USE OF THE SYRPH THE NET DATABASE 2000 - · PDF fileUSE OF THE SYRPH THE NET DATABASE 2000 Chapter 1. INTRODUCTION ... Verneaux et al., 1982; Wright et al., 1984; Foeckler, 1991)

USE OF THE SYRPH THE NET DATABASE 2000

M.C.D.Speight, E.Castella & P. Obrdlik

SYRPH THE NET: THE DATABASE OF EUROPEAN SYRPHIDAE(DIPTERA)

Volume 25

Series Editors:Martin C.D.Speight, Emmanuel Castella, Petr Obrdlik & Stuart Ball


M.C.D.SpeightResearch Branch, National Parks and Wildlife,

7 Ely Place, Dublin 2, Ireland

E.Castella, Laboratoire d'Ecologie et de Biologie Aquatique, Université de Genève,

18 chemin des Clochettes, CH - 1206 GENEVE, SWITZERLAND

P.ObrdlikWWF Auen Institut, Josefstraße 1,

D-7550 RASTATT, GERMANY

Syrph the Net: the database of European Syrphidae (Diptera)Volume 25

Speight, M.C.D., Castella, E., Obrdlik, P. and Ball, S. (eds.)2000

compilation of the Syrph the Net database received funding from:contract STEP/CT90/0084 (Science and Technology for Environmental Protection),European Commission

this publication may be referred to as:

Speight, M.C.D., Castella, E. & Obrdlik, P. (2000) Use of the Syrph the Net database2000. In: Speight, M.C.D., Castella, E., Obrdlik, P. and Ball, S. (eds.) Syrph the Net, thedatabase of European Syrphidae , vol.25, 99 pp., Syrph the Net publications, Dublin

ISSN 1393-4546 (Series)

Syrph the Net PublicationsDublin2000© M.C.D.Speight 2000


CONTENTS

Preface

Chapter 1: INTRODUCTION

1.1. Invertebrates in environmental interpretation and evaluation1.2. The basic approach adopted in the syrphid database1.3. The ingredients of the predictive process1.3.1. Regional lists1.3.2. Syrphid Habitats1.4. Modelling1.5. Origin and development of the syrphid database

Chapter 2: FIELD PROCEDURES

2.1. Site description2.1.1. Use of the Habitat Survey Form2.2. Field-sampling procedures2.2.1. Placing of Malaise traps2.2.2. Sample collection and trap maintenance

2.2.3. Field sampling strategy: obtaining representative samples ofsite faunas

2.2.3.1. Choice of sampling period2.2.3.2. Duration of field campaigns2.2.4. Inventory survey

Chapter 3: LABORATORY PROCEDURES

3.1. Treatment of samples3.2. Determination of sorted specimens3.3. Recording the determined specimens

Chapter 4: DATA PROCESSING PROCEDURES

4.1. Field data files4.2. The basic site interpretation procedure4.3. Statistical/analytical techniques4.3.1. Use of multivariate ordination techniques with the database4.3.1.1. Reciprocal ordination of the species and sampling stations

4.3.1.2. Reciprocal ordination of the species and their attributes4.3.1.3. Simultaneous ordination of two matrices

Chapter 5: APPLICATIONS OF THE DATABASE

5.1 Application of the FAEWE procedure for assessment of the “ecosystemmaintenance” function of a site5.1.1. The functional assessment procedure (FAP)5.1.2. Salient features of the functional assessment procedure

5.2. Use of the database in general site management5.2.1. Use of the database in site restoration5.2.1.1. Replacement of missing ecosystem components5.2.1.2. Replacement of one ecosystem by another

5.3. Comparisons between regional lists

Chapter 6. PROGRESS & LIMITATIONS

REFERENCES

Appendix 1. Habitat Survey Form

Appendix 2. Nomenclaturally complete species list

Appendix 3. Taxonomic literature: genera keyed out by major works

1

PREFACE

By far the greater part of this volume has been culled from material already published bythe authors (see Castella and Speight 1996, Castella et al 1994, Murphy et al 1994,Speight 1996b, Speight 1997, Speight and Castella 1995), though the published materialhas had to be augmented to provide a coherent picture. It is not intended as a manual forthe interrogation of the syrphid database, but more as a collection of examples ofpotential usage, together with suggestions on how field, laboratory and interpretationwork might be standardised to serve particular objectives. It is assumed that the potentialuser has a familiarity with the manipulation of Excel spreadsheets, or access toinstruction manuals on their use. The first version of the database was produced for use inan EU funded research project which formed part of the STEP programme. This project,the “Functional Analysis of European Wetland Ecosystems” project, or FAEWE project,is referred to at various points in the present text.

2


Chapter 1. INTRODUCTION

The syrphid database has been set up for use as a tool in:a) environmental interpretation,b) site evaluation/management,c) the study of Syrphidae.

It comprises a series of spreadsheets and text files grouped into volumes, each of whichdeals with a particular topic. The topics covered so far are:Species accountsMacrohabitatsMicrosite featuresTraitsRange and StatusUse of the database

The Species Accounts volume is text throughout, but the other volumes each include bothtext and spreadsheet files, as is the case in the present volume, which is focused broadlyon use of the database. Details of the coverage of each volume are given in anintroductory text at the beginning of each volume, and are not repeated here. A readmefile is provided to help the user associate the constituent files of each volume of thedatabase correctly. More than 550 European syrphid species are now covered by thedatabase, out of a total European fauna of c750 species.

The spreadsheets have been created, saved and used in an Excel™ spreadsheetenvironment. Excel has been used because it allows maximal flexibility of use of the filessubsequently. Any user who has need to repeatedly interrogate the database in a specificway can convert the files into, for example, Microsoft Access files and constructwhatever database management system best suits his/her requirements for speeding upthe interrogation process.

The spreadsheets provide a digitised transcription of information available about thespecies considered. Information digitisation has been carried out using the system

3

proposed by Bournaud et al. (1982), where 4 integer values are used to describe thedegree of association between a species and the categories of a variable, for example, thecategories of a habitat variable in the Macrohabitats file:0 - no association,1- minimal association (i.e. the habitat category is only marginally used by the species);2- medium association (i.e. the habitat category is part of the normal range of the

species);3- maximal association (i.e. the habitat category is optimally preferred by the species).

The link between the spreadsheet files is provided by the species list, which is commonto all of them, allowing sections of different spreadsheets to be joined together asrequired. A nomenclaturally correct list of the species covered by the database is alsogiven, in Appendix 2 to the present volume..

Up to now, the need to regionalise the information about species coded into thespreadsheets has proved minimal. The most notable exception is coding of the flightperiod data in the Traits file. Variation in the length and timing of the flight period ofmany species, in different parts of Europe covered by the database, is sufficient tosignificantly reduce species predictability, were only a generalised flight period to becoded for each species. This has led to inclusion of sets of regional flight period codingsfor each species. Unfortunately, regional flight period data are not available for all partsof Europe covered by the database, so that generalised flight period coding still has to beused for some parts. It is anticipated that, as the coverage provided by the databaseexpands, so will the need to progressively regionalise the coded habitat data. Already,certain habitat categories covered by the Macrohabitats file are only found in parts of thegeographic area covered by the database. The most obvious examples are coastal habitatcategories.

Although the main bulk of the present volume has been culled from material alreadypublished by the authors, it goes considerably beyond what has been published,particularly in its provision of background information.

So far, this introduction has been concerned primarily with the anatomy and coverage ofthe database, but it was felt that an attempt should be made to also present something ofthe philosophy behind the database, and the remainder of the Introduction is devoted to

4

that and allied issues. The database is essentially a tool for use in interpretation of datagathered in the field, so Chapter 2 of this volume is concerned with preferred fieldtechniques employed for collecting adult syrphids, and their standardisation. It does notrepresent a review of all sampling methods currently in use. No attempt has been made toreview procedures for sampling syrphid larvae in the field - although techniques arearguably available for use in a limited range of habitat/micro-habitat types, standardisedlarval collection methods are otherwise non-existent, or require substantial research effortto increase their reliability to an acceptable level. In Chapter 3 the processing of field-collected material is considered. Once again, this is not an attempt to review all availablealternatives, but more an outline of a tried and trusted approach, which may be adoptedby those wishing to deal with syrphid material collected using the techniques described inChapter 2. Chapter 4 focuses on manipulation of the spreadsheets and a particularstatistical treatment of results which is of potentially wide application in use of thedatabase. Chapter 5 provides examples of use of the database in various contexts,demonstrating, in particular, what can be achieved without recourse to statistics beyondproduction of the humble histogram. The volume concludes with an overview of thedatabase’s progress to-date, in Chapter 6. Three appendices to the volume are provided,in the form of Excel files. These are referred to at appropriate points in the main body ofthe text: Appendix 1 under section 2.1.1; Appendices 2 and 3 under section 3.2.

1.1. Invertebrates in environmental interpretation and evaluation.

The invertebrates play key roles in wetland ecosystem functions and processes (e.g.decomposition of organic matter, flower pollination, predation). They are also able toprovide a holistic picture of the interaction between fundamental ecological processes andto rapidly adjust their occurrence and abundance following modification of theirenvironment. Therefore, several invertebrate-based systems of bioevaluation have beendeveloped. Examples for the aquatic environments are well known (Sladecek, 1973;Verneaux et al., 1982; Wright et al., 1984; Foeckler, 1991). Among terrestrialinvertebrates, some groups, such as the carabid beetles, have been repeatedly used for siteevaluation purposes Refseth, 1980; Luff, 1987; Eyre & Rushton, 1989; Stork, 1990).Furthermore, invertebrates have frequently been addressed in integrated studies ofalluvial wetland systems, an example of which is the comprehensive study of the SouthMoravian floodplain forests in Czechoslovakia (Penka et al.; 1985, 1991).

5

Use of invertebrates in evaluation of terrestrial sites has been explored by variousauthors, using a variety of different approaches. Disney (1986) and Day (1987) focusedon comparison between sites. Decleer (1990) and Brunel et al. (1990) concernedthemselves with comparison between different parts of one site. Some authors (eg.Disney, 1986; Speight, 1986; Eyre et al., 1986) considered the relative suitability ofdifferent taxonomic groups for use in such studies. Siepel (1989) has sought to establish amethod for assessing the efficiency of individual species as tools in site evaluation. Morefrequently, authors simply employ taxonomic groups known to them, without comment.

In Europe, the Syrphidae meet most of the criteria listed by Speight (1986), for selectionof insect groups to use in site evaluation processes and additional criteria recognisedmore recently:a) Less than 5% of the genera pose significant identification problems and the taxonomicliterature is readily accessible, although scattered. The species may be identified usingexternal morphology. Following extensive revisionary work in the period 1960-80 andappearance of the relevant volume of the Catalogue of Palaearctic Diptera (Peck, 1988), areliable nomenclature has emerged which is increasingly being used by Europeanworkers.b) Reliable, recent, species lists are available for various European countries, especiallyin western Europe and the entire European fauna has been catalogued recently (Peck,1988), totaling approximately 700 species. There has been no pan-European study toestablish to which IUCN status category each species should be consigned, but mostrecently-published national lists provide status data.c) Ecological information about the species is generally sufficient to characterise theirhabitat associations in terms of generally understood habitat categories and todemonstrate that the species exhibit a high degree of ecological fidelity. Syrphid faunasoccur in nearly all terrestrial and freshwater habitats except cave systems, main channelsof rivers and open waters of lakes. Larval microhabitat may be characterised for nearlyall species.d) The range of generation times exhibited by different species (8 weeks to 2 years),coupled with their rapid mobility and various microhabitat preferences, results in thesyrphid species on a site providing information about both short (e.g. seasonal) andlonger term changes in site conditions.e) On-site sampling of Syrphidae can be standardised and carried out over short periodsusing commercially-available equipment. Storage of samples is undemanding in terms of

6

space, labour and facilities and processing of samples is rapid, such that complete resultscan be obtained within two months of a standard site visit.

1.2. The basic approach adopted in the syrphid database.

The keystone concept behind the data files and their structure is that enough is known ofthe habitat associations and other attributes of European Syrphidae for the syrphid faunaof a site to be predicted, from a knowledge of the habitats present on-site and the speciesrecorded from the part of Europe in which the site is located. But the information codedinto the database provides for a wide range of applications at site, landscape, regional,national and international levels. Such information is largely unused in traditional formsof treatment of species lists, in which the species names simply become integers in alargely statistical operation, divorced from all other information about the speciesthemselves. In those circumstances, the questions which can be addressed are largelystatistical rather than biological in nature and are circumscribed by the limitations ofstatistical techniques, rather than those of biological information, with analyses truncatedby the difficulties of dealing with species represented by both large numbers ofspecimens or very few specimens, and numbers of specimens collected being regarded asof greater significance than the biology of the species they represent. The files in thesyrphid database are structured to maximise the use of the biological information aboutthe species, enabling the biological attributes of species collected to be compared andanalysed, not just the relative frequency of the species. The attributes of predicted speciescan also be compared and analysed. The predictive process is equivalent to putting theEuropean syrphid fauna through a series of sieves, with the species which pass throughall of the sieves together constituting the final predicted species list. It is repeatedlyreferred to in different sections of this text.

