without the express and written approval of English Nature. This document has been prepared in accordance with ERT (Scotland) Ltd's quality procedures and has been authorised for issue by the following signatory. ______________________________________________ _____________________ Iain Dixon, Project Manager Date of issue Report approval/authorisation for issue

9 March 2006

ERT 1342/R003 i

Executive summary • ERT (Scotland) Ltd (ERT) was contracted by English Nature (EN) to undertake the project

Biological Survey of the Intertidal Sediments of Solent Maritime Special Area of Conservation (SAC). The aims of the survey were to undertake Phase 1 survey and mapping along pre-determined belt transects, and Phase 2 quantitative sampling using cores at mid shore and lower shore levels.

• The deliverables from this study are the present report with maps, an electronic copy of

the report and other data files on CD, and a MapInfo project on DVD. The originals of all field notes and data have also been provided.

• Limited sampling occurred in August 2005, but the main survey took place over four days

between 17 and 22 September 2005, coinciding with spring tides. Two survey teams carried out the sampling, each with one hovercraft, a pilot and relief pilot, and two surveyors. A total of 42 transects was sampled including 11 in Langstone Harbour and ten in Chichester Harbour, five in the Hamble estuary, six in Southampton Water, five on the northwest coast of the Isle of Wight, and five on the Hampshire shore of the West Solent.

• The Phase 1 data set collected shows that certain species observed in the field were

widespread in the SAC including the polychaetes Arenicola marina, the snail Hydrobia ulvae, the cockle Cerastoderma edule, fucoid algae, and the green alga Enteromorpha sp. Supporting forms included the ragworm Hediste diversicolor, juvenile shore crabs Carcinus maenas, winkles Littorina spp, the barnacles Semibalanus balanoides and Elminius modestus and the slipper limpet Crepidula fornicata.

• The main observable differences across the SAC occurred in the associated shore type and

sediments, and most of the differences apparent between areas in the Phase 1 biological data are substratum-related. In qualitative terms, no significant changes in shore type or in sediment composition have been highlighted by the present study.

• Over 100 taxa were identified from cores taken in the mid and lower shores at 21 transects.

Over the whole survey area, the macrofauna was characterised by the polychaetes Tharyx sp, Pygospio elegans, Eteone cf longa, Streblospio shrubsolii, Melinna palmata and Ampharete grubei, oligochaetes Tubificoides benedii and T pseudogaster (agg), the mud snail Hydrobia ulvae, and the bivalve molluscs Cerastoderma edule and possible Abra tenuis.

• The macrofauna was numerically dominated at nearly all stations by relatively large

numbers of just two or three taxa, mainly Hydrobia ulvae and Tubificoides benedii, and occasionally T pseudogaster (agg) also. The degree of this numerical dominance was highest in Langstone and Chichester Harbours, but decreased in Southampton Water and the Hamble and even more so in the West Solent. In the lower shore stations, the dominance of Hydrobia and Tubificoides benedii was generally lessened, except in Langstone Harbour and at one or two transects in Chichester. Such dominance may be indicative of anthropogenic disturbance, but such influences have been part of the ecology of the area for most of the 20th Century and no changes in recent years are indicated.

• The range in biomass over all areas for the mid shore stations was 0.19 to 1,623.2 g/m2, and

that for the lower shore stations was 0.53 to 509.28 g/m2. Throughout the SAC the biomass was heavily dominated by molluscs, in particular by the cockle Cerastoderma edule and to a lesser extent by the snail Hydrobia ulvae.

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• In addition to standard univariate and multivariate methods used for the analysis of the

macrofaunal data, the AMBI benthic classification process being developed for use by Agencies under the Water Framework Directive, was tried together with the average taxonomic distinctness routine available in the PRIMER package. These procedures were employed on the macrofaunal data collected as part of the present study, but in addition were used on a historical data set compiled from various studies carried out in the Solent over the last 30 years. The purpose of this was to make comparisons of current data with old data more than just a quick qualitative process.

• The results of analysis using AMBI indicated that changes in environmental quality had

taken place between the latter quarter of the 20th Century and the present day. Most of the changes in Langstone Harbour were negative, whilst changes over the rest of the Solent Maritime SAC were either neutral or positive in effect. However, caution is required in considering these results due to the sampling conditions specified in the user notes for the spreadsheet that are not met by the methods used in the present survey. In addition, the historical data set is built up from several studies carried out at different times and using various sample sizes, sieve meshes and methodologies. Quantitative comparisons drawn using such data sets are likely to be suspect.

• The average taxonomic distinctness approach, based on qualitative data, is independent of

the constraints of sample size and methodology. Results indicated that in the 2005 data set several stations, some located in Langstone Harbour, fell below the lower 95% confidence limit line of the expected taxonomic distribution. This could be indicative of changes in community structure, whether natural or anthropogenic. In contrast, results from applying the method to the historical data set indicated that very few of the macrobenthic communities sampled 10 to 25 years ago fell outside or below the 95% confidence limits of the expected taxonomic distribution. The implication is that changes have been taking place in the condition of intertidal sediment flat communities, when ‘expert eye’ assessment of the two data sets indicate how little change there appears to have been. However, it is possible that differences in the taxonomic approach to taxon identification and naming could have occurred between the two sets of data under comparison. The degree to which such differences in taxonomic treatment might have affected AvTD is not clear. Caution is advised in the application of this analysis and interpretation of its results. In addition, the need for consistency in the approach to sampling and analysis of macrofauna in a monitoring programme is highlighted.

• Overall, in qualitative terms, it is clear that differences probably occur from year to year in

the abundances of individual taxa. Due to variation in the data collection methods, timing of surveys (in relation to likely seasonal variation) and because station locations in the two data sets under comparison are only approximately similar, it is not feasible to be more precise about temporal variations in species presence, abundance or biomass. However, it is equally clear that the essential character of the macrofauna in the Solent system remains similar to that evident from previous studies.

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Contents Exective Summary i 1 Introduction 1-1 2 Previous information from the Solent sediment flats 2-1 2.1 Chichester Harbour 2-1 2.2 Langstone Harbour 2-2 2.3 Southampton Water 2-2 2.4 Northwest Solent 2-3 2.5 Isle of Wight 2-4 3 Methods 3-1 3.1 Approach and planning 3-1 3.2 Fieldwork 3-2 3.3 Analysis 3-4 4 Results 4-1 4.1 Phase 1 data 4-1 4.2 Core data 4-7 5 Discussion 5-1 5.1 Comparison with previous data 5-1 5.2 Recommendations for future work 5-6 5.3 Conclusions 5-7 6 References 6-1 Appendix 1 Survey and sample log A1 Appendix 2 Sediment maps for all transects A2 Biotope maps for all transects Lifeform maps for all transects Phase 2 sampling locations (both 2005 and historical data) Appendix 3 Sediment particle size histograms for all core stations A3 Appendix 4 Replicate macrofaunal abundance data and biomass data by station A4

Annex (supplied separately) Field data (field notes, annotated aerial photographs, and completed Site and Habitat forms) GIS project on DVD Electronic copy of report plus figures on CD, plus data files

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1 Introduction ERT (Scotland) Ltd (ERT) was contracted by English Nature (EN) to undertake the project Biological Survey of the Intertidal Sediments of Solent Maritime Special Area of Conservation (SAC); Contract no FIN/T05/02. The SAC encompasses the shores of the northwest Solent, the northwest coast of the Isle of Wight, parts of Southampton Water including the River Hamble, and Chichester and Langstone Harbours (Figure 1.1). The objective of this contract was to survey the marine communities on and within the intertidal mudflats and sandflats as part of the long-term monitoring programme for the SAC required by the European Habitats Directive. In addition, the data will be used by EN to report on the condition of the Sites of Special Scientific Interest (SSSI) that underpin the SAC. The aims of the survey were to obtain standardised infaunal and epibiotic information for the littoral sediment habitats of the Solent Maritime SAC as follows: • To take samples representative of the littoral sediment feature and its variation over the

whole of the SAC, based on a belt transect sampling design; • To undertake sampling based on Marine Nature Conservation Review (MNCR) Phase 1

and Phase 2 sampling methods and to map the biotopes present within each belt transect; • Phase 2 sampling methodology to incorporate core samples for macrofauna and sediment

particle size and organic matter content from mid and lower shore levels of selected transects.

The report resulting from the survey was to include comparison of the data obtained with historical studies from the same area.

Figure 1.1 The survey area and SAC boundary, intertidal sediment survey of the Solent Maritime SAC, August to September 2005

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2 Previous information from the Solent sediment flats The Solent system is situated midway along the English Channel on the Hampshire and Sussex coasts, and is bound on its southern side by the Isle of Wight. Encompassing the Western Solent, Southampton Water, and the natural harbours of Langstone and Chichester, the Solent Maritime Special Area of Conservation (SAC) covers an area of approximately 11,244 ha (English Nature 2005). The benthic habitats of the Solent system are predominantly sedimentary in nature, with extensive intertidal mud and sand flats, and areas of gravelly and pebbly sediments (Dixon & Moore 1987). Hard substrata are limited to the relatively small limestone outcrops on the Isle of Wight, and to cobbles and pebbles overlying the muddy sediments.

2.1 Chichester Harbour Chichester is the largest and most easterly of the interlinked Portsmouth, Langstone and Chichester Harbour complex. It is composed of two major channels, the Emsworth and Chichester Channels, which come together at the harbour mouth. Sandflats occur in the region of the harbour mouth and mudflats in each of the channels. The infaunal communities of Chichester Harbour were described by Thomas (1986). The mudflats were typically dominated by the oligochaete Tubificoides benedeni (=T benedii), the polychaetes Manayunkia aestuaria and Scoloplos armiger, the bivalve Abra tenuis and the gastropod Hydrobia ulvae. Areas of coarse muddy gravel were dominated by the polychaetes Amphitrite johnstoni, Arenicola marina, Capitella capitata and the cockle Cerastoderma edule. The harbour mouth, the most exposed region of the harbour, has the coarsest sediments. The faunal composition was similar to that of a rocky shore, with the barnacle Elminius modestus dominating where large stones were present (Thomas & Culley 1981). Pilsey Sands, a large flat sand bank lying between the two major channels, was composed of generally well sorted, fine to medium sand, often with a small amount of silt included. Crustacea dominated the fauna in this area. Emsworth Channel Emsworth Channel lies to the west of the harbour, with Hayling Island on its western shore. The main section of the channel consisted mostly of muddy sand. Creeks branching from the main Emsworth Channel were made up of polychaete-dominated soft mud, although areas of gravel were also present. Healthy Spartina marsh occurred at the head of the channel north of Sweares Deep, although in areas where marsh die-back had occurred the mud surface was smothered by green algae (Thomas & Culley 1981). In these areas, the fauna was dominated by epifaunal taxa, predominantly prosobranch molluscs. Chichester Channel The Chichester Channel lies to the east of the harbour, and branches into three smaller channels along its northern side. Thomas & Culley (1981) found areas around the entrance to the Chichester Channel, as well as to the east of the Thorney Channel, to be dominated by healthy Spartina marsh. These areas, although impoverished in terms of species number, held a high density of individuals, with the gastropod Hydrobia ulvae generally contributing the greatest proportion. The sediment of the main channel was largely composed of silt and clay,

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supporting a uniform fauna throughout in which polychaetes dominated the biomass (Unicomarine & Rees-Jones 2004). The western shore and head of Thorney Channel was mainly bare mud, although areas affected by Spartina die-back were covered with green algal mats. The species-diverse northeast corner of the channel was dominated by Zostera, mixed with extensive areas covered with the green alga Enteromorpha (Thomas & Culley 1981). The Bosham Channel was largely composed of mudflats covered by mats of Enteromorpha and Ulva spp (Thomas & Culley 1981). Spartina marsh did occur in small patches in both the Bosham and the neighbouring Fishbourne Channel, although there was a trend towards Spartina die-back exposing mud which in turn became smothered with green algal mats. Recent surveys have shown that the sediment in the narrow Fishbourne Channel is predominantly silt-clay with small amounts of fine sand, although several coarse sand and gravel patches exist (Unicomarine & Rees-Jones 2004). Molluscs dominated the fauna in this area, typically representing over 88% of the biomass. The fauna, comprising estuarine burrowing animals typical of intertidal mud flats, was dominated by the gastropod Hydrobia ulvae, the polychaetes Tharyx sp and Hediste diversicolor, and the oligochaetes Tubificoides benedii, T pseudogaster agg and Heterochaeta costata. The polychaete Streblospio shrubsolii and the amphipod Corophium volutator were also widespread and common (Unicomarine & Rees-Jones 2004).

2.2 Langstone Harbour Langstone Harbour is the central of three linked harbours, with Portsmouth Harbour to the west and Chichester Harbour to the east. Unlike the obviously separate channels that make up Chichester, Langstone Harbour resembles a land-locked lake at high water. However, low water exposes extensive mudflats and two sand flats, drained by three channels which meet to form a narrow exit at the harbour mouth. To date, no spatially extensive intertidal surveys have been conducted in Langstone Harbour, although numerous small studies have been completed over the years in relation to potential developments or perceived impacts. Thomas & Culley (1981) found the range of substrata in Langstone Harbour to be similar to those in Chichester, although more extensive areas of sand occured at the mouth of the harbour, in the shallows off Portsea Island. Withers & Thorp (1978) recorded 49 invertebrate species, the dominants being the polychaete Scoloplos armiger and two species of amphipod Bathyporeia sarsi and Urothoe brevicornis, in a survey of the macrobenthos of these sandbanks. Extensive areas of the harbour, around a third of the intertidal mudflats, were covered by the green algae Enteromorpha spp (Thomas & Culley 1981). These mudflats also supported extensive beds of the eelgrass Zostera angustifolia, which first began to spread, both widely and rapidly, in the mid-1950s (Tubbs 1975). At the beginning of this century, mudflats in the upper reaches of the harbour were colonised by the cord grass Spartina. However, these marshes have since exhibited advanced die-back and disintegration (Thomas & Culley 1981).

2.3 Southampton Water Southampton University (1987) described the shores of Southampton Water as predominantly mudflat, with a band of shingle running along its eastern bank. Small areas of Spartina marsh have also been found on its western side (Environment Agency 2004). Unicomarine &

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Rees-Jones (2004) carried out sampling in a number of small creeks along the southwest shore of Southampton Water. The sediments within these creeks were predominantly silt and fine sand, while outer creek areas contained higher proportions of coarse sediment. The fauna comprised estuarine burrowing animals typical of intertidal mudflats, although the species diversity was found to be low in some areas suggesting some form of disturbance. This part of Southampton Water has long been influenced by industry and major shipping activity, with a power station and refineries nearby, whilst the upper reaches of the waterway are heavily urbanised with docks and harbour installations. Test Estuary The composition of intertidal sediments in the Test Estuary has been found to be very mixed, although still with a high proportion of silt and fine sand. The mudflats in this area were largely bare, with only small areas of algal cover (Environment Agency 2004). The fauna has been shown to comprise typical infaunal estuarine mudflat species, dominated by the polychaetes Tharyx sp, Pygospio elegans and Hediste diversicolor, the oligochaete Tubificoides benedii, and the gastropod Hydrobia ulvae (Unicomarine & Rees-Jones 2004). There were also large numbers of the cockle Cerastoderma edule. Hamble Estuary The narrow Hamble Estuary is situated on the eastern bank of Southamton Water, near the channel entrance. Previous surveys have indicated that the banks of this estuary are made up of mixed saltmarsh and algae covered mudflats (Gray et al 1991), along with small patches of bare sediment and Spartina marsh (Environment Agency 2004). Gravel has built up near the mouth of the estuary, creating the ridge of Hook Spit (British Geological Survey 1996).

2.4 Northwest Solent Gray et al (1991) described the northern coastline of the West Solent between Hurst Spit and the Beaulieu Estuary as varying between saltmarsh, mudflat and shingle. From Keyhaven to Lymington the extreme high tide level was characterised by a series of man-made sea walls and embankments. The intertidal areas below these were made up of mudflats and Spartina anglica dominated marsh deeply dissected by numerous muddy channels, although at Pennington the marsh was replaced by stony mud. Holme & Bishop (1980) further described the shore at Pennington, where anaerobic muddy sand was dominated by species of Nereis. Lymington Estuary As part of a study of the south coast inlets by the Nature Conservancy Council, Johnston (1989) described the Lymington Estuary, finding the fauna to be impoverished along the lower intertidal zone. More recent surveys have shown the mudflats in the outer region of the estuary to be covered in large areas of Spartina marsh (Environment Agency 2004). This estuary has been greatly altered by human activities including the building of embankments, moorings, jetties and dredging to maintain the navigation channel (Covey 1998). Beaulieu Estuary Although a relatively extensive inlet, the Beaulieu Estuary has not been surveyed for its benthic communities (Covey 1998). A vegetated shingle bank has been shown to cross the mouth of this narrow meandering estuary (Gray et al 1991), enclosing a range of habitats, including Spartina marsh which continues throughout the estuary (Environment Agency 2004). Towards the

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eastern side of the estuary mouth, mudflats were highly eroded, causing marsh to be replaced by algal cover.

2.5 Isle of Wight Other than the dock walls and pilings within certain harbours or inlets, few areas of hard substrata are found on the northern coast of the Isle of Wight. Along this stretch of coast, the intertidal sediments were generally mixed, with mostly sand and shingle beaches (Gray et al 1991). Four small estuaries, each less than 500 ha in total area and varying in form, are situated on the north coast of the Isle of Wight within the Solent Maritime SAC and each is described below. King’s Quay Johnston (1989) described King’s Quay Estuary, situated on the northeast coast of the Isle of Wight, as a small muddy inlet which dries at low water. At the entrance to this inlet, on the edge of the Solent, the mixed sediment shore was composed of mud, sand and shingle, with clay outcrops that supported the polychaetes Lanice conchilega, Neanthes virens, the anemone Anemonia viridis, and the crabs Pagurus bernhardus and Carcinus maenas. A spit of boulders extending along the lower shore was colonised by the algae Sargassum muticum, Laminaria saccarhina, Fucus serratus and Griffithsia flosculosa and the sponges Hymeniacodon perleve and Myxilla incrustans, together with a typical range of barnacles and molluscs. While the mudflats at the mouth of the estuary were covered with algae, a small area of Spartina marsh was found further inside (Environment Agency 2004). Beds of the eelgrass Zostera sp have also been reported to occur on the lower shore (Johnston et al 1989). Medina Estuary The narrow and muddy Medina Estuary enters the Solent at Cowes, in the north of the Isle of Wight. Withers (1979) surveyed the marine macrofauna and flora of this estuary, describing the intertidal area as predominantly mudflat with varying quantities of shell debris, shingle and, occasional boulders. Although a large number of invertebrates were recorded, only relatively few were common, including the anemone Cereus pedunculatus, the polychaetes Cirriformia tentaculata and Neanthes spp, the gastropods Hydrobia ulvae and Littorina spp, and the bivalves Cerastoderma edule and Mya arenaria. The dominant algae were Enteromorpha spp and Ulva lactuca, with Fucus spiralis attached to many of the larger stones in upper shore areas. This estuary has been described as having one of the best examples of mature mixed saltmarsh on the southern British coast (Davidson 1996). The upper reaches of the Medina Estuary were predominantly made up of fine sands and silt, although there were patches of coarse sand and gravel (Unicomarine & Rees-Jones 2004). The fauna was dominated by oligochaetes including Tubificoides benedii, and the gastropod Hydrobia ulvae. Newtown Harbour Newtown Harbour has been extensively studied, initially by Howard et al (1988). The harbour, which opens into the western arm of the Solent, included extensive fringing mudflats and sublittoral channels. The substrata making up the greater part of the harbour were sedimentary, comprising of soft muds. However, some stones, pebbles and shell gravel were distributed along the western arms of the harbour and at its entrance. In some areas, a subsurface coarse layer of stones and shells was found beneath the muddy surface.

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Howard et al (1988) described three main shore types within Newtown Harbour. Mixed sediments of fine sandy mud, with the occasional lugworm Arenicola marina, occurred near the entrance to the harbour. The sheltered central region of the harbour consisted of fine sediments, with the polychaetes Aphelochaeta marioni and Ampharete finmarchica found throughout. Within this region, the ragworm Hediste diversicolor was abundant at sites along Clamerkin Lake to the east of the harbour. However, the lugworm Arenicola marina, not found in Clamerkin Lake, was most abundant in the western arms of the harbour. The innermost reaches of the tidal creeks were extremely sheltered, with fine sediments. In addition to the polychaetes found in the central region, high densities of the polychaete Streblospio shrubsolii occurred. Few crustaceans or molluscs were found in the harbour. Enteromorpha sp was common on many areas of the mudflats, but other algae were largely restricted to areas of pebbles and cobbles, particularly along the western arms and at the harbour entrance. As the flats were almost entirely composed of sediment, epibiota was sparse, although the winkle Littorina littorea and the slipper limpet Crepidula fornicata were present in significant numbers. Yar Estuary The small, narrow muddy Yar Estuary is located near the western tip of the island. Johnston (1989) showed that most of this estuary consisted of saltmarsh and mudflat exposed at low water, with a narrow channel running down the centre. Current-swept cobbles colonised by a rich and diverse fauna of anemones, ascidians and sponges, occurred in upper reaches of the estuary north of King’s Manor. The sponge fauna included large colonies of Suberites domuncula, unusual in the intertidal zone, and the rarely recorded Suberites massa. The shoreline to either side of the estuary mouth was made up of extensive sandflats, below boulder-strewn sand and shingle beach (Gray et al 1991).

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3 Methods

3.1 Approach and planning A series of transects was selected, based on the combination of previous survey work carried out by others, access considerations, and the objective of the project to represent the full range of intertidal sediment habitats within the SAC. Ordnance Survey (OS) data and aerial photography for the Solent were provided by EN, together with several geo-referenced survey datasets. These were used to select transect locations, and subsequently provided the basis for a series of laminated colour photographs and maps for use in the field. Not all of the aerial photographic coverage was taken at low water, slightly limiting the confidence with which transects were selected. However, following review and consultation, approximately 51 suitable transect locations were selected including 12 in Langstone Harbour and 12 in Chichester Harbour, five in the Hamble estuary, seven in Southampton Water, nine on the northwest coast of the Isle of Wight, and six on the Hampshire shore of the West Solent. The intention was to sample 48 transects within a period of four days, aiming for 12 in Langstone Harbour, 12 in Chichester Harbour, 12 in Southampton Water and the Hamble, six on the northwest coast of the Isle of Wight, and six on the Hampshire shore of the West Solent. Intertidal mudflats, often extensive and composed of soft sediment, and sometimes with complex networks of channels and creeks, can pose significant health and safety risks to surveyors. Systematic sampling of these habitats over the full shore width, often in the order of hundreds or thousands of metres and flanked in addition by extensive salt marsh, can take considerable time. Also, soft sedimentary habitats (and associated salt marsh) tend to be more vulnerable to the impacts of disturbance caused by access such as noise from boats or vehicles and trampling from surveyors. In order to get as much coverage within a short space of time, and to minimise the risks to health, safety and the environment, mini hovercraft were chosen as the chief aids to sampling. The hovercraft used for the survey included an Osprey Mk 5 and a Skimmer, typically employed together in the more confined and sheltered estuarine environments where one could act as back-up to the other if necessary. In addition, a larger diesel-engined Griffon 380 was used on its own for work in the more extensive and open areas of the Solent. Craft, pilots and back-up crew were provided through Hover Marine Services. For work in Langstone Harbour, the hovercraft were launched and recovered at the public slipway at the north end of the Hayling Island bridge. This slip was also used for work in Chichester Harbour, together with the beach-launching site at West Itchenor. Work in Southampton Water was based at the Calshot Spit slipway, whilst the slip at Warsash was used for operations in the Hamble estuary. For work on the Isle of Wight and the West Solent, the hovercraft was launched and recovered at the Griffon yard at Woolston on both days. Prior to survey work, permission was sought from landowners and harbour authorities for shore access and to check that hovercraft operations were acceptable. The responses to these enquiries had a bearing on the timing of the survey and the final transect locations, and resulted in certain conditions being placed on survey conduct in particularly sensitive areas. As a blanket condition, hovercraft were prohibited from travelling over salt marsh or pioneer salt march vegetation.

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3.2 Fieldwork 3.2.1 Survey mobilisation The survey initially mobilised in the third week of August 2005, but after a small amount of sampling in Langstone Harbour was terminated for logistical reasons. The survey finally took place over four days between 17 and 22 September 2005, coinciding with spring tides and a workable daylight length of approximately 12 hours. The surveyors were Iain Dixon, Jacco Veenboer, Peter Barfield and Gregor McNiven, although Jonathan Hunt, Chris Pirie, Jen Ashworth, Robert Irving and Gregor McNiven were present on the initial mobilisation. The weather was mostly fine and no weather downtime was incurred. 3.2.2 Intertidal mapping Two survey teams carried out the sampling, each with one hovercraft and pilot and two surveyors. With 48 transects to be sampled within four days of fieldwork, each team was tasked with completing six transects per day. In the event, it was not possible to sample all the intended transects due to loss of time to mechanical failure or, in one instance, to a craft becoming temporarily stuck in a mudflat gulley. In addition, some transects were moved during fieldwork due to access issues or discovering that a chosen site consisted of salt marsh rather than intertidal sediment flat. A total of 42 transects was sampled including 11 in Langstone Harbour and ten in Chichester Harbour, five in the Hamble estuary, six in Southampton Water, five on the northwest coast of the Isle of Wight, and five on the Hampshire shore of the West Solent. The locations of these are shown in Figures 3.1 to 3.5. At transect 14 in Newtown Harbour on the Isle of Wight, hovercraft were prohibited from entering the harbour. In this case, the survey team were met at the harbour entrance by the harbourmaster in a small outboard-powered dory and taken to the chosen transect location. The boat provided safety cover for the surveyors during this part of the survey work. At each transect, sampling consisted of a combination of mapping and Phase 1 recording within a belt 400 m wide (200 m either side of a central line running between the transect start and end points in the littoral fringe and lower shore respectively). In addition, quantitative sampling was required at selected transects using cores at a mid shore station and at a lower shore station. Navigation and mapping was based on the use of handheld global positioning system (GPS) receiver units onto which transect locations had been downloaded from the GIS. On each transect, surveyors travelled a zig-zag route within the 400 m wide belt transect in order to locate biotope boundaries down the shore and record the key fauna and flora present within each biotope according to MNCR Phase 1 methodology. The sediment was dug over within each putative biotope in order to evaluate the infauna present; however, sediment was usually not sieved as suggested in the MNCR method for logistical reasons (related to distance from water, the difficulties of moving around on mudflats, the stickiness of the mud, and the number of quantitative samples for sieving). If seagrass beds were present within the belt, then the intention was to map their distribution out to 400 m either side of the transect centreline.