1.3. The ingredients of the predictive process.

The predictive capabilities of the database can be used in various ways, only some ofwhich will be explored in this volume. Its basic use is in conjunction with species listsderived from individual sites, such as protected areas or other areas in a natural/semi-natural condition. Interpretation of such species lists is liable to be of interest to a widerange of potential users of the database, from syrphid specialist to land manager andenvironmental consultant, and is judged to become one of the most frequent applications

7

of the database. So for introducing the predictive process, the approach to predicting asite species list is used here. In order to run a basic prediction of the syrphid fauna of asite, two sets of information are needed:

a) a reliable species list for the region within which the site is located,b) a list of the syrphid habitats occurring on the site.

Use of a predictive mechanism based on a species pool makes this approach akin tocertain others, such as the English system used in running water assessment (Wright etal., 1984), or the "assembly rules" approach proposed by Keddy (1992).

1.3.1. Regional lists

A basic premise of the predictive process is that the fauna of a site is a sub-set of thefauna occurring in the “region” within which the site is located, i.e. that the site fauna isderived from the species pool of that region. The species pool relevant to a particularprediction process varies in its geographic coverage with the geographic scale at whichthe database is being used. Thus, for considering the significance of a site at Europeanscale, the fauna of the entire land mass of Europe would be the appropriate species pool,while for considering its significance at national level the national species list would bethe relevant species pool. For considering the management of a site within a NationalPark, the faunal list for the National Park might be the appropriate species pool.

During course of the FAEWE project regional species lists were needed for Ireland andcentral France. For Ireland, the list existed already and required only a small amount ofupdating (Speight & Nash, 1993, Maibach et al, 1994, Speight & Chandler, 1995,Speight, 1996a). For central France, the nomenclatural confusion surrounding theexisting national list made production of a regional list impossible, without firstestablishing a verifiable list for the country as a whole. Revision of the French list tookfive years (Speight, 1993, 1994; Speight et al, 1998). The subsequently publishedregional list for central France (Speight, 1996b) comprised 223 species.Similarendeavours may be needed to produce reliable regional lists for other parts of Europewhere the database is employed, although various lists are in existence already and mayonly require updating. A range of available national and other regional lists isincorporated into the database in the Range and Status volume.

8

1.3.2. Syrphid Habitats.

The array of syrphid habitats covered by the database is detailed in the Macrohabitatsvolume, which also discusses the difficulties of deriving generally applicable habitatcategories. The habitat concept employed is essentially that its habitat is where a speciescan live out its entire life cycle. The term habitat is not employed simply as an expressionof where the adults of a syrphid species can be found. Adult habitats in that sense aredetailed in the Species Accounts volume. Each habitat category used is defined in theMacrohabitats volume, in the Glossary of Macrohabitat categories, which also shows theextent to which the categories recognised coincide with habitat categories recognised inthe CORINE system ( and hence the EU Habitats Directive). The coverage is aimedprimarily at so-called natural/semi-natural habitats and the database is least effective inlandscape intensively used by man, because of the difficulties of identifying meaningfulhabitat categories. For instance, one man-made landscape feature which is easilyrecognisable is a quarry. However, if an attempt is made to code species according to thelikelihood of their occurrence in quarries, it becomes immediately apparent that thecondition of the quarry is more important than the fact that it is a quarry. A partially-flooded quarry will potentially support some species associated with temporary orpermanent pools, while its sloping side-walls may support some species of dry grassland.It is more effective to classify the habitat representation on such totally artificial sitesaccording to its most similar natural analogues, so that a quarry might be regarded as drygrassland with temporary or permanent pools. But even then, prediction of the associatedspecies is not reliable, because man-made sites include combinations of features whichdo not occur naturally, as well as features which do not occur at all under naturalconditions.

In order to obtain a knowledge of the syrphid habitats occurring on a site it is necessaryto conduct a habitat survey. A habitat survey procedure is detailed later in this text, in thesection relating to Field Procedures.

9

1.4. Modelling

Use of the syrphid database does not involved modelling as generally perceived.However, prediction of a site fauna depends upon a form of modelling of the site, inwhich salient site characteristics are observed and recorded in a standardised manner,using a classified system of habitat categories readily accessible to interpretation by thehuman eye and capable of differentiating a wide range of biotopes/ecosystems and theircomponents from one another. These particular habitat categories have been selected alsobecause syrphids respond to them i.e. they are features which may be used to describedifferences between these species in their habitat requirements. Using the habitat datacollected on-site in conjunction with the database thus involves a form of reconstructionof the site within the machine, linking each of the species in the database to thatconstruction by means of the degree of association between the habitats and each species,as coded into the data files. This albeit crude model of the site is thus produced completewith its associated syrphid fauna, providing the prediction mechanism.

1.5. Origin and development of the syrphid database.

The syrphid database was developed during the STEP programme of the EU, under theproject on Functional Analysis of European Wetland Ecosystems (FAEWE). Threetaxonomic groups of invertebrates were employed as tools in the FAEWE project,Carabidae (Coleoptera), gastropod molluscs (excluding slugs of the families Milacidae,Limacidae, Agrolimacidae, Boettgerillidae and Arionidae) and Syrphidae (Diptera).Together, these groups comprised more than 700 species, in the geographic areas coveredby the project (Ireland and central France). The method of their use was to transcribebiological and other information about them into databases and then design a procedurefor interrogation of the databases in a prescribed fashion, in order to provide non-specialists with a mechanism for interpretation of invertebrate species lists, in particularspecies lists derived from sites located on river floodplains. For purposes of that project,database interrogation was progressively focused upon gaining an overview of a site’scondition, in terms of its degree of function in maintaining biodiversity as expressed byits invertebrate fauna, in so far as this may be adduced from the taxonomic groupscovered.

10

In focusing upon assessment of site function in maintaining biodiversity, the immediateobjective of the invertebrate studies of the FAEWE project was design and testing of amechanism for integrating invertebrates into the functional analysis procedure being setup for the FAEWE project in general. This mechanism took the form of a “decision tree”,which allows a standardised form of interrogation of the database, and its use is shownlater in this text.

At the end of the FAEWE project, the syrphid database was simply a set of Excelspreadsheets covering the syrphid faunas of Ireland and Central France, unusable as areferenced source of information and with an uncertain future. Since then, the coverageof the Excel files has been extended to the syrphid fauna of the entire Atlantic zone ofEurope and beyond, a text file of species accounts of all the species covered has beenprepared to accompany the spreadsheets and these files, together with explanatorymaterial and the present text on use of the database, have together been published, so thatthe database may be cited by its users.

The 1999 version of the database covers the syrphid faunas and habitats of the Centraland Atlantic Regions of the EU, and extends to provide partial coverage of theMediterranean and Northern Regions. The material in the existing files is updatedannually, to keep abreast of developments in our knowledge of the species, and to takeaccount of criticisms and comments received. In an attempt to provide an automatedoutlet for dissemination of information about the database, a demonstration version wasinstalled on an internet website shortly after termination of the FAEWE project. It was atthis stage that the database acquired the name “Syrph the Net”.

11

Chapter 2. FIELD PROCEDURES

Field information of two types is used with the database: information about the characterof the target site(s) and samples or inventories of the on-site syrphid fauna. In thiscontext, a site may be defined as a piece of ground forming the object of a study orinquiry. As such, it is not necessarily a homogenous patch of a single habitat typerecognised in the database, and field survey requires to be adapted to the degree ofheterogeneity exhibited by the terrain under examination. Essentially, each habitat typerepresented requires both recording and sampling.

2.1. Site description.

This procedure is based on use of the Habitat Survey form provided in Appendix 1.Although it is possible to gain information on which syrphid habitats are present on asite, from surveys carried out by, for instance, botanists, the product is not usuallysatisfactory for use with the syrphid database, so that a habitat survey based on use of theHabitat Survey form is normally necessary, whatever other forms of habitat survey havebeen carried out on a site to serve the needs of other disciplines..

2.1.1. Use of the Habitat Survey Form

A Habitat Survey form was first provided as part of the 1998 version of the database. Ithas since been redesigned, because the previous version proved awkward to handle in thefield and required a lot of space, if stored for reference purposes. The revised versionrequires a record to be made of the the habitats observed per sampling station, aspreviously, but recording the habitats by means of their code-numbers has reduced thesize of each form to a single sheet. For easy reference to the code numbers for habitatcategories, and to match habitats on-site with those in the database, it is necessary to takeinto the field not only copies of the Habitat Survey form, but also a print-out of theSummary Table of habitat categories used in the Macrohabitats spreadsheet (which liststhe habitats and their code numbers). That Summary Table may be found in theMacrohabitat Associations text file. Use of the Habitat Survey form has alsodemonstrated that it is invaluable to have the Glossary of Macrohabitat Categories (alsoin the Macrohabitat Associations text file) available, while filling out the form in thefield. This is particularly necessary because observers often have different interpretations

12

of habitats, but in order to use the database to maximum advantage it is necessary to usethe interpretations laid out in the Glossary of Macrohabitat Categories.

The Habitat Survey form should be filled out in the field, while on-site. Experienceshows that completion of the form for up to ten different locations on a site can beachieved in a day (once some familiarity has been gained with use of the form it may becompleted for one sampling station within 10 minutes - the time taken to carry out a sitehabitat survey is dependent more upon the distance between sampling stations than onthe time taken to fill out the form), and may be carried out at almost any time of the yearthat the site is not either flooded or covered in snow, though best results can be expectedduring the growing season for local vegetation. A complication is provided by temporarywater bodies, which may add significantly to the diversity of a syrphid fauna, but which,by definition, are only observable at certain times of the year. Ideally, habitat surveywould be carried out twice on a site, once during the period of annual high water-levelfor ground-water and then again during time of low ground-water level. Failure torecognise the presence of temporary water bodies (seasonal streams, springs, flushes andpools) can lead to significant under-prediction of a site fauna and consequent failure torecognise the potential for some of the species recorded from a site to actually breedthere.

Completion of Habitat Survey forms well in advance of any sampling programme can bevaluable, in that it allows prediction of the most appropriate periods of the year in whichsampling programmes might be conducted, from the information on seasonal availabilityof the predicted fauna provided in the Flight Period tables in the Traits spreadsheet.

Some general habitat categories are un-necessary to record in the field, because theirpresence can be adduced from the presence of other recorded categories. For instance, ifcategory 11211 (mesophilous Fagus forest) is recorded for a site, on a Habitat SurveyForm, this automatically means that the more general categories 1121 (Fagus forest), 112(mesophilous/humid deciduous forest), 11 (deciduous forest) and 1 (forest) can berecorded from the site, so these categories do not require to be separately recorded on theform.

On the Habitat Survey Form, the categories to be recorded are of two types,macrohabitats and supplementary habitats, as in the Macrohabitats file. The form allows

13

recording of each supplementary habitat found in association with a macrohabitat. It isnecessary that the supplementary habitats associated with each macrohabitat arerecorded, since these associations have a significant influence on the potentialconstitution of a site fauna. For instance, a brookside in grassland can have a verydifferent associated syrphid fauna from a brookside under the canopy of a forest, and abrook may pass from within a forest out into grassland within one site, or be present on asite in association with one of those macrohabitats but not the other.

In order to record the data collected on Habitat Survey Forms it is advisable to set up aseparate Excel file of the Macrohabitat categories in the Macrohabitats file, into whichthe site survey data can be transcribed.

2.2. Field-sampling procedures

In the case of Syrphidae, field-sampling is dependent upon collection of the flightedadults. For operating the database, sampling procedure has been standardised around useof the Malaise trap as the sample unit. The relative efficiency of various trap designs inthe capture of different sorts of flying insect is reviewed by Southwood (1978) andMuirhead-Thomson (1991).These authors do not specifically consider trap efficiency inrelation to capture of Syrphidae, but they do demonstrate that any trapping mechanismhas its own bias and that each taxonomic group responds somewhat differently to anyparticular trapping technique and regime. In deciding upon the Malaise trap as thestandard sampling unit to use for Syrphidae, the following points were taken intoconsideration:a) analysis of results is dependent upon adequate samples of the local fauna, not acomplete inventory of the local fauna,b) The analysis procedures employed depend primarily upon use of presence/absencedata,c) Ease of transport of trapping equipment to and from possibly remote sites, rapidity ofinstallation and removal of trapping equipment and ease of servicing of equipmentinstalled are all of primary concern,d) Rapidity and simplicity of sample handling is important.

Little information about use of Malaise traps is yet available in the literature.Thestandard, commercially available Malaise trap can be erected and maintained by non-

14

specialists, with very little prior training. Similarly, on-site servicing of the traps andsample collection can be carried out swiftly and simply by non-specialists. Further, theplastic bottles attached to the traps, and into which samples are collected, can be used fortransport of the samples and for storage throughout the sample processing phase. Whileinstalled on a Malaise trap, a collection bottle is part-filled with 70% alcohol or somesimilar preservative, into which the collected specimens fall.This also provides forpreservation of the sample during transport from the field and subsequent laboratoryprocessing. There is thus no need for transfer of samples from one container to another,from the time the bottle is installed on the trap until it is in use in the laboratory.Collection of samples and their transport can be carried out by non-specialist personnel.

While there is no standardised methodology for use of Malaise traps in sampling syrphidfaunas, various applications of Malaise trap survey to work on Syrphidae are exemplifiedin the literature, from the scale of national distribution survey (e.g. Verlinden andDecleer, 1987) to site investigations (e.g. Haslett, 1988). Other authors have used watertraps (e.g. Chemini et al, 1983), or hand nets (e.g. Kassebeer, 1993; Marcos-Garcia,1990), but in these cases longitudinal surveys have been undertaken, carried outintermittently over months or even years. On adequately protected sites where agreementwith land owners has been reached as to when and where a Malaise trap survey will takeplace, the Malaise trap provides rapid results without requiring constant on-site presenceof a specialist (as required for hand-net survey) or frequent collection of samples and trapmaintenance (as is required for water-trap survey). On inadequately protected sites,Malaise traps, being highly visible structures in most landscapes, are highly susceptibleto vandalism or removal and to damage by livestock.

2.2.1 Placing of Malaise traps.

Where and whether insects fly is determined by many factors, including climate, time ofday and site topography. When in flight they are not evenly distributed, within thatfraction of the air column above a site intruded upon by flight interception traps like theMalaise trap. The position in which a Malaise trap is installed and its orientation thusinfluence its efficiency. Basically, Malaise traps can be positioned either on or off flightlines and either orientated or not along a north/south axis. Flight lines are largely dictatedby local micro-topography and the location and direction of many of them can bedetected by human eye, from juxtaposition of site features. It is evident from the work of

15

authors such as Aubert et al (1976) and Gatter and Schmid (1990) that positioning aMalaise trap across a flight line maximises the catch of syrphids flying through a sitefrom elsewhere (including migrators). Conversely, placing a trap off flight linesmaximises the catch of syrphids engaged in local, on-site movements. Orienting a trapnorth/south, with its high point facing south, maximises catches of insects liable to flytowards the point of highest light intensity (i.e. the sun) on contact with a trap (i.e.heliophile, day-flying insects like syrphids). Trap alignment in a north/south directioncan be achieved using a compass.

Site factors operating over short periods can also have a significant effect on Malaise trapcatches, for instance a large patch of some low-growing plant which comes into bloom inthe vicinity of a trap during a trapping campaign can greatly increase the number ofsyrphids caught. Conversely , the efficiency of Malaise traps left in situ for an entireflight season (i.e. spring to autumn) can be reduced by change in the condition of theground vegetation as the growing season progresses. Installation of traps in a crop ofmaize (Zea mais) provides an extreme example - at the beginning of the season theground around the trap is virtually bare, whereas at the end the maize is higher than thetrap itself, having clear implications to its accessibility as an interception trap for flyinginsects. In deciding where to position a Malaise trap, such features can be either soughtor avoided, as a matter of choice, but cannot be simply ignored.

In conducting a short duration (e.g. ten-day) field campaign, it might be considered self-evident that Malaise traps should be positioned to obtain the maximum quantity of data inthe minimum time. However, as indicated in the previous paragraph, maximising the trapcatch is not necessarily synonymous with maximising the catch of species which havedeveloped locally, for instance, and the questions to be answered by conducting thetrapping programme require to be considered carefully in deciding trap placement. Inorder to overcome the potential influence of trap placement on trap catch it is advisableto use Malaise traps in pairs, the two traps of a pair being placed close to each other(though sufficiently far apart that they do not interfere with each other’s action) at thechosen trapping station. The degree of similarity between the catches made by two trapsinstalled at a trapping station can be ascertained, and compared with the catches of trapsfrom other trapping stations, to verify that the catch of a particular trap is less affected byits placement than by the character of its surrounding habitats.

16

The need to sample the fauna of each principal habitat type observed on-site determinesthe minimum number of Malaise traps to be positioned there - it being advisable to placeat least one pair of traps within the area occupied by each of the observed habitats. It maybe necessary to install traps at additional locations, as required by co-workers.

2.2.2 Sample collection and trap maintenance.

Sample collection from a Malaise trap entails simply unscrewing and capping thecollection bottle and transporting it to the laboratory. In temperate conditions 70%alcohol makes an acceptable preservative for use in collection bottles, but in the warmerconditions of the summer months of central France a 30% solution of the less volatileethylene glycol is more appropriate. Windy conditions can also result in higherevaporation rates of alcohol and can make ethylene glycol a preferrable option for use inthe field, in Malaise trap bottles. If ethylene glycol has been used, it is desirable to strainit from the caught insects and replace it with 70% alcohol within 3 weeks from the date atwhich the collection bottle was put in place on the trap, to prevent disintegration ofspecimens.

It is advisable to check collection bottles in place on traps at least once every two weeks,and once a week in conditions of high wind or high temperature, in case there has beenincreased evaporation of preservative. Catch rate varies considerably and there is alsoneed to ensure that bottles do not fill with collected insects to above the surface of thepreservative. In conditions where rapid catch rates might be anticipated it can benecessary to check bottles every few days. In exceptional circumstances it may benecessary to replace bottles on a daily basis. Correct labelling of collection bottles iscritically important, to ensure it is known from which trap each is derived. To help ensurethat the sample bottle collected from a trap is labelled correctly, it is advisable to markthe permanently attached upper bottle on the Malaise trap with the code name for thattrap, using non-water-soluble ink. This code name is then immediately available forreference when the sample-bottle is labelled, which should be undertaken either as part ofthe process of attaching the sample-bottle to the trap, or as part of the removal process, toensure there is no confusion between sample-bottles from different traps. It is preferableto use code systems which can be used to refer to particular traps, or their products,throughout the field and laboratory procedures, so that the code name attached to a trap

17

may finally be used for the column(s) referring to the syrphids recorded from that trap, inthe Excel file set up to hold the transcribed field data in the computer.

In most instances damage to traps is limited to guy ropes being severed or pulled out ofthe ground. This rarely results in loss of a sample, but can reduce trap efficiency. If trapscarry waterproof and sunlight-stable notices, explaining their purpose and asking for co-operation, incidence of vandalism is surprisingly rare. But when it occurs it almostinvariably results in loss of samples. High wind can also wreak havoc and any trap whichsuffers from the attentions of one of the larger forms of domestic stock, such as cows orhorses, can be totally destroyed. Traps can only be effective in the presence of these largeanimals if protected from them by strong, temporary fencing or electric fencing - or byreaching agreement with landowners which results in domestic stock being grazedelsewhere for the duration of a sampling campaign.This latter alternative it eminentlypreferable to erection of temporary fencing of any sort, which tends to be both very time-consuming and unreliable. For any field campaign it is advisable to hold a few spare trapsin reserve, in order to guard against possible trap destruction. Under most circumstances,the time taken to complete a trap round is largely dependent upon the distance betweentraps and how closely they may be approached by vehicle, rather than the time requiredto service the traps themselves.

2.2.3 Field Sampling Strategy: obtaining representative samples of site faunas

There are various factors that require to be considered in designing a fieldwork campaignaimed at obtaining a representative sample of the syrphid fauna of a site, using Malaisetraps. Survey aimed at inventorising the syrphid fauna of a site requires less rigorousconsideration of optimal sampling periods, but is more demanding of man-power andtime.

2.2.3.1 Choice of sampling period

Over most of Europe, adult syrphids are on the wing between April and September(inclusive), so Malaise-trap sampling outside this period is not practical, except withinthe Mediterranean zone. A field campaign which had to be conducted during the wintercould not usefully include adult syrphids in site investigation processes. Within theperiod April-September the various species are in flight at different times, and unless

18

sampling can be carried out throughout that period, choice has to be made of when tosample. Most univoltine species are only in flight at the beginning of the summer,whereas polyvoltine species recur again later in the year. This is illustrated in Figs. 2.1and 2.2.. So, to sample univoltine species the optimal period is April/beginning June,over most of Europe. Figs 2.1. and 2.2. also indicate that a second sampling campaign, inJuly/August, might be expected to show which polyvoltine species move into a siteduring the summer, though absent there earlier in the year.The periods of the yearoptimal for sampling can also be influenced by the type of habitat in which sampling isbeing carried out. This is illustrated for the potential fauna of the FAEWE site at Decizein Figs. 2.3. and 2.4..

In Fig.2.3, the flight season data for all the species represented on the regional list forcentral France that are associated with habitats observed on the Decize site have been puttogether, to give a composite flight season profile. This shows that, in the latter half ofMay/first half of June, the number of species available there should be at a maximum,suggesting this would be the optimal period for a field campaign.This composite flightprofile is typical for most habitats in atlantic parts of Europe, so in principle it is true thatin this region of the continent the most opportune time for sampling a syrphid fauna isend May/beginning June. However, this can be a period of very variable weather and inyears in which spring is retarded the fauna is as well, reducing sample catches. Undersuch conditions, sampling should be postponed to mid-June, if possible.

In Fig. 2.4. two groups of species contributing to Fig. 2.3. have been taken separately: theflight season profile of the species associated with the mature/overmature alluvialsoftwood forest has been compared with that of the unimproved pasture species. Fig.2.4.shows that while the period end May/beginning June is an optimal sampling period forspecies associated with both types of habitat on the Decize site, the pasture species mightalso reasonably be sampled through into July/August, whereas the forest species wouldbe only half as well represented during this period as in end May/beginning June. Inorder to optimise a sampling programme it is necessary to have a clear understanding ofwhich habitats in the target area are the particular objects of concern. In the event thatfree choice of sampling period cannot be exercised, it is necessary to take into accountthe flight period profile of the fauna associated with each habitat observed on site whenanalysing results. This can be achieved using the database.

19

2.2.3.2 Duration of field campaigns

Optimisation of field campaign duration brings into consideration such issues as the costof a field campaign and the length of time a farmer, or other land owner/user, mightreasonably be expected to modify his/her schedule for use of a site in order toaccomodate survey needs. These logistical considerations dictate that on most sites noMalaise-trap-based on-site sampling campaign should continue for more than a fewweeks. In a nature reserve, national park or other protected site, field campaigns canreasonably continue for much longer than this, but only a proportion of sites requiringinvestigation are likely to fall into these categories. Working on the basis that installingan average set (twenty) of Malaise traps takes two days and that a similar length of timeis also required to remove them, based on expert advice fourteen days has been identifiedas the minimum period in which a Malaise trap field campaign could usefully be carriedout. This then provides for a ten-day sampling period, which allows for the occurrence offlight-inhibiting weather (e.g. high wind or rain) for part of the period. Two such fieldcampaigns, carried out within the period beginning June/end August and giving togethera total of 20 days of sample collection, have similarly been taken as the minimumrequired to amass an adequate sample of the syrphid fauna of a target site (see below). Inmost circumstances the optimal timing of these two sample periods is probably June andAugust.

Fig.2.5. shows how the number of species collected increased as the sampling period wasextended, during course of a longitudinal Malaise trap survey conducted in an IrishNational Park. As might be expected, with the addition of each ten-day sampling periodthe total number of species collected continued to rise, from June through to September.However, after the first 20 days of sampling more than half the total number of specieshad been collected and from then on the species increment resulting from each additionalten-day period reduced. Fig.2.6. shows what would have been the effect of timing thefirst of two ten-day field campaigns in the second half of June and the second fieldcampaign at each of the subsequent ten-day periods through to September. Whateverdates the second ten-day sampling period covered, the number of different speciescollected by the two campaigns put together amounts to at least half the total number ofspecies trapped in the entire season June/October.

20

Longitudinal sets of Malaise trap-collected data like those derived from the KillarneyPark are not available from many sites, so it is uncertain how typical the Killarney resultsmay be. However, they do show that 20 days' sampling by Malaise trap within the periodmid June/September can collect half the species available to the traps during the entire110 day period mid-June/October. Precht and Cölln (1996a,b) report on a longitudinalMalaise-trapping exercise conducted by themselves on a site in Germany, with more-or-less the same objective. They conclude that 80% of the syrphids which may be trappedon a site using Malaise traps may be collected by four weeks of Malaise trap activity inJune/July. A similar data-set from one site in New Zealand was used by Hutcheson(1990), as a basis for concluding that 28 days of Malaise-trapping represent an adequatebasis for sampling flying beetles (Coleoptera) for purposes of site characterisation.

2.2.4. Inventory survey

Survey carried out, with the objective of compiling an inventory of the syrphid fauna of asite, requires to accommodate the requirement for all habitats (including supplementaryhabitats) present on the site to be sampled and through the flight period of all the speciespredicted to occur on the site. The array of habitats present can be established by habitatsurvey carried out in advance of installation of the Malaise traps. In inventory work it ismore important to have the Malaise traps in place before, or at least by, the earliest datepredicted for the onset of the flight season, because there can be as much as a monthdifference between years in the date at which the early spring species actually start to fly.Installation of traps by some later date, at which most of the early species would besupposedly on the wing, could easily result in a number of them being missed, in a yearin which spring started earlier than usual. This is particularly true, given that so many ofthe early spring species are also univoltine, and so cannot be collected at any other timeof the year.

Even though it is advisable to obtain samples from all parts of the flight season, whenunderstaking inventory work, this does not imply a need for continuous sampling. Ingeneral, one 20-day time unit of sampling within each month of the flight season shouldprove adequate. It is advisable to use 20-day time units, rather than 10-day units, tominimize the frequency with which it is necessary to visit the traps.It is to beremembered that, if an inventory survey results in collection of a superabundance ofmaterial, it is always possible to process only a subset of the collected material, if that is

21

deemed adequate for compilation of the inventory. But, if insufficient material iscollected, there is no easy way to deal with the situation other than to carry outsupplementary survey work, an option which is frequently unavailable.