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The identification of biological zones down each belt transect was supported by photographs, notes and hand-drawn sketches as required to complete the standard ‘site’ and ‘intermediate littoral habitat’ MNCR recording forms. Forms used for each transect were as follows: • Purpose-designed form for recording waypoints, times, re-location data, photograph log,

Phase 1 and Phase 2 (coring) sample points, and a sketch shore profile. • Aerial photograph with intended transect highlighted, for annotating with notes on

zonation, boundaries and sampling points. The observed zonation on the shore at each transect was drawn directly onto the aerial photographs, since some of the boundaries visible on the shore were also evident on the photograph. This aid to mapping was not available in certain areas where the aerial photography had not been undertaken at low water. Nevertheless, all photographs were of considerable use for site location in the field. Handheld GPS units were used to record the position of biotope boundaries, target notes and photographs in the form of stored waypoints. As far as possible each area (or polygon) mapped corresponded to a single biotope. Features or biotopes of note too small for mapping were recorded as a target note within the polygon. Any notable species not readily identified in situ were collected for later examination, and preserved if necessary for identification following completion of the survey. For the most part, transects within each area were simply completed one after the other. However, due to tides and the necessity of sampling the full width of the shore, it was sometimes necessary to sample the upper half of several transects on one tide, followed by the lower half of these transects on the following ebb. As far as possible, sampling on the lower shore of each transect was carried out within two hours either side of low water. Following each day’s fieldwork, all GPS units and cameras were downloaded, and the data checked and backed up, in addition to which any specimens collected were identified or preserved for later identification. Field notes and species records were transferred to MNCR sheets each day as far as possible, but the rate of field sampling meant that, in practice, this had to be completed after survey work. 3.2.3 Intertidal coring Quantitative samples of sediment infauna were collected at mid shore and lower shore stations at selected transects. Three macrofauna cores of 10 cm diameter were collected to a depth of 15 cm at each station, together with a further core for sediment characterisation. The main additional elements of the methodology are as follows: • Each biological sample will be washed over a 0.5 mm mesh sieve and the retained material

fixed and preserved in a final solution of approximately 4% formalin in sea water (which equates to a 10% solution of formaldehyde).

• Vital stain, rose bengal, will be added to aid in the sorting of the animals in the laboratory. This may be added in the field or during later processing.

• Sieves will be checked for trapped fauna which will be retrieved with forceps and added to the sample, prior to the sieve being cleaned by backwashing and scrubbing in order to avoid cross-sample contamination.

• Sediment characterisation samples will be stored in a cool box and frozen at the first available opportunity for later analysis.

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3.3 Analysis 3.3.1 Field records Following fieldwork, the transfer of field notes to MNCR sheets was completed and biotope codes were assigned to each shore zone identified using the current 05.04 version of the biotope classification system (Connor et al 2004). In addition, the field specimens requiring identification were examined and the data sheets adjusted accordingly. Waypoint data were compared with intended transect locations using MapInfo Professional version 7.0 GIS and generally compared very well. Final transect locations differed markedly from the intended location in one or two cases as a result of decisions made in the field resulting from access limitations or because intended locations turned out to be on salt marsh. GIS layers were developed from the point data to create maps showing digitised versions of the polygons identified in the field, Phase 1 sample points, Phase 2 sample points, photograph locations and target notes. For the final map representation, biotopes were coloured according to a custom colour scheme, and to the Life Forms format (Foster-Smith et al 2000) for comparison. A custom biotope colour scheme was used, with a different colour for each biotope to improve the map display, rather than the MNCR scheme in Connor et al (1997a, b) in which adjacent biotopes tend to be assigned the same colours. Sediment particle size analysis Sediment particle size analysis was undertaken using a combination of two techniques; sieve analysis for all material retained by a 500 µm sieve, followed by laser diffraction analysis of the finer material. The sediment was first treated with 30% hydrogen peroxide to remove organic material. Sediment was then filtered and washed with distilled water to remove any remaining salts and dried at approximately 60 °C. The dried material was then passed through a Wentworth series of analytical sieves (4,000 to 500 µm) and the weight of material retained at each stage recorded. A sub-sample of the <500 µm material was analysed using the laser diffraction technique. Sediment particle size statistics are referred to on the phi (ø) grade scale. This is a logarithmic transformation of the Wentworth scale of sediment particle size categories based on the negative log to the base2 of the particle diameter in millimetres (Buchanan 1984). Total organic matter content was determined by ignition after the removal of calcium carbonate (shell debris) by treatment with hydrochloric acid. The sediment was then washed and dried to a constant weight before being ignited in a muffle furnace at 600 °C for 2 hours. The organic content of the sediment was then calculated using the weight difference between the original dry weight and that of the ignited residue, taking into account the loss of carbonate. 3.3.2 Macrobenthos analysis Once samples had been received, checked and logged at ERT in Edinburgh, they were washed on a 0.5 mm mesh to remove the formaldehyde prior to work-up in the laboratory. The retained material was placed back in the original container and the preservative changed to 2% phenoxetol. Biological material was then separated from the sediment residue by hand and sorted into a separate container.

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Following checks by a biologist on the efficiency of the sorting procedure all of the animals were then identified and enumerated by specialist taxonomists. Identification was to species level where possible. A few specimens, due to their immaturity, damage incurred during processing, or lack of suitable taxonomic literature, could not be identified to species and were identified to higher taxonomic levels as appropriate. After identification, samples were stored in 70% ethanol/1% propylene glycol/29% water. The biomass (blotted wet weight) of each species in each sample was recorded using a Sartorius MC210P electronic balance calibrated and reading to four significant figures (to the nearest 0.1 mg). Species abundances were entered into a spreadsheet package and checked. The nomenclature conforms largely to that suggested by Howson & Picton (1997) and taxonomic ordering conforms to Howson (1987). Prior to numerical manipulation, the macrofaunal data were adjusted where appropriate to avoid spurious enhancement or degradation of community statistics (eg by omitting taxa consisting of large numbers of juveniles, or by combining indeterminable species with other taxa). The computer program DIVCALC (Rolph, unpublished) was used to calculate univariate statistics such as the numbers of individuals and taxa in each sample, and various diversity indices (Simpson’s, Brillouin’s and the Shannon-Wiener information function) and evenness indices (Pielou's and Heip’s). This program also lists the ten most numerically abundant taxa at each station, with the proportion they contribute to the total at each station and their cumulative percentage abundances. The abundance data were further analysed using the multivariate techniques cluster analysis and non-metric multi-dimensional scaling (MDS) ordination. These were performed using the PRIMER (version 5.2.1) package developed at the Plymouth Marine Laboratory (Clarke & Gorley 2001). The Bray-Curtis Similarity Index was applied within each of these techniques. Multivariate procedures augment the univariate measures of community structure in gaining an understanding of variations and gradients within the data. Additional techniques used to examine the macrofaunal data were the AMBI (a marine biotic index) benthic classification process (Borja et al 2000) and average taxonomic distinctness (Clarke & Gorley 2001). AMBI was devised as an additional tool to establish the ecological quality of European coasts under the terms of the Water Framework Directive, using the response of soft-bottom communities to natural and man-induced changes in water quality. The index is derived from the degree to which five ecologically-distinct macroinfaunal groups (Borja et al 2000) are represented in the samples being tested. These in turn are related to the degree of sensitivity/tolerance to environmental stresses, and particularly to organic enrichment (after the model of Pearson & Rosenberg 1978). A biotic coefficient is derived that is related to a pollution scale divided into five categories (unpolluted; slightly polluted; meanly polluted [sic]; highly polluted; extremely polluted) and which are categorized as grades of Ecological Status for the Water Framework Directive (high; good; moderate; poor; bad). AMBI is available as a multimetric spreadsheet workbook for evaluation in monitoring trials. In addition to using this tool on the present survey data, AMBI was also run using a matrix of species abundance data from previous survey work that covered the same areas (Emu 2004). Average taxonomic distinctness (AvTD or ∆+) is a biodiversity index based on the taxonomic distance between species, defined by Clarke & Warwick (1998) and regarded as being

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independent of sampling effort. Thus a sample that consists of 10 species from the same genus is considered less diverse than a sample of 10 species which come from 10 distinct families or orders. AvTD or ∆+ is defined as the expected taxonomic distance apart of any two individuals chosen at random from a sample, provided those two individuals are not from the same species. Warwick & Clarke (1998) provided evidence for a loss of AvTD in locations that were affected by various types of pollution such as sewage, industrial pollution and heavy metal pollution. The program PRIMER 5 (Clarke & Gorley 2001) incorporates a routine for the calculation of AvTD (TAXDTEST) and the graphical plotting of the results. This programme was also used to process the historic macrofaunal data set used in investigating the AMBI tool (Emu 2004).

Figure 3.1 Numbered transect locations (C indicates Phase 2 core sampling) in Langstone Harbour,

intertidal sediment survey of the Solent Maritime SAC, August to September 2005 (scale & orientation indicated by 1 km OS grid)

NB Shaded area indicates area used by roosting seabirds, to be avoided three hours either side of high water

This map is reproduced from the OS map by English Nature with the permission of Ordnance Survey on behalf of The Controller of Her Majesty’s Stationery Office, © Crown copyright. All rights reserved. Unauthorised reproduction infringes Crown Copyright and may lead to prosecution or civil proceedings. License Number GD272299.

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Figure 3.2 Numbered transect locations (C indicates Phase 2 core sampling) in Chichester Harbour,

intertidal sediment survey of the Solent Maritime SAC, August to September 2005 (scale & orientation indicated by 1 km OS grid)

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Figure 3.3 Numbered transect locations (C indicates Phase 2 core sampling) in Southampton Water and the

Hamble estuary, intertidal sediment survey of the Solent Maritime SAC, August to September 2005 (scale & orientation indicated by 1 km OS grid)

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Figure 3.4 Numbered transect locations (C indicates Phase 2 core sampling) on the Isle of Wight, intertidal

sediment survey of the Solent Maritime SAC, August to September 2005 (scale & orientation indicated by 1 km OS grid)

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Figure 3.5 Transect locations in the West Solent, intertidal sediment survey of the Solent Maritime SAC,

August to September 2005 (scale & orientation indicated by 1 km OS grid) NB Shaded area indicates Lymington Harbour area forbidden to hovercraft operations

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4 Results Original field notes, maps and logs completed during the survey, together with electronic data files, and photographs, are supplied as a separate Annex to this report. In addition, the maps and data presented below have been supplied electronically as image and document files, as well as in a MapInfo GIS project. As outlined in Section 3, it had been planned to carry out Phase 1 sampling at 48 pre-determined transects, and to undertake Phase 2 sampling by coring at mid shore and lower shore stations at 24 of these transects. After the initial false start in August, during which three transects were completed and one started in Langstone Harbour, sampling was resumed in September and proceeded more or less to plan. During fieldwork some of the transects were re-located or shortened due either to access issues or occasionally because of the presence of salt marsh over much of the planned transect. In addition, the Osprey hovercraft (used mostly in Langstone and Chichester Harbours) broke down or suffered from reliability issues on two or three occasions, and became stuck temporarily in one of the mudflat gullies on another occasion. These factors, coupled with short daylight hours, meant that some of the planned transects were not visited or that the visit was shortened. A total of 42 transects was sampled over the area as a whole, including 11 in Langstone Harbour and ten in Chichester Harbour, five in the Hamble estuary, six in Southampton Water, five on the northwest coast of the Isle of Wight, and five on the Hampshire shore of the West Solent (Figures 3.1 to 3.5). In addition, 21 of these transects were sampled using cores (Figures 3.1 to 3.5). Time constraints meant that lower shore cores were not taken at transect 31 in Langstone Harbour, and that mid shore cores were not collected at transect 14 in Newtown Harbour. In addition, the lower shore at transect 20 in the West Solent was not cored due to the hard nature of the shore. The Griffon hovercraft used for the Isle of Wight and West Solent sections of the survey was ideal for these more open waters, being very fast and reliable. Nevertheless the distances involved, together with access issues for Newtown Harbour and the Lymington estuary as outlined in Section 3, were the main reasons for not fully achieving the planned sampling effort on these coastlines. A summary of the sampling achieved is given in the survey log presented in Appendix 1. The results presented below are organised by data category, starting with an overview of the SAC sediment flats as observed and sampled, then presenting the Phase 1 data, and then the Phase 2 coring data data.

4.1 Phase 1 data 4.1.1 Habitat overview The distribution of substratum type found on transects within each of the main survey sectors (Langston, Chichester, Southampton Water & Hamble, Isle of Wight, Northwest Solent) is illustrated in A3 fold-out maps in Appendix 2 (Figures A2.1 to A2.5). The shores sampled in the present survey range in exposure from sheltered along the Hampshire and Isle of Wight shores of the West Solent, to extremely sheltered in the estuarine habitats of Langstone, Chichester and Newtown Harbours, and the Hamble and Medina estuaries.

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The intertidal extent along both open coasts of the West Solent is generally narrow, with most of the transects sampled being of the order of 100 m or less in length. The Isle of Wight shoreline is generally backed by unstable low clay or mudstone cliffs, whilst the shores consist of sticky but firm mudstone overlain by flint pebbles. One exception to this pattern was in Thorness bay where the shore-backing was low-lying and the relatively wide intertidal extent consisted of firm sand overlain by gravel, pebbles and shells. Small, low-lying rocky reefs occasionally outcropped along the lower shore and sublittoral fringe of this shoreline. A high proportion of the Hampshire shoreline was backed by sea defence levees resulting in upper shores of steeply sloping concrete or gravel and pebbles, and flatter mid to lower shore zones of sand and mudstone overlain with pebbles and shells and supporting areas of shallow standing water. These parts of the shoreline also featured groyne structures at regular intervals to minimise sediment removal by long shore drift. At the entrances to the Lymington and Beaulieu Rivers there were large expanses of salt marsh that were fringed at the shoreline with firm sticky clay that sloped rapidly into the sea giving a very narrow intertidal zone. A higher degree of shelter and softer sediment flats are found within the Medina estuary and Newport Harbour on the Isle of Wight (and in the Yar, though this was not sampled in the present survey). The mudflats in Newtown Harbour were particularly soft and required the safety back-up of a boat. Similarly sheltered habitats occur up the western side of lower Southampton Water where salt marsh grades into extensive soft intertidal sediment flats between Calshot Spit and Hythe. The sediment flats flanking the channel of the Hamble estuary were firm near the opening into Southampton Water and included stony admixtures, but became finer and softer with distance into the estuary. The sediment flats within Langstone and Chichester Harbours were sheltered, but the transects sampled ranged from predominantly sand at the entrances to sticky mud in the innermost reaches and often included stony material in the form of pebbles, cobbles or boulders. Sediments were generally finest, softest and wettest in the channels, and coarsest, mixed and firmest or driest towards the top of the shore. 4.1.2 Species data The Phase 1 species records, abstracted from the field sheets, are shown in summarised form for Langstone Harbour in Table 4.1, for Chichester Harbour in Table 4.2, for Southampton Water and Hamble in Table 4.3 and for the Isle of Wight and mainland coasts of the West Solent in Table 4.4. Langstone Harbour (Table 4.1) The main taxa identified on each transect included the lugworm Arenicola marina, the mud snail Hydrobia ulvae, the cockle Cerastoderma edule, the bladder wrack Fucus vesiculosus and the green alga Enteromorpha sp. In addition, mobile epifaunal taxa such as shore crabs Carcinus maenas (mostly juvenile) and the winkle Littorina littorea also occurred frequently around the harbour. Many of these taxa range over the full width of the intertidal, or at least over the mid to lower shore area. On the other hand most of the less frequently recorded taxa, such as the sponge Hymeniacodon perleve, the anemone Anemonia viridis, the infaunal ragworm Hediste diversicolor, filamentous red algae indet and the serrated wrack Fucus serratus for example, were only found towards the lower shore. Exceptions to this rule are evident in the channelled wrack Pelvetia canaliculata, which is characteristic of upper shore areas, and the seagrass Zostera noltii, which tended to be most abundant in the mid shore. Many of the upper shore zones on each transect

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did not support any marine species at all, whilst the lack of hard substrata on the lower shore all around the harbour is illustrated by the relative paucity of Fucus serratus records. Chichester Harbour (Table 4.2) The range of taxa found in Chichester Harbour was similar to that seen in Langstone Harbour. Thus Arenicola marina, Hydrobia ulvae, Cerastoderma edule and Enteromorpha sp were prominent at most stations, although their distribution was not as apparently uniform around the harbour as in Langstone. Fewer occurrences of fucoid algae on each transect possibly indicate less suitable hard substrata for their attachment. Southampton Water and the Hamble (Table 4.3) The range of taxa recorded differed subtly from the lists from Langstone and Chichester Harbours. Species typically present on most transects included the ragworm Hediste diversicolor, Hydrobia ulvae and Cerastoderma edule. Arenicola marina did not occur as widely over the transects as in Langstone and Chichester Harbours, in addition to which occurrences of fucoid algae and the green mats of Enteromorpha sp were fewer also. Within Table 4.3 it is also evident that range of species found was higher in the Hamble (transects 2 to 6) than down the west side of Southampton Water (transects 8 to 12). This was a function of the wider occurrence of hard substrata (boulders and stones mainly) in the Hamble, to which fucoids, red algae and barnacles could attach themselves. Isle of Wight and the Northwest Solent (Table 4.4) The range of species found was greater than in the areas outlined above, possibly reflecting a greater range of habitat types on these shorelines (ranging from sheltered silty harbour areas to compacted stony sediments on the open coasts) but more likely due to the wider occurrence of hard substrata. Despite the habitat variability, it is still possible to recognise a group of the more widely occurring taxa which characterise this area, such as Hediste diversicolor, Arenicola marina, Littorina littorea, Cerastoderma edule, Fucus serratus, F spiralis, F vesiculosus and Enteromorpha sp. The higher species richness compared to other survey sectors was due to a wider range of more rarely occurring taxa, particularly small red foliose and filamentous algal forms, the sea squirt Ascidiella aspersa, sponges and anemones, and the bivalve molluscs Tapes decussata and Ostrea edulis. Most of these require hard substrata for attachment, and these were slightly more prevalent (as stony mixed sediments) on the Northwest Solent shore than on the Isle of Wight. 4.1.3 Biotope data A total of 33 intertidal biotopes was recognised during the survey, and these are listed in Table 4.5 which also give an impression of the way in which they are distributed across the Solent SAC as a whole.

Although sediment flats were the features of interest in the present study, almost half of the biotopes identified (15 out of 33) were rocky shore biotopes. This was due in nearly all cases to the presence of stones of various grades in or on the sediment surface, creating habitat for visually prominent fucoid seaweeds. As noted in the species data above, the range and frequency of occurrence of rocky shore biotopes is highest in Langstone Harbour, and on the Isle of Wight and mainland shorelines of the West Solent.

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Many biotopes were designated as relatively high level codes (eg LS.LSA, LS.LMu, LS.LMx or LR). In the case of the sediment biotopes, this was because of inherent difficulties in characterising habitats and communities on the basis of limited visual cues and using a classification that is largely derived from more detailed infaunal analysis (based on small species that would not be identifiable in the field, even following sediment washing). The Phase 1 species records from most of the habitats identified were centred on a limited range of ubiquitous taxa. These included the lugworm Arenicola marina, the ragworm Hediste sp, the snail Hydrobia sp, the cockle Cerastoderma edule, fucoid seaweeds and the green algae Enteromorpha sp and Ulva sp (from hereon the name Enteromorpha sp will be used to imply records of either green algal genus). Most other taxa reliably recorded on the intertidal sediment flats (predominantly epifaunal organisms such as the sponge Hymeniacodon perleve, the barnacles Semibalanus balanoides and Elminius modestus, winkles Littorina spp, topshells, Gibbula sp, the opisthobranch Akera bullata and red filamentous algae) are not key to the classification system for sedimentary biotopes. Thus in the absence of the detailed infaunal information necessary to differentiate biotopes on the basis of species content, the factors used to designate biotope codes were generally fairly limited. Detailed infaunal information (ie to a Phase 2 level) was collected from certain transects (see Sections 3.2.3 and 4) but the resultant data are presented and discussed separately. The biotope code LR was used once, at transect 26 in Chichester Harbour where there was a man-made boulder slope in the littoral fringe with no visible marine biota. Similar habitat occurred at the top of transect 4 at the entrance to the Hamble River, though these boulders occurred in the mid to upper shore and supported fucoids and barnacles and were therefore designated as LR.LLR.F. Biotopes characterised by the dwarf seagrass Zostera noltii (LS.LMp.LSgr.Znol) were found in Langstone and Chichester Harbours, being mapped on transects 40 and 44 respectively. A patch of Z noltii was also identified in the midshore to the south of transect 31 in Langstone Harbour; this was not mapped owing to technical problems with the hovercraft at the time. Distribution and zonation Table 4.6 summarises the characteristics and distribution of biotopes across the Solent SAC as a whole. The distribution of the biotopes and lifeforms found on transects within each of the main survey sectors (Langston, Chichester, Southampton Water & Hamble, Isle of Wight, West Solent) is also illustrated in A3 fold-out maps in Appendix 2 (Figures A2.6 to A2.10). Of the biotopes found, the most ubiquitous in the Solent Maritime SAC were LS.LCS.Sh.BarSh, LS.LMu.MEst and LS.LMx. These were found in four out of the five survey sectors. In addition to these, four biotopes (LS.LCS.Sh, LS.LSa.MuSa, LS.LMu and LR.LLR.FVS.Fcer) were found in three of the survey sectors. On the other hand, most biotopes (26 in total) were only recorded in one or two of the survey sectors.

In terms of commonness, LS.LMu.MEst and LS.LMx were the most frequently recorded (31 times and 22 times respectively), whilst 16 out of the total of 33 biotopes were each only recorded once during the survey. The estuarine mud biotope LS.LMu.MEst was commonest in Langstone and Chichester Harbours as well as in Southampton Water and Hamble. The mixed sediment biotope LS.LMx was more characteristic of Langstone Harbour, Southampton Water and the Hamble, and the Northwest Solent.

Most of the mixed sediment fucoid-dominated biotopes found were of relatively low diversity and occurred within the sheltered and variable salinity regimes of harbours or estuaries. Under such conditions these were usually confined to mid or upper shore regions and characterised by

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Fucus spiralis or F vesiculosus, whilst the mid to lower shore consisted of finer and smoother sediment flats. The only transects where hard substrata extended into the lower shore and supported rocky shore-type fucoid-dominated biotopes were in the Isle of Wight (on transects 21, 22 and 23) and the Northwest Solent (transect 16). These biotopes were characterised by Fucus serratus. The other notable fucoid-dominated biotope recorded was LR.LLR.FVS.Fcer, characterised by F ceranoides and confined to stony substrata under the influence of fresh water. Fucus ceranoides occurred widely within the SAC but was usually mixed with and less abundant than F spiralis. As a dominant species, F ceranoides was found in Langstone, Chichester and Newton Harbours, and in the Medina estuary. Langstone (Figure A2.6). The estuarine mud biotope LS.LMu.MEst and the mixed sediment biotope LS.LMx were the most commonly recorded biotopes in Langstone Harbour, and both were recorded widely throughout the basin between the mid and lower shore levels. The only sandy biotopes were those recorded on transect 28 (LS.LSa and LS.LSa.MuSa) near the mouth of the harbour. Many transects included shingle-dominated habitats at or near the top of the shore (eg; LS.LCS.Sh or LS.LCS.Sh.BarSh) and several also had sufficient hard substrata near the top of the shore to support fucoid seaweed-dominated biotopes characteristic of variable salinity or freshwater influence (eg; unidentified fucoids, LR.LLR.FVS; Fucus spiralis, LR.LLR.FVS.FspiVS; or F ceranoides, LR.LLR.FVS.Fcer). The comparative rarity of hard substrata in lower half of the shore is signalled by the absence of biotopes dominated by the bladder wrack Fucus vesiculosus (LR.LLR.FVS.FvesVS) below mid shore level, and the absence of biotopes dominated by other lower shore algae. Of note was the occurrence of the seagrass Zostera noltii (LS.LMp.LSgr.Znol) along transect 40 on the southeast side of the harbour. Seagrass was also observed in the midshore to the south of transect 31, though its full extent here was not mapped owing to technical problems with the hovercraft in use at that location at the time. Chichester (Figure A2.7). As in Langstone Harbour, the estuarine mud biotope LS.LMu.MEst was commonest in Chichester Harbour, together with the littoral mud biotope LS.LMu. Together, these two muddy biotopes were characteristic of the inner, more sheltered, areas of Chichester Harbour and took up the greater proportion of all transects where they were recorded. The upper shores typically had either narrow bands of barren shingle at the top (LS.LCS.Sh.BarSh) or stony substrata capable of supporting upper shore fucoids such as Fucus ceranoides (LR.LLR.FVS.Fcer) or Fucus spiralis (LR.LLR.FVS.FspiVS) Transects 27, 44 and 46 closer to the mouth of the harbour, or near where two main channels join (and thus subject to stronger tidal streams) consisted almost entirely of sandy sediments. The entire length of transect 27 in the mid to lower shore was identified as littoral fine sand characterised by polychaetes (LS.LSA.FiSa.Po). Similarly, the shore between midshore and lower shore levels at transect 46 consisted of muddy sand dominated for the most part by the lugworm Arenicola marina (LS.LSA.MuSa). On transect 44, the upper shore consisted of sandy mud with the salt marsh snail Hydrobia ulvae and burrows of the polychaete Hediste diversicolor (LS.LMu.MEst). This changed to seagrass on muddy sand in the midshore (LS.LMp.LSgr.Znol), and then to fine to medium sand with Cerastoderma edule and Arenicola marina (LS.LSa.MuSa.MacAre) in the mid to lower shore. Southampton Water and Hamble (Figure A2.8). The estuarine mud biotope LS.LMu.MEst was commonest overall in Southampton Water and the Hamble. This biotope occurred in the mid or lower shore in the Hamble, and was characterised by Hediste diversicolor and Hydrobia ulvae although the cockle Cerastoderma edule was often present also. In Southampton Water, on transects 8, 9, 10 and 12, this biotope extended down almost the whole shore width between salt

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marsh and the lower shore and was characterised by the same species recorded in this biotope in the Hamble. The mixed sediment biotope LS.LMx occurred more frequently in the Hamble than in the region of Southampton Water surveyed, and supported a mixture of infaunal and epifaunal forms such as ragworm, cockles, barnacles and winkles together with an inconsistent variety of other species. This biotope appeared to be characteristic of areas where tidal streams were possibly accelerated, such as on the shingle spits at the mouth of the Hamble estuary, and also off Calshot spit (transect 1), just outside Southampton Water in the Northwest Solent. Shingle biotopes (either LS.LCS.Sh or LS.LCS.Sh.BarSh) were recorded in narrow bands at the top of the shore on certain transects in the Hamble, and on transect 12 just north of the refinery jetties in Southampton Water. Also of note was the biotope LS.LMu.MEst.HedMacScr (littoral sandy mud dominated by the polychaete Hediste diversicolor and the bivalve molluscs Macoma balthica and Scrobicularia plana) on transects 3 and 5 in the Hamble. These were the only records of this biotope in the Solent Maritime SAC in the present survey. Isle of Wight (Figure A2.9). None of the biotopes recorded from the Isle of Wight shoreline can be described as ubiquitous and the range recorded overall was more characteristic of rocky shores than sediment flats. From a total of five transects sampled, four biotopes were recorded more than once but none occurred on more than two transects. The talitrid amphipod-dominated strandline biotope LS. LSa.St.Tal was recorded on transect 24 in the Medina estuary and at transect 21 on the open coast. Also, the littoral shingle biotope LS.LCS.Sh was observed on the upper shore at transect 23. On the sheltered transects in the Medina estuary and Newtown Harbour (transects 24 and 14 respectively) the upper shores were also characterised by stony substrata influenced by freshwater and dominated by narrow bands of Fucus ceranoides (LR.LLR.FVS.Fcer). On transect 22 on the open coast this was replaced by the upper shore fucoid biotope LR.LLR.FVS.FspiX where F spiralis and F ceranoides were both present. The lower parts of the open coast transects consisted of mixed sediment with Fucus vesiculosus dominating (LR.LLR.F.Fves or LR.LLR.F.FvesX) in the midshore and F serratus (LR.LLR.F.Fserr.FS or LR.LLR.F.FserrX) dominating on the lower shore. Within the shelter of Newtown Harbour, the mid to lower shore on transect 14 consisted of soft muddy sand characterised by the lugworm Arenicola marina, the salt marsh snail Hydrobia ulvae and green algal mats (LS.LSa.MuSa). In the Medina estuary, the midshore was soft muddy sand with green algal mats and Hydrobia ulvae (LS.LMu.MEst) whilst the lower shore consisted of sandy mud supporting Hediste diversicolor and Cerastoderma edule (LS.LMu.MEst.HedMac). Northwest Solent (Figure A2.8 for transect 1, and Figure A2.10). On this shoreline, the most widespread biotope was mixed sediments (LS.LMx), which occurred on five out of the six transects sampled and which occupied the greater part of the shore extent on each. On transects 1, 13, 19 and 20, mixed sediments extended more or less between the upper shore and the sublittoral fringe and were characterised by a relatively diverse range of mostly epifaunal forms. The species present included various red and brown algae (fucoids, Sargassum muticum, Colpomenia peregrina, Chorda filum, Mastocarpus stellatus and Osmundea pinnatifida) and several animals such as the sponge Hymeniacodon perleve, the anemone Anemonia viridis, and the molluscs Crepidula fornicata and Ostrea edulis. The infauna in these areas typically included Hediste diversicolor, Arenicola marina and the cockle Cerastoderma edule. On transect 17, however, LS.LMx occurred on the upper shore and supported a very sparse and low diversity mix of the green alga Enteromorpha sp, green diatoms, Fucus spiralis and the lugworm Arenicola marina. The mid and lower shore here consisted of soft sticky clay with Hediste diversicolor and sparse green and red algae (LS.LMu.UEst.Hed, or Hediste diversicolor in littoral mud).