Malaise traps are not mobile and habitat survey is fallible, so that it is well possible forcertain habitats on a site to be too distant from any Malaise trap emplacement to ensuretheir fauna will be comprehensively collected by the traps. To minimize such effects it ishelpful to employ a second collection method, when conducting inventory work bymeans of Malaise trap survey. Collection by direct observation, using an insect net,carried out by an experienced syrphid worker, provides the ideal supplement, since theexperienced observer both can and will visit parts of the site remote from the traps. If theMalaise traps are operating efficiently, supplementing their catch by insect net work isunlikely to add dramatically to the resultant species lists. But if there are elements of siteheterogeneity that have been inadvertently overlooked in placing the Malaise traps, orwhich it has been impractical to sample using Malaise traps, then collecting by net shouldhelp to ensure that any part of the syrphid fauna of the site that is dependent upon suchneglected site elements will be added to the inventory.

0 102030405060708090

Fig.2.1.: Relation between flight period and number of generations/annum: central France speciespool, showing number of species in each generation category on the wing in each month.Rectangles denote species with no more than 1 generation/annum; diamonds denote species which may beunivoltine or divoltine; triangles denote species with two or more generations/annum.

22

0

10

20

30

40

50

60

70

Fig.2.2.: Relation between flight period and number of generations/annum: Irish species pool, showingnumber of species in each generation category on the wing in each month.Rectangles denote species with no more than 1 generation/annum;Diamonds denote species which may be univoltine or divoltine;Triangles denote species with two or more generations/annum.

��

��

��

��

��

��

��

��

��

��

��

��

0

50

100

150

200

250

Fig.2.3.: Combined flight period profile for all syrphid species associated with the habitats observed on theFAEWE Decize site and represented in the central France species pool. Derived from the flight seasondata-file for central France, used with the species list for central France and the list of syrphid habitatsobserved on the Decize site.

23

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

0

20

40

60

80

100

120

Fig 2.4.: Flight period profiles of the syrphid species associated with two different habitat types observedon the FAEWE Decize site compared. Hollow columns = unimproved pasture species; striped columns =mature/overmature alluvial softwood species.

0 5

1015202530354045

Fig.2.5.: Showing increment in number of species collected with increased length of sampling period,using Malaise-trap data from the Killarney National Park, Ireland.Each contiguous sampling period is ten days. During the first sampling period, 16-26 June 1993, 15 specieswere collected. Sampling continued for 110 days and by the end of the last sample period a total of 42species had been collected.

24

��

��

��

��

��

��

��

��

��

��

��0

5

10

15

20

25

30

35

Fig.2.6.: Total number of different syrphid species obtained from combining the results of a field campaign16-26 June (first column) with those of a second field campaign of the same length at different dates up to7 October, using Malaise trap data from the Killarney National Park, Ireland, in 1993. The total number ofspecies collected 16 June-4 October was 42.1 = 16-26.6; 2 = 26.6-6.7; 3 = 6-16.7; 4 = 16-26.7; 5 = 26.7-5.8; 6 = 5.8-15.8; 7 = 15-25.8; 8 = 25.8-4.9; 9= 4-14.9; 10 = 14-24.9; 11 = 24.9-4.10.

25

Chapter 3. LABORATORY PROCEDURES

Although the actual techniques employed in the laboratory depend on which taxonomicgroup is involved, the same processes are common to all groups. The target organismshave to be sorted from among other invertebrates and debris collected with them, stored,determined and recorded for transcription into the computer.

3.1. Treatment of samples

A collection bottle removed from a Malaise trap can be used to store the insects collecteduntil the samples are required for sorting. Sorting is best carried out under a binocularmicroscope, using a petri dish to sort, one after the other, decanted fractions of thematerial from the collection bottle, until the entire content of the bottle has beenexamined. The alcohol in the collection bottle is likely to become clouded by shed scalesfrom the wings of Lepidoptera collected and it is advisable to strain this off through afine sieve and sort using clean alcohol in the petri dish. If the alcohol strained from thecollection bottle is filtered it may be reused for storage of collected material. Clear andunambiguous labelling of each container storing collected material is vital - confusionbetween material collected by different traps, or at different dates, renders samplesunusable. The syrphid specimens extracted from a sample are best retained (in alcohol) ina separate, smaller, closed container, labelled to show their sample of origin, so that theymay be determined together with the syrphid material extracted from other trap samplesfrom the same field campaign. Following determination, the syrphid sub-sample sortedfrom a collection bottle may be re-united with the parent sample, but it is prudent simplyto insert the small, closed container holding the syrphids into the parent sample bottle asa discrete entity, in case there is need to re-examine one or more of the syrphidspecimens at a later date.

Sorting syrphids from other insects collected by the traps is time-consuming anddemands a trained eye. An experienced sorter can be expected to sort syrphids from up to300ml of insect material in four hours, and 10 collection bottles can take from 2 days to aweek to sort.

26

3.2. Determination of the sorted specimens.

For use with the database, specimens have to be identified accurately and to species, thusrequiring specialist attention. The need for accurate determinations is paramount, sinceuse of the procedure is entirely dependent upon species-related information. The processof determination is time-consuming. With experience, the material extracted from 10collection bottles all derived from the same local fauna can usually be determined tospecies in 1 or 2 days. But extra time may be needed for particular specimens. In someinstances, there may be need to remove specimens from alcohol and dry them, prior todetermination, because the existing identification keys are all based on dry specimens.For an inexperienced observer, the process of determining syrphids preserved in alcoholis a frustrating, tedious business, fraught with difficulty. There is no recent publication inwhich all known European genera of Syrphidae are keyed out. However, there are quasi-regional works which cover most genera. The most comprehensive accounts are those ofthe following authors: Bradescu (1991), Stubbs & Falk (1983), Torp (1994), van derGoot (1981), Verlinden (1991), Violovitsch (1986), Vockeroth & Thompson (1987).Which genera are covered by each of these accounts is detailed in tabular form inAppendix 3 to this volume. In addition to indicating which of the genera covered by thedatabase are keyed out in those publications, Appendix 3 also shows which otherEuropean genera they key out. For completeness, certain genera whose range isperipheral to Europe are included in Appendix 3. These genera comprise Allograpta,Asarcina, Ischiodon and Megaspis. Further information on identification is given in theSpecies Accounts volume, under the sub-heading “Determination” included in theaccount of each species. That focuses, in particular, on literature for determination ofindividual species. The Species Accounts also provide details of literature available foridentification of developmental stages, under the subheading “Larva”.The mostcomprehensive recent texts dealing with identification of larvae are those of Rotheray(1994, 1999) and Torp (1994).

For purposes of publication, the names of species listed as occurring in a site or regionnormally require to be quoted complete, i.e. followed by both name of author and date ofdescription. Putting this information together for even a small number of species can bean irksome task, so a complete list of nomenclaturally correct names of the speciescovered by the database is incorporated into Appendix 2 of this volume. The species

27

listed there are the same, and in the same order, as in the other Excel files in the database,so that the list in Appendix 2 may be used in conjunction with the other spreadsheets.

Papers on taxonomy and ecology of European syrphids are scattered through a vast rangeof scientific periodicals. Only the recently-established journal Volucella dealsexclusively with the syrphid fauna of the western Palaearctic. Volucella provides anoutlet for autecological, distributional and taxonomic information on the Europeanspecies and an increasing proportion of material for up-dating the syrphid database isnow coming from its pages. Further information about Volucella may be obtained from:Dr.U.Schmid, Staatliches Museum für Naturkunde, Rosenstein 1,D-70191 Stuttgart, Germany.

3.3. Recording the determined specimens.

It is advisable to retain the most detailed record possible of the species identified in eachsample, and in such a way that transcription of the recorded information, into an Excelfile which may be used with the database, can be carried out simply.

Part of a simple recording form is shown in Fig.3.1 The format used allows the syrphidspecimens from each Malaise trap sample to be recorded on a separate record sheet. It isimperative that the trap sample from which the syrphid records are derived is alsoindicated on each record sheet, preferably using some code which can employed todenote this trap sample in the Excel file to which the recorded syrphid data are to betranscribed.

TAXONOMIC GROUP SITE Trap No.: DATE

Species no.males no.females

remarks

28

Fig.3.1: Part of a form for recording syrphid specimens from a trap sample.Chapter 4. DATA PROCESSING PROCEDURES

The spreadsheets are set up for use with species lists, species lists being regarded as themost likely type of information generally available about the syrphids of a site or region.This does not preclude the use of the spreadsheets with quantitative data. Butinterpretation of quantitative data may be treated as a separate issue and the logic implicitin the approach adopted here is that once species presence/absence data can beinterpreted, then it becomes worthwhile to consider quantitative information, with all theadditional problems of interpretation that entails. The basic procedure outlined hereassumes use of presence/absence data.

4.1. Field data files

The need to transcribe site data into spreadsheets has been alluded to earlier in this text.If the data on habitats observed on-site are transcribed to an Excel file, with the habitatcategories arranged exactly as in the Macrohabitats file, this can facilitate extraction ofthe habitat array required for carrying out the prediction procedure for a site.

The species-observed data for sites can all be transferred from record forms to one Excelfile set up to hold the information. The observed-species categories should be clearlylabelled to avoid confusion between them. If the species are listed as in the other Excelfiles in the database, this greatly simplifies file manipulation procedures..

4.2. The basic site interpretation procedure

As indicated earlier in this text, for purposes of employing the database a site may bedefined as a piece of ground forming the object of a study or inquiry. Parts of sites fromwhich data are collected by some sampling procedure are then considered as sub-sites orsampling stations. Interpretation of species lists from sub-sites, sites, groups of sites orregions can be carried out using the same basic procedure. The flow diagram in Figure4.1a illustrates the first steps in a basic site interpretation procedure.

29

a) the species associated with the habitats observed on site are extracted from the regionallist; using the habitat coding to extract only expected species i.e. those coded “2” or “3”for the relevant habitat categories,b) the species potentially in flight at the time of the field survey are extracted from the listobtained in a), using the relevant flight period categories in the Traits file. This provides alist of predicted species for a given site and a given sampling periodc) the list of species actually sampled during the field survey is then compared with thelist of predicted species obtained in b).

��

��

��

��

REGIONAL LIST OF SPECIES

Habitat preferences of the species

Flight period data

HABITAT TYPES OCCURING ON SITE

List of predicted species

List of predicted species for a given sampling period

LIST OF OBSERVED SPECIESFOR A GIVEN DATE(field data)

COMPARISON

Figure 4.1a. Basic site interpretation procedure: production of the list of predicted species and its

comparison with the list of observed species..

The comparison can be conducted using a great many different combinations of datacategories from the spreadsheet files of the database. The actual combinations ofcategories used in any one instance will depend upon the requirements of theinvestigation. Fig.4.1b shows diagramatically an example of the procedure involved,which is very reminiscent of employing a catenary series of sieves of decreasing mesh-size, with data categories from the spreadsheet files taking the place of the sieves.

30

The example used in Fig.4.1b assumes the investigation relates to a fen site in Ireland, forwhich a reliable inventory of the syrphid fauna exists. The first operation is to make up aspreadsheet work file containing the relevant data categories, which in this instance aretaken to comprise the following:1. A copy of the database species list which accompanies the spreadsheet files,2. The list of species observed on the site (from the file set up to hold site data),3. The “Ireland” category, “European Range” variable, Range and Status file.4. The “Fen (gen.)” category, “Wetlands” variable, Macrohabitats file.5. A copy of the Microsite Features file (entire).6. A copy of the Traits file (entire).7. The 3 categories from the “Status, Ireland” variable, Range and Status file.

Sorting the work file, using the Irish species list category (sort 1), reduces the number ofspecies considered to only those which occur in Ireland. Sorting the work file again,using first the “fen” category (sort 2), further reduces the number of species to beconsidered, to those which might be expected in fen in Ireland. This then is the predictedsite-species-list, since on this imaginary site there is only the one habitat “fen”represented. By the same sorting process, the list of species observed on-site has beenreduced to those associated with fen, so the list of on-site species associated with fen maynow be compared with the list of species predicted for this habitat. The example assumesthat, from direct comparison between these two lists, it is decided to examine certaindifferences between them further, commencing with a comparison between the expectedand observed species associated with the “on tall herbs” category from the MicrositeFeatures file. Sorting the work file using this category (sort 3) reduces the observed andpredicted lists to species associated with tall herbs in fen, so that this comparison may bemade. Traits of these species may then be considered and, in this instance, it is decided tocompare the representation of species with predatory larvae, in the predicted andobserved lists, using the “living animals” category from the “Food source (larvae)”variable (sort 4). Finally it is decided to consider the representation of threatened speciesamong the predicted and observed species with predatory larvae on tall herbs in fen (sort5). At this final level, the number of species involved may be very small.

This example is of a simplified case, in that it would be rare for only a single habitatcategory to be represented on a site, or for only one microsite feature or trait category tobe brought into consideration during the process of comparison. For instance, it would be

31

more normal to consider the representation of all three categories of larval feeding type(predators, plant feeders and detritivores) at once. A more complex procedure thenresults, producing a dendritic structure to the comparison process and ending with amutliplicity of final products for comparison.

It is necessary to take into consideration the differences between lists of observed speciesbased on production of inventories, and lists of observed species based on production ofrepresentative samples, in conducting a comparison between predicted and observed lists.The types of comparison which can be meaningfully conducted are fewer whenrepresentative samples are involved, than when inventory lists are involved.

Sort 1: regional list- Ireland

↓↓↓↓↓

Sort 2: habitats on-site - fen↓↓↓↓↓

Sort 3: Microhabitat -on tallherbs↓↓↓↓↓

Sort 4: Trait - predatory larvae↓↓↓↓↓

Sort 5: Status, - Ireland,threatened↓↓↓↓↓

Threatened Irish species with predatory larvae living on tall herbs, predicted in fen, plus threatened specieswith predatory larvae on tall herbs in fen, observed on site

Fig.4.1b: Progressive sorting procedure, used in comparing species lists (diagrammatic).

4.3. Statistical/analytical techniques

Atlantic zone species + habitats + traits + microhabitats + status+ site species listc400 species

Irish species + habitats + traits + microhabitats + status + sitespecies list171 species

Irish species predicted in fen + traits + microhabitats + status +species from fen observed on site

Irish species predicted in fen, with larvae on tall herbs + traits +status + species from tall herbs in fen observed on site

Irish species with predatory larvae living on tall herbs,predicted in fen + status + species with predatory larvae on tallherbs in fen observed on site

32

No advanced statistical techniques are needed in order to carry out most of theprocedures presented here, including the predictive procedure which is intended as ageneral use of the data base - the prediction of a site fauna and its comparison with thespecies actually sampled are solely based upon counts of numbers of species, andpercentage calculations. However, the data files can be explored and described withappropriate multivariate ordination techniques, and coupled with the results of sitesurveys following the procedures set up by Dolédec & Chessel (1994) or Chevenet et al.(1994). An example of such multivariate investigations using the ADE software is givenbelow, derived from Castella & Speight (1996). The ADE software is available free ofcharge, and may be downloaded from the following internet address (URL):http://biomserv.univ-lyon1.fr/ADE-4.html

4.3.1. Use of multivariate ordination techniques with the database

In this example, syrphid microhabitat and biological trait data are incorporated into theanalysis of field data, providing insights into the extent to which particular speciesattributes are manifest in the fauna of different sampling stations. All the calculationswere carried out using the ADE software. The procedures described follow the guidelinessuggested by Dolédec and Chessel (1993a and b) and Chevenet et al (1994).

The first step is ordination of each of the two input data sets:- field data tabulating occurrences (as presence or absence) of the 78 syrphid speciesrecorded at the 13 stations sampled during the two field programmes carried out on theFrench FAEWE sites,- microhabitat and trait data (78 species x 6 variables totaling 28 categories), extractedfrom the microhabitats and traits spreadsheets. For the purpose of the present exampleonly a restricted number of categories of microhabitat and traits data are included in theanalysis.

Characteristics of the French FAEWE sites and the sampling stations used there may besummarised as follows:

Four sampling stations were selected on each site on the basis of geomorphological, pedological andhydrological characteristics. These "HGMUs" (stations L1 to L4 and A1 to A4 for the Loire and Allierrivers respectively) were located along a 200 metre long transect, perpendicular to the river, starting at itsbank and ending on the higher terrace of the floodplain. Each station was equipped for the regular

33

measurement of physico-chemical characteristics of the soil and groundwater and served as a referencepoint for the various experiments carried out within the frame of the project.The macroinvertebrate fauna was sampled at these 8 stations and at 5 supplementary stations (i.e. notinstalled for soil measurements): L0 and L2a on the Loire transect, AI, A0 and A5 on the Allier transect.These various sampling stations can be briefly characterised as follows:AI: riparian soft wood forest located on an island of the R.AllierL0 and A0: muddy sand (L0) or sand (A0) bank on the shore of the river, partly shaded by the adjacentPhalaris (L0) and scrub Salix (A0, L0). These stations were influenced by the frequent and rapidoscillations of the river water level and annually flooded.L1: Phalaris arundinacea and Salix sp. scrub on a sandy mud; partly shaded and annually flooded, beingwith LO on the lowest part of the transect.L2, A1, A2: riparian soft wood forest (Populus and Salix) with Urtica dioica (L2, A2) or Phalarisarundinacea (A1), flooded during spring floods.L2a: on the shore of an abandoned channel of the R.Loire (upstream disconnected, but almost permanentlyconnected downstream with the river) and therefore as frequently flooded as LO or L1. Shaded by theriparian forest described for L2.L3: an extensively and not permanently grazed pasture on the higher alluvial terrace with a well drainedsandy soil. Flooded only occasionally and submerged for only very short periods (1 to 2 days).A3: a more intensively grazed and humid pasture. Flooded each year (up to 10 days a year).L4: a depression (2 to 3 m deep) located in the pasture L3. The substrate was sand, locally covered with ashallow, poorly drained soil. This station was vegetated with grass and could be overflooded for periods ofseveral days or weeks each year by rise in groundwater level.A4: a shallow depression with sedge communities, in the pasture A3 .A5: on the shore of a former channel of the Allier (oxbow lake with hydrophyte communities).

4.3.1.1. Reciprocal ordination of the species and sampling stations

The field data are processed by Correspondence Analysis (CA) Greenacre, 1984), whichprovides a reciprocal ordination of the species and of the sampling units. CorrespondenceAnalysis was chosen instead of its detrended version (DCA) for several reasons, but inparticular because:i) control over the geometry is lost in the process of detrending and DCA breaks up theoptimal properties of CA, such as the maximisation of correlations or the reciprocalaveraging (Greenacre, 1984, Lebreton and Yoccoz, 1987);ii) DCA is a rather arbitrary adjustment of CA and lacks mathematical coherency(Wartenberg et al., 1987; Digby and Kempton, 1987), hence it does not allow subsequentinter-battery analyses.

Fig..4.2 shows that, in this example the first two axes from the Correspondence Analysisordinate the 13 sampling stations along a diagonal line from dense, shaded softwoodriparian forest (A1, A2) at the top right to more open sites like dry unimproved pasture(L3, L4) or muddy sand flat along the river (L0) at the bottom left. This gradient can beassociated along F1 with the increased occurrence of forest-dwelling species like Syrphusvitripennis or Myathropa florea and the parallel decrease of the open-ground / grassland

34

dwellers (e.g. Sphaerophoria scripta). The poorly-drained pasture A3 is an outlier to thisgradient, with a particular assemblage mixing open ground species like Chrysotoxumarcuatum or Eumerus tuberculatus, together with forest dwellers, like Temnostomabombylans, Brachyopa scutellaris or Meligramma cincta, the adults of which visit thepasture to feed upon flowers. Another reading of this ordination plane evidences for bothsites (Allier and Loire) the repetition of the same ordination pattern for the four majorsampling units from right to left along F1 (thick lines in Fig. 4.2) and a tendency tosegregate these two transects along F2.

1.8-1-1.3

1.6

AI

AO

A1

A2

A3

A4A5

LO

L1

L2a

L3

L4

��

��

��

��

��

��

��

��

��

��

��

��

F1

F2

L2

F1 F2

Eigen values

0

0.70

-

-

Factorial axes

Figure 4.2. First factorial plane of the Correspondence Analysis of the field data (occurrence of 78 Syrphidspecies in 13 sampling units of the Allier (AI to A5) and Loire (L0 to L4) floodplains). The thick lines jointhe four main sampling units of each transect.

4.3.1.2. Reciprocal ordination of the species and their attributes

35

In the microhabitats and traits files, several data transformations are necessary before theordination can be performed. The numerical system based on four values (0 to 3),adopted in order to describe the degree of association between the species and thecategories of the variables, allows rapid transcription of available knowledge by theexpert. However, in such data bases the relevant feature is provided by the relativedistribution of the information among the categories of each variable. For example, forthe species Eupeodes latifasciatus and the four categories of the variable "duration of thedevelopment phase", the sequence of values in the traits file was: 1 / 2 / 1 / 0. Forpurposes of ordination this sequence was transformed to the equivalent form: 0.25 / 0.50/ 0.25 / 0. This transformation sets the variations of the fuzzy codes between 0 and 1 andmakes them add up to 1 per variable for each species. In the case of missing informationfor one species and one variable, the average profile of all the species for this variablecan be ascribed to the species not documented. That species then plays no role in thecalculation of this variable’s weight in the ordination procedure (Chevenet et al., 1994).This treatment should be limited to a very restricted number of instances .

Following these transformations, the microhabitat and trait file data are subjected to the"Fuzzy Correspondence Analysis" described by Chevenet et al., (1994), which can beregarded as a Correspondence Analysis of the data expressed as percentages per variable,or as an extension of Multiple Correspondence Analysis for use with fuzzy data. As inthe case of these classical ordination methods, the analysis provides reciprocally i)species scores, which maximize the discrimination of the categories of the variables, andii) category scores, which maximize the discrimination of the species.

Fig. 4.3a provides a picture of the ordination of the species along the first two ordinationaxes of the Fuzzy Correspondence Analysis. The decrease of the eigen values indicatesthat the first four ordination axes describe the most significant part of the totalinformation, according to the principle proposed by Diday et al. (1982). Along the firstordination axis, the categories of the variables "microhabitat", "inundation tolerance" and"food type" are well separated, each variable explaining more than 80% of the totalvariance. The variables "migratory status", "microhabitat" and "food type" alsocontribute to a large extend to the second and third axis ordinations with more than 50%of the explained variance. The categories of the variables "number of reproductioncycles" and "overwintering phase" are the least well separated by the four axes.

36

1.4-1.3-1.3

2.2

2

13

4

5

6 7

8

9

11

1

2

3

4

1

2

3

123

4

1

2

3

12

3

��

��

��

��

��

��

��

��

��

��

��

��

��

��

Eigen values:

Larval microhabitat Inundation tolerance

Food type of larvae Number of reproduction cycles per year

Migratory status Overwintering phase

10

F1

F2

F1

F2

0

0.51

-

-

Factorial axes

Figure 4.3a. First factorial plane from the Fuzzy Correspondence Analysis of the fuzzy-coded trait data for78 Syrphid species caught during the sampling programme on the Loire and Allier riverine wetlands. The78 species (small squares) are grouped according to the categories of the six microhabitat and traitvariables shown in Fig. 4.3b.

37

VARIABLES CATEGORIES SPECIES: 1 2 78 102Microhabitat (larvae)

1 tree, free on foliage 12 tree, overmature, senescent 33 shrubs 24 on low growing plants, above ground 15 in low growing plants, above ground 26 litter / grass root zone, free7 litter / grass root zone, in wood 18 litter / grass root zone, in bulbs 29 herbivore dung 210 water-saturated sediment, debris 3 211 aquatic, submerged sediment, debris 211 aquatic, submerged plants

Inundation tolerance (larvae)1 short respiratory tube, non tolerant 3 32 short respiratory tube, tolerant3 medium respiratory tube 34 long respiratory tube 3

Food type (larvae)1 microphagous 3 32 living plants 33 living animals 3

No. of reproduction cycles per year1 <1 12 1 1 3 33 2 3 34 >2

Migratory status (adult)1 not known to migrate 3 3 1 32 recorded migrant 23 strongly migratory

Overwintering phase1 larva 3 3 3 32 puparium3 adult

Fig. 4.3b. Table of the 6 variables and their categories from the Microsite features and Traits files, used inthe analysis. The categories are numbered as in Fig.4.3a..Species: 1-Baccha elongata, 2-Brachyopa scutellaris, 78-Eristalis interrupta, 102-Cheilosia ahenea

38

Two groups of species are evidenced along the first axis:- On the right-hand side, the species' larvae inhabit either decaying wood (categories 2and 7), water saturated matter (categories 10 and 11), or herbivore dung (category 9).They exhibit long or medium respiratory tubes as larvae and can therefore be regarded asinundation tolerant. They are also microphagous.- On the left-hand side of the first ordination axis, the species' larvae live either free onplant material (categories 1, 3, 4, 6), or within living plants (categories 5 and 8). Theyexhibit short respiratory tubes and feed on living plant or animal material.

The species belonging to these two groups are scattered along the second axis, which wasassociated with a gradient of increasing migratory capability and number of generationper year.

4.3.1.3. Simultaneous ordination of two matrices

The second step in the procedure looks for the common structures between thedistribution of the species as sampled on site and the coded information about some oftheir microhabitats or traits. This can be achieved using the method of inter-batteryanalysis introduced recently by Chessel and Mercier (1993) and Doledec and Chessel,(1993b). This method, also presented as "Co-inertia analysis" (Dolédec and Chessel,1994) allows the simultaneous ordination of two data matrices sharing the same set oflines. It calculates co-inertia axes, maximizing the co-variance of the factorial scoresgenerated in the separate ordinations of the two input files. It provides therefore anordination of the common structure of the two data sets, which maximizessimultaneously i) the variance of the factorial scores from the two separate tables, and ii)their correlation. The co-inertia analysis generates factorial scores which can be used forgraphical displays as in standard ordination methods.

The co-inertia analysis looks for relationships between the distribution of the speciesrecords among the sampling units and elements of their microhabitats and traits. InFig.4.4 it can be seen that the eigen values of the co-inertia ordination single out the firstordination axis as being generally predominant. A test of the significance of the commonstructure obtained may be used to compare the eigen values actually observed in the co-inertia analysis with the eigen values generated from 80 similar analyses derived from

39

random permutations of the lines of the matched tables. The results of this test, shown inFig.4.5, demonstrate that in this case the eigen value observed for the first axis of the co-inertia analysis is significantly higher than those obtained in the random permutations,but that this is not so along the second axis. Only interpretation of the first axis is thusconsidered here. Along this axis, the correlation between the two matched tables is 0.63and the explained inertia represents 94% of the inertia of the field data table and 72% ofthe inertia of the trait data table. The largest contribution to the ordination obtained alongthe first axis is the information described along the first axis of each of the previousseparate ordinations.