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As on the Isle of Wight, the upper shores often had narrow bands of coarse sediment (LS.LCS.Sh) or barren shingle (LS.LCS.Sh.BarSh) and included the talitrid amphipod-dominated strandline biotope LS. LSa.St.Tal. On transect 19, there was a midshore band of mixed sediment with the ragworm Hediste diversicolor, the slipper limpet Crepidula fornicata, and the algae Enteromorpha sp and Fucus vesiculosus, which was assigned the biotope code LS.LMx.GvMu.HedMx (Hediste diversicolor in littoral gravelly muddy sand and gravelly sandy mud). Transect 16 near Pennington was unusual in that it occurred within the shelter of a substantial concrete municipal outfall and, perhaps as a result of this, was covered with heavy accumulations of dead drift algae at low water. With the degree of shelter offered by the outfall, the very stony mixed sediments here were algal dominated (though care had to be taken not to mix the drift deposits with what was actually growing on the shore) and therefore the biotopes recorded were similar to those of a rocky shore. The biotopes ranged from Fucus spiralis and Pelvetia canaliculata growing on concrete sea defences in the upper shore (LR.LLR.F.Fspi), through mixed sediments in the midshore with Fucus vesiculosus (LR.LLR.F.FvesX), to mixed sediments in the lower shore dominated by F serratus (LR.LLR.F.FserrX). Apart from the algal domination, the mixed sediments here supported similar animal species to those found on other mixed sediment shores along the Northwest Solent shoreline.

4.2 Core data 4.2.1 Sediment data Results of the sediment particle size and organic matter content analyses from the core samples taken at 21 of the transects are shown in Tables 4.7 and 4.8. In addition, the dominant sediment fraction from each core station is displayed on the sediment maps shown in Appendix 2 (Figures A2.1 to A2.5), and the histograms obtained from particle size analysis are presented in Appendix 3. Note that the silt and clay fractions for the mid and lower shore stations on transect 1 in the West Solent were lost during processing, so no data are available for the finest fractions of these stations. Over the SAC as a whole, the sediment samples showed great variability, with the dominant size fraction ranging from granules (2 to 4 mm in diameter) down to very fine silt (3.9 to 7.8 µm) on the Wentworth scale. The silt/clay (or ‘mud’) content of samples ranged overall from 2.07% to 96.9%, and the degree of sorting shown by all samples was generally very low. Langstone Harbour The dominant sediment type ranged from very coarse sand on the lower shore at transect 32 to fine silt in the mid shore on transects 30 and 31 and on the lower shore at transects 41 and 42. Sediments were coarsest at transect 28 near the harbour entrance and at transect 32 situated on the confluence of two major channels. There was a slight tendency for the sediment to become finer between the mid shore and the lower shore, though the reverse situation also occurred on transects 30 and 32. The silt/clay content of sediments varied from 11.33% on the lower shore at transect 28, to 92.03% on the mid shore at transect 30. There were no consistent gradients in sediment silt/clay content between the mid and lower shore, and sediment sorting varied between moderate and extremely poor. Sediment organic matter content varied from 1.41% at transect 28 lower shore to 8.47% at transect 41 mid shore, with no marked hot spots or gradients evident.

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Chichester Harbour Sediments were much finer than in Langstone, ranging from very fine sand on the lower shore at transects 44 and 46 to fine silt in the mid and lower shore on transects 26, 27 and 36 and on the lower shore at transect 47. Again, the sandy sediments were found on lower shores near the harbour entrance at transects 44 and 46. The silt/clay content of sediments varied from 15.73% and 15.90%on the lower shore at transect 46 and 44 respectively near the harbour mouth, to 96.33% on the mid shore at transect 26. There were no consistent gradients in sediment silt/clay content between the mid and lower shore, and sediment sorting varied between moderate and very poor. Sediment organic matter content varied from 0.64% at transect 27 mid shore to 13.9% at transect 47 lower shore. Levels were also relatively high at transect 26 mid shore (10.7%), and both transects 26 and 47 were sited close to the population centres of Emsworth and Bosham respectively. Southampton Water and Hamble Sediments were again very fine in these waterways. The dominant size fractions ranged from fine sand on the lower shore at transect 6 to fine silt in the mid shore on transects 9, and 11 and on the lower shore at transect 8. There were no consistent patterns of variation in dominant sediment type. The silt/clay content of sediments varied from 31.76% on the mid shore at transect 5, to 94.44% on the mid shore at transect 9. Along the west shore of Southampton water, the silt/clay content tended to decrease markedly between the mid and lower shore, but this pattern was reversed on transects 5 and 6 in the Hamble. Sediment sorting varied between poor and extremely poor. Sediment organic matter content varied from 3.54% at transect 5 mid shore to 11.89% at transect 9 mid shore. The highest levels occurred at transects 8 and 9 (<11%), and this is likely to be related to the close proximity of salt marsh along this part of the coast. Isle of Wight The only core samples taken on the Isle of Wight were on the lower shore at transect 14 in Newtown Harbour. Here, the sediment was moderately sorted very fine silt, with a silt/clay content of 96.90% and an organic matter content of 11.51%. Northwest Solent Sediments were extremely variable on the Northwest Solent shoreline. The dominant size fractions ranged from granule on the mid shore at transect 1 at Calshot Spit to fine silt in the mid and lower shore on transect 17 outside Lymington Harbour. There were no consistent patterns of variation in dominant sediment type. The silt/clay content of sediments varied from 2.07% on the mid shore at transect 20, to 95.07% on transect 17. Sediment sorting varied between moderate and poor. Sediment organic matter content varied from 0.56% at transect 1 mid shore to between 8.0 and 8.84% at transect 17. 4.2.2 Macrofaunal data Macrofaunal data are shown in full in Appendix 4. Summary data for each station are shown in Table 4.9 for the mid shore stations and Table 4.10 for the lower shore stations. Univariate community statistics including numbers of species, numbers of individuals, and diversity and evenness index values are listed for mid shore stations in Table 4.11 and for the lower shore stations in Table 4.12. The top ten species (in numerical terms) are shown for each mid shore core station in Table 4.13 and for each lower shore core station in Table 4.14.

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With regard to the mid shore stations, taxon richness (number of species) showed similar ranges in each of the four main survey areas. In Langstone, the range was 9 to 20 taxa per sample, in Chichester 8 to 19 taxa per sample, in Southampton Water and Hamble 7 to 18 taxa per sample, and in the Northwest Solent 3 to 15 taxa per sample. On the other hand, faunal density tended to be highest at stations in Langstone Harbour (523 to 2,438 individuals per sample) and in Chichester Harbour (85 to 1,239 individuals per sample), lower in Southampton Water and Hamble (42 to 753 individuals per sample), and lowest of all in the Northwest Solent (14 to 406 individuals per sample). This pattern is reflected in the diversity and evenness index values calculated. Diversity index values were generally low, but were lowest of all in Langstone Harbour and increased down the table through Chichester Harbour, Southampton Water and Hamble, and were highest in the Northwest Solent. The evenness index values show that all samples were numerically dominated by a few taxa (a reflection of the generally low diversity index values), but in Table 4.11 it can be seen that evenness was lowest in Langstone, slightly higher in Chichester, higher still in Southampton Water and Hamble, and highest in the Northwest Solent. In the lower shore cores (Table 4.12), taxon richness was higher and faunal density generally lower than at equivalent mid shore cores. This resulted in higher diversity and evenness index values at most lower shore core stations. Again, diversity and evenness was lowest in Langstone Harbour, and higher (but with roughly equivalent ranges) in Chichester Harbour, Southampton Water and Hamble, and the Isle of Wight and Northwest Solent. The top ten species (in numerical terms) are shown for each mid shore core station in Table 4.13 and for each lower shore core station in Table 4.14. Overall, these confirm the numerical dominance shown over the macrofauna at nearly all mid shore stations by just two or three taxa, mainly Hydrobia ulvae and Tubificoides benedii, and occasionally T pseudogaster (agg) also. The degree of this dominance is highest in Langstone and Chichester Harbours, but decreases in Southampton Water and Hamble and even more so in the Isle of Wight and the Northwest Solent. In the lower shore stations, the dominance of Hydrobia and Tubificoides benedii was generally lessened but remained apparent in Langstone Harbour, and at one or two transects in Chichester. Instead, a greater variety of other species appeared towards the top of the list at each core station, including the bivalve mollusc Abra tenuis, the polychaetes Scoloplos armiger, Galathowenia oculata, Aphelochaeta sp and Chaetozone gibber, and the amphipods Corophium volutator and Phtisica marina. Langstone Harbour In Langstone Harbour, taxon richness (or number of species) ranged from 9 to 20 taxa per sample in the mid shore, and from 10 to 13 taxa per sample in the lower shore. In the case of the mid shore samples taxon richness was similar to other areas, but taxon richness in the lower shore was generally lower than elsewhere. Faunal density, or the number of individuals per unit area, was generally high in Langstone Harbour, varying from 523 individuals per sample at transect 32 to 2,438 at transect 41, and 145 individuals per sample at transect 42 to 750 at transect 30 in the lower shore. Most of this faunal density was due to the abundance of one or two species, and consequently the evenness with which individuals were allocated amongst species was low; Pielou’s evenness index range 0.28 to 0.43 mid shore (at transects 32 and 41), and 0.38 to 0.56 lower shore (at transects 32 and 42). Since eveness is a component of diversity, diversity index values were also low, with the Shannon Wiener information function ranging from 0.89 to 1.72 in mid shore and 1.26 to 2.01 in the lower shore at transects 32 and 42 again.

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The two most abundant species at most mid shore stations were the marsh snail Hydrobia ulvae and the oligochaete Tubificoides benedii, although the oligochaete T pseudogaster (agg) and the spionid polychates Pygospio elegans and Streblospio shrubsolii were also characteristic (Table 4.13). In addition, the tube-dwelling amphipod Corophium arenarium was relatively prominent at transects 28 and 42, whilst the polychaete Capitella capitata was abundant at transect 41 in Eastney Lake. Capitella is known be opportunistic and hence to thrive under conditions of physical disturbance or organic enrichment, but was also present in low numbers at transects 31 and 32 in the mid shore. In the lower shore Hydrobia ulvae and Tubificoides benedii were again dominant (Table 4.14), though the abundance and hence degree of dominance by these species was lower than in the mid shore. However, at transect 42 the most abundant species were the polychaetes Aphelochaeta spp and Melinna palmata. Capitella capitata was present in small numbers at transects 41 and 42. Overall the same few species appear to be dominant in the macrofauna throughout Langstone Harbour in spite of the variation in sediment type noted between the harbour entrance and more sheltered inner sampling points. However, the highest abundances of Capitella capitata coincided with the highest measured sediment organic matter content at transect 41 in the mid shore. Chichester Harbour Taxon richness (or number of species) ranged from 8 to 19 taxa per sample in the mid shore, and from 9 to 28 taxa per sample in the lower shore. In the case of the mid shore samples taxon richness was similar to other areas, but taxon richness in the lower shore was slightly higher than in Langstone and similer to the other main areas surveyed. Faunal density was of a similar order to that observed in Langstone Harbour, varying from 85 individuals per sample at transect 46 to 1,239 at transect 47 in the mid shore, and 16 individuals per sample at transect 27 to 1,214 at transect 47 in the lower shore. At most stations this faunal density was due to high numbers of one or two species, and consequently the evenness with which individuals were distributed amongst species was generally low. Pielou’s evenness index ranged from 0.29 to 0.74 in the mid shore (at transects 44 and 46), and from 0.5 to 0.82 in the lower shore (at transects 36 and 44). Diversity index values were also low, with the Shannon Wiener information function ranging from 1.0 to 2.33 in the mid shore and 1.9 to 3.52 in the lower shore at transects 36 and 46. The most abundant species at mid shore stations were generally either the marsh snail Hydrobia ulvae or the oligochaete Tubificoides benedii, although the amphipod Corophium arenarium dominated at transect 27 whilst Enchytraeidae spp and the oligochaete Tubificoides pseudogaster (agg) were the most numerous of a sparse fauna at transect 46. The spionid polychates Pygospio elegans and Streblospio shrubsolii were additionally characteristic at transects 26, 27 and 36, whilst the bivalve mollusc Abra tenuis and the ampharetid polychaete Manayunkia aestuarina were numerous at transect 26 and the polychaete Scoloplos armiger at transect 27. The polychaete Capitella capitata was abundant at transect 47 by Bosham. In the lower shore Hydrobia ulvae and Tubificoides benedii were only dominant together at transect 47, and a variety of other species topped the lists at other sampling locations. These included Enchytraeidae spp and Abra tenuis at transect 26 by Emsworth, the crustaceans Bodotria sp and Bathyporeia spp at transect 27, Tubificoides benedii, P elegans and A tenuis at transect 36, Scoloplos armiger and P elegans at transect 44 and the polychaete Galathowenia oculata and the

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caprellid amphipod Phtisica marina at transect 46. Capitella capitata was present in small numbers at the lower shore on transect 47. Although faunal communities in Chichester Harbour were slightly more diverse than in Langstone and dominated by a larger variety of species, oligochaete taxa (mainly T benedii) and Hydrobia ulvae were still amongst the more abundant macrofaunal taxa just as in Langstone. Again, as in Langstone Harbour, the highest abundances of Capitella capitata coincided with the highest measured sediment organic matter content (this time at transect 47 adjacent to Bosham). Southampton Water and Hamble Taxon richness ranged from 7 to 18 taxa per sample in the mid shore, and from 7 to 33 taxa per sample in the lower shore. In the case of the mid shore samples taxon richness was similar to other areas, but taxon richness in the lower shore was higher than in Langstone and similer to that in other areas surveyed. Faunal density was of a similar order to that observed in Langstone Harbour, varying from 42 individuals per sample at transect 8 to 753 at transect 11 in the mid shore, and from 23 individuals per sample at transect 8 to 1,016 at transect 5 in the lower shore. The evenness with which individuals were distributed amongst species was generally higher than in Langstone and Chichester Harbours. Pielou’s evenness index ranged from 0.44 to 0.61 in the mid shore (at transects 5 and 6), and from 0.31 to 0.88 in the lower shore (at transects 5 and 8 respectively). Diversity index values were correspondingly higher also, with the Shannon Wiener information function ranging from 1.59 to 2.5 in the mid shore and from 1.32 to 3.64 in the lower shore. The most abundant species at mid shore stations generally included the marsh snail Hydrobia ulvae and the oligochaete Tubificoides benedii, although the amphipod Corophium volutator was abundant at transects 5 and 11. The spionid polychates Pygospio elegans and Streblospio shrubsolii were generally only present in small numbers (other than P elegans at transect 11), and the range of other species making up the lists were similar to those seen other area. The polychaete Capitella capitata did not occur in any great numbers at any of the mid shore core locations. In the lower shore Hydrobia ulvae and Tubificoides benedii were usually present amongst the top 10 most abundant species at core stations, but a variety of other species topped the lists at this set of transects. These included Corophium volutator at transects 5 and 8, the cirratulid polychaete Tharyx sp at transects 6, 9 and 11, the cirratulid polychaete Chaetozone gibber at transects 6 and 11, and the polychaete Aphelochaeta spp at transects 5 and 6. Capitella capitata was present in small numbers at the lower shore on transect 11. Macrofaunal communities in Southampton Water and the Hamble were slightly more diverse than those in Langstone or Chichester Harbours, and tended not to be so numerically dominated by one or two species (with the exception of C volutator at transect 5, both mid and lower shores). The oligochaetes and Hydrobia ulvae so prevalent in Langstone and Chichester were much less numerous down the west side of Southampton Water and in the Hamble estuary. Isle of Wight The only core samples taken on the Isle of Wight were on the lower shore at transect 14 in Newtown Harbour. In the very fine silty sediment here, 17 taxa and 938 individuals were identified, with eveness and diversity index values similar to those recorded in Chichester Harbour and in Southampton Water and the Hamble. The fauna was heavily dominated in

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numerical terms by the snail Hydrobia ulvae and the polychaete Aphelochaeta spp, but the oligochaete Tubificoides benedii, the polychaetes Mediomastus fragilis, Melinna palmata and Scoloplos armiger, and aorid amphipods were also present in numbers. Northwest Solent Taxon richness ranged from 3 to 15 taxa per sample in the mid shore, and from 17 to 21 taxa per sample in the lower shore. Taxon richness was comparatively low in the mid shore at transect 17, but otherwise was similar to that seen in Chichester Harbour, Southampton Water and the Hamble, and Newtown Harbour. Faunal density varied from 14 individuals per sample at transect 17 to 406 at transect 20 in the mid shore, and from 224 individuals per sample at transect 1 at Calshot Spit to 369 at transect 17 in the lower shore. The evenness with which individuals were distributed amongst species was higher than in Langstone and Chichester Harbours. Pielou’s evenness index ranged from 0.55 to 0.61 in the mid shore (at transects 1 and 20), and from 0.54 to 0.66 in the lower shore (at transects 17 and 1 respectively). Diversity index values were correspondingly higher also, with the Shannon Wiener information function ranging from 1.41 to 2.35 in the mid shore and from 2.19 to 2.91 in the lower shore. Only a few individuals of Pygospio elegans, Tharyx sp and Tubificoides benedii were identified from the mid shore at transect 17. On transect 20, the most abundant species in the mid shore the oligochaete Tubificoides pseudogaster (agg) and the ragworm Hediste diversicolor, together with the spionid polychaete Malacocerus vulgaris, plus Hydrobia ulvae and T benedii. In the lower shore on transect 1 Tubificoides pseudogaster (agg) and T benedii were most abundant, together with numbers of the amphipod Melita palmata, whilst Pygospio elegans and Tharyx sp dominated this zone on transect 17. 4.2.3 Multivariate analysis Cluster analysis was performed on the full macrofaunal data set, in which mid shore and lower shore stations had been combined. The resultant dendrogram is plotted in Figure 4.1. At a similarity level of approximately 50% or higher, three main station groups are evident: • Group 1 – station 14 low (Newtown Harbour), 41 mid (Langstone Harbour), 47 mid

(Chichester Harbour); • Group 2 – station 9 mid (Southampton Water), 28 mid, 28 low, 42 mid, (Langstone

Harbour), 44 mid (Chichester Harbour); • Group 3 – stations 5 mid, 6 mid (Hamble), 11 mid (Southampton Water), 17 low

(Northwest Solent), 30 mid, 30 low, 31 mid, 41 low (Langstone Harbour), 26 mid, 36 mid, 36 low, 47 low (Chichester Harbour).

Comparison of the main environmental and macrofaunal characteristics within and between these groups does not reveal any obvious or identifiable trends through the data: • Group 1 stations had sediment types ranging from very fine silt to coarse silt,

moderately to very poorly sorted, silt/clay contents of 51.08 to 96.9% and with organic matter contents of 1.41 to 11.89%. They also supported high faunal densities (930 to 2,438 per 0.03m2) in which Hydrobia ulvae and Tubificoides benedii were amongst the top three most abundant taxa;

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• Group 2 stations had sediment types ranging from fine silt to fine sand, moderately to very poorly sorted, silt/clay contents of 11.33 to 94.4% and with organic matter contents of 8.47 to 11.51%. They also supported moderate numbers of individuals (226 to 908 individuals per 0.03m2) in which Hydrobia ulvae and Tubificoides benedii were usually the top two most abundant taxa (except at transect 44 mid shore cores in which these were within the top four);

• Group 3 stations had sediment types confined within the range fine silt to coarse silt,

moderately to very poorly sorted, silt/clay contents of 31.76 to 96.33% and with organic matter contents of 3.54 to 13.9%. They also supported high numbers of individuals (237 to 1,822 individuals per 0.03m2) in which Hydrobia ulvae and Tubificoides benedii were not the most abundant taxa (except at transects 30, 31, 36 and 41 in the mid shore and transect 47 in the lower shore).