The major output of this analysis is demonstration of the existence of a direct relationshipbetween the ordination of the sampling stations and some of the microhabitats and traitsof the species found at each sampling station (Fig. 4.4). The first axis (F1) of the co-inertia analysis discriminates the forested (A1, A2, AI) and river marginal (A0) sites ofthe Allier from their Loire counterparts (L1, L2, L0). When observed in relation tomicrohabitats, this separation can be seen to be associated with a major subdivision ofthe species preferences. On the left-hand side of the F1 axis, the Allier units areassociated with species whose larvae are wood- and plant-tissue miners. Thesemicrohabitat categories are not or under-represented on the right-hand side of the F1 axis,where syrphids with free living larvae are mostly encountered in the units. Thismicrohabitat segregation along F1 is also associated with different types of larval food(plant-feeding and microphagous larvae associated with miners and aquatic microhabitatcategories, animal-feeding larvae mostly free-living). The third active variable along thisF1 axis is inundation tolerance. Among the three other variables, one was totally nonactive here (migratory status), while two others (number of reproduction cycles andoverwintering phase) contribute through their sparsely represented categories, whichsingle out the more extreme units along the F1 axis. This is the case for speciesoverwintering as puparia (Cheilosia impressa, Eupeodes luniger) and having less thanone reproduction cycle per year (Temnostoma vespiforme, T. bombylans, Brachyopascutellaris) in A1 and A2; for species overwintering as adults (Scaeva selenitica, S.pyrastri, Eristalis tenax) in L0 and L3.It can be seen from this example that simultaneous ordination, by means of co-inertiaanalysis of species distribution among sampling stations and some of their traits andmicrohabitats data, can make possible a functional interpretation of the differencesbetween sampling stations, not solely based upon variations in their species composition.

40

In this process, as evidenced in Fig. 4.4, the actual species composition of the observedfauna of each station is hidden, but nonetheless serves as a link to match the two datasets.

.4-.7-.3

.5AI

AO

A1A2

A3

A4

A5 LO

L1

L2

L2a

L3

L4

��

��

��

��

tree foliageovermature tree

on plants

in plants

in wood (litter)

in bulbs

dungwater-satur. sediment

aquatic

short tube non tolerant

short tube tolerant

medium tubelong tube

microphageous

plants

animals

<1

1

2>2

not migratory

recorded migrant

strongly migratory

larva

pupae

adult

free in littershrubs

Larval microhabitat Inundation tolerance

Food type of larvaeNumber of reproduction cycles per year

Migratory status Overwintering phase

F1

F2

F1

F2

��

Eigen values

0

0.09

-

-

Factorial axes

Figure 4.4. First factorial planes of the co-inertia analysis (occurrence of 78 Syrphid species in 13sampling units vs. ordination of the same species on the basis of six biological traits).

41

��

��

��

��

��

��

��0

5

10

15

20

25

��

��

��

��

��

��

��

��

��

��

��0

2

4

6

8

10

12

14

.03 .04 .05 .06 .07 .08 .09

.03 .04 .05 .06 .07 .08 .09

F1

F2 Observed eigen value =

0.037

Observed eigen value =

0.095

eigen values

number of

values

number of

values

eigen values

Figure 4.5. Test of the significance of the co-inertia analysis. The eigen values of the first (F1) and second(F2) axes of the co-inertia analysis are compared with the distribution of eigen values generated by 80similar analyses with random permutations of the lines of the matched tables.

This example uses data from individual sampling stations. But an improvement in thefunctional interpretation of the results would be expected if species representation hadbeen considered in terms of habitats present on site, irrespective of the sampling stations,thereby avoiding any difficulties caused by the high mobility of adult syrphids ininterpreting results from individual sampling stations. This approach would entail use ofthe Macrohabitats file, together with the list of the habitats observed on site.

42

Chapter 5. APPLICATIONS OF THE DATABASE

One prime objective in development of the database has been to provide a tool for use inthe process of assessing site quality or site management requirements, in relation tonature conservation.

Only within the last 25 years have serious attempts been made to incorporateinvertebrates into the nature conservation process. The significance or otherwise of theinvertebrates of European sites designated for protection of fauna and flora has, in mostcases, been disregarded during processes of site selection. But now that the concept ofconservation of biodiversity draws attention to the fact that the major proportion ofEurope’s biodiversity is its invertebrates, more attention is being focused oninventorisation of invertebrate faunas of protected areas. This at least makes it possible toconsider the needs of parts of the invertebrate fauna when management plans forprotected sites are being designed or revised, even if it is now frequently too late toensure that the quality of the invertebrate fauna plays a role in prioritising sites forprotection, or deciding where the boundary of a protected site should be.

5.1. Application of the FAEWE procedure for assessment of the “ecosystemmaintenance” function of a site

A formal procedure for use of the database in site evaluation was established duringcourse of the FAEWE project. This is used here as an example of site evaluationmethodology employing the database. The FAEWE procedure dealt equally with twoother invertebrate groups employed in the project and the results from the use of all threeinvertebrate databases are shown here, to indicate how results from syrphids may beintegrated with and compared with results from other invertebrates. A potentialadvantage of employing invertebrates in environmental interpretation/evaluation work isthe diversity of taxonomic groups available: careful selection of a small number oftaxonomic groups providing complementary information can enable a wide variety ofdeductions to be made and establish a sounder basis for extrapolation, than can beobtained from use of one taxonomic group in isolation. Suggestions on the constitution ofa cadre of taxonomic groups to use in this way are made by Speight (1986a).

43

A refinement of the use of the database employed in the FAEWE procedure was that itincorporated recognition of certain habitats as typical of active river floodplains (or river-marginal-wetlands: RMWs), so that consideration of the observed fauna of a site could becarried out not only within a framework provided by the fauna predicted for the habitatsrepresented on-site, but also within a more restricted framework provided by whichRMW-typical habitats were represented on-site. This refinement can be useful, since itcarries with it the implication that if certain of these predicted RMW-typical habitats areabsent from a site under investigation, then their associated species would be expected tobe absent, too. This process of predicting which habitats should occur on a site can beextended beyond floodplain systems and is touched upon again in section 5.2.1.

Site evaluation may be carried out without recourse to any formal procedure like thatused in the FAEWE project, but nonetheless inevitably follows an analogous step-wiseprocess. Whatever ingredients are used in an evaluation process they require to be clearlystated, so that the logic employed can be understood.

There is not, and could never be, any absolute measure of site quality. Site quality canonly be assessed through imposition of some human valuation system. It has recentlybecome popular to choose from among various ecological approaches in selecting avaluation system to use for nature conservation purposes. But there is little stability in theresultant valuation systems, because fashions in ecology change and the products ofusing different attributes of ecosystems for evaluation cannot be easily compared. Thisquagmire may be circumnavigated by using the regional list as a basis for prediction of asite fauna, and comparing the list of observed species with the list of predicted species, solong as some standardised method can be used to calibrate the results of this comparison.In the FAEWE procedure, figures of 40% representation and 50% representation of thepredicted species, on the observed species lists, have been used as a basis for decision-taking. In general, representation on-site of 50% of the species predicted for a particularnatural/semi-natural habitat can be taken as indicating a reasonable representation of thefauna of that habitat on that site, in our experience, while figures higher than 50% can beused to identify sites of exceptional quality. There are no agreed international standardsfor recognising the quality of a site for nature conservation, whether based on use ofinvertebrates as tools, or on other criteria. Recommendations have been made, seeking toderive an agreed basis for recognition of sites as important at the international level forconservation of invertebrates (Speight et al, 1992), and have been followed here.

44

The format of the FAEWE site evaluation procedure based on macroinvertebrates isdesigned to facilitate its integration with other components of the FAEWE functionalanalysis procedure. At each stage of progress through the “decision tree”, the results offollowing the procedure with the invertebrate data from the French and Irish sitesexamined during course of the FAEWE project are given, in tabular form. The ecosystemfunction addressed by the procedure was ecosystem maintenance, as manifested throughbiodiversity.

5.1.1. The functional assessment procedure (FAP)Function: Ecosystem maintenanceProcess: Maintenance of Biodiversity

Definition: biodiversity

Biodiversity is understood not only as the diversity of taxa, but also as the diversity of life strategies

represented by species assemblages (e.g. modes of reproduction, feeding, dispersal,...). Because of their

intrinsic habitat patchiness and environmental fluctuations, river marginal wetlands are potential sites for

the coexistence of species with highly contrasted life strategies.

Definition: macrohabitat and microsite feature

The CORINE system set up by the EC can be used as a starting point for identifying invertebrate

macrohabitats. However, the recognition of macrohabitats categories for macroinvertebrates cannot be

based solely on phytosociological criteria (see Speight et al, 1997a). Therefore, a list of invertebrate

macrohabitats categories has been established for use in the macrohabitats files of the database, based on

CORINE categories, but incorporating additional categories important for the invertebrates covered.

Furthermore, the extent to which each macrohabitat category is typical for River Marginal Wetlands

(RMWs) has been coded. Within each macrohabitat type, processes such as local hydrological and

microclimatic fluctuations, vegetation dynamics, local variations in sediment or debris accumulation and

erosion lead to a potentially high availability of diverse microsites, which are called microsite features for

the purpose of this study.

Definition: RMW-Typical Macro-habitats

A natural or semi-natural category occurring in the Macrohabitats files of the database is regarded as

typical of river-marginal wetlands if it occurs on naturally-flooding river floodplains as a product of the

dynamics of river-flow, particularly within braided and meandered stretches (the potamal stretches) of

larger rivers. The database is not tuned to operate specifically for brook floodplains (floodplains in the

crenal or rhitral stretches of rivers). Entirely man-made habitats introduced into functioning floodplains

45

(e.g. plantations of Salix alba) are not included as RMW-typical. A list of RMW typical macrohabitats

valid for floodplain situations developed in the Atlantic and Continental zones of Europe is provided as

Appendix 4 to this text. In other biogeographical zones additional macrohabitat categories could be

recognised as typical for natural floodplains. Thus in the northern European zone categories of coniferous

forest would be recognised as RMW typical.

Definition: typical microsite features on-site RMW typical macrohabitats :

Microsite features which occur naturally on RMW typical habitats during either unflooded or flooded

conditions are regarded as typical. They are described in terms of their structural attributes and may be

either authochthonous or allochthonous in origin. A list of them is given in Appendix 5 (an Excel file) to

this text.

Definition: RMW-Typical Species

In the database, a species which is coded 2 or 3 for an RMW-Typical Macrohabitat is regarded as an

RMW-Typical species.

Controlling variables (Cvs) and background rationaleCVHabitat "faunal completeness"

The occurrence in a habitat type of the species, or functional groups of species, thatcan be expected given their availability in the regional species pool, is consideredas a sign of biodiversity maintenance. The difference between the fauna actuallypresent and the expected one is a measure of the "functionality" of this habitat.

Information required1- Regional list of species. The region has to be defined according to the scale and

purpose of the investigation (e.g. catchment, administrative region, country, EU,...)2- Macrohabitat and microsite feature preferences of the species in the regional list

(macrohabitats and microsite features defined according to the categories defined inthe Glossaries)

3- List of on-site Macrohabitats and their identification as being typical or not for RMWsin the assessment region.

4- List of species recorded on site5- For faunistic groups with marked seasonal occurrence, phenology of the species in the

regional list.6- Threat status of the species in the regional list.7- Regional list of RMW typical species

46

8- List of on-site microsite features and their identification as being typical for on-siteRMW typical macrohabitats

Source of information1- Published faunistic lists, experts, museum collections (Desk)2- Expert knowledge, published information, existing data bases (Desk)3- Site survey (Desk/Field), list of typical RMW Macrohabitats and associated typical

microsite features (Appendices 4 and 5)4- Already existing faunistic survey or faunistic survey to be carried out. In both cases

ensure compatibility with the methodological guidelines indicated in the methodsmanual. (Desk/Field)

5 and 6- as 27- Regional list of floodplain typical species to be derived from regional species list and

existing data base of species macrohabitat preferences, used in conjunction with thelist of typical RMW habitats

IdentificationThe completeness of a Macrohabitat fauna is assessed from the difference betweenexpected and observed faunas. This assessment requires several steps:1- Within the regional list of species, extraction of the species associated with on-site

macrohabitats, according to the macrohabitat preference data base2- For species with distinct seasonal occurrence, extraction of the species occurring at the

time of the on-site faunistic survey(s).3- Comparison of the predicted list obtained in 1 or 2, with the list of species recorded

on-site. This can be achieved through calculation of the percentual representation ofthe list of species predicted for each on-site macrohabitat. Interpretation of thesevalues is dependent upon the purpose of the assessment.

4- If data are available about the threat status of the species, the comparison can besupplemented by consideration of the threatened species associated with each on-sitemacrohabitat.

5- This procedure can be used not only to assess the present biodiversity of the on-sitefauna, but also to anticipate its modification by known impacts that would modify on-site macrohabitats in predictable ways.

47

Tentative decision treeThe following decision tree may be followed for each faunal group separately.Q1If you wish to consider the representation of all RMW-Typical species on the site,

go to Q2If you wish to consider the representation of only endemic and/or threatenedspecies, go to Q5If you wish to use both options, proceed through questions Q2-Q4 and thenthrough questions Q5-Q8

Q2At the site scale, consider the percent representation of the regional list of RMW-typical speciesif > 40% of the predicted RMW-Typical species occurring in the regionstudied are observed on-site: high overall contribution of the site to biodiverrsitymaintenance for the taxonomic group investigated.whether or no 40% of the predicted RMW-Typical species occurring in theregion studied are observed on-site, go to Q3 for estimation of contribution tobiodiversity maintenance of macrohabitats.

CLONLTBRDECZAPREMollusca48%45%38%36%Carabidae23%26%--Syrphidae28%29%34%38%

Molluscs: On both Irish sites RMW-typical species reach a level of representationindicative of a high contribution to biodiversity maintenance, contrasting with the twoFrench sites, neither of which reach that level.Syrphids: Low values are obtained from all 4 sites for syrphids in Q2, despite the highvalues obtained for nearly all on-site macrohabitats in Q3, because the maximal diversityof syrphid faunas is attained in deciduous hardwood forest, of which alluvial hardwoodforest is an example, and all alluvial hardwood forest macrohabitats are missing from thesites studied. In other words, most RMW-typical syrphid species are associated withalluvial hardwood forest macrohabitats. Since these macrohabitats are absent from thesites studied the maximal faunal diversity of syrphids which could occur there is less than50% of RMW-typical syrphid faunas.

The results from Q2 demonstrate an omission from the structure of the existing decisiontree which could easily be made good. At present, the proportion of the entire, regionalRMW-typical fauna occurring on a site is calculated (in Q2), but the next logical step ismissing, namely calculation of the proportion occurring of the RMW-typical fauna of the

48

complete set of on-site RMW-typical macrohabitats, taken together. For syrphids, theexisting Q2 essentially provides an overview of the condition of the investigatedfloodplain system in general, since it is almost inconceivable that a site could possessmore than 40% of the entire regional RMW-typical syrphid fauna without being situatedin a functioning, more or less complete floodplain system. As proposed above, themissing question would address the general condition of the sub-set of RMW-typicalmacrohabitats occurring on the site(s) investigated, in this way providing an overview ofthe site in general.

Q3At the site scale, consider the percentual representations of the predicted list ofspecies in each on-site RMW -Typical macrohabitat- for each RMW -Typical macrohabitat >50% = high contribution by that RMW-typical macrohabitat to biodiversity maintenance- for all Macrohabitats go to Q4 for estimation of contribution to biodiversitymaintenance of individual microsite features

SiteLTBR CLONSyrphidae Mollusca Carabidae Syrphidae Mollusca Carabidae

15 Alluvial forest(gen.)

30% 39% 35%

151 Softwood(gen.) 43% 29%1514 Gallery Softwood 48%15141 Gallery Softwood overmature 56%15142 Gallery Softwood mature 75%15143 Gallery Softwood saplings 70%

Scatteredtrees/Salix/mature

0%

21 Tall herbcommunities

70% 42% 46% 61% 46% 40%

2312 unimp. grass. 36% 40%23121 unimp. grass. eutroph.(gen.) 70% 57% 64% 64%231212 unimp. grass. eutroph.floode

d75% 69%

64 Reed/tall sedgebeds (gen.)

55% 77% 33%

641 Reed beds 64% 82%665 Running water edge 100% 80%6651 River bank 26% 23%713 Temporary pool 62%

49

DECZ APRE

Syrphidae Mollusca Syrphidae Mollusca15 Alluvial forest (gen.) 48% 43% 49% 47%151 Softwood(gen.) 70% 40% 68% 50%151a Softwood(gen.) overmature 68% 65%151b Softwood(gen.) mature 73% 71%151c Softwood(gen.) saplings 92% 90%1514 Gallery Softwood15141 Gallery Softwood overmature15142 Gallery Softwood mature15143 Gallery Softwood saplings

Scatteredtrees/Populus/overmature

78%

Scattered trees/Salix/overmature 100% 100%Scattered trees/Salix/mature 100% 100%

21 Tall herb communities 55% 50% 60% 47%23112 unimp. grass. dry, no stones 76% 21%23121 unimp. grass. eutroph.(gen.) 70% 67% 60% 67%231212 unimp. grass. eutroph.flooded 68% 66%64 Reed/tall sedge beds (gen.) 54% 50%641 Reed beds 56% 43%642 Tall sedge beds 47% 70%6611 water edge / unvegetated mud 67%6612 water edge / vegetated mud 80% 80%662 water edge / sand 100% 100%664 water edge / standing 86% 86%665 water edge / running 83% 83%

River edge, sand/gravel 83% 83%

Molluscs: Despite the result produced by Q2, the two Irish sites show representation ofless than 50% of the expected species for 2 of the RMW-typical macrohabitatsrepresented on-site, namely softwood alluvial forest and tall herb communities. However,the other 4 achieve more than 50% representation, indicating a high contribution tobiodiversity maintenance. The two French sites also show most on-site RMW-typicalmacrohabitats represented by more than 50% of the predicted species, which might notbe expected given the outcome to Q2 for those sites. A lower contribution to biodiversitymaintenance is indicated for the macrohabitat categories softwood forest, dry/semiariduinimproved grassland without stones and reeds on the DECZ site and for tall herbcommunities on the APRE site.

50

Comparing representation of faunas for softwood forest on the two French sites showsthat this macrohabitat is better developed on APRE than on DECZ. Character andstructure of the unimproved, dry grassland without stones macrohabitat on that part of theDECZ site subject to flooding does not allow occurrence off all the species associatedwith this macrohabitat, a factor which must contribute to the poor representation of itsassociated fauna. Reeds on the DECZ site occupy a relatively small area, which may bethe reason that not all species associated with large reed beds occur there.

It is noticeable that a low representation of the species predicted for tall herbcommunities was observed on both French and Irish sites. It is probable that thismacrohabitat category is too heterogeneous for molluscs, as defined at present.

Syrphids: The significance of the RMW-typical syrphid fauna of alluvial hardwoodforests is again indicated by the Q3 results, in that the level of faunal representationattained for alluvial forest in general, on the sites where some form of alluvial forestmacrohabitat could be observed, was in each case below 50%. This said, the level ofrepresentation of the syrphid species typical for on-site RMW-typical macrohabitats wasotherwise almost universally above 50%, indicating a reasonable level of function on allsites studied, in respect of biodiversity maintenance. One exception is the result foralluvial softwood gallery forest on the LTBR site. The explanation may be sought in theresults for Q4, which show that, while the fauna associated with the herb layer of alluvialsoftwood forest is reasonably represented, that associated with the trees (live or dead)themselves is extremely poor, indicating they are now playing little direct part inmaintaining biodiversity. The same is true of the scattered trees present on the CLONsite. The only other on-site RMW-typical macrohabitat failing to attain a 50% level in itsrepresentation of associated syrphid species is the tall sedge-bed category on the APREsite. The Q4 results show that, while the vegetation-associated species from thismacrohabitat are mostly reasonably represented, all groups associated with water andwater-sodden ground in this macrohabitat are not. It would have been interesting tocompare these results with their equivalents for the molluscs, but since more than 50% ofthe molluscan fauna of the tall sedge-bed macrohabitat was observed on the APRE site(Q3), its disposition between microsite features was not investigated in Q4.

Q4For each RMW-Typical Macrohabitat shown in Q3 to be represented on-site by<50% of the predicted species, consider the species associated with its typicalmicrosite features:

51

- for each microsite feature for which >50% of associated, predicted specieswere observed: high contribution of this microsite feature to biodiversitymaintenance- for each microsite feature for which <50% of predicted species wereobserved: consult specialist if this result requires further investigation.

The following tables list for the macrohabitats with less than 50% of predicted speciesobserved, which typical microsite features have 50% or more of associated predictedspecies:

MOLLUSCS-French sitesmacrohabitats DECZ APRE151.Softwood forest A11225 strand-line debris

A31 wet mud/oozeA112172 under low growingplants, sparseA111312 on/in low growing plantsA111313 on/in tussocksA11111 FoliageA11152 fallen, timberA112222 leaves,among/underforest litter

21.Tall herb communities A111313 on/in tussocksA11131on herb layer plantsA11223 among/under herb layerlitter

23121.no stones dry/semiaridunimproved grassland

A111311 on tall strong herbs

641.Reeds A11223 among/under herb layerlitterA22112 submerged mud/oozeA22213 below surface emergentwater plantsA31 wet mud/oozeA11214 among reed/tall sedgebedsA33 sodden plant debrisA111312 on/in low growing plants

52

SYRPHIDAE French sitesmacrohabitats DECZ APRE15. Alluvial forest (gen) A111151 tall shrubs/ bushes/

saplingsA111152 low shrubs/ bushes/saplingsA1112 upward climbing lianasA11311 tall strong herbsA11312 low growing plantsA11311 tussocksA11151 standing timberAA112171 dense low growingplantsA112221 woody surface debris +leavesA112222 dead leavesA11223 herb layer litterA113 nests of social insectsA1213 bulbs/ tuberA1215 rotting tree rootsA31 wet mud/ oozeA331 sodden timberA332 sodden twigs

A111121 trunk cavitiesA11113 mature treesA11114 understorey treesA111151 tall shrubs/ bushes/saplingsA111152 low shrubs/ bushes/saplingsA1112 upward climbing lianasA11311 tall strong herbsA11312 low growing plantsA11151 standing timberA111521 fallen timber with barkA111522 fallen timber no barkA11153 stumpsAA112171 dense low growingplantsA112221 woody surface debris +leavesA112222 dead leavesA11223 herb layer litterA113 nests of social insectsA1213 bulbs/ tuberA1215 rotting tree rootsA31 wet mud/ oozeA33 sodden plant debris (general)A331 sodden timberA333 sodden non-woody plantdebris

642 Tall sedges A111 on/in plants (gen)A1113 herb layer (gen)A11131 on herb layer plants (gen)A111312 low-growing plantsA1122 among/under surface debrisA11223 herb layer litterA121 root zone (gen)

MOLLUSCS - Irish sitesmacrohabitats CLON LTBR151.Softwood forest not represented A11225 strand-line debris

A11234 on sand21.Tall herb communities none _50% none _50%23121.Eutr.humid/floodedunimproved grassland

A111312 on low growingplants

none _50%

641.Reeds A11214 among reed/tall sedgebeds

not represented

665.Running water edge

713 temporary pool

A11225 strand-line debrisA33 sodden plant debrisnot represented

A33 sodden plant debrisA11225 strand-line debrisA33 sodden plant debris

53

CARABIDAE - Irish sitesmacrohabitats CLON LTBR15.Alluvial forest not represented A11212 liana-covered bushes

A11235 mud/ooze21.Tall herb communities none >50% none >50%2312.Humid or floodedunimproved grassland

A11215 grassland vegetation none >50%

64.Reed/tall sedge beds A112172 sparse low growingplantsA11234 sandA11235 mud/ooze

not represented

6651.Riverbank A11212 liana-covered bushes A11212 liana-covered bushes

SYRPHIDAE Irish sitesmacrohabitats CLON LTBR15. Alluvial forest (gen) A111152 low shrubs/ bushes/ saplings

A1112 upward climbing lianasA11311 tall strong herbsA11312 low growing plantsA11311 tussocksAA112171 dense low growing plantsA112221 woody surface debris + leavesA112222 dead leavesA11223 herb layer litterA113 nests of social insectsA1213 bulbs/ tuberA31 wet mud/ oozeA33 sodden plant debris (general)A333 sodden non-woody plant debris

151. Softwood alluvial forest (gen) A111121 trunk cavitiesA111152 low shrubs/ bushes/ saplingsA1112 upward climbing lianasA11311 tall strong herbsA11312 low growing plantsA11311 tussocksAA112171 dense low growing plantsA112221 woody surface debris + leavesA112222 dead leavesA11223 herb layer litterA113 nests of social insectsA1211 grass rootsA1213 bulbs/ tuberA1214 stem basesA1215 rotting tree rootsA31 wet mud/ oozeA33 sodden plant debris (general)A333 sodden non-woody plant debris

54

Molluscs: In the gallery softwood forest macrohabitat of LTBR 8 of a total of 35 typicalmicrosite features harbor >50% of predicted species. This macrohabitat is notfunctioning, and its typical microsite features are hardly developed or missing. Two froma total of six typical microsite features of the tall herb communities macrohabitat have>50% of the predicted species on both Irish sites.

In the softwood forest macrohabitat of the DECZ site, eight from a total of 35 typicalmicrosite features harbor >50% of the predicted species. Two from a total of six typicalmicrosite features of the tall herb communities macrohabitat have >50% of theirpredicted species on site APRE. Both microsite features belong to the same categories asare on the Irish sites. Only one from 11 typical microsite features of the dry/semiarid,unimproved grassland without stones macrohabitat contributes acceptably to maintenanceof biodiversity. This is one explanation for the general low level of functioning of thatmacrohabitat, indicated in Q3. The majority of typical microsite feature of the reed bedsmacrohabitat contribute to maintenance of biodiversity.This confirms indirectly theassumption that low representation of predicted snails is caused by the small area of reedbeds observed on the DECZ site.