Of the remaining 19 stations, a further three pairs are clustered at a similarity level higher than 50%: stations 9 low and 8 mid, adjacent to each other in Southampton Water, stations 32 low and 32 mid from the same transect in Langstone Harbour, and station 17 mid from Northwest Solent with station 8 low from Southampton Water. These pairings occurred because of clear similarities in macrofaunal composition and density between the stations concerned, resulting either from the proximity of two stations (eg the mid and lower shore stations on transect 32) or possibly to serendipitous matching of faunal characteristics between stations that are widely separated geographically. What the analysis has not done is to separate stations reflecting the geography of the survey area for example, or separated the mid shore cores from those of the lower shore, or grouped stations according to sediment-related faunal characteristics (reflecting, say, the preferences of species groups for particular sediment types or sediment organic matter loadings). This has occurred because of the heterogeneity of of the sedimentary environment across the Solent Maritime SAC as a whole and within each of its constituent sectors or basins. Running these data through the MDS procedure resulted in the plot shown in Figure 4.2. The indistinct station grouping in this plot broadly matches the results seen from the clustering procedure in Figure 4.1. The macrofaunal data were also split according to the main geographical sectors within the survey area and analysed using the clustering procedure in PRIMER. The results are shown in Figures 4.3 and 4.4. Langstone Harbour Core stations within Langstone Harbour have been grouped in a manner reflecting harbour geography (Figure 4.3a). The mid and lower shore cores from transect 32 on the north side of the harbour form one distinct cluster (Group 1), as do the cores from transects 28 and 42 on the southeast side of the harbour (Group 2). In addition, the cores from transects 30 and 31 from the central and western part of Langstone have been grouped together, together with the lower shore cores from transect 41 in the sheltered backwater of Eastney Lake on the west side (Group 3). The mid shore sample from transect 41 has been loosely clustered with those from Groups 2 and 3, whilst the lower shore sample from transect 42 is an outlier. Group 1 cores were from coarse sands with low-diversity macrofauna characterised by the oligochaetes Tubificoides benedii and T pseudogaster (agg), and the cirratulid polychaete Cirriformia tentaculata. Group 2 cores were from fine or very fine muddy sand dominated by Hydrobia ulvae,

4-14 ERT 1342/R003

T benedii and the spionid polychaete Pygospio elegans. Group 3 cores from the central harbour area were of silt dominated by H ulvae, T benedii, the spionid Streblospio shrubsolii and the cirratulid Tharyx sp. Chichester Harbour The station clustering pattern within Chichester Harbour also mirrored the geographical spread of the sampling stations (Figure 4.3b). Group 1 consisted of transects at the innermost sheltered reaches of each of the main channels (transects 47 and 26 by Bosham and Emsworth, and transect 36 in Thorney Channel). Group 2 on the other hand included the core stations on transects 44 and 27 closest to the harbour entrance (with the lower shore cores from transect 27 as an outlier connected to this group). The cores from 46 mid shore and 46 lower shore are not really grouped together, and only connect at a 25% level of similarity. However, these originate from transect 46 at the confluence of the Thorney and Chichester Channels. Group 1 stations were on silt substrata supporting a macrofauna dominated by Hydrobia ulvae and Tubificoides benedii, but also characterised by the organic enrichment opportunist Capitella capitata, Pygospio elegans and Abra tenuis. Group 2 stations had sediments composed of silt or very fine sand characterised by the burrow-building Corophium arenarium and C acherusicum together with Hydrobia ulvae and Scoloplos armiger. The lower shore at transect 27 (a loosely connected outlier in this group) supported a very low-density fauna that included the cumacean Bodotria sp and the amphipod Bathyporeia spp. The mid shore and lower shore cores of transect 46 were not included within either Group 1 or Group 2, but consisted of silt or very fine sand dominated by Tubificoides pseudogaster (agg). The lower shore at this transect was additionally characterised by the polychaete Galathowenia oculata and the caprellid amphipod Phtisica marina. Southampton Water and Hamble No real pattern of station clusters emerged from Southampton Water and the Hamble (Figure 4.4a). All core locations consisted primarily of relatively soft silt, and supported sometimes dense populations of Tubificoides benedii, Tharyx sp, Pygospio elegans and Corophium volutator. Lower shore stations on transect 6 in the Hamble and on transect 11 on the west side of Southampton Water differed slightly from this pattern, and supported Tubificoides pseudogaster (agg), Tharyx sp and Chaetozone gibber. Isle of Wight and Northwest Solent As in Southampton Water and the Hamble, no real clustering of stations emerged from the Isle of Wight and the Northwest Solent data (Figure 4.4b). This is most likely to be due to the relatively large geographical spread of these survey areas coupled with the low density of sampling. 4.2.4 AMBI analysis The data set based on species abundance data from previous survey dates between 1975 and 1997 is shown in Table 4.15, and the positions of these stations in relation to those sampled in the present survey are shown in Appendix 2 (Figures A2.16 to A2.20). Stations were selected for proximity to those sampled in the present survey, and the distances between equivalent stations in the two data sets are tabulated in Table 4.16. The results of running the present (2005) data through the AMBI multimetric procedure are shown in Table 4.17, whilst the results of the analysis of the historic dataset are listed in Table 4.18. It should be noted that the instructions

ERT 1342/R003 4-15

for using the AMBI stipulate that the samples should have been collected using a 0.1m2 grab and processed using a 1.0 mm sieve. The current data were collected using 0.01m2 cores and washed over 0.5 mm sieves. Furthermore, the historic data were collected using a variety of sampling equipment and sieve sizes. The potential impact of applying this technique to data sets collected by different sampling methods to those stipulated on the validity of the results are not yet clear. For the 2005 data, of the 117 replicate samples analysed, 7 (6%) were classed as Bad, 47 (40%) as Poor, 51 (44%) as Moderate, 7 (6%) as Good, and none were classed as having High ecological status. In addition, three samples were unclassified because more than 10% of the taxa in the samples were not assigned during the truncation process. For comparison, in the case of the historical data, of the 21 samples analysed, 2 (10%) were classed as Bad, 4 (20%) as Poor, 11 (55%) as Moderate, 2 (10%) as Good, and 1 (5%) was classed as having High ecological status. In addition, one sample was unclassified because more than 10% of the taxa were not assigned during the truncation process. On an area by area and individual station basis, most of the 2005 samples in Langstone Harbour were classed as Moderate, with an overall range of Moderate to Bad. Samples from the lower shore were no different to those from the mid shore. In previous years (1975 to 1991) most samples were classed as Moderate and the sample closest to the lower shore sample from transect 28 was classed as High. Overall therefore, it appears that ecological status in Langstone Harbour may have declined by one or two grades, with the exception of transect 42 lower shore where there has been no change. In Chichester Harbour most of the 2005 samples were classed as Poor or Moderate except for transect 27 mid (Good) and transect 46 lower (Good). Samples from the lower shore were generally of better quality than those from the mid shore. In previous years (1980 and 1997) most samples were classed as Moderate with three Poor and one Good. On the whole therefore, 50% of these samples appear to have improved in status, 30% have decreased slightly and 20% have shown no change. In Southampton Water the 2005 samples were mostly classed as moderate. In 1987 most of the samples were Bad, so that there may have been an improvement in ecological status between then and now. In Newtown Harbour on the Isle of Wight, transect 14 lower has Moderate status, and this represents a slight decrease in ecological status since the previous measurement indicating Good ecological status Finally, on transect 1 off Calshot Spit in the Northwest Solent, current assessments indicated Moderate status, compared to Moderate and Poor in 1987. 4.2.5 Analysis for Taxonomic Distinctness The results of running the current macrofaunal data through TAXDTEST in PRIMER are listed in Table 4.19 and illustrated in a ‘funnel plot’ in Figure 4.5. The funnel plot is one of the easier ways to interpret the results of AvTD analysis (Clarke & Gorley 2001; Clarke & Warwick 2001). Here, the expected mean AvTD is plotted for theoretical samples of different size drawn from the master list and presented with upper and lower 95% confidence limits (or ‘confidence funnel’). Once test results are superimposed on this theoretical plot, samples which lie within the funnel are 95% sure to be within the expected AvTD values. Samples which lie above the

4-16 ERT 1342/R003

upper confidence limit line can be interpreted as having a higher AvTD than expected and samples which lie below the lower confidence limit line have a lower than expected AvTD. In Figure 4.5, it can be seen that approximately 13 stations have plotted out below the expected distribution, and therefore have a lower than expected AvTD or taxonomic diversity. These include seven stations from Langstone (30 low, 31 mid, 32 mid and low, 41 low, and 42 mid and low), one station from Chichester (46 mid and low), two stations from Southampton Water and the Hamble (9 mid and 11 low), and two stations from the Northwest Solent (1 low and 17 mid). The results of analysing the historical data set in the same fashion are shown in Table 4.20 and plotted in Figure 4.6. The plotted results show that just three stations, IPA5.1 (equivalent to transect 11 mid shore in 2005), IPA28.52 (transect 26 mid shore) and IPA28.6 (transect 44 lower shore) fell below the 95% confidence limits of the expected taxonomic distribution. 4.2.6 Biomass Summary macrofaunal biomass values, as grams per station (0.03 m2) are tabulated for the mid shore and lower shore stations in Table 4.21. Full species biomass data are presented in Appendix 3 with the replicate biological data. The overall range in biomass over all areas for the mid shore stations was 0.0057 to 48.73 g/0.03 m2 (0.19 to 1,623.2 g/m2), and that for the lower shore stations was 0.016 to 15.28 g/0.03 m2 (0.53 to 509.28 g/m2). Whilst the biomass of individual stations showed considerable variation, the biomass range shown by stations within each of the main survey sectors was on average very similar to the overall ranges quoted for mid shore and lower shore stations. On all transects, mid shore and lower shore, the biomass was dominated by the molluscs and in particular by the cockle Cerastoderma edule and to a lesser extent by the snail Hydrobia ulvae. The fact that the highest biomass values were generally seen at mid shore stations is a reflection of the distribution of Cerastoderma down the shore. After the molluscs, annelid worms typically ranked second in terms of contribution to the biomass.

ERT 1342/R003 4-17

Table 4.1 Phase 1 species data records summarised for Langstone Harbour (presence/absence indicated for each zone down the shore, starting with zone 1 in the upper shore), intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Langstone Harbour

Transect 28 29 30 31 32 34 37 38 40 41 42

No of zones 4 4 5 3 5 5 4 5 7 6 5

Hymeniacodon perleve 4 4 4,5

Anemonia viridis 4

Hediste diversicolor 4 4 4

Arenicola marina 2,3,4 2,3,4 1,2,3 3 4 4,5 2,3 5 4,5

Cirripedia indet 4 5,6

Chthamalus sp 3

Semibalanus balanoides 3 2,3 4 3,4,5

Elminius modestus 2 2 4 3

Carcinus maenas 2,3 3 1,2 2,3 2,3 5

Akera bullata 7

Patella vulgata 4

Gibbula cineraria 4

Littorina littorea 3 2,3 2 5 2,3,4 3,5 4,5

Littorina obtusata 4

Littorina saxatilis 2,3

Crepidula fornicata 5

Hydrobia ulvae 4 2,3,4 3,4 2 2,3,4 4,5,6 4,5,6

Mytilus edulis 3 4,5

Cerastoderma edule 3,4 4 2,3 4 4 3,4 2 4,5,6 5 4,5

Macoma balthica 3

Porphyra sp 2

Filamentous red algae indet 4

Ascophyllum nodosum 2 1 3 4

Fucus ceranoides 2 2 2

Fucus serratus 3

Fucus spiralis 2 1 1 3 2,3 2 4

Fucus vesiculosus 2,3 3,4 2 2,3 3,4 4 3 3,4

Pelvetia canaliculata 1

Fucoid indet 2

Enteromorpha sp 2,3,4 3,4 3,4 1,2,3 2,3,4 1,2,3,4 3 3,7 2,4,5,6 5

Zostera noltii (3) 5 The bracketed zone for transect 31 indicates that Zostera noltii was observed near this transect, but was not mapped.

4-18 ERT 1342/R003

Table 4.2 Phase 1 species data records summarised for Chichester Harbour (presence/absence indicated for each zone down the shore, starting with zone 1 in the upper shore), intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Chichester Harbour

Transect 25 26 27 33 36 43 44 46 47 48

No of zones 4 4 1 3 1 1 3 3 3 4

Nepthtys sp 2

Hediste diversicolor 1 1 1,3 2 4

Arenicola marina 1 1,2,3 1 1 1,2,3 1,2,3 2,3 3

Scoloplos armiger 1

Lanice conchilega 3

Polychaete tubes indet 3

Semibalanus balanoides 3 2 2,3

Elminius modestus 3 2 2,3

Amphipoda indet 3

Carcinus maenas 1,2,3 2 1 1,3,4

Akera bullata 3

Littorina littorea 1,4 2,3 2 2 1,2,3,4

Littorina saxatilis 2 2,3 2

Hydrobia ulvae 1,2,3 2 1 1 1,2,3 1 3 2,3

Cerastoderma edule 3,4 1 1,2,3 1,2,3 2,3 3 4

Mya arenaria 1

Alcyonidium gelatinosum 2,3

Ascidiella scabra 3

Filamentous red algae indet 3 2

?Polyides rotundus 1,3

Ceramium sp 1,3

Ascophyllum nodosum 2 3

Fucus ceranoides 2 2 2

Fucus serratus 3

Fucus spiralis 2 2,3 1 2 1,2

Fucus vesiculosus 3 3 2 2 3

Enteromorpha sp 1,2,3,4 2,3,4 1 2,3 1 1,2,3 1,2 3 1,2,3,4

Filamentous green alga indet 1 1,3 3

Zostera noltii 1,2

Salicornia sp 1 1

Spartina sp 1

ERT 1342/R003 4-19

Table 4.3 Phase 1 species data records summarised for Southampton Water and Hamble (presence/absence indicated for each zone down the shore, starting with zone 1 in the upper shore), intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Southampton Water and Hamble

Transect 2 3 4 5 6 8 9 10 11 12

No of zones 2 2 3 4 4 1 2 1 3 3

Anemonia viridis 2 3

Haliplanella lineata 4

Hydroida indet 2

Nephtys sp 3

Hediste diversicolor 2 1,2 1,2,3,4 1,2 1 3

Arenicola marina 2 1 2 2

Notomastus latericeus 2

Cirratulidae indet 3 2,4

Serpulidae indet 2 2

Cirripedia indet 2 1

Semibalanus balanoides 1

Elminius modestus 2 2,3

Corophium sp 4

Amphipoda indet 3 2

Carcinus maenas 3 1,2,3 2,4 2

Natantia indet 3

Lepidochitona cinerea 3

Patella vulgata 1

Gibbula umbilicalis 3 1

Littorina littorea 2,3 1 1

Littorina saxatilis 3

Crepidula fornicata 2 3 1

Hydrobia ulvae 1,2 1,2,3,4 1,3 1 1,2 1 1 2,3

Mytilus edulis 3

Cerastoderma edule 2 3 3,4 1 2 1 3 3

Ostrea edulis 2

Scrobicularia plana 1 1

Ascidia sp 2

Filamentous red algae indet 2 3 3,4 1 2,3

Chondrus crispus 2

Mastocarpus stellatus 2

Ascophyllum nodosum 1 1 3

Fucus vesiculosus 1

Fucoid indet 1 1,3 2

Enteromorpha sp 2 1,2,3,4 1,2,3,4 1,3

Filamentous green alga indet 4

4-20 ERT 1342/R003

Table 4.4 Phase 1 species data records summarised for Isle of Wight and Northwest Solent (presence/absence indicated for each zone down the shore, starting with zone 1 in the upper shore), intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Isle of Wight Northwest Solent

Transect 14 21 22 23 24 1 13 16 17 19 20

No of zones 3 3 3 3 4 2 3 3 3 4 4

Hymeniacodon perleve 2 4

Anemonia viridis 3 2,3 3 4

Nephtys sp 2

Hediste diversicolor 3 3 4 2 3 2,3 3

Arenicola marina 2,3 2,3 2 3 3 2 2 2,3,4

Scoloplos armiger 3 ?2

Cirratulidae indet 2 2

Spirorbidae indet 3 2

Semibalanus balanoides 3 2 4

Elminius modestus 2 4

Idotheidae indet 3

Talitridae indet 1 1 1 1

Amphipoda indet 2 2,3 2

Carcinus maenas 1 2,3 3 1,2 2,3,4 2,3

Patella vulgata 1 2,3

Gibbula umbilicalis 2

Littorina littorea 1 2 2 4 2 3 1,2,3 2

Littorina obtusata 2,3

Littorina saxatilis 3 2

Crepidula fornicata 3,4 3,4

Hydrobia ulvae 1,2,3 1,2,3

Cerastoderma edule 2,3 3 3 1,4 3 3 4

Ostrea edulis 3 4

Tapes decussata 2

Ascidiella aspersa 4

Porphyra sp 3 3 2 3

Filamentous red algae indet 2,3 3

Corallinaceae indet (crusts) 2 3 4

Dumontia contorta 3

Chondrus crispus 2

Mastocarpus stellatus 3 3

Ceramium sp 3 3 3 3,4

Osmundea pinnatifida 2 3

Polysiphonia lanosa 2

Colpomenia peregrina 3

Chorda filum 4

Ascophyllum nodosum 1,2 3 1,2,3

Fucus ceranoides 1 1 2 2,3

Fucus serratus 3 2,3 2,3 3 3,4 4

Fucus spiralis 1 1 2 3 1 1 2 2

Fucus vesiculosus 2 2,3 2,3 2 3,4 3 1,2,3 3 3,4

Sargassum muticum 3 4

Ectocarpaceae indet 3 3 4

Enteromorpha sp 1,2,3 2,3 1,2,3 1,3 2,3,4 2,3 1 1,2,3 2,3 2,3,4

Cladophora rupestris 3

Table 4.5 List of biotopes recorded (with equivalence to the 97.06 classification) with the transect number and zone where found, intertidal sediment survey of the Solent Maritime SAC, August to September 2005

04.05 code Description 97.06 code equivalent Langstone Chichester Southampton

Water & Hamble Isle of Wight

Northwest Solent

1 LS.LCS.Sh Shingle (pebble) and gravel shores

LS.LGS.Sh 29(1), 38(1), 41(3), 42(1)

23(1) 1(1)

2 LS.LCS.Sh.BarSh Barren littoral shingle LS.LGS.Sh.BarSh 28(1), 32(1), 34(1), 40(1)

47(1) 2(1),12(1) 13(2), 19(1)

3 LS.LSa Littoral sands and muddy sands

LS.LGS 28(4)

4 LS.LSa.St.Tal Talitrids on the upper shore and strandline

LS.LGS.S.Tal 21(1), 24(1)

13(1), 20(1)

5 LS.LSa.FiSa.Po Polychaetes in littoral fine sand

LGS.S.AP.Pon (part)/LGS.S.AP.P (part)

27(1)

6 LS.LSa.MuSa Polychaete/bivalve dominated muddy sand shores

LS.LMS.MS 28(3), 40(2) 46(1,2,3) 14(2,3)

7 LS.LSa.MuSa.MacAre Macoma balthica and Arenicola marina in littoral muddy sand

LS.LMS.MS.MacAre 29(3) 44(3)

8 LS.LMu Littoral mud LS.LMU 30(3), 38(3,5), 41(6) 25(3), 26(4), 33(1,2), 43(1)

11(1)

9 LS.LMu.MEst Polychaete/bivalve dominated mid estuarine mud shores

LS.LMU.SMu 29(4), 30(5), 31(3), 34(5), 37(3,4), 38(4), 40(6,7), 41(5), 42(4,5)

25(4), 33(3), 36(1), 44(1), 47(3), 48(3,4)

3(2), 5(2,3), 6(1,3), 8(1), 9(1,2), 10(1), 11(3), 12(3)

24(3)

10 LS.LMu.MEst.HedMac Hediste diversicolor and Macoma balthica in littoral sandy mud

LS.LMU.SMU.HedMac 24(4)

11 LS.LMu.MEst.HedMacScr Hediste diversicolor, Macoma balthica and Scrobicularia plana in littoral sandy mud

LS.LMU.SMU.HedScr;(part); LMS.SMu.HedMac (part)

3(1), 5(4)

12 LS.LMu.UEst.Hed Hediste diversicolor in littoral mud

LS.LMU.MU.HedOl/HedStr (part)

30(4) 17(3)

13 LS.LMx Littoral mixed sediments

LS.LMX 28(2), 29(2 part), 32(3,4), 34(2 part, 3 part), 40(3), 41(4)

25(1), 2(2), 4(2), 6(2,4) 1(2), 13(3), 17(1,2), 19(2,4), 20(2,3,4)

ER

T 1342/R

003 4-21

Table 4.5 Continued

04.05 code Description 97.06 code equivalent

Langstone Chichester Southampton


Northwest Solent

14 LS.LMx.GvMu Hediste diversicolor dominated gravelly sandy mud shores

None 12(2)

15 LS.LMx.GvMu.HedMx Hediste diversicolor in littoral gravelly muddy sand and gravelly sandy mud

None 19(3)

16 LS.LMx.Mx Species-rich mixed sediment shores

None 4(3), 11(2)

17 LS.LMp.Sm Saltmarsh LS.LMU.Sm 41(1) 18 LS.LMp.LSgr.Znol Zostera noltii beds in littoral

muddy sand LS.LMS.ZOS.Znol 40(4,5) 44(2)

19 LR Littoral rock LR 26(1) 20 LR.LLR.F Fucoids on sheltered marine

shores LR.SLR.F 4(1)

21 LR.LLR.F.Fspi Fucus spiralis on sheltered upper eulittoral rock

LR.SLR.F.Fspi 16(1)

22 LR.LLR.F.Fspi.X Fucus spiralis on full salinity upper eulittoral mixed substrata

LR.SLR.F.Fspi (part) 22(1)

23 LR.LLR.F.Fves Fucus vesiculosus on moderately exposed to sheltered mid eulittoral rock

LR.SLR.F.Fves 22(2)

24 LR.LLR.F.Fves.X Fucus vesiculosus on mid eulittoral mixed substrata

LR.SLR.FX.FvesX 21(2), 23(2) 16(2)

25 LR.LLR.F.Fserr.FS Fucus serratus on full salinity sheltered lower eulittoral rock

LR.MLR.BF.Fser.Fser 23(3)

26 LR.LLR.F.Fserr.X Fucus serratus on full salinity sheltered lower eulittoral mixed substrata

LR.SLR.FX.FserX 21(3), 22(3) 16(3)

27 LR.LLR.FVS Fucoids in variable salinity None 38(2) 28 LR.LLR.FVS.FspiVS Fucus spiralis on variabale

salinity upper eulittoral rock LR.SLR.F.Fspi (part) 29(2 dominant), 30(1),

31(1), 34(2 dominant,3 dominant), 37(2), 42(2)

25(2), 26(2), 47(2), 48(1)

29 LR.LLR.FVS.FvesVS Fucus vesiculosus on variable salinity mid eulittoral boulders and stable mixed substrata

LR.SLR.F.Fves (part) 30(2), 31(2), 34(4), 42(3)

26(3)

4-22

ER

T 1342/R

003

Table 4.5 Continued

04.05 code Description 97.06 code equivalent

Langstone Chichester Southampton


Northwest Solent

30 LR.LLR.FVS.AscVS Ascophyllum nodosum and Fucus vesiculosus on variable salinity mid eulittoral rock

LR.SLR.F.Asc.VS 5(1)

31 LR.LLR.FVS.Fcer Fucus ceranoides on reduced salinity eulittoral rock

LR.SLR.FX.FcerX 41(2) 48(2) 14(1), 24(2)

32 LR.FLR.Eph Ephemeral green or red seaweed communities (freshwater or sand-influenced)

LR.MLR.Eph 37(1)

33 LR.FLR.Eph.EphX Ephemeral green or red seaweed communities on variable salinity and/or disturbed eulittoral mixed substrata

LR.SLR.FX.EphX 32(2)

ER

T 1342/R

003 4-23

4-24 ERT 1342/R003

Table 4.6 Intertidal biotope listing with summary habitat and species information, intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Biotope Situation Habitat Characteristic species

1 LS.LCS.Sh Recorded at four transects in Langstone Harbour, and once in the Hamble and the Isle of Wight

Mid to upper shore sheltered mixed sandy sediment.

None recorded

2 LS.LCS.Sh.BarSh Found in all areas except for the Isle of Wight

Generally clean sand, gravel, pebbles and cobbles in the upper shore or littoral fringe

None recorded

3 LS.LSa Recorded at transect 28 in Langstone Harbour

Firm fine sand in the lower shore

Arenicola and Hydrobia, with patches of Enteromorpha

4 LS.LSa.St.Tal Found along upper shores of Northwest Solent and Isle of Wight

Mix of sand and gravel in a band along the upper shore, with a strandline of algae

Talitrid amphipods

5 LS.LSa.FiSa.Po At one location, in Chichester Harbour 27(1), near Thorney Island

Fine to medium rippled sand in mid shore

Scoloplos armiger and Arenicola

6 LS.LSa.MuSa Within Langston, Chichester and Newtown Harbours, in outer half of harbours

Sheltered fine muddy sand usually in mid to lower shore

Usually with Arenicola, Hydrobia and patches of Enteromorpha

7 LS.LSa.MuSa. MacAre

Within Langston and Chichester Harbours at two locations at or near entrances

Fine muddy sand in mid to lower shore

Arenicola, Cerastoderma and Hediste

8 LS.LMu In the western side of Langstone and Chichester Harbours

Mud or sandy mud (sometimes sticky and usually anoxic) in mid to lower shore

Sometimes with Arenicola or patches of Enteromorpha, but often with no visible biota

9 LS.LMu.MEst Common in Langstone and Chichester Harbours, Southampton Water and Hamble, plus also in Medina

Mud or sandy mud (sometimes sticky and usually anoxic) from upper to lower shore

Usually with Cerastoderma, Enteromorpha and Hydrobia; often with Arenicola

10 LS.LMu.MEst. HedMac

Only recorded in Medina Soft mud in lower shore With Hediste, Cerastoderma, and Enteromorpha

11 LS.LMu.MEst. HedMacScr

Only found in Hamble Sandy mud in upper and lower shore

Scrobicularia & Hydrobia common to both biotopes; plus Hediste and Arenicola at one and Corophium and Cerastoderma at the other

12 LS.LMu.UEst.Hed Found once in Langstone Harbour and once in Northwest Solent

Sticky or viscous mud in mid to lower shore

Hediste and Enteromorpha common to both biotopes, plus Cerastoderma and Hydrobia in Langstone and red algae in Northwest Solent

13 LS.LMx Common in Langstone Harbour, Southampton Water, Hamble and Northwest Solent

Sandy or muddy sediments with pebbles and or cobbles that do not support fucoid-based communities, from upper to lower shore

Infauna may include Arenicola and Hediste, in addition to a diverse epibiota including algae, barnacles and winkles

14 LS.LMx.GvMu Only recorded once in Southampton Water

Gravelly sand in mid shore Arenicola and Hydrobia

15 LS.LMx.GvMu. HedMx

At one location, in Northwest Solent 19(3)

Gravelly pebbly mud in mid shore

Fucoids, Hediste and Crepidula

16 LS.LMx.Mx Southampton Water and Hamble

Gravelly sandy mud in mid to lower shore

Cerastoderma plus a relatively diverse epifauna and a few some red algae

4-25 ERT 1342/R003

Table 4.6 Continued

Biotope Situation Habitat Characteristic species

17 LS.LMp.Sm One location in Langstone Harbour

Supralittoral gravel and saltmarsh

None recorded

18 LS.LMp.LSgr.Znol Once in Langstone and once in Chichester Harbours

Sandy or pebbly mud in mid shore

Zostera noltii, Cerastoderma, Hydrobia and either Arenicola or Fucus vesiculosus

19 LR Once in northern side of Chichester Harbour

Supralittoral boulder wall No biota recorded

20 LR.LLR.F One location at north side of entrance to Hamble

Sea defence boulder slope in upper shore

Fucoids including Ascophyllum, and barnacles

21 LR.LLR.F.Fspi One location near Pennington in Northwest Solent

Concrete sea defence slope in upper shore

Fucoids including Fucus spiralis and Ascophyllum

22 LR.LLR.F.Fspi.X One location on Isle of Wight

Mixed sediment and fallen trees in upper shore

Fucus spiralis and F ceranoides

23 LR.LLR.FVS One location in inner reaches of Langstone Harbour

Mixed sediment with boulders in upper shore subject to variable salinity

Unidentified fucoids

24 LR.LLR.FVS.FspiVS All around main Langstone Harbour basin, and throughout Chichester Harbour

Mixed sediments in upper shore subject to variable salinity

Fucus spiralis, F ceranoides, and often with Arenicola

25 LR.LLR.F.Fves One location on Isle of Wight

Mudstone and mudstone fragments in mid shore

Fucus vesiculosus, Enteromorpha and F serratus

26 LR.LLR.F.Fves.X Three locations on Isle of Wight and Northwest Solent

Scoured mixed sandy sediment in mid shore

Enteromorpha and Fucus vesiculosus with polychaete infauna sometimes including Arenicola

27 LR.LLR.FVS.FvesVS Several locations around main Langstone Harbour basin, and at one location on north side of Chichester Harbour

Mixed muddy or sandy sediment in mid shore subject to variable salinity

Very little apart from Fucus vesiculosus, Arenicola and Cerastoderma

28 LR.LLR.FVS.AscVS One location at south side of entrance to Hamble

Cobbles and concrete blocks on sandy mud in mid shore subject to variable salinity

Ascophyllum, Enteromorpha, Hydrobia and sparse epifauna

29 LR.LLR.F.Fserr.FS One location on Isle of Wight

Sand-influenced mudstone in lower shore

Fucus serratus with Enteromorpha and Cladophora

30 LR.LLR.F.Fserr.X Three locations on Isle of Wight and Northwest Solent

Firm pebbly mixed sediment in lower shore

Fucus serratus with Enteromorpha on Isle of Wight shores, and F serratus with Osmundea and relatively diverse fauna on mainland shore

31 LR.LLR.FVS.Fcer Single locations in Langstone and Chichester Harbours, and in Medina estuary and Newtown Harbour

Mixed sediments in upper shore of enclosed harbour areas subject to fresh water influence

Fucus ceranoides with lesser amounts of F spiralis

32 LR.FLR.Eph Single location in Langstone Harbour

Sea defence rip-rap slope in upper shore

Sparse Enteromorpha

33 LR.FLR.Eph.EphX Single location in Langstone Harbour

Pebble bank in upper shore Enteromorpha

Table 4.7 Sediment particle size data, intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Mean diameter

Mean diameter

Standard deviation

Skewness Silt/Clay Silt Clay Transect number

Height on

shore X µm X ø S ø Skq ø % % % Wentworth Scale Sorting index

Langstone 28 Mid 148 2.75 2.68 0.78 16.17 11.10 5.07 Fine sand Very poor 28 Low 109 3.20 1.98 1.43 11.33 7.07 4.26 Very fine sand Moderate 30 Mid 11 6.49 2.32 -0.43 92.03 68.12 23.91 Fine silt Poor 30 Low 18 5.76 2.49 0.03 73.72 55.29 18.43 Medium silt Poor 31 Mid 14 6.12 2.54 -0.14 81.58 59.40 22.18 Fine silt Very poor 32 Mid 627 0.67 3.37 1.59 26.46 19.75 6.70 Coarse sand Extremely poor 32 Low 1026 -0.04 3.25 1.91 17.91 13.01 4.90 Very coarse sand Extremely poor 41 Mid 16 5.96 2.67 -0.18 83.02 63.74 19.28 Medium silt Very poor 41 Low 14 6.18 2.51 -0.03 82.93 61.04 21.89 Fine silt Very poor 42 Mid 74 3.75 2.30 1.00 21.41 14.65 6.75 Very fine sand Poor 42 Low 15 6.01 2.55 -0.04 79.22 59.53 19.69 Fine silt Very poor

Chichester 26 Mid 10 6.58 1.90 0.16 96.33 74.04 22.29 Fine silt Moderate 26 Low 14 6.19 2.28 0.03 83.06 61.18 21.87 Fine silt Poor 27 Mid 14 6.12 2.49 -2.66 88.34 63.12 25.22 Fine silt Poor 27 Low 14 6.17 2.32 0.00 80.83 58.53 22.30 Fine silt Poor 36 Mid 12 6.33 2.66 -0.35 84.04 60.05 23.99 Fine silt Very poor 36 Low 19 5.72 2.50 0.08 70.44 51.52 18.92 Medium silt Very poor 44 Low 104 3.26 2.14 1.33 15.90 10.56 5.34 Very fine sand Poor 46 Mid 52 4.26 2.38 0.82 33.66 24.36 9.31 Coarse silt Poor 46 Low 100 3.32 2.25 1.23 15.73 9.80 5.93 Very fine sand Poor 47 Mid 40 4.65 2.84 0.13 51.08 39.01 12.07 Coarse silt Very poor 47 Low 10 6.60 2.67 -0.67 92.57 66.32 26.24 Fine silt Very poor

4-26

ER

T 1342/R

003

Table 4.7 Continued

Mean diameter

Mean diameter

Standard deviation

Skewness Silt/Clay Silt Clay Transect number

Height on

shore X µm X ø S ø Skq ø % % % Wentworth Scale Sorting index

Southampton Water & Hamble 8 Mid 29 5.09 3.15 -2.01 73.70 48.92 24.79 Medium silt Extremely poor 8 Low 9 6.86 2.39 -1.10 94.51 65.11 29.40 Fine silt Poor 9 Mid 9 6.82 2.37 -0.86 94.44 65.79 28.65 Fine silt Poor 9 Low 57 4.13 3.44 -0.88 62.83 42.36 20.47 Coarse silt Extremely poor

11 Mid 9 6.82 2.31 -0.31 93.64 64.37 29.27 Fine silt Poor 11 Low 48 4.37 3.30 -0.23 51.77 36.57 15.19 Coarse silt Extremely poor 5 Mid 57 4.14 2.40 0.66 31.76 24.41 7.35 Coarse silt Poor 5 Low 44 4.50 2.47 0.49 46.16 37.25 8.91 Coarse silt Poor 6 Mid 31 5.01 2.92 -0.35 63.17 48.83 14.34 Medium silt Very poor 6 Low 162 2.63 3.49 0.38 39.36 27.97 11.39 Fine sand Extremely poor

Isle of Wight 14 Low 7 7.25 1.96 -0.21 96.90 61.37 35.53 Very fine silt Moderate

Northwest Solent 1 Mid 2,323 -1.22 1.88 0.32 no data no data no data Granule Moderate 1 Low 1,843 -0.88 1.96 0.23 no data no data no data Very coarse sand Moderate

17 Mid 9 6.86 2.24 -0.18 92.93 63.04 29.90 Fine silt Poor 17 Low 9 6.78 2.17 -0.12 95.07 68.69 26.38 Fine silt Poor 20 Mid 933 0.10 2.49 0.34 2.07 1.52 0.56 Coarse sand Poor

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003 4-27

4-28 ERT 1342/R003

Table 4.8 Sediment organic matter and fine particle content, intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Organic Silt/Clay Silt Clay Transect

number % % % % Langstone

28 mid 2.06 16.17 11.10 5.07 28 low 1.41 11.33 7.07 4.26 30 mid 6.67 92.03 68.12 23.91 30 low 4.39 73.72 55.29 18.43 31 mid 7.73 81.58 59.40 22.18 32 mid 5.47 26.46 19.75 6.70 32 low 7.99 17.91 13.01 4.90 41 mid 8.47 83.02 63.74 19.28 41 low 7.55 82.93 61.04 21.89 42 mid 2.46 21.41 14.65 6.75 42 low 6.05 79.22 59.53 19.69

Chichester 26 mid 10.70 96.33 74.04 22.29 26 low 8.52 83.06 61.18 21.87 27 mid 0.64 88.34 63.12 25.22 27 low 1.08 80.83 58.53 22.30 36 mid 8.36 84.04 60.05 23.99 36 low 7.74 70.44 51.52 18.92 44 low 2.14 15.90 10.56 5.34 46 mid 3.32 33.66 24.36 9.31 46 low 3.51 15.73 9.80 5.93 47 mid 8.70 51.08 39.01 12.07 47 low 13.90 92.57 66.32 26.24

Southampton Water and Hamble 8 mid 11.76 73.70 48.92 24.79 8 low 11.64 94.51 65.11 29.40 9 mid 11.89 94.44 65.79 28.65 9 low 8.36 62.83 42.36 20.47

11 mid 9.64 93.64 64.37 29.27 11 low 4.12 51.77 36.57 15.19 5 mid 3.54 31.76 24.41 7.35 5 low 4.30 46.16 37.25 8.91 6 mid 5.60 63.17 48.83 14.34 6 low 7.09 39.36 27.97 11.39

Isle of Wight 14 low 11.51 96.90 61.37 35.53

Northwest Solent 1 mid 0.56 no data no data no data 1 low 0.66 no data no data no data

17 mid 8.84 92.93 63.04 29.90 17 low 8.00 95.07 68.69 26.38 20 mid 1.23 2.07 1.52 0.56

Table 4.9 Macrofauna species and abundance for midshore stations on each transect (numbers per 0.03 m2 sample), intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Langstone Chichester Southampton Water &

Hamble IOW

Northwest Solent Taxon Authority

28 30 31 32 41 42 26 27 36 44 46 47 8 9 11 5 6 14 1 17 20

ANTHOZOA spp - 3 - 2 - - 5 - - - - - - - - - 3 1 - - - 1

Tubulanus polymorphus Reiner 1804 - - - - - - - - - - - - - 1 - - - - - - -

Cerebratulus spp Renier 1804 1 - 1 - - - 1 - - - - 2 - - - - - - - - -

Eteone cf longa (Fabricius 1780) 3 - 3 - 1 5 3 8 2 - 3 13 - 1 21 5 1 - - - -

Anaitides mucosa (Oersted 1843) - - 1 - - 1 5 3 1 - - - - - 1 2 3 - - - -

Glycera tridactyla Schmarda 1861 3 - - 1 - 1 2 1 - 1 - - - - - - - - - - -

Microphthalmus sp Mecznickow 1865 1 - - - - - - - - - - - - - - - - - - - -

Nereididae spp juv - - 1 - 2 - - - - 1 2 15 - - 4 1 - 4 - - - 36

Hediste diversicolor (O F Muller 1776) - - 1 8 - - 1 - - - 11 - - 2 - 2 - - - - 129

Nephtys spp juv Cuvier 1817 - - 1 - - - - - 1 - - - - - - - - - - - -

Nephtys hombergii Savigny 1818 - 2 2 - 1 - - 1 2 - 1 - - - - 1 1 - - - -

Ophryotrocha spp Claparede & Mecznikow 1869 - - 1 - - - - - - - - - - - - - - - - - -

Parougia eliasoni (Oug 1978) - - - - - - - 1 - - - - - - - - - - - - -

Scoloplos armiger (O F Muller 1776) - - - - - 1 - 90 - 24 - - - - - - - - - - -

Aricidea minuta Southward 1956 - - - - - - - 2 - - - - - - - - - - - - -

Malacoceros vulgaris (Johnston 1927) - - - - - - - - - - - - - - - - - - - - 44

Polydora cornuta Bosc 1802 - - - - - - - - - - - - 1 2 - - - - - - -

Polydora quadrilobata Jacobi 1883 - - - - - - - - - - - - - - - - 1 - - - -

Pygospio elegans Claparede 1863 46 5 53 - - 37 50 10 7 5 7 1 - 7 38 3 13 - 1 8 1

Streblospio shrubsolii (Buchanan 1890) 2 27 11 - - - 20 - 23 - - - - - 6 1 2 - - - 6

Caulleriella zetlandica (McIntosh 1911) - - - - - - - - - - - - - - - - - - - - 4

Chaetozone setosa Malmgren 1867 - - - - - - - - - - - - - - 1 - - - - - -

Cirriformia tentaculata (Montagu 1808) - - - 14 - - - - - - - - - - - - - - - - -

Aphelochaeta spp Blake 1991 1 - - - - 4 - - - - - - - - 7 - - - - - -

Tharyx sp Webster & Benedict 1887 1 10 77 - - 9 9 - 32 1 - - 4 12 233 44 51 - - 3 2

Capitella capitata (agg) (Fabricius 1780) 1 - 4 5 131 - 106 - - - - 212 - 1 - 1 2 - - - 5

Maldanidae sp - - - - - - - - 1 - - - - - - - - - - - - -

Ophelia limacine (Rathke 1843) - - - - - - - - - - - - - - - - - - 2 - -

Melinna palmata Grube 1869 - 3 9 - - 2 4 - 4 - - - - - 5 1 - - - - -

1342/R003

4-29

Table 4.9 Continued


Hamble IOW


28 30 31 32 41 42 26 27 36 44 46 47 8 9 11 5 6 14 1 17 20

Ampharete grubei (Malmgren 1866) - 8 5 2 - 16 - - 8 - - - - - 3 2 7 - - - -

Sabellidae spp juv - - - - - - - 21 - - - - - - - - - - - - - -

Manayunkia aestuarina (Bourne 1883) - - 5 - - - 42 - - - - - - - - - - - - - -

Tubificoides amplivasatus (Erseus 1975) - - - 1 - - - - - - - - - - - - - - - - -

Tubificoides benedii (Udekem 1855) 227 80 1535 450 1390 120 465 1 631 16 3 291 4 162 311 29 47 - - 3 27

Tubificoides pseudogaster (agg) (Dahl 1960) 35 - 11 36 - 1 13 1 - 1 29 2 - 16 - 6 3 - - - 151

Enchytraeidae spp - - - 4 - - - - - - - 30 - - 2 - - - - 29 - -

Bathyporeia spp Lindstom 1855 - - - - - - - 1 - - - - - - - - - - - - -

Melita palmata (Montagu 1804) - - - 6 - - - - - - - - - - - - - - - - 1

Aoridae spp indet (female) - - - - - 18 - 8 - 1 - - 1 2 - - - - - - - -

Microdeutopus gryllotalpa Costa 1853 - - - - 2 - - - - - - - - - - - - - - - -

Microdeutopus versiculatus (Bate 1856) - - - - - - - - - - - - 1 - - - - - - - -

Corophium acherusicum (da Costa 1851) - - - - - - - - - - - - - - - - 1 - - - -

Corophium arenarium Crawford 1937 7 - - - - 12 - 119 - 24 - - - - - - - - - - -

Corophium volutator (Pallas 1766) - - - - - - - - - - - - - - 56 307 3 - - - -

Phtisica marina Slabber 1769 - - - - - - - - 5 - - - - - - - - - - - -

Cyathura carinata (Kroyer 1847) - - - - - - 1 - - - - - - - - - - - - - -

Sphaeroma spp Bosc 1801 - 1 - - - - - - - 1 - - - - - - - - 8 - -

ONISCIDEA spp - - - - - - - - - - - - - - - 1 - - - - - 1

Crangon crangon (Linnaeus 1758) - 1 - - - - - - - - - - - - - - - - - - -

Carcinus maenas juv (Linnaeus 1758) - - - 1 1 - - - 1 - - 1 - - - - 1 - 1 - 4

Pinnotheres pisum (Linnaeus 1767) - - - - - - - - - - - - - - - 1 - - - - -

Littorina littorea (Linnaeus 1758) - - - - - - - - - - - - - - - - - - - - 1

Littorina saxatilis (Olivi 1792) - - - - - - - - - - - - - - - - - - 1 - -

Hydrobia ulvae (Pennant 1777) 575 465 92 - 888 417 10 31 72 464 - 712 28 20 54 17 96 - 1 - 32

Roxania utriculus (Brocchi 1814) - - - - - - 1 - - - - - - - - - - - - - -

Retusa obtusa (Montagu 1803) - - - - - - - - - - - - - - 8 - - - - - -

4-30

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003

Table 4.9 Continued


Hamble IOW


28 30 31 32 41 42 26 27 36 44 46 47 8 9 11 5 6 14 1 17 20

NUDIBRANCHIA spp - - - - - - 1 - - - - - - - - - - - - - - -

PELECYPODA spp juv - - - - - - - - - 3 1 - - - - - 4 - - - - -

Cerastoderma spp juv Poli 1795 4 2 - 1 1 3 - 4 2 1 - - 2 1 13 2 6 - - - -

Cerastoderma edule (Linnaeus 1758) 1 12 2 - - 4 - 1 - 10 - - 2 - 4 8 - - - - -

Macoma balthica (Linnaeus 1758) - - - - - - - - - - - - - - - - 1 - - - -

Abra prismatica (Montagu 1808) - - - - - - - - - - - - - - 1 - - - - - -

Abra tenuis (Montagu 1803) 1 - - - 1 - 122 - - 1 1 - - - 3 9 4 - - - 1

Mya spp juv Linnaeus 1758 - - - - - - - - - - - - 1 - - - - - - - -

Mya arenaria Linnaeus 1758 - - - - - - - - - - - 1 - - - - - - - - -

Chironomid Larvae - - 3 - 6 - 4 1 - - - 4 - - - - - - - - -

1342/R003

4-31

Table 4.10 Macrofauna species and abundance for lower shore stations on each transect (numbers per 0.03 m2 sample), intertidal sediment survey of the Solent Maritime SAC, August to September 2005


Hamble IOW


28 30 31 32 41 42 26 27 36 44 46 47 8 9 11 5 6 14 1 17 20

ANTHOZOA spp - - - - - - - - - - - - - - - - - 3 - - - - NEMERTEA spp - - - - - - - - - - - - - - - - - - 1 - - - Cerebratulus spp Renier 1804 - - - - - - - - - - - 2 - - - - 7 2 2 - - Eteone cf longa (Fabricius 1780) 6 28 - - 3 - 1 - 10 2 2 - - - 1 - - - - - - Anaitides mucosa (Oersted 1843) 1 - - 2 - - 1 - 3 - 5 1 - - 3 - - 7 - 1 - Glycera tridactyla Schmarda 1861 - - - 4 - - - - - - - - - - - - 1 - - - - Syllidia armata Quatrefages 1866 - - - - - - - - - - - - - - 1 - - - - - - Typosyllis sp A Langerhans 1879 - - - - - - - - - - - - - - - - - - 1 - - Exogone hebes (Webster & Benedict 1884) - - - - - - - - - - - - - - - - - - 4 - - Exogone naidina Oersted 1845 - - - - - - 1 - 1 - - - - - - - - - - - - Sphaerosyllis taylori Perkins 1980 - - - - - - - - - - 1 - - - - - - - - - - Nereididae spp juv - - 21 - 1 - - - - 6 - - 1 - - 3 2 53 - 1 - - Hediste diversicolor (O F Muller 1776) - 28 - - - - 1 - - - - 2 - - 3 - - - - - - Neanthes virens (M Sars 1835) - - - - - - - - - - - - - 3 6 - 2 - - - - Nephtys spp juv Cuvier 1817 - - - - - - - - - - 2 - - - - - - - 1 - - Nephtys hombergii Savigny 1818 1 4 - 1 1 - 6 1 8 1 9 - - 1 1 - - - - - - Ophryotrocha spp Claparede & Mecznikow 1869 - - - - - - - - - - 4 - - - 1 - - - - - - Parougia eliasoni (Oug 1978) - - - - - - - - - - - - - - - - - - 2 - - Scoloplos armiger (O F Muller 1776) 4 - - - - - - 1 - 17 - - - - 8 - 1 30 1 - - Aricidea minuta Southward 1956 - - - - - - - - - - 1 - - - 7 - - - - - - Malacoceros vulgaris (Johnston 1927) - - - - - - - - - - - - - - - - - - 1 - - Polydora cornuta Bosc 1802 - - - - - - - - - - - 3 4 1 - - - - - 2 - Polydora quadrilobata Jacobi 1883 - - - - - - - - - - 1 - - - - 5 - - - - - Pygospio elegans Claparede 1863 10 43 - - 1 1 - 1 64 10 21 21 5 - 1 7 - - - 160 - Spio spp indet Fabricius 1785 - - - - - - - 1 - - - - - - - - - - 1 - - Spio martinensis Mesnil 1896 - - - - - - - 3 - - - - - - - - - - - - -

4-32

ER

T 1342/R

003

Table 4.10 Continued


Hamble IOW


28 30 31 32 41 42 26 27 36 44 46 47 8 9 11 5 6 14 1 17 20

Streblospio shrubsolii (Buchanan 1890) - 23 - - 2 1 18 - 1 - 8 78 - - - 25 - 1 - - - Caulleriella cf viridis Chamberlin 1919 - - - - - - - - - - - - - - - - 1 - 1 - - Caulleriella alata (Southern 1914) - - - - - - - - - - - - - - - - 2 - 3 - - Caulleriella zetlandica (McIntosh 1911) - - - - - - - - - - - - - - 5 - - - - - - Chaetozone gibber Woodham & Chambers 1994 - - - - - 1 - - - 5 3 - - - 88 3 44 - 6 - - Cirriformia tentaculata (Montagu 1808) - - - 12 - 1 - - - - - - - - - - 11 - 1 - - Aphelochaeta spp Blake 1991 - - - - - 87 - - - - - - - - 3 45 94 100 - 1 - Tharyx sp Webster & Benedict 1887 6 28 - - 142 10 - - 9 2 68 76 4 46 74 58 40 - - 124 - Cossura longocirrata Webster & Benedict 1887 - - - - - - 10 - - - 14 - - - 3 - 3 - - - - Capitella capitata (agg) (Fabricius 1780) - 2 - - 17 2 - - - - 1 38 - - 14 1 9 4 6 3 - Heteromastus filiformis (Claparede 1864) - - - - - - - - - - - - - - - - 1 - - - - Mediomastus fragilis Rasmussen 1973 - - - - - - - - - - - - - - 6 7 9 53 - - - Notomastus latericeus M Sars 1851 - - - - - - - - - - - - - - 11 - - - 8 - - Ophelia limacine (Rathke 1843) - - - - - - - - - - - - - - - - - - 18 - - Galathowenia oculata Zaks 1922 - - - - - - - - - - 131 - - - - - - - - - - Melinna palmata Grube 1869 - 1 - - 1 24 3 - 16 - 64 2 - - 19 4 3 32 - 3 - Ampharete grubei (Malmgren 1866) - 1 - 2 5 5 - - 22 - - 2 - - 1 - 6 - - 5 - Ampharete lindstroemi (Malmgren 1867) - - - 1 - - - - - - - 1 - - 2 - - - - - - Polycirrus norvegicus Wollebaek 1912 - - - - - 2 - - - - - - - - - - 34 - - - - Sabellidae spp juv - - - - - - - 4 - - - - 21 - - - - - - - - - Manayunkia aestuarina (Bourne 1883) - - - - - - 1 - - - - 1 - - - - - - - - - Tubificoides amplivasatus (Erseus 1975) - - - 3 - - 1 - - - 12 138 - - - - 18 - - - - Tubificoides benedii (Udekem 1855) 97 546 - 161 145 9 38 - 510 1 21 402 1 - 1 13 30 90 37 34 - Tubificoides pseudogaster (agg) (Dahl 1960) 8 - - 15 - - - - - - 84 97 1 3 53 19 60 2 92 1 - Enchytraeidae spp - - - - - - - 53 - - - - - - - - - - - 4 - - Achelia echinata Hodge 1864 - - - - - - - - - - - - - - - - 1 - - - - Urothoe elegans (Bate 1856) - - - - - - - 1 - - - - - - - - - - - - -

1342/R003

4-33



Hamble IOW


28 30 31 32 41 42 26 27 36 44 46 47 8 9 11 5 6 14 1 17 20

? Atylus spp indet Leach 1815 - - - - - - 3 - - - - - - - - - - - - - - Ampelisca brevicornis (da Costa 1853) - - - - - - - - - - 3 - - - - - - - - - - Ampelisca tenuicornis Lilljeborg 1855 - - - - - - - - - 1 1 - - - 4 - - - - 1 - Bathyporeia spp Lindstom 1855 - - - - - - - 3 - - - - - - - - - - - - - Megaluropus agilis Hoek 1889 - - - - - - - - - 1 - - - - - - - - - - - Melita palmata (Montagu 1804) - - - - - - - - - - - - - - - - - - 28 - - Microprotopus maculatus Norman 1867 - - - - - - 2 - - - 27 - - - - - - - - - - Aoridae spp indet (female) - - - - - - - 1 - - - 8 14 - - 16 - 1 38 - 1 - Aora gracilis (Bate 1857) - - - - - - - - - - 1 - - - - - - - - - - Microdeutopus damnoniensis (Bate 1856) - - - - - - - - - - 8 - - - - - - - - - - Microdeutopus gryllotalpa Costa 1853 - - - - - - - - - - - 6 - - - - - 12 - - - Microdeutopus versiculatus (Bate 1856) - - - - - - - - - - - - - - - - 2 - - - - Corophium spp indet Latreille 1806 1 - - - - - - - - - - - - 1 - - - - 1 - - Corophium acherusicum (da Costa 1851) - - - - - - - - - 7 - - - - - - 1 - - - - Corophium arenarium Crawford 1937 9 - - - - - 1 - - 3 - - - - - - - - - - - Corophium volutator (Pallas 1766) - - - - - - - 1 - - - 1 7 - - 816 - - - 13 - Pariambus typicus (Krøyer 1845) - - - - - - - - - - 6 - - - - - - - - - - Phtisica marina Slabber 1769 - - - - - - - - - 1 96 - - - 5 - - - - - - Gnathia spp indet (female) Leach 1814 - - - - - - - - - - - - - - - - - 1 - - - Sphaeroma spp Bosc 1801 1 - - - - - - - - - - - - - - - 1 - 5 - - Akanthophoreus gracilis (Kroyer 1842) - - - - - - - - - 1 - - - - - - - - - - - Bodotria spp (Goodsir 1843) - - - - - - - 4 - - - - - - - 1 - - - - - Hippolyte sp indet Leach 1814 - - - - - - - - - - - - - - - - 1 - - - - Carcinus maenas juv (Linnaeus 1758) - - - - 1 - 1 - - - 2 - - 1 1 - 2 1 - - - Littorina littorea (Linnaeus 1758) - - - - - - - - - - - - - - - - - - 2 - - Hydrobia ulvae (Pennant 1777) 371 26 - 2 498 - 4 - 23 - - 322 1 56 - 7 35 557 - 14 - Hinia reticulate (Linnaeus 1758) - - - - - - - - - - - - - - - 1 - - - - - Roxania utriculus (Brocchi 1814) - - - - - - 1 - - - 1 - - - - - - - - - -

4-34

ER

T 1342/R

003



Hamble IOW


28 30 31 32 41 42 26 27 36 44 46 47 8 9 11 5 6 14 1 17 20

Retusa obtusa (Montagu 1803) - - - - - - - 1 - 3 - - - - - - - - - - - NUDIBRANCHIA spp - - - - - - - 2 - 24 - - - - - - - - - - - - PELECYPODA spp juv - 4 - - - - 1 2 1 - 5 - - - - - 2 - 2 - - - Nucula nitidosa Winckworth 1930 - - - - - - - - - - 1 - - - 1 - - - - - - Cerastoderma spp juv Poli 1795 5 2 - 2 - 2 3 - 5 14 1 - - - - 14 9 4 1 1 - Cerastoderma edule (Linnaeus 1758) 2 - - - - - - - - 2 - 1 - 2 1 - - - 1 - - Cerastoderma glaucum (Poiret 1798) - - - - - - - - - - - - - - 1 - - - - - - Macoma balthica (Linnaeus 1758) - - - - - - - - - - - 1 - 1 - - - - - - - Abra spp indet Lamarck 1818 - - - - - - - - - - - - - - - 3 - - - - - Abra nitida (O F Muller 1776) - - - - - - - - - - - - - - - - 1 - - - - Abra tenuis (Montagu 1803) - 11 - - 2 2 40 - 55 - - 4 - - - - - 6 - 4 - Tapes sp juv Muhlfeld 1811 - - - - - - - - - 1 - - - - - - - - - - - Tapes decussates (Linnaeus 1758) - - - - - - - - - - - - - 4 1 1 - - 1 - - Mya spp juv Linnaeus 1758 - - - 1 - - - - - - - - - - - - - - - - - Mya truncata Linnaeus 1758 - - - - - - - - - - - - - - - 1 - - - - - Corbula gibba (Olivi 1792) - - - - - - - - - - - - - - 1 1 - - - - - Phoronis muelleri Selys-Longchamps 1903 - - - - - - - - - - - - - - 1 1 - - - - - ENTEROPNEUSTA spp - - - - - - - - - - - - - - - - - 1 - - 1 - Chironomid Larvae - 9 - - - - 1 - 9 1 - 1 - - 1 - - 2 - 1 -