Syrphids: The significance of the absence of alluvial hardwood forest macrohabitats fromall sites studied, in respect of the syrphid fauna, has already been referred to. The resultsfrom examining in more detail, in Q4, the under-representation of alluvial forest specieson the sites studied highlights the significance of certain microsite features in maintainingthe biodiversity of the alluvial forest syrphid fauna. In particular, the role of micrositefeatures dependent upon overmature trees and timber is demonstrated. On the Frenchsites, the syrphid fauna of young and understorey trees, shrubs and non-woody plants isat an observably satisfactory level of representation, but the fauna of overmaturetree/timber microsites is in general not, and contributes in large measure to the low levelsof representation of alluvial forest syrphids on these sites, as indicated in Q3. The faunaof timber and hollow trees on the APRE site is one exception to this generalisation, andthe fauna of rotting tree roots provides another. On the LTBR site, it is only the low-growing shrubs and non-woody vegetation which is playing a satisfactory role inmaintaining a fauna in the rudimentary alluvial softwood gallery forest present on thesite.

55

The only non-alluvial forest category attaining less than 50% of its expected fauna is thetall-sedge bed category on the APRE site. Examination of the microsite feature resultsshows that for this macrohabitat, the vegetation components are generally contributingsatisfactorily to maintenance of biodiversity, with the exception of tall strong herbs.

One somewhat misleading consequence of attempting to code species from all threetaxonomic groups for the same categories is manifest from the syrphid results for Q4,which may be illustrated by reference to the microsite feature “upward-climbing lianas”.This category has no known syrphid species particular to it and the only syrphids codedfor it are generalists, whose larvae will feed on aphids on various plant types in a widerange of different biotopes. The presence of the known syrphid fauna of upward-climbinglianas is thus of no particular ecological interest and would be expected almost whereverthis microsite feature occurs - 100% representation of the associated species is not anexceptional situation. Were this microsite feature category not required for one of theother taxonomic groups involved in the project, it would not be coded for syrphids. Arefinement of the database content could be achieved by careful consideration of suchfeatures to decide whether coding them adds anything which aids in interpretation. It maybe wiser to leave such features entirely uncoded for taxonomic groups which have nofauna specifically associated with them, even though they may be used by generalistspecies.

Q5At the site scale, consider the representations of species endemic to a restrictedpart of Europe (localised endemic + point endemic categories in database) ineach on-site typical RMW habitatfor each RMW -Typical habitat presence of 1 or more restricted endemic =high contribution by that RMW-typical macrohabitat to biodiversity maintenance

Molluscs: In Ireland there is only one localised european endemic snail, Ashfordiagrannularis. It is not associated with any RMW typical macrohabitat. Neither of theFrench sites harbor any localised, European endemic mollusc species.

Carabids: For the three groups and the four sites investigated, only one carabid species,Bembidion clarcki, belonging to the category "localised endemic" was sampled on theIrish site LTBR. It is associated with macrohabitat categories Alluvial forest, and Tallherb communities.

56

Syrphids: There are no localised syrphids endemic to Europe recorded from any of thesites studied. More than anything else, this is a reflection of the small number of suchspecies that are associated with RMW-typical macrohabitats in the Atlantic zone ofEurope. Only two of the localised endemic syrphid species in the database, Chrysogasterrondanii and Sphaerophoria potentillae, might be expected to occur in RMW-typicalmacrohabitats and neither of these species has been recorded from either Ireland orFrance. In total, there are only 6 localised European endemic syrphid species recordedfrom the entire Atlantic zone of Europe.

Q6At the site scale, consider the number of threatened European species present, orof threatened national species present. If there is 1 or more threatened speciespresent: high contribution of site to maintenance of biodiversity

Molluscs: Because of the tentative nature of the list of threatened European molluscs,only the list of threatened Irish gastropods has been used for the Irish sites. 17 species areregarded as threatened in Ireland. None of them have been found on site CLON. Onethreatened species, Succinella oblonga, has been found on site LTBR, reinforcing thehigh contribution of this site to maintenance of biodiversity suggested by Q2. Since thereis no list of molluscs regarded as threatened in France and the existing list of gastropodsthreatened at European level is of questionable reliability, it has not been possible tocarry out a Q6 calculation for the French sites. It follows that there are no data availableto use to carry out Q7 or Q8 calculations for the French sites.

Carabids: There is no threat status information available for carabids at European level.No Carabids which can be regarded as threatened in Ireland were found on the Irish sites.

Syrphids: More threatened species were observed for the Syrphidae than for the twoother groups. The following table gives the numbers of species threatened at variouslevels, sampled on the studied sites.

Europe: Atlant,zone France Central.France Irelandthreatened threatened threatened threatened threatened

SITELTBR not relevant not relevant 1CLON not relevant not relevantAPRE not relevantDECZ 2 2 2 2 not relevant

57

One syrphid species which may be regarded as threatened in Ireland, Helophilustrivittatus, was found on the LTBR site, categorising that site as making a highcontribution to biodiversity maintenance. But H.trivittatus is by no means threatened inEurope in general, so the LTBR site can only be viewed as making a high contribution tobiodiversity maintenance within an Irish context, on this basis. By contrast, the DECZsite in France can be regarded as making a high contribution to biodiversity maintenancein a broader European context, through the presence there of the two internationallythreatened syrphids Eristalis picea and Sphiximorpha subsessilis. By the same token, thesite makes a high contribution to biodiversity maintenance in both central France andFrance in general.

Q7For each threatened species observed, consult database to identify Macrohabitatpreferences. If there is a preferred Macrohabitat on-site: high contribution ofthat Macrohabitat to biodiversity maintenance

Molluscs: Succinella oblonga, observed on LTBR, is associated with the followingmacrohabitats: 23121 - eutroph. humid/flooded grassland, 322 - grey dunes, 324 - duneslacks, 665 - running water edge. Only the macrohabitats 23121 and 655 occur on site.

The macrohabitat associations of Succinella oblonga suggest that the eutrophicatedflooded unimproved grassland and running water edge macrohabitats on the LTBR sitecontribute highly to biodiversity maintenance, confirming the result obtained for thesemacrohabitats in Q3.

Syrphids: The following tables detail the macrohabitat preferences of the three Syrphidspecies sampled.Helophilus trivittatus, site LTBR23121 eutrophic humid or flooded

unimproved grassland1

brook edge in open ground 2permanent pool in open ground 2edge of permanent pool in openground

2

Eristalis picea, site DECZtemporary pool under canopy 2Spring in forest 2Flush in forest 2

15 Alluvial forest (gen) 1151 Softwood alluvial forest (gen.) 1

58

151a overmature 1151b mature 1151c saplings 1

Sphiximorpha subsessilis, site DECZ15 Alluvial forest (gen) 3151 Softwood alluvial forest (gen.) 3151a overmature 3151b mature 1

Scattered trees / Populus overmature 2

Q8For each threatened species observed, consult database to identify Micrositefeatures (if known) associated with the preferred on-site Macrohabitat(s) : Ifthere is a preferred Microsite feature on-site: high contribution of thatMicrosite feature to biodiversity maintenance.

Molluscs: The microsite features preferred by Succinella oblonga are:A11213 among tall strong herbsA11215 among grassland vegetationA11217 among low growing plantsA11223 among/under herb layer litterA11236 on soilAll were observed on site LTBR.

Syrphids: The following tables detail the microsite feature preferences of the 3 Syrphidspecies:Helophilus trivittatus, site LTBRM22 small water movement 2A22 In surface water 3A221 Submerged sediment/debris 3A2211 Fine sediment 3A22112 mud/ooze 2A22113 organic detritus 2A2212 Coarse sediment 2A22125 non-woody plant debris 2

Eristalis picea, site DECZM2 In standing water (gen.) 2M22 small movement 2A21 In ground water 3A22 In surface water 2A221 Submerged sediment/debris (gen.) 2A2211 Fine sediment (gen) 2A22112 mud/ooze 2A22113 organic detritus 1

59

A22125 non-woody plant debris 2A3 Water-saturated ground (gen.) 2A332 twigs 2A333 non-woody 2

Sphiximorpha subsessilis, site DECZA111 On/in plants 3A1111 Trees (gen) 3A11112 Overmature/senescent trees 3A111122 rot-holes 3A111123 sap runs/lesions 3

The association of the threatened syrphid species Sphiximorpha subsessilis with themacrohabitat categories of overmature and mature alluvial, softwood forest indicates ahigh contribution of these categories to biodiversity maintenance on the DECZ site,reinforcing the result obtained in Q3 in respect of this site. The fact that in Q4 the syrphidfauna of overmature tree microsite features on the DECZ site was shown to be under-represented demonstrates also that, even when a feature may be generally “under-performing” it may still support individual species of particular significance. Thepresence of Eristalis picea on the DECZ site similarly re-enforces the significance of thealluvial softwood forest macrohabitat there, but focuses on the water-sodden groundmicrosite features as playing a particular role. Helophilus trivittatus on the LTBR sitereinforces the value of the aquatic microsite features of the unimproved, humid grasslandmacrohabitat, whose significance was already demonstrated in Q3.

5.1.2. Salient features of the Functional Assessment Procedure.

The results presented here show how a standardised evaluation procedure may beoperated and that it produces an understandable and acceptable product. The sites studiedduring course of the project are arguably situated along some of the most importantremaining floodplains in Atlantic parts of Europe - if the fauna of such sites faileddemonstrably to reach the levels of completeness necessary to indicate that the sitescontributed significantly to maintenance of biodiversity, it could reasonably be concludedthat it was the procedure itself that was not functioning adequately, rather than thefloodplain. But a corollary to this argument is that there is equivalent need to demonstratethe procedure operates as well with dysfunctional sites, demonstrating there a failure tocontribute significantly to biodiversity maintenance Examples of use of the procedure ona range of sites of different apparent quality, both on and off floodplains, are not

60

available. The example provided is simply to demonstrate one potential use of thedatabase.

In its present form, the FAP employed here represents a stepwise investigation of thedegree of function of progressively smaller entities, the first level essentially providinginformation on the floodplain in general, the second on the site, the third onmacrohabitats on that site, the fourth on components of particular macrohabitats on thesite. It is debatable whether the user requires to pursue the interrogation of the databasefurther than the first level, in the event that a positive outcome is obtained there. But, ascan be seen from the worked examples, continuing through the process provides insightsinto the degree of functionality of components, even on sites shown at the first level to begenerally in functional condition.

It is pertinent to question which parts of an ecosystem are addressed by the taxonomicgroups employed as tools here, and whether use of any one of them alone can give asufficiently holistic picture of a site for it to be safe to extrapolate from the resultsobtained to the condition of the site fauna in general. Together, the three taxonomicgroups cover in the order of a 2% sample of the invertebrate fauna of the terrestrial partsof a floodplain site. While clearly better than no sample of invertebrates at all, this is nota very substantial proportion of the invertebrate fauna. Further, the three groups usedhere were chosen, in part at least, for their capacity to provide complementary, butdifferent, information on the condition of a site. That they provide somewhat differentinformation is evident from the few microsite features, in particular, for which there areresults obtained in common in the worked examples. Differences between the groups, inthe observed degree of completeness of their site faunas, just appear as apparentlycontradictory results, unless they can be explained. A good example is provided by theresults from Q2, in which the molluscan calculation shows the 2 Irish sites to be highlyfunctional, but the other two groups do not. Is this because the molluscs are reflectingconditions in components of sites to which the other taxonomic groups do not respond? Isit because molluscs reflect only certain aspects of a site’s potential, whereas the other twogroups provide a more holistic reflection, indicating that components of the site nottapped by the molluscs are in poor condition? Until clear answers to questions of thistype can be given and the potential of the different taxonomic groups can be more clearlystated, the non-expert user of the procedure could be forgiven for being confused byresults such as have been obtained here. An approach which would avoid creation of

61

confusion in this way would be to run all available taxonomic groups of invertebratesthrough the FAP together, as one data set. This has not been attempted with the threetaxonomic groups employed here and would entail modification of the existing databasestructure before it could be done. Nonetheless, it remains a possibility.

In the notes on the output obtained from each question, for the different taxonomicgroups, frequent reference is made to the levels used for deciding whether the degree offaunal representation indicates a high degree of function in maintenance of biodiversity.The 40% level is used for Q2, the 50% level is used for questions Q3 and Q4. Calibrationof the procedure in this way is necessary for it to work, but it requires emphasising thatthe percentages referred to are percentages of the fauna predicted for the times of the year(e.g. end May/beginning June + first half August for the French sites) that the sites weresampled, not of the entire predicted fauna. There can be no absolute measure ofbiodiversity and any evaluation system introduced is ultimately subjective, howeversurrounded by criteria. The levels used in the FAP here are based on the best professionaljudgement of invertebrate specialists who have been working in the field of siteevaluation, but clearly these figures are not immutable. If experience in the use of aprocedure showed that the levels used were unrealistic, they could be adjusted, so long asit were clearly stated what levels were employed and the same levels were usedthroughout any comparison of a set of sites.

In progressing through the decision tree, there is a noticeable tendency to use the outputobtained from later questions to aid in explanation of the output of previous questions.This process stops with Q4, no finer dissection of the data being possible beyond thispoint using the existing structure. However, the data on species traits remains largelyuntapped in the decision tree as presented, and there is considerable potential for gainingclearer understanding of the results by harnessing the traits data in such a way as toprovide a fifth level of precision. This