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4-36 ERT 1342/R003

Table 4.11 Macrobenthos sample diversity indices for mid shore stations (numbers per 0.03 m2), intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Diversity Evenness

Transect Taxa Individuals Simpson 1-D Brillouin

Shannon-Wiener

Pielou Heip

Langstone 28 16 908 56.75 0.53 1.51 1.55 0.39 0.13 30 11 614 55.82 0.41 1.28 1.33 0.38 0.15 31 20 1,822 91.10 0.28 1.04 1.07 0.25 0.06 32 9 523 58.11 0.25 0.85 0.89 0.28 0.11 41 9 2,438 270.89 0.54 1.31 1.32 0.42 0.19 42 16 636 39.75 0.53 1.66 1.72 0.43 0.15

Chichester 26 19 867 45.63 0.67 2.27 2.33 0.55 0.22 27 16 272 17.00 0.68 2.01 2.12 0.53 0.22 36 12 788 65.67 0.35 1.15 1.19 0.33 0.12 44 11 548 49.82 0.28 0.96 1.00 0.29 0.10 46 8 85 10.63 0.73 2.04 2.23 0.74 0.53 47 10 1,239 123.90 0.59 1.52 1.54 0.46 0.21

Southampton Water and Hamble 8 7 42 6.00 0.53 1.45 1.71 0.61 0.38 9 11 226 20.55 0.47 1.49 1.59 0.46 0.20

11 17 753 44.29 0.72 2.30 2.35 0.58 0.26 5 18 442 24.56 0.50 1.73 1.81 0.44 0.15 6 17 237 13.94 0.75 2.36 2.50 0.61 0.29

Isle of Wight (no mid shore station on transect 14) Northwest Solent

1 6 42 7.00 0.48 1.21 1.42 0.55 0.33 17 3 14 4.67 0.58 1.13 1.41 0.89 0.83 20 15 406 27.07 0.74 2.27 2.35 0.60 0.29

ERT 1342/R003 4-37

Table 4.12 Macrobenthos sample diversity indices for lower shore stations (numbers per 0.03 m2), intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Diversity Evenness

Transect Taxa Individuals Simpson 1-D Brillouin

Shannon-Wiener

Pielou Heip

Langstone 28 12 516 43.00 0.45 1.34 1.39 0.39 0.15 30 13 750 57.69 0.46 1.63 1.68 0.45 0.18 32 10 203 20.30 0.36 1.16 1.26 0.38 0.15 41 11 817 74.27 0.57 1.55 1.59 0.46 0.20 42 12 145 12.08 0.60 1.85 2.01 0.56 0.27

Chichester 26 21 189 9.00 0.82 2.79 3.01 0.68 0.35 27 9 16 1.78 0.84 2.16 2.91 0.92 0.81 36 14 755 53.93 0.53 1.85 1.90 0.50 0.21 44 17 59 3.47 0.86 2.86 3.35 0.82 0.57 46 28 609 21.75 0.88 3.40 3.52 0.73 0.39 47 23 1214 52.78 0.79 2.68 2.73 0.60 0.26

Southampton Water and Hamble 8 7 23 3.29 0.79 2.00 2.47 0.88 0.76 9 9 117 13.00 0.61 1.61 1.75 0.55 0.30

11 33 344 10.42 0.85 3.30 3.50 0.69 0.32 5 19 1016 53.47 0.35 1.28 1.32 0.31 0.08 6 30 423 14.10 0.89 3.48 3.64 0.74 0.40

Isle of Wight 14 17 938 55.18 0.62 2.12 2.16 0.53 0.22

Northwest Solent 1 21 224 10.67 0.78 2.72 2.91 0.66 0.33

17 17 369 21.71 0.69 2.09 2.19 0.54 0.22

4-38 ERT 1342/R003

Table 4.13 Top ten species at mid shore stations on each transect (numbers per 0.03 m2), intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Species Abund % tot Cum % Species Abund % tot Cum %

Langstone Transect 28 Transect 30 Hydrobia ulvae 575 63.33 63.33 Hydrobia ulvae 465 75.73 75.73 Tubificoides benedii 227 25 88.33 Tubificoides benedii 80 13.03 88.76 Pygospio elegans 46 5.07 93.39 Streblospio shrubsolii 27 4.4 93.16 Tubificoides pseudogaster (agg) 35 3.85 97.25 Cerastoderma edule 12 1.95 95.11 Corophium arenarium 7 0.77 98.02 Tharyx sp 10 1.63 96.74 ANTHOZOA spp 3 0.33 98.35 Ampharete grubei 8 1.3 98.05 Eteone cf longa 3 0.33 98.68 Pygospio elegans 5 0.81 98.86 Glycera tridactyla 3 0.33 99.01 Melinna palmata 3 0.49 99.35 Streblospio shrubsolii 2 0.22 99.23 Nephtys hombergii 2 0.33 99.67 Cerebratulus spp 1 0.11 99.34 Sphaeroma spp 1 0.16 99.84 Transect 31 Transect 32 Tubificoides benedii 1,535 84.25 84.25 Tubificoides benedii 450 86.04 86.04 Hydrobia ulvae 92 5.05 89.3 Tubificoides pseudogaster (agg) 36 6.88 92.93 Tharyx sp 77 4.23 93.52 Cirriformia tentaculata 14 2.68 95.6 Pygospio elegans 53 2.91 96.43 Hediste diversicolor 8 1.53 97.13 Tubificoides pseudogaster (agg) 11 0.6 97.04 Melita palmata 6 1.15 98.28 Streblospio shrubsolii 11 0.6 97.64 Capitella capitata (agg) 5 0.96 99.24 Melinna palmata 9 0.49 98.13 Ampharete grubei 2 0.38 99.62 Manayunkia aestuarina 5 0.27 98.41 Tubificoides amplivasatus 1 0.19 99.81 Ampharete grubei 5 0.27 98.68 Glycera tridactyla 1 0.19 100 Capitella capitata (agg) 4 0.22 98.9 Transect 41 Station 42 Tubificoides benedii 1,390 57.01 57.01 Hydrobia ulvae 417 65.57 65.57 Hydrobia ulvae 888 36.42 93.44 Tubificoides benedii 120 18.87 84.43 Capitella capitata (agg) 131 5.37 98.81 Pygospio elegans 37 5.82 90.25 Aoridae spp indet (female) 18 0.74 99.55 Ampharete grubei 16 2.52 92.77 Chironomid Larvae 6 0.25 99.79 Corophium arenarium 12 1.89 94.65 Microdeutopus gryllotalpa 2 0.08 99.88 Tharyx sp 9 1.42 96.07 Nephtys hombergii 1 0.04 99.92 ANTHOZOA spp 5 0.79 96.86 Abra tenuis 1 0.04 99.96 Eteone cf longa 5 0.79 97.64 Eteone cf longa 1 0.04 100 Aphelochaeta spp 4 0.63 98.27 Cerastoderma edule 4 0.63 98.9

Chichester Transect 26 Transect 27 Tubificoides benedii 465 53.63 53.63 Corophium arenarium 119 43.75 43.75 Abra tenuis 122 14.07 67.7 Scoloplos armiger 90 33.09 76.84 Capitella capitata (agg) 106 12.23 79.93 Hydrobia ulvae 31 11.4 88.24 Pygospio elegans 50 5.77 85.7 Pygospio elegans 10 3.68 91.91 Manayunkia aestuarina 42 4.84 90.54 Eteone cf longa 8 2.94 94.85 Streblospio shrubsolii 20 2.31 92.85 Anaitides mucosa 3 1.1 95.96 Tubificoides pseudogaster (agg) 13 1.5 94.35 Aricidea minuta 2 0.74 96.69 Hydrobia ulvae 10 1.15 95.5 Glycera tridactyla 1 0.37 97.06 Tharyx sp 9 1.04 96.54 Maldanidae sp 1 0.37 97.43 Aoridae spp indet (female) 8 0.92 97.46 Nephtys hombergii 1 0.37 97.79 Transect 36 Transect 44 Tubificoides benedii 631 80.08 80.08 Hydrobia ulvae 464 84.67 84.67 Hydrobia ulvae 72 9.14 89.21 Corophium arenarium 24 4.38 89.05 Tharyx sp 32 4.06 93.27 Scoloplos armiger 24 4.38 93.43 Streblospio shrubsolii 23 2.92 96.19 Tubificoides benedii 16 2.92 96.35 Ampharete grubei 8 1.02 97.21 Cerastoderma edule 10 1.82 98.18 Pygospio elegans 7 0.89 98.1 Pygospio elegans 5 0.91 99.09 Phtisica marina 5 0.63 98.73 Glycera tridactyla 1 0.18 99.27 Melinna palmata 4 0.51 99.24 Tubificoides pseudogaster (agg) 1 0.18 99.45 Eteone cf longa 2 0.25 99.49 Tharyx sp 1 0.18 99.64 Nephtys hombergii 2 0.25 99.75 Sphaeroma spp 1 0.18 99.82

ERT 1342/R003 4-39


Species Abund % tot Cum % Species Abund % tot Cum % Chichester

Transect 46 Transect 47 Enchytraeidae spp 30 35.29 35.29 Hydrobia ulvae 712 57.47 57.47 Tubificoides pseudogaster (agg) 29 34.12 69.41 Tubificoides benedii 291 23.49 80.95 Hediste diversicolor 11 12.94 82.35 Capitella capitata (agg) 212 17.11 98.06 Pygospio elegans 7 8.24 90.59 Eteone cf longa 13 1.05 99.11 Eteone cf longa 3 3.53 94.12 Chironomid Larvae 4 0.32 99.44 Tubificoides benedii 3 3.53 97.65 Cerebratulus spp 2 0.16 99.6 Nephtys hombergii 1 1.18 98.82 Tubificoides pseudogaster (agg) 2 0.16 99.76 Aoridae spp indet (female) 1 0.08 99.84 Mya arenaria 1 0.08 99.92 Pygospio elegans 1 0.08 100

Southampton Water and Hamble Transect 8 Transect 9 Hydrobia ulvae 28 66.67 66.67 Tubificoides benedii 162 71.68 71.68 Tharyx sp 4 9.52 76.19 Hydrobia ulvae 20 8.85 80.53 Tubificoides benedii 4 9.52 85.71 Tubificoides pseudogaster (agg) 16 7.08 87.61 Aoridae spp indet (female) 2 4.76 90.48 Tharyx sp 12 5.31 92.92 Cerastoderma edule 2 4.76 95.24 Pygospio elegans 7 3.1 96.02 Microdeutopus versiculatus 1 2.38 97.62 Hediste diversicolor 2 0.88 96.9 Polydora cornuta 1 2.38 100 Polydora cornuta 2 0.88 97.79 Enchytraeidae spp 2 0.88 98.67 Capitella capitata (agg) 1 0.44 99.12 Eteone cf longa 1 0.44 99.56 Transect 11 Transect 5 Tubificoides benedii 311 41.3 41.3 Corophium volutator 307 69.46 69.46 Tharyx sp 233 30.94 72.24 Tharyx sp 44 9.95 79.41 Corophium volutator 56 7.44 79.68 Tubificoides benedii 29 6.56 85.97 Hydrobia ulvae 54 7.17 86.85 Hydrobia ulvae 17 3.85 89.82 Pygospio elegans 38 5.05 91.9 Abra tenuis 9 2.04 91.86 Eteone cf longa 21 2.79 94.69 Cerastoderma edule 8 1.81 93.67 Retusa obtusa 8 1.06 95.75 Tubificoides pseudogaster (agg) 6 1.36 95.02 Aphelochaeta spp 7 0.93 96.68 Eteone cf longa 5 1.13 96.15 Streblospio shrubsolii 6 0.8 97.48 Pygospio elegans 3 0.68 96.83 Melinna palmata 5 0.66 98.14 ANTHOZOA spp 3 0.68 97.51

Southampton Water and Hamble Northwest Solent Transect 6 Transect 1 Hydrobia ulvae 96 40.51 40.51 Enchytraeidae spp 29 69.05 69.05 Tharyx sp 51 21.52 62.03 Sphaeroma spp 8 19.05 88.1 Tubificoides benedii 47 19.83 81.86 Ophelia limacina 2 4.76 92.86 Pygospio elegans 13 5.49 87.34 Pygospio elegans 1 2.38 95.24 Ampharete grubei 7 2.95 90.3 Littorina saxatilis 1 2.38 97.62 Abra tenuis 4 1.69 91.98 Hydrobia ulvae 1 2.38 100 Anaitides mucosa 3 1.27 93.25 Tubificoides pseudogaster (agg) 3 1.27 94.51 Corophium volutator 3 1.27 95.78 Capitella capitata (agg) 2 0.84 96.62

Northwest Solent Transect 17 Transect 20 Pygospio elegans 8 57.14 57.14 Tubificoides pseudogaster (agg) 151 37.19 37.19 Tharyx sp 3 21.43 78.57 Hediste diversicolor 129 31.77 68.97 Tubificoides benedii 3 21.43 100 Malacoceros vulgaris 44 10.84 79.8 Hydrobia ulvae 32 7.88 87.68 Tubificoides benedii 27 6.65 94.33 Streblospio shrubsolii 6 1.48 95.81 Capitella capitata (agg) 5 1.23 97.04 Caulleriella zetlandica 4 0.99 98.03 Tharyx sp 2 0.49 98.52 Pygospio elegans 1 0.25 98.77

4-40 ERT 1342/R003

Table 4.14 Top ten species at lower shore stations on each transect (numbers per 0.03 m2), intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Species Abund % tot Cum % Species Abund % tot Cum %

Langstone Langstone Transect 28 Transect 30 Hydrobia ulvae 371 71.9 71.9 Tubificoides benedii 546 72.8 72.8 Tubificoides benedii 97 18.8 90.7 Pygospio elegans 43 5.73 78.53 Pygospio elegans 10 1.94 92.64 Hediste diversicolor 28 3.73 82.27 Corophium arenarium 9 1.74 94.38 Tharyx sp 28 3.73 86 Tubificoides pseudogaster (agg) 8 1.55 95.93 Eteone cf longa 28 3.73 89.73 Eteone cf longa 6 1.16 97.09 Hydrobia ulvae 26 3.47 93.2 Tharyx sp 6 1.16 98.26 Streblospio shrubsolii 23 3.07 96.27 Scoloplos armiger 4 0.78 99.03 Abra tenuis 11 1.47 97.73 Cerastoderma edule 2 0.39 99.42 Chironomid Larvae 9 1.2 98.93 Sphaeroma spp 1 0.19 99.61 Nephtys hombergii 4 0.53 99.47 Transect 32 Transect 41 Tubificoides benedii 161 79.31 79.31 Hydrobia ulvae 498 60.95 60.95 Tubificoides pseudogaster (agg) 15 7.39 86.7 Tubificoides benedii 145 17.75 78.7 Cirriformia tentaculata 12 5.91 92.61 Tharyx sp 142 17.38 96.08 Glycera tridactyla 4 1.97 94.58 Capitella capitata (agg) 17 2.08 98.16 Tubificoides amplivasatus 3 1.48 96.06 Ampharete grubei 5 0.61 98.78 Hydrobia ulvae 2 0.99 97.04 Eteone cf longa 3 0.37 99.14 Anaitides mucosa 2 0.99 98.03 Streblospio shrubsolii 2 0.24 99.39 Ampharete grubei 2 0.99 99.01 Abra tenuis 2 0.24 99.63 Ampharete lindstroemi 1 0.49 99.51 Nephtys hombergii 1 0.12 99.76 Nephtys hombergii 1 0.49 100 Pygospio elegans 1 0.12 99.88 Transect 42 Aphelochaeta spp 87 60 60 Melinna palmata 24 16.55 76.55 Tharyx sp 10 6.9 83.45 Tubificoides benedii 9 6.21 89.66 Ampharete grubei 5 3.45 93.1 Capitella capitata (agg) 2 1.38 94.48 Polycirrus norvegicus 2 1.38 95.86 Abra tenuis 2 1.38 97.24 Pygospio elegans 1 0.69 97.93 Cirriformia tentaculata 1 0.69 98.62

Chichester Chichester Transect 26 Transect 27 Enchytraeidae spp 53 28.04 28.04 Bodotria spp 4 25 25 Abra tenuis 40 21.16 49.21 Bathyporeia spp 3 18.75 43.75 Tubificoides benedii 38 20.11 69.31 Spio martinensis 3 18.75 62.5 Streblospio shrubsolii 18 9.52 78.84 Nephtys hombergii 1 6.25 68.75 Cossura longocirrata 10 5.29 84.13 Pygospio elegans 1 6.25 75 Nephtys hombergii 6 3.17 87.3 Urothoe elegans 1 6.25 81.25 Hydrobia ulvae 4 2.12 89.42 Corophium volutator 1 6.25 87.5 ? Atylus spp indet 3 1.59 91.01 Scoloplos armiger 1 6.25 93.75 Melinna palmata 3 1.59 92.59 Retusa obtusa 1 6.25 100 NUDIBRANCHIA spp 2 1.06 93.65 Transect 36 Transect 44 Tubificoides benedii 510 67.55 67.55 Scoloplos armiger 17 28.81 28.81 Pygospio elegans 64 8.48 76.03 Pygospio elegans 10 16.95 45.76 Abra tenuis 55 7.28 83.31 Corophium acherusicum 7 11.86 57.63 NUDIBRANCHIA spp 24 3.18 86.49 Chaetozone gibber 5 8.47 66.1 Hydrobia ulvae 23 3.05 89.54 Corophium arenarium 3 5.08 71.19 Ampharete grubei 22 2.91 92.45 Retusa obtusa 3 5.08 76.27 Melinna palmata 16 2.12 94.57 Tharyx sp 2 3.39 79.66 Eteone cf longa 10 1.32 95.89 Cerastoderma edule 2 3.39 83.05 Tharyx sp 9 1.19 97.09 Eteone cf longa 2 3.39 86.44 Chironomid Larvae 9 1.19 98.28 Nephtys hombergii 1 1.69 88.14

ERT 1342/R003 4-41


Species Abund % tot Cum % Species Abund % tot Cum % Chichester

Transect 46 Transect 47 Galathowenia oculata 131 21.51 21.51 Tubificoides benedii 402 33.11 33.11 Phtisica marina 96 15.76 37.27 Hydrobia ulvae 322 26.52 59.64 Tubificoides pseudogaster (agg) 84 13.79 51.07 Tubificoides amplivasatus 138 11.37 71 Tharyx sp 68 11.17 62.23 Tubificoides pseudogaster (agg) 97 7.99 79 Melinna palmata 64 10.51 72.74 Streblospio shrubsolii 78 6.43 85.42 Microprotopus maculatus 34 5.58 78.33 Tharyx sp 76 6.26 91.68 Tubificoides benedii 21 3.45 81.77 Capitella capitata (agg) 38 3.13 94.81 Pygospio elegans 21 3.45 85.22 Pygospio elegans 21 1.73 96.54 Cossura longocirrata 14 2.3 87.52 Aoridae spp indet (female) 14 1.15 97.69 Tubificoides amplivasatus 12 1.97 89.49 Microdeutopus gryllotalpa 6 0.49 98.19

Southampton Water and Hamble Transect 8 Transect 9 Corophium volutator 7 30.43 30.43 Hydrobia ulvae 56 47.86 47.86 Pygospio elegans 5 21.74 52.17 Tharyx sp 46 39.32 87.18 Polydora cornuta 4 17.39 69.57 Tapes decussatus 4 3.42 90.6 Tharyx sp 4 17.39 86.96 Neanthes virens 3 2.56 93.16 Tubificoides benedii 1 4.35 91.3 Tubificoides pseudogaster (agg) 3 2.56 95.73 Tubificoides pseudogaster (agg) 1 4.35 95.65 Cerastoderma edule 2 1.71 97.44 Hydrobia ulvae 1 4.35 100 Nephtys hombergii 1 0.85 98.29 Macoma balthica 1 0.85 99.15 Polydora cornuta 1 0.85 100 Transect 11 Transect 5 Chaetozone gibber 88 25.58 25.58 Corophium volutator 816 80.31 80.31 Tharyx sp 74 21.51 47.09 Tharyx sp 58 5.71 86.02 Tubificoides pseudogaster (agg) 53 15.41 62.5 Aphelochaeta spp 45 4.43 90.45 Melinna palmata 19 5.52 68.02 Streblospio shrubsolii 25 2.46 92.91 Aoridae spp indet (female) 16 4.65 72.67 Tubificoides pseudogaster (agg) 19 1.87 94.78 Capitella capitata (agg) 14 4.07 76.74 Tubificoides benedii 13 1.28 96.06 Notomastus latericeus 11 3.2 79.94 Pygospio elegans 7 0.69 96.75 Scoloplos armiger 8 2.33 82.27 Mediomastus fragilis 7 0.69 97.44 Aricidea minuta 7 2.03 84.3 Hydrobia ulvae 7 0.69 98.13 Neanthes virens 6 1.74 86.05 Polydora quadrilobata 5 0.49 98.62 Transect 6 Aphelochaeta spp 94 22.22 22.22 Tubificoides pseudogaster (agg) 60 14.18 36.41 Chaetozone gibber 44 10.4 46.81 Tharyx sp 40 9.46 56.26 Hydrobia ulvae 35 8.27 64.54 Polycirrus norvegicus 34 8.04 72.58 Tubificoides benedii 30 7.09 79.67 Tubificoides amplivasatus 18 4.26 83.92 Cirriformia tentaculata 11 2.6 86.52 Mediomastus fragilis 9 2.13 88.65

4-42 ERT 1342/R003


Species Abund % tot Cum % Species Abund % tot Cum % Isle of Wight

Transect 14 Hydrobia ulvae 557 59.38 59.38 Aphelochaeta spp 100 10.66 70.04 Tubificoides benedii 90 9.59 79.64 Mediomastus fragilis 53 5.65 85.29 Aoridae spp indet (female) 38 4.05 89.34 Melinna palmata 32 3.41 92.75 Scoloplos armiger 30 3.2 95.95 Microdeutopus gryllotalpa 12 1.28 97.23 Anaitides mucosa 7 0.75 97.97 Abra tenuis 6 0.64 98.61

Northwest Solent Transect 1 Transect 17 Tubificoides pseudogaster (agg) 92 41.07 41.07 Pygospio elegans 160 43.36 43.36 Tubificoides benedii 37 16.52 57.59 Tharyx sp 124 33.6 76.96 Melita palmata 28 12.5 70.09 Tubificoides benedii 34 9.21 86.18 Ophelia limacina 18 8.04 78.13 Hydrobia ulvae 14 3.79 89.97 Notomastus latericeus 8 3.57 81.7 Corophium volutator 13 3.52 93.5 Capitella capitata (agg) 6 2.68 84.38 Ampharete grubei 5 1.36 94.85 Chaetozone gibber 6 2.68 87.05 Abra tenuis 4 1.08 95.93 Sphaeroma spp 5 2.23 89.29 Capitella capitata (agg) 3 0.81 96.75 Enchytraeidae spp 4 1.79 91.07 Melinna palmata 3 0.81 97.56 Exogone hebes 4 1.79 92.86 Polydora cornuta 2 0.54 98.1

Chi 27 LowNWS 1 MidChi 46 MidSot 8 LowNWS 17 MidChi 27 MidChi 44 LowNWS 1 LowLan 32 MidLan 32 LowSot 11 LowChi 46 LowSot 8 MidSot 9 LowChi 26 LowLan 42 LowHam 5 LowHam 6 LowNWS 20 MidChi 47 LowChi 26 MidLan 31 MidHam 5 MidSot 11 MidNWS 17 LowLan 30 LowChi 36 LowLan 30 MidChi 36 MidHam 6 MidLan 41 LowSot 9 MidChi 44 MidLan 28 MidLan 28 LowLan 42 MidIOW 14 LowLan 41 MidChi 47 Mid

0 20 40 60 80 100

Similarity

Figure 4.1 Results of classification of macrobenthos data from mid and lower shore cores, intertidal sediment survey of the Solent Maritime SAC, August to September 2005

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Figure 4.2 Plot of MDS results for macrobenthos data from mid and lower shore cores, intertidal sediment survey of the Solent Maritime SAC, August to September 2005

4-44

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003

ERT 1432/R003 4-45

Figure 4.3a Results of classification of macrobenthos data from mid and lower shore cores from

Langstone Harbour, intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Figure 4.3b Results of classification of macrobenthos data from mid and lower shore cores from

Chichester Harbour, intertidal sediment survey of the Solent Maritime SAC, August to September 2005

4-46 ERT 1342/R003

Figure 4.4a Results of classification of macrobenthos data from mid and lower shore cores from

Southampton Water and Hamble, intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Figure 4.4b Results of classification of macrobenthos data from mid and lower shore cores from

the Isle of Wight and the Northwest Solent, intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Table 4.15 Historic Solent intertidal data (as compiled by Emu 2004; numbers per m2) for comparison with 2005 data, intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Langstone Chichester Soton & Hamble IOW NW Solent

Ref (ERT 2005 stations) 28 low

31 mid

32 mid

41 mid

42 low

26 mid

27 mid

27 mid

27 mid

27 mid

36 mid

44 mid

44 low

47 mid

47 low

5 low

11 mid

11 low

14 low

1 low

1 low

Ref (EMU station identifier)

IPA 39.2

IPA 20.1

IPA 9.2 H2A

IPA 37.11

IPA 9.4 W2A

IPA 28.52

IPA 28.4

IPA 28.36

IPA 28.39

IPA 28.40

IPA 33. Th19

IPA 28.51

IPA 28.6

IPA 28.23

IPA 33.26

IPA 42.2

IPA 5.1

IPA 5.17

IPA 40.1

IPA 5.13

IPA 5.14

Sampling date 1976 1975 1991 1979 1991 1980 1980 1980 1980 1980 1997 1980 1980 1980 1997 1987 1987 1987 1995 1987 1987 Cereus pedunculatus 50 Diptera indet (inc larvae) 22 56 Dolichopodid larvae 130 64 Nemertae indet. 10 126 68 Cerebratalus sp. 2 Lineus ruber 60 189 Nematoda indet. 3087 42 51 2586 4095 2773 12348 388 Axelsonia sp. 64 Spadella cephaloptera 60 Golfingia sp. 126 Annelida polychaeta 826 Eteone sp. 30 16 17 Eteone flava 19 Eteone longa 126 141 28 47 64 189 94 80 Anaitides maculata 19 14 188 Eumida sanguinea 10 Phyllodoce sp 10 47 Glycera sp. 3 Glycera convoluta 20 144 14 4 Exogone hebes 40 Hediste diversicolor 116 56 51 40 Nereis pelagica 20 Nereis zonata 144 144 Nephtys caeca 3 20 Nephtys ciliata 144 144

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31 mid

32 mid

41 mid

42 low

26 mid

27 mid

27 mid

27 mid

27 mid

36 mid

44 mid

44 low

47 mid

47 low

5 low

11 mid

11 low

14 low

1 low

1 low


IPA 39.2

IPA 20.1

IPA 9.2 H2A

IPA 37.11

IPA 9.4 W2A

IPA 28.52

IPA 28.4

IPA 28.36

IPA 28.39

IPA 28.40

IPA 33. Th19

IPA 28.51

IPA 28.6

IPA 28.23

IPA 33.26

IPA 42.2

IPA 5.1

IPA 5.17

IPA 40.1

IPA 5.13

IPA 5.14

Sampling date 1976 1975 1991 1979 1991 1980 1980 1980 1980 1980 1997 1980 1980 1980 1997 1987 1987 1987 1995 1987 1987 Nephtys cirrosa 20 Nephtys hombergii 50 4 19 39 14 130 14 42 19 Orbiniidae indet 25 Scoloplos armiger 1060 16 693 288 472 1386 472 441 94 240 Aricidea minuta 160 60 60 Paraonis fulgens 10 Spionidea indet. 1689 Malacocerus fuliginosus 80 Polydora caulleryi 200 20 Polydora ciliata 64 Pygospio sp 100 Pygospio elegans 330 132 1071 126 94 1034 1134 94 504 20 500 20 Scolelepis foliosa 10 Scolelepis squamata 30 Spio sp. 3 Spio filicornis 20 11 Spio martinensis 100 Spiophanes bombyx 110 Streblospio shrubsoli 6174 258 141 189 Cirratulidae indet 14 14 64 7622 Aphelochaeta marioni 2583 1645 1429 Caulleriella zetlandica 42 5734 9009 Cirratulus spp. 100 Cirratulus filiformis 576 Cirriformia tentaculata 360 Tharyx killariensis 5040 60 160 1340

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Langstone Chichester Soton & Hamble IOW NW Solent Ref (ERT 2005 stations)

28 low

31 mid

32 mid

41 mid

42 low

26 mid

27 mid

27 mid

27 mid

27 mid

36 mid

44 mid

44 low

47 mid

47 low

5 low

11 mid

11 low

14 low

1 low

1 low


IPA 39.2

IPA 20.1

IPA 9.2 H2A

IPA 37.11

IPA 9.4 W2A

IPA 28.52

IPA 28.4

IPA 28.36

IPA 28.39

IPA 28.40

IPA 33. Th19

IPA 28.51

IPA 28.6

IPA 28.23

IPA 33.26

IPA 42.2

IPA 5.1

IPA 5.17

IPA 40.1

IPA 5.13

IPA 5.14

Sampling date 1976 1975 1991 1979 1991 1980 1980 1980 1980 1980 1997 1980 1980 1980 1997 1987 1987 1987 1995 1987 1987 Pherusa plumosa 10 Capitelida indet 6 1008 126 1820 Capitella capitata 10 6200 189 284 504 141 63 20 1000 400 100 Notomastus latericeus 10 Arenicola marina 40 3 144 75 8 100 Ophelia rathkei 10 Ampharetidae 4 Melinna spp 3 Melinna palmata 118 28 Ampharete sp 1000 Ampharete grubei 38 8 42 1898 810 380 40 Sabellides octocirrata 2016 144 Lanice conchilega 100 20 20 Manayunkia aestuarina 64 5733 517 126 Oligochaeta indet 40 11400 64 64 420 720 Tubificidae indet 1000 83 504 423 693 11421 Tubificoides benedeni 3024 576 14175 58 47 63 472 388 26901 13563 18900 582 19960 66860 140 3540 Tubificoides diazi 80 60 Ammonia sp. 2392 130 Brizalina sp. 6984 Quinqueloculina sp. 64 Elminius modestus 16 Semibalanus balanoides 41700 8 Balanus sp. 13 Harpaticoida indet. 6984 252 Calliopius laeviusculus 40 20 Gammarellus homari 20

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31 mid

32 mid

41 mid

42 low

26 mid

27 mid

27 mid

27 mid

27 mid

36 mid

44 mid

44 low

47 mid

47 low

5 low

11 mid

11 low

14 low 1 low 1 low


IPA 39.2

IPA 20.1

IPA 9.2 H2A

IPA 37.11

IPA 9.4 W2A

IPA 28.52

IPA 28.4

IPA 28.36

IPA 28.39

IPA 28.40

IPA 33. Th19

IPA 28.51

IPA 28.6

IPA 28.23

IPA 33.26

IPA 42.2

IPA 5.1

IPA 5.17

IPA 40.1

IPA 5.13

IPA 5.14

Sampling date 1976 1975 1991 1979 1991 1980 1980 1980 1980 1980 1997 1980 1980 1980 1997 1987 1987 1987 1995 1987 1987 Talitroides dorrieni 30 Urothoe brevicorns 130 Urothoe poseidonis 330 14 72 Atylus swammerdami 10 Dexamine spinosa 4 Ampelisca brevicornis 10 8 Bathyporeia elegans 40 Bathyporeia guilliamsoniana 50 Bathyporeia pilosa 2190 60 Bathyporeia sarsi 660 54 28 14 Haustorius arenarius 130 Gammarus sp. 158 3764 Gammarus locusta 10 Gammarus salinus 144 Melita palmata 21 106 Jassa falcata 28 Microdeutopus gryllotalpa 301 Corophium sp. 3 Corophium arenarium 90 206 1341 519 59 Corophium volutator 38 560 Phistica marina 20 Gnathia sp. 10 Paragnathia formica 4 Cyathura carinata 382 180 Eurydice pulchra 740 Sphaeroma monodi 10 25

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31 mid

32 mid

41 mid

42 low

26 mid

27 mid

27 mid

27 mid

27 mid

36 mid

44 mid

44 low

47 mid

47 low

5 low

11 mid

11 low

14 low

1 low

1 low


IPA 39.2

IPA 20.1

IPA 9.2 H2A

IPA 37.11

IPA 9.4 W2A

IPA 28.52

IPA 28.4

IPA 28.36

IPA 28.39

IPA 28.40

IPA 33. Th19

IPA 28.51

IPA 28.6

IPA 28.23

IPA 33.26

IPA 42.2

IPA 5.1

IPA 5.17

IPA 40.1

IPA 5.13

IPA 5.14

Sampling date 1976 1975 1991 1979 1991 1980 1980 1980 1980 1980 1997 1980 1980 1980 1997 1987 1987 1987 1995 1987 1987 Sphaeroma serratum 21 Jaera albifrons 17 280 Idotea chelipes 340 4 Cumopsis goodsiri 94 Cumopsis longipes 10 47 Vaunthompsonia cristata 47 Diastylis bradyi 10 Crangon crangon 10 3 Corystes cassivelaunus 10 Macropipus depurator 10 Carcinus maenas 10 32 45 19 13 20 Neoloricata indet 8 Lepidochitona cinerea 50 Littorina littorea 20 15 150 28 48 20 Hydrobia ulvae 10000 432 44800 864 1822 259 3490 59.5 3234 5332.5 527 31949 57230 Potamopyrgus jenkinsi 64 Buccinum undatum 8 Retusa obtusa 64 Limapontia depressa 378 1575 329 Pectinidae indet 267 Lucinoma borealis 40 Cerastoderma 100 200 130 Cerastoderma edule 432 144 56 33 122.5 204.5 79 119.5 153 220 220 60 100 Cerastoderma glaucum 610 15 130 Solen marginatus 10 Macoma sp 10

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31 mid

32 mid

41 mid

42 low

26 mid

27 mid

27 mid

27 mid

27 mid

36 mid

44 mid

44 low

47 mid

47 low

5 low

11 mid

11 low

14 low

1 low

1 low


IPA 39.2

IPA 20.1

IPA 9.2 H2A

IPA 37.11

IPA 9.4 W2A

IPA 28.52

IPA 28.4

IPA 28.36

IPA 28.39

IPA 28.40

IPA 33. Th19

IPA 28.51

IPA 28.6

IPA 28.23

IPA 33.26

IPA 42.2

IPA 5.1

IPA 5.17

IPA 40.1

IPA 5.13

IPA 5.14

Sampling date 1976 1975 1991 1979 1991 1980 1980 1980 1980 1980 1997 1980 1980 1980 1997 1987 1987 1987 1995 1987 1987 Macoma balthica 10 14 14 8 140 8 Abra tenuis 670 1000 864 1875 144 333.5 58.5 29 646 9073.5 1523 165 258 1400 Scrobicularia plana 72 Mya spp. 144 Mya arenaria 4

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Table 4.16 Distance between stations sampled in the present survey and those used for historical comparisons, intertidal sediment survey of the Solent Maritime SAC, August to September 2005

2005 station reference

Historic station reference (Emu, 2004)

Distance (m)

Langstone 28 low IPA39.2 346.8 31 mid IPA20.1 79.6 32 mid IPA9.2H2A 815 32 low IPA9.2H2A 795 41 mid IPA37.11 70 42 low IPA9.4W2A 859 Chichester 26 mid IPA28.52 69 27 mid IPA28.40 176 36 mid IPA33.Th19 99.4 36 low IPA38 1.10 151 44 mid IPA28.51 399 44 low IPA28.6 376 47 mid IPA28.23 85.8 47 low IPA33.26 27.1 Southampton Water & Hamble 5 low IPA42.2 55.8 11 mid IPA5.1 41.6 11 low IPA5.17 54.9 Isle of Wight 14 low IPA40.1 77.3 Northwest Solent 1 low IPA5.13 86.7 1 low IPA5.14 51.7

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Table 4.17 Results of AMBI analysis on macrobenthic data (shown for each of three cores at each station) from mid and lower shore stations, intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Mid shore stations Lower shore stations

Transect Ecological status* Ecological status

Langstone 28 Moderate; poor; moderate Moderate; moderate; moderate 30 Moderate; poor; moderate Poor; poor; poor 31 Bad; bad; poor - 32 Bad; bad; bad Poor; poor; bad 41 Poor; poor; poor Poor; poor; poor 42 Moderate; moderate; moderate Moderate; moderate; poor

Chichester 26 Poor; poor; poor Moderate; moderate; poor 27 Good; good; moderate >10% of taxa not assigned 36 Poor; poor; poor Poor; poor; poor 44 Moderate; moderate; moderate Moderate; good; good 46 Poor; poor; poor Good; good; good 47 Poor; poor; poor Poor; moderate; poor

Southampton Water and Hamble 8 Moderate; poor; moderate Poor; poor; moderate 9 Bad; poor; poor Poor; poor; moderate

11 Moderate; poor; moderate Moderate; moderate; moderate 5 Moderate; moderate; moderate Moderate; moderate; moderate 6 Moderate; moderate; moderate Moderate; moderate; moderate

Isle of Wight 14 - Moderate; moderate; moderate

Northwest Solent 1 Poor; poor; poor Moderate; poor; moderate

17 Bad; poor; poor Moderate; moderate; moderate 20 Moderate; poor; moderate -

* Ecological status as defined for the Water Framework Directive, and its

equivalence to Pollution classification classes (Borja et al 2005):

Pollution classification Water Framework Ecological status Unpolluted High Slightly polluted Good Meanly polluted Moderate Highly polluted Poor Extremely polluted Bad

ERT 1342/R003 4-55

Table 4.18 Results of AMBI analysis on historic macrobenthic data from each of the four main survey areas, intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Historic data* 2005

equivalent

Original Ecological

status

Current ecological status (from Table 4.17)

Change in status

Station Date Langstone

IPA39.2 1976 28 low High Moderate; moderate; moderate Down

IPA20.1 1975 31 mid Moderate Bad; bad; poor Down

IPA9.2H2A 1991 32 mid Moderate Bad; bad; bad Down

IPA37.11 1979 41 mid Moderate Poor; poor; poor Down

IPA9.4W2A 1991 42 low Moderate Moderate; moderate; poor No change

Chichester IPA28.52 1980 26 mid Moderate Poor; poor; poor Down

IPA28.4 1980 27 mid Poor Good; good; moderate Up

IPA28.36 1980 27 mid Good Good; good; moderate No change

IPA28.39 1980 27 mid Moderate Good; good; moderate Up

IPA28.40 1980 27 mid Moderate Good; good; moderate Up

IPA33.Th19 1997 36 mid Moderate Poor; poor; poor Down

IPA28.51 1980 44 mid Moderate Moderate; moderate; moderate No change IPA28.6 1980 44 low Poor Moderate; good; good Up

IPA28.23 1980 47 mid Moderate Poor; poor; poor Down

IPA33.26 1997 47 low Poor Poor; moderate; poor No change

Southampton Water and Hamble IPA42.2 1987 5 low >10% taxa

not assigned Moderate; moderate; moderate

-

IPA5.1 1987 11 mid Bad Moderate; poor; moderate Up

IPA5.17 1987 11 low Bad Moderate; moderate; moderate Up Isle of Wight

IPA40.1 1995 14 low Good Moderate; moderate; moderate Down Northwest Solent

IPA5.13 1987 1 low Moderate Moderate; poor; moderate No change

IPA5.14 1987 1 low Poor Moderate; poor; moderate Up

* Data sourced from Emu (2004)

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Table 4.19 Average taxonomic distinctness (AvTD) calculated for macrobenthic data (three cores combined) from mid and lower shore stations, intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Mid shore stations

Lower shore stations Transect

AvTD AvTD Langstone

28 85.83 83.84 30 84.85 79.06 31 80.53 - 32 71.3 70.37 41 91.67 76.36 42 82.78 68.18

Chichester 26 85.77 87.14 27 83.61 87.96 36 79.80 81.32 44 87.88 88.73 46 76.62 82.89 47 91.11 85.51

Southampton Water and Hamble 8 90.48 80.95 9 76.97 84.26 11 84.56 82.07 5 83.66 85.58 6 84.07 84.29

Isle of Wight 14 - 89.22

Northwest Solent 1 91.11 81.27 17 66.67 87.01 20 85.71 85.77

ERT 1342/R003 4-57

Table 4.20 Average taxonomic distinctness (AvTD) calculated for historic macrobenthic data, intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Historic data*

Original AvTD

Current AvTD (from Table

4.19) Station Date

2005 equivalent

Langstone

IPA39.2 1976 28 low 86.33 83.84 IPA20.1 1975 31 mid 88.18 80.53

IPA9.2H2A 1991 32 mid 87.27 71.3 IPA37.11 1979 41 mid 89.70 91.67

IPA9.4W2A 1991 42 low 83.33 68.18 Chichester

IPA28.52 1980 26 mid 78.89 85.77 IPA28.4 1980 27 mid 87.96 83.61 IPA28.36 1980 27 mid 88.89 83.61 IPA28.39 1980 27 mid 89.63 83.61 IPA28.40 1980 27 mid 88.03 83.61

IPA33.Th19 1997 36 mid 81.68 79.80 IPA28.51 1980 44 mid 85.58 87.88 IPA28.6 1980 44 low 79.65 88.73 IPA28.23 1980 47 mid 86.15 91.11 IPA33.26 1997 47 low 88.89 85.51

Southampton Water and Hamble IPA42.2 1987 5 low 89.93 85.58 IPA5.1 1987 11 mid 71.85 84.56 IPA5.17 1987 11 low 82.96 82.07

Isle of Wight IPA40.1 1995 14 low 86.67 89.22

Northwest Solent IPA5.13 1987 1 low 83.44 81.27 IPA5.14 1987 1 low 85.28 81.27

* Data sourced from Emu (2004)

Figure 4.5 Average taxonomic distinctness (AvTD) for mid and lower shore stations represented as a funnel plot, intertidal

sediment survey of the Solent Maritime SAC, August to September 2005

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Figure 4.6 Average taxonomic distinctness (AvTD) for historic macrofaunal dataa represented as a funnel plot, intertidal

sediment survey of the Solent Maritime SAC, August to September 2005

Ave

rage

Tax

onom

ic D

istin

ctne

ss

Number of species

Lan IPA39.2 Lan IPA20.1 Lan IPA9.2H2A

Lan IPA37.11

Lan IPA9.4W2A

Chi IPA28.52 (26 mid)

Chi IPA28.4Chi IPA28.36

Chi IPA28.39

Chi IPA28.40

Chi IPA33.Th19

Chi IPA28.51

Chi IPA28.6 (44 low)

Chi IPA28.23

Chi IPA33.26Ham IPA42.2

Sot IPA5.1 (11 mid)

Sot IPA5.17

IOW IPA40.1

NWS IPA5.13

NWS IPA5.14

70

75

80

85

90

95

100

0 10 20 30 40 50

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Table 4.21 Summary biomass data (grams per 0.03 m2) for mid and lower shore stations on each transect, intertidal sediment survey of the Solent Maritime SAC, August to September 2005

Langstone Chichester Southampton & Hamble IOW Northwest Solent

Mid shore 28 30 31 32 41 42 26 27 36 44 46 47 8 9 11 5 6 14 1 17 20 Annelida 0.1873 0.2048 1.1312 1.8875 0.9282 0.1321 0.5925 0.5828 0.6158 0.0794 0.3672 0.3289 0.0037 0.1344 0.3504 0.2204 0.3323 - 0.0069 0.0057 5.9184 Crustacea 0.0015 0.0126 - 0.0590 0.0887 0.0070 0.0049 0.0436 0.0044 0.0189 - 0.1190 0.0027 - 0.0455 0.4754 0.2428 - 0.1897 - 0.1043 Mollusca 5.4724 48.5077 10.9149 0.0017 7.0254 14.4829 0.3472 0.2315 0.4797 42.9581 0.0036 11.3061 1.3311 0.2671 3.8540 46.9864 1.3935 - 1.1911 - 0.2959 Varia 0.0114 - 0.0053 - 0.0017 0.0375 0.0476 0.0006 - - - 0.0065 - 0.0002 - 0.0755 0.0015 - - - 0.0349 5.6726 48.7251 12.0514 1.9482 8.0440 14.6595 0.9922 0.8585 1.0999 43.0564 0.3708 11.7605 1.3375 0.4017 4.2499 47.7577 1.9701 - 1.3877 0.0057 6.3535

Langstone Chichester Southampton & Hamble IOW Northwest Solent Lower shore 28 30 31 32 41 42 26 27 36 44 46 47 8 9 11 5 6 14 1 17 20 Annelida 0.0882 0.7818 - 0.5222 0.4667 0.7019 0.5646 0.0283 0.8281 0.1040 1.1604 0.9676 0.0025 2.2112 1.8242 0.1739 1.2998 0.8918 0.1331 0.2132 - Crustacea 0.0023 - - - 0.0389 - 0.1126 0.0070 - 0.0032 0.1200 0.0086 0.0087 0.0756 0.1122 0.8831 0.1693 0.0935 0.0578 0.0260 - Mollusca 4.3857 0.1499 - 0.0352 2.4281 0.0042 0.0432 0.0016 0.1222 8.3024 0.2660 13.8203 0.0050 12.9928 0.9172 0.8756 0.3047 8.1793 12.2133 0.1537 - Varia - 0.0048 - - - - 0.0003 - 0.0047 0.0006 - 0.0075 - - 0.0046 0.0009 0.1319 0.0026 0.0058 0.0105 - 4.4762 0.9365 - 0.5574 2.9337 0.7061 0.7207 0.0369 0.9550 8.4102 1.5464 14.8040 0.0162 15.2796 2.8582 1.9335 1.9057 9.1672 12.4100 0.4034 -

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ERT 1342/R003 5-1

5 Discussion

5.1 Comparison with previous data The data obtained on the intertidal sediments of the Solent Maritime SAC broadly agree with previous information for the area, as reviewed most recently by Emu (2004). Despite the history of marine studies in the Solent, gaps exist in the coverage of Langstone Harbour and the West Solent which the present survey has contributed to filling. Two categories of data were obtained during the survey work; Phase 1 data, based on qualitative but systematic observation of habitats and communities, and Phase 2 data, based on quantitative sampling of sediments by cores for particle size and macrofaunal analysis. 5.1.1 Phase 1 data The Phase 1 data set collected shows that certain species observed in the field were widespread in the SAC. These included the polychaetes Arenicola marina, the snail Hydrobia ulvae, the cockle Cerastoderma edule, fucoid algae, and the green alga Enteromorpha sp. Supporting forms included the ragworm Hediste diversicolor, juvenile shore crabs Carcinus maenas, winkles Littorina spp, the barnacles Semibalanus balanoides and Elminius modestus and the slipper limpet Crepidula fornicata. Whilst the extent and variety of the species lists from Langstone and Chichester Harbours were very similar, some variation was indicated in other sectors. Thus the variety of species recorded was greatest in the Hamble, Isle of Wight and Northwest Solent areas and least in Southampton Water. Arenicola, fucoids and Enteromorpha did not occur on the mudflats of Southampton Water as widely as in other areas of the SAC, and Hydrobia ulvae was absent from the more open shores of the Isle of Wight and the Northwest Solent. The seagrass Zostera noltii was found in Langstone and Chichester only, and the sponge Hymeniacodon perleve and the anemone Anemonia viridis occurred widely on the mainland shore of the Northwest Solent but were also sparsely present in Langstone Harbour. The variety of algae was greatest along the Hampshire shoreline, and native oyster Ostrea edulis were present here also as well as in the Hamble. The main observable differences across the SAC occurred in the associated shore type and sediments, and most of the differences apparent between areas in the Phase 1 biological data are substratum-related. The sediment flats within Langstone and Chichester Harbours were very sheltered, with sediments ranging from sand at the entrances to soft or sticky muds in the innermost reaches. Sediments often included stony material in the form of pebbles, cobbles or boulders, but were generally finest, softest and wettest in the channels, and coarsest or more mixed and firmest towards the top of the shore. Sheltered and silty sediment flats were also found within the Medina estuary and Newport Harbour in the Isle of Wight, and down the western shore of lower Southampton Water and in the inner parts of the Hamble. In the more open, but still sheltered shores of the Isle of Wight and Northwest Solent, intertidal areas were narrower. The Isle of Wight shoreline was generally backed by unstable low clay or mudstone cliffs, whilst much of the Hampshire shoreline was backed by man-made sea defences, resulting in upper shores of steeply sloping concrete or gravel and pebbles. On both shorelines, the mid to lower shore generally consisted of sticky but firm clay overlain by pebbles and shells. Although sediment flats were the feature of interest in the present study, almost half of the 33 biotopes identified were rocky shore biotopes due to the present of stones of various grades on the sediment surface. The most widespread biotopes were LS.LCS.Sh.BarSh, LS.LMu.MEst, LS.LMx, LS.LCS.Sh, LS,LSa.MuSa, LS.LMu and LR.LLR.FVS.Fcer. Many sediment biotopes were designated as relatively high-level codes, since classification that is more detailed required

5-2 ERT 1342/R003

infaunal data. The sediment was dug over within each putative biotope in order to evaluate the infauna present, but sediment was usually not sieved as suggested in the MNCR method manual for logistical reasons. In addition, experience from sieving the Phase 2 core samples showed that most of the macrofauna was too small to see by eye and was difficult to separate from the clay balls that tended to accumulate in the sieve during the process. Withers (1979) undertook a survey of the marine macrofauna and flora of the Medina estuary in the late 1970s, and his station 9 was apparently located close to transect 24 of the present survey. As in the present survey, the main visible species recorded on a presence/absence basis wer Hediste diversicolor, Hydrobia ulvae, Carcinus maenas, Cerastoderma edule, Littorina littorea and L saxatilis, in addition to various infaunal polychaetes, Tubificoides benedii, amphipods and bivalve molluscs identified from core samples. Just as in the present survey, Withers also recorded the presence of Fucus vesiculosus and Enteromorpha sp. In general terms therefore, the epibiota elements of the shoreline do not appear to have changed significantly over the intervening 25 years or so. Whilst many sediment flat surveys have been undertaken in the Solent in the past, these have tended to use quantitative methods to examine the infauna. Environment Agency monitoring work based on sewage treatment works outflow locations have incorporated the determination of biotope codes for point sample locations (Unicomarine & Rees-Jones 2004). However, these classifications have been based on core sample analysis rather than on in-field observations. Therefore there is little previous work available with which to compare the Phase 1 survey data and biotope inventory directly. Just four biotopes were identified (LMU.HedMac, LMU.HedScr, LMU.HedStr, and LMU.HedOl based on 97.06 classification; see Table 4.5 for equivalence to current 04.05 classification) for the whole Solent, and it is of interest to note that LMU.HedOl encompassed community types ranging from impacted (reduced species richness and dominance by Capitella capitata) to unimpacted (with the typical range of species). 5.1.2 Phase 2 data The broad scale observations of the Phase 1 survey were augmented by core sampling for analysis of sediment particle size and organic matter content. These provide a different type of sediment description to that gained by observation, but they nevertheless confirmed the variable and generally poorly sorted nature of the sediment flats in all areas. Over 100 taxa were identified from cores taken in the mid and lower shores at 21 transects. Over the whole survey area, the macrofauna was characterised by the polychaetes Tharyx sp, Pygospio elegans, Eteone cf longa, Streblospio shrubsolii, Melinna palmata and Ampharete grubei, oligochaetes Tubificoides benedii and T pseudogaster (agg), the mud snail Hydrobia ulvae, and the bivalve molluscs Cerastoderma edule and possible Abra tenuis. This is very similar to the results of past surveys in the area (eg Withers & Thorpe 1978; Withers 1979; Withers 1980; Thomas & Culley 1981; Emu 2004; Unicomarine & Rees-Jones 2004). The macrofauna was numerically dominated at nearly all stations by relatively large numbers of just two or three taxa, mainly Hydrobia ulvae and Tubificoides benedii, and occasionally T pseudogaster (agg) also. The degree of this numerical dominance was highest in Langstone and Chichester Harbours, but decreased in Southampton Water and the Hamble and even more so in the Northwest Solent. In the lower shore stations, the dominance of Hydrobia and Tubificoides benedii was generally lessened, except in Langstone Harbour and at one or two transects in Chichester. Instead, the ranked abundance lists were headed by a greater variety of other species including the bivalve mollusc Abra tenuis, the polychaetes Scoloplos armiger, Galathowenia oculata, Aphelochaeta sp and Chaetozone gibber, and the amphipods Corophium volutator and Phtisica marina.

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The range in biomass over all areas for the mid shore stations was 0.19 to 1,623.2 g/m2, and that for the lower shore stations was 0.53 to 509.28 g/m2. Throughout the SAC the biomass was heavily dominated by molluscs, in particular by the cockle Cerastoderma edule and to a lesser extent by the snail Hydrobia ulvae. Biomass varied considerably between stations, but the range in biomass values within each survey sector was similar; this was undoubtedly due to the varying abundance of Cerastoderma in individual samples, and its ubiquity across the SAC as a whole. Unicomarine & Rees-Jones (2004) found a similar range in biomass, 0.1 to 2,376 g /m2, over the Solent area. The wide range and high station-to-station variability was also thought to be due to the varying abundance of molluscs (mostly Hydrobia ulvae or Cerastoderma edule but also Scrobicularia plana in the Rivers Test and Itchen, which were not visited in the present survey). A ‘historic data’ set was compiled from data for the Solent area as a whole that was collated by Emu (2004). The Emu review drew together macrobenthos data from a number of studies completed over the last thirty years or so. Macrobenthos abundance data from locations as close as possible to those sampled in the present survey were selected (distances within the range 27 to 860 m). As such, the historic data set represents ten separate studies carried out over the period 1975 to 1997, using various methods including cores, grabs and quadrats of various sizes and processed using different protocols (Emu 2004). This limits the analytical techniques that can be meaningfully applied to the data set, but it nevertheless permits some interesting temporal comparisons. Ignoring the insect, nematode, foraminiferan and harpacticoid taxa, the range of species found was similar to that reported from the present 2005 study, with the most widespread and abundant taxa including Pygospio elegans, Scoloplos armiger, Tubificoides benedii, Hydrobia ulvae, Cerastoderma edule and Abra tenuis. The two species dominating the macrofauna numerically were generally Tubificoides benedii and Hydrobia ulvae, similar to the position currently. In terms of differences between the two data sets, Eteone longa was less widespread than in 2005, and appears to have been absent from Langstone Harbour and Southampton Water and the Hamble in the past. The spionid polychaete Streblospio shrubsolii was also less widespread than in the present survey. The mud snail Hydrobia was absent from the records for Southampton Water and the Hamble in previous years. On the other hand, the bivalve mollusc Abra tenuis may have been more widespread and numerous in the past compared to the 2005 data. One other point of note is that the polychaete Capitella capitata does not appear to have changed significantly in distribution or numbers at the locations being compared since the mid 1970s. Its localised presence in the past has been linked to organic enrichment close to sewage outfalls and due to the seasonal presence of smothering mats of green algae on the surface of mudflats, particularly in Langstone Harbour (Withers 1980). Withers (1980) also commented on the relative absence of the bivalve mollusc Macoma balthica from the macrofauna in Langstone and Chichester Harbours, compared to Abra tenuis. From the results of the present survey, M balthica remains scarce in the Solent, and A tenuis (which Withers speculated could be filling a gap in bird diets caused by the scarcity of M balthica) remains patchily present. It is interesting to note that A tenuis can itself be an opportunistic species, occurring in large numbers in response to organic enrichment. In the present survey however, A tenuis only co-occurred with Capitella capitata in large numbers at one station. Withers (1980) also commented on the rarity of the amphipod Corophium volutator and related species in Langstone and Chichester Harbours (C volutator at just 10/m2 and C arenarium at up to 90/m2 in Langstone harbour). In the present survey, C volutator was not found in Langstone, but C arenarium was found at up to 400/m2 on the sandier substrata near the harbour mouth.

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On the other hand, C volutator was found at densities of up to approximately 4,000/m2 in Chichester Harbour and at 10,000 to 25,000/m2 in the Hamble. The most recent infaunal study of the Solent based on intertidal core sampling, is that carried out in 2002 by the Environment Agency (Unicomarine & Rees-Jones 2004). The purpose of this study was to determine the areas of sediment flat impacted by sewage treatment works (STW) outfalls, and therefore core stations tended to be concentrated around outfall locations (and were for the most part different to the locations sampled in the present survey). The areas influenced by these discharges were negligible in most cases, or restricted to within 45 m of the end of the pipe at three locations in Chichester Harbour and the Rivers Test and Itchen. However, areas of up to 100 m from the discharge point were recorded at Thorney STW and out to 900 m in the case of process discharges at the Fawley refinery in Southampton Water. Neither of these areas of effect overlapped with core stations sampled in the present survey. However, in spite of the different objectives of Unicomarine & Rees-Jones (2004) compared to the present survey, and the concentration of sampling effort around sewage outfalls, the macrofauna recorded in 2002 was qualitatively very similar to that reported here for 2005 with a similar range of species and numerical domination chiefly by Hydrobia ulvae and Tubificoides benedii. Evidence of outfall impact was only clearly present at two of the Fawley refinery outfalls, where a very low diversity fauna dominated by large numbers of Capitella capitata was apparent. Overall, in qualitative terms, it is clear that differences probably occur from year to year in the abundances of individual taxa. Due to variation in the data collection methods, timing of surveys (in relation to likely seasonal variation) and because station locations in the two data sets under comparison are only approximately similar, it is not feasible to be more precise or conclusive about temporal variations in species presence, abundance or biomass. However, it is equally clear that the essential character of the macrofauna in the Solent system remains similar to that evident from previous studies. Whether the AMBI analysis results also demonstrate this is not totally clear. It should be noted that the instructions for using AMBI stipulate that samples should have been collected using a 0.1m2 grab and processed using a 1.0 mm sieve. The current data were collected using 0.01m2 cores and washed over 0.5 mm sieves. Furthermore, the historic data set was collected using a variety of sampling equipment and sieve sizes. The potential impact of violating the sample collection rules, or of using data sets in which sampling methods are not consistent, is probably similar to the limitations placed on direct comparison of diversity index values between samples of different size; ie a certain ‘fuzziness’ or lack of clarity is introduced into interpretation. This is obviously undesirable in an index that aims to describe ecological ‘health’ or status in clear-cut terms for environmental management purposes. The AMBI results appeared to indicate that ecological status had mostly declined in Langstone Harbour, mostly improved in Chichester Harbour, improved in Southampton Water and the Hamble, worsened in Newtown Harbour, and had remained similar or improved slightly on Calshot Spit in the West Solent. Bearing in mind the limitations of the historic data set outlined above in terms of variable sample size and collecting methods, and possibly the non-applicability of the method even to the present data set, these results should be treated with caution. Average taxonomic distinctness or AvTD was calculated for all samples in both data sets also, and the advantage of this procedure (based as it is on presence/absence data) is that it can be used on data derived from different sample sizes and collection methods. The results indicated that, for the 2005 data, AvTD was lower than expected at several sampling points in Langstone Harbour and at one or two stations from each of the other main survey sectors. On the evidence

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of Clarke & Warwick (1998), this could imply that some form of pollution or disturbance is affecting these stations. When applied to the previous survey data set, AvTD was lower than expected at two stations in Chichester Harbour and at one station in Southampton Water. Interestingly however, on the other hand, a below par AvTD was not evident at any of the historic Langstone Harbour stations, in contrast to the picture in 2005. On the basis of evidence from Clarke & Warwick (1998), the interpretation of this could be that most stations within the historic data set were unaffected by pollution or disturbance, whereas by 2005 the picture had changed to one where most of the Langstone stations and several from each of the other sectors were affected by pollution. Plainly, this runs counter to the qualitative observations made above, on the basis of numbers, species richness, and the dominant species present, that the macrofauna found in previous years appears similar to that sampled in 2005. Although the AvTD statistic has been shown to be relatively independent of sampling effort, one factor possibly contributing to the apparent changes between the historic and current data sets is differences in taxonomic treatment between different laboratories or identifiers. At its simplest, this could be differences in the degree to which personnel ‘lump’ or ‘split’ taxa within different phyla, or to which workers operate to different standards of taxonomic rigour (Clarke & Warwick 1998). An example of this might be the careful identification of oligochaete species in one survey, as opposed to lumping species together under the term ‘oligochaeta indet’ in another survey. AvTD has also been shown to vary with habitat, eg water depth, latitude (Ellingsen et al 2005), and this variation is different when considering a whole macrofaunal data set as opposed to discrete phyla (ie polychaetes, crustaceans or molluscs) on their own. 5.1.3 Condition assessment The Solent system is dynamic, and beach profile studies and aerial photographic time series taken over the last 50 years highlight a coastline morphology that is under continual change. The unstable and slumping clay or mudstone cliffs at the top of certain shore transects on the Isle of Wight provide evidence of this. This dynamism is also highlighted by the extensive coastal protection measures that have been put in place throughout the system over the last century, and which in turn are indicative of a high degree of anthropogenic influence on the marine environment generally. Against this moving background some change to the intertidal sediment flats across the Solent must have occurred within the approximately 30 year span of previous data that have been used for comparisons with the present survey. However, in qualitative terms, no significant changes in shore type or in sediment composition have been highlighted by the present study. With regard to the biological data, a basis for future monitoring has been established that incorporates assessment of the sediment surface and associated epibiota on a broad in scale with the more traditional quantitative point sampling approach. The former provides the context for the latter, and both have a valid place even though it is the quantitative methodology that will provide the most solid auditable monitoring trail. Examination of the basic species abundance data, in conjunction with univariate community statistics, has indicated that the macrobenthic communities present are similar in character to those reported from similar locations over the past 30 years. The use of the AMBI and AvTD metrics in comparing data sets has been inconclusive in the present study, but will provide useful supporting information in future monitoring work in which information has been gathered in a consistent fashion. There are no analytical tools, including AMBI and AvTD, that can be applied without an understanding of their underlying principles and shortcomings; and none can simply distinguish anthropogenic from natural change. This latter distinction is generally a qualitative judgement based on available evidence.

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From the data obtained in the present survey, the main indications of anthropogenic influence were those observed in the field such as commercial docks and jetties, marinas, moorings on mudflats, coastal defence constructions, municipal outfalls, evidence of bait digging, fishing and wildfowling, and walkers using the shore. Indicators of anthropogenic influence in the biological data obtained, however, would include the presence of wide areas of sediment flat covered by green algal mats (eg Withers 1980, Soulsby et al 1982) within most of the enclosed harbours, and the widespread domination of the macrofauna by tubificid oligochaetes. Polychaetes such as capitellids and certain cirratulids and spionids are often present in macrobenthic communities and are not necessarily indicative of huge organic enrichment. Capitella capitata occurred throughout the Solent intertidal, but occurred in high numbers at one or two localised quiescent areas in Langstone and Chichester Harbours (sometimes adjacent to centres of population such as at Emsworth or Bosham). Overall, anthropogenic influence is evident throughout the Solent Maritime SAC, but it appears to be at a level that has not resulted in noticeable change in the macrobenthos over the last 30 years or so.

5.2 Recommendations for future work • Based on the fieldwork experience gained in the present study, more time is needed to

complete the transect surveys. Time is required on the one hand for full application of Phase 1 survey methods (including the washing of spade fulls of sediment for in-situ assessment of the macrofauna). Intertidal sediment from all areas of the Solent Maritime SAC is heavy and sticky and cannot be sieved quickly, added to which the mudflats in the harbours are extensive, making it difficult to get access to water for washing samples. In addition, time is needed for survey staff to complete the write-up of their field notes in the same day. This also makes quality assurance of the data by the survey leader easier. Overall, for a similar type of mapping exercise as attempted in the present study, this could mean cutting the survey rate to two transects per team per day.

• For the mapping work, both at the planning stages and in the field, aerial photography

taken at low water is required. In the present survey, much of the coverage was taken at mid or high water so that the extent of the sediment features was not known in advance.

• The biotope classification system for intertidal sediments at present is based almost

exclusively on infaunal data. More development is needed to integrate the epibiota present on sediments with the infaunal data.

• The recommendations of Bunker et al (2003) regarding development of the AMBI

multimetric tool need to be implemented, with respect to the internal species list used in the data truncation process. In addition, clarity is required over the data collection methods it can accommodate, and limits of use to which it is suited.

• The underlying principles of statistics such as taxonomic distinctness and its derivatives,

and the limitations of their application, need to be understood in line with the literature on the topic that has grown since the publication of the most recent PRIMER manual.

• In future survey work of this kind, it might be useful to consider breaking the tasks down

differently. For example, Phase 1 mapping and Phase 2 sampling could be conducted together as in the present survey but only covering a single survey sector at a time. Alternatively the mapping could be split from the Phase 2 monitoring entirely, to simplify the sampling logistics.

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• In its present form, this fieldwork could not have taken place without hovercraft for transporting fieldworkers and samples. However, arranging access for these craft to certain parts of the Solent was difficult and time-consuming, due mainly to the anticipated impacts of noise. Permission for hovercraft access was not possible for one or two key areas for mudflats, in addition to which the bird interests in Langstone Harbour mean that hovercraft access is not possible for much of the summer sampling period. Reducing the scope of the survey, either task-wise or geographically or both, could enable the work to be achieved by means other than hovercraft, or possibly for aspects of it to be integrated with the Environment Agency sampling programme (which also uses hovercraft, and which could therefore assist with planning logistics).

• The quantitative sampling work requires more design work in terms of a survey strategy

and methodology, and the analytical methods to be employed, so that data can be collected as part of a repeatable monitoring series.

5.3 Conclusions • The main observable differences across the SAC occurred in the associated shore type and

sediments, and most of the differences apparent between areas in the Phase 1 biological data are substratum-related.

• In qualitative terms, no significant changes in shore type or in sediment composition have

been highlighted by the present study. • The Phase 1 data set collected shows that certain species observed in the field were

widespread in the SAC including the polychaetes Arenicola marina, the snail Hydrobia ulvae, the cockle Cerastoderma edule, fucoid algae, and the green alga Enteromorpha sp. Supporting forms included the ragworm Hediste diversicolor, juvenile shore crabs Carcinus maenas, winkles Littorina spp, the barnacles Semibalanus balanoides and Elminius modestus and the slipper limpet Crepidula fornicata.

• Although sediment flats were the feature of interest in the present study, almost half of the

33 biotopes identified were rocky shore biotopes due to the present of stones of various grades on the sediment surface. The most widespread biotopes were LS.LCS.Sh.BarSh, LS.LMu.MEst, LS.LMx, LS.LCS.Sh, LS,LSa.MuSa, LS.LMu and LR.LLR.FVS.Fcer.

• Over 100 taxa were identified from cores taken in the mid and lower shores at 21 transects.

Over the whole survey area, the macrofauna was characterised by the polychaetes Tharyx sp, Pygospio elegans, Eteone cf longa, Streblospio shrubsolii, Melinna palmata and Ampharete grubei, oligochaetes Tubificoides benedii and T pseudogaster (agg), the mud snail Hydrobia ulvae, and the bivalve molluscs Cerastoderma edule and Abra tenuis.

• The macrofauna was numerically dominated at nearly all stations by relatively large

numbers of just two or three taxa, mainly Hydrobia ulvae and Tubificoides benedii, and occasionally T pseudogaster (agg) also. The degree of this numerical dominance was highest in Langstone and Chichester Harbours, but decreased in Southampton Water and the Hamble and even more so in the West Solent. In the lower shore stations, the dominance of Hydrobia and Tubificoides benedii was generally lessened, except in Langstone Harbour and at one or two transects in Chichester. Such dominance may be indicative of anthropogenic disturbance, but such influences have been part of the ecology of the area for most of the 20th Century and no changes in recent years are indicated.

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• The range in biomass over all areas for the mid shore stations was 0.19 to 1,623.2 g/m2, and

that for the lower shore stations was 0.53 to 509.28 g/m2. Throughout the SAC the biomass was heavily dominated by molluscs, in particular by the cockle Cerastoderma edule and to a lesser extent by the snail Hydrobia ulvae.

• In addition to standard univariate and multivariate methods used for the analysis of the

macrofaunal data, the AMBI benthic classification process being developed for use by Agencies under the Water Framework Directive, was tried together with the average taxonomic distinctness routine available in the PRIMER package. These procedures were employed on the macrofaunal data collected as part of the present study, but in addition were used on a historical data set compiled from various studies carried out in the Solent over the last 30 years. The purpose of this was to make comparisons of current data with old data more than just a quick qualitative process.

• The results of analysis using AMBI indicated that changes in environmental quality had

taken place between the latter quarter of the 20th Century and the present day. Most of the changes in Langstone Harbour were negative, whilst changes over the rest of the Solent Maritime SAC were either neutral or positive in effect. However, caution is required in considering these results due to the sampling conditions specified in the user notes for the spreadsheet that are not met by the methods used in the present survey. In addition, the historical data set is built up from several studies carried out at different times and using various sample sizes, sieve meshes and methodologies. Quantiative comparisons drawn using such data sets are likely to be suspect.

• The average taxonomic distinctness approach, based on qualitative data, is independent of

the constraints of sample size and methodology. Results indicated that in the 2005 data set several stations, some located in Langstone Harbour, fell below the lower 95% confidence limit line of the expected taxonomic distribution. This could be indicative of changes in community structure, whether natural or anthropogenic. In contrast, results from applying the method to the historical data set indicated that very few of the sampled macrobenthic communities 10 to 25 years ago fell outside or below the 95% confidence limits of the expected taxonomic distribution. The implication is that changes have been taking place in the condition of intertidal sediment flat communities, when ‘expert eye’ assessment of the two data sets indicate how little change there appears to have been. However, it is possible that differences in the taxonomic approach to taxon identification and naming could have occurred between the two sets of data under comparison. The degree to which such differences in taxonomic treatment might have affected AvTD is not clear. Caution is advised in the application of this analysis and interpretation of its results. In addition, the need for consistency in the approach to sampling and analysis of macrofauna in a monitoring programme is highlighted.

• Overall, in qualitative terms, it is clear that differences probably occur from year to year in

the abundances of individual taxa. Due to variation in the data collection methods, timing of surveys (in relation to likely seasonal variation) and because station locations in the two data sets under comparison are only approximately similar, it is not feasible to be more precise about temporal variations in species presence, abundance or biomass. However, it is equally clear that the essential character of the macrofauna in the Solent system remains similar to that evident from previous studies.

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6 References BUCHANAN, J.B. 1984. Sediment Analysis. In IBP Handbook No 16. Methods for the Study of Marine Benthos. 2nd edition. Ed Holme NA & McIntyre AD, Blackwell Scientific Publications, Oxford. BORJA, A., FRANCO, J. & PEREZ, V. 2000. A marine biotic index to establish the ecological quality of soft-bottom benthos within European estuarine and coastal environments. Marine Pollution Bulletin, 40. 1100 to 1114. BUNKER, F., HOWSON, C. & MERCER, T. 2003. On the use of two functional biotic indices in English Nature Condition assessments. A report to English Nature from Aquatic Survey and Monitoring Ltd. BRITISH GEOLOGICAL SURVEY 1996. Sediment transport. In: J.H. BARNE, C.F. ROBSON, S.S. KAZNOWSKA, J.P. DOODY & N.C. DAVIDSON, eds. Region 9 Southern England: Hayling Island to Lyme Regis. Joint Nature Conservation Committee, Peterborough (Coasts and seas of the United Kingdom Series). CLARKE, K.R. & WARWICK, R.M. 1998. A taxonomic distinctness index and its statistical properties. Journal of Applied Ecology, 35, 523-531. CLARKE, K.R. & WARWICK, R.M. 2001. A further biodiversity index applicable to species lists: variation in taxonomic distinctness. Marine Ecology Progress Series, 216, 265-278. CLARKE, K.R. & GORLEY, R.N. 2001. Primer v5: User Manual/Tutorial, Primer-E: Plymouth. CONNOR, D.W., DALKIN, M.J., HILL, T.O., HOLT, R.H.F. & SANDERSON, W.G. 1997a. Marine Nature Conservation Review: marine biotope classification for Britain and Ireland. Volume 1. Littoral biotopes. Version 97.06. Joint Nature Conservation Committee, Peterborough. Report no 229. CONNOR, D.W., DALKIN, M.J., HILL, T.O., HOLT, R.H.F. & SANDERSON, W.G. 1997b. Marine Nature Conservation Review: marine biotope classification for Britain and Ireland. Volume 2. Sublittoral biotopes. Version 97.06. Joint Nature Conservation Committee, Peterborough. Report no 230. CONNOR, D., ALLEN, J., GOLDING, N., HOWELL, K., LIEBERKNECHT, L., NORTHERN, K. & REKER, J. 2004. The Marine Habitat Classification for Britain and Ireland. Version 04.05 2004, JNCC, Peterborough, ISBN 1 861 07561 8 (internet version) http://www.jncc.gov.uk/MarineHabitatClassification/ COVEY, R. 1998. Eastern Channel (Folkstone to Durlston Head) (MNCR Section 7). In: K. HISCOCK, ed. Marine Nature Conservation Review. Benthic marine ecosystems of Great Britain and the north-east Atlantic. Joint Nature Conservation Committee, Peterborough (Coasts and Seas of the United Kingdom. MNCR Series). DAVIDSON, N.C. 1996. Estuaries. In: J.H. BARNE, C.F. ROBSON, S.S. KAZNOWSKA, J.P. DOODY & N.C. DAVIDSON, eds. Region 9 Southern England: Hayling Island to Lyme Regis. Joint Nature Conservation Committee, Peterborough (Coasts and seas of the United Kingdom Series).

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DIXON, I. & MOORE, J. 1987. Survey of Harbours, Rias and Estuaries in Southern Britain: The Solent System (Volume 1). A report to the Nature Conservancy Council from the Field Studies Council Oil Pollution Research Unit (CSD report no 723). ELLSINGEN, K.E., CLARKE, K.R., SOMERFIELD, P.J. & WARWICK R.M. 2005. Taxonomic distinctness as a measure of diversity applied over a large scale: the benthos of the Norwegian continental shelf. Journal of Animal Ecology, 74, 1069-1079. Emu 2004. Solent Bird Invertebrate Prey Availability Study. Draft Final, February 2004. Contract No: FIN/TO3/01 – Solent European Marine Site – Monitoring of Bird Invertebrate Prey. Emu Report No: 01/J/1/06/0575 ENGLISH NATURE 2005. English Nature: Nature on the Map website (Accessed December 2005). www.natureonthemap.org.uk ENVIRONMENT AGENCY 2004. Solent CASI Survey (Project PM-0202). FOSTER-SMITH, R.L., DAVIES, J. & SOTHERAN, I. 2000. Broad Scale Remote Survey and Mapping of Sublittoral Habitats and Biota: technical report of the Broad scale Mapping Project. Scottish Natural Heritage Research, Survey and Monitoring Report no 167. GRAY, A.J., SNAZELL, R.G., MOY, I.L. & WARMAN, E.A. 1991. The Solent: Ecological Sensitivity Analysis of the Shoreline. Report by the Institute of Terrestrial Ecology, Natural Environment Research Council. HOLME, N.A. & BISHOP, G.M. 1980. Survey of the Littoral zone of the Coast of Great Britain. 5. Report of the Sediment Shore of Dorset, Hampshire and the Isle of Wight. Report for the Nature Conservancy Council (CSD report no 280). HOWARD, S., MOORE, J. & DIXON, I. 1988. Survey of Harbours, Rias and Estuaries in Southern Britain: Newtown and Bembridge Harbours (Volume 1). A report to the Nature Conservancy Council from the Field Studies Council Oil Pollution Research Unit (CSD report no 852). HOWSON, C.M. & PICTON, B. (1997). The Species Directory of the Marine Fauna and Flora of the British Isles and Surrounding Seas. Marine Conservation Society. 508 pages. HOWSON, CM. (1987). Species Directory of the British Marine Fauna and Flora. Marine Conservation Society, Ross-on Wye. 471pp. JOHNSTON, C.M. 1989. Survey of Harbours, Rias and Estuaries in Southern Britain: Minor South Coast Inlets. A report to the Nature Conservancy Council from the Field Studies Council Oil Pollution Research Unit (CSD report no 978). PEARSON T.H. & ROSENBERG, R. 1978. Macrobenthic succession in relation to organic enrichment and pollution of the marine environment. Oceanography and Marine Biology Annual Review, 16, 229-311. RANDALL, R.E. 1966. Vegetated shingle structures and shorelines. In: BARNE, J.H., ROBSON, C.F., KAZNOWSKA, S.S., DOODY, J.P. & N.C. DAVIDSON, eds. Region 9 Southern England: Hayling Island to Lyme Regis. Joint Nature Conservation Committee, Peterborough (Coasts and seas of the United Kingdom Series).

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ROLPH (UNPUBLISHED). DIVCALC. Software commissioned by ERT for analysis of benthic community structure. SOULSBY, P.G., LOWTHION, D. & HOWSTON M., 1982. Effects of macroalgal mats on the ecology of intertidal mudflats. Marine Pollution Bulletin 13, 162-166. SOUTHAMPTON UNIVERSITY, 1987. The Solent Estuary. Environmental Background. Publication prepared for Shell UK Ltd. THOMAS, N.S. 1986. Aspects of the ecology of the macroinvertebrates of the intertidal zone of Chichester Harbour. PhD Thesis, Portsmouth Polytechnic. Cited in: K. HISCOCK, ed. Marine Nature Conservation Review. Benthic marine ecosystems of Great Britain and the north-east Atlantic. Joint Nature Conservation Committee, Peterborough (Coasts and Seas of the United Kingdom. MNCR Series). THOMAS, N.S. & CULLEY, M.B. 1981. The macroinvertebrates in the intertidal soft sediments of Chichester Harbour. Report of the Nature Conservancy Council (CSD report no 383). TUBBS, C.R. 1975. Langstone Harbour, Hampshire. A review of its ecology and conservation objectives. Unpublished report for the Nature Conservancy Council, South Region. UNICOMARINE & REES-JONES, S. 2004. Habitats Directive - Stage 3 Review of Consents (Technical report). Impact of effluent discharges on the intertidal benthic community in the Solent Maritime European site. Report undertaken by the Southern Region Environment Agency. WARWICK, R.M. & CLARKE, K.R. 1998. Taxonomic distinctness and environmental assessment. Journal of Applied Ecology, 35, 532-543. WITHERS, R.G. 1976. The Marine Macrofauna and Flora of the Medina Estuary. Proceedings of the Isle of Wight Natural History and Archaeological Society, 7. 19 to 30. WITHERS R.G., 1980. The macro-invertebrate fauna of the mudflats of Eastney Lake (Langstone Harbour). Journal of the Portsmouth & District Natural History Society, 3 (2), 59-67. WITHERS, R.G. & THORP, C.H. 1978. The macrobenthos inhabiting sandbanks in Langstone Harbour, Hampshire. Journal of Natural History, 12. 445 to 455.

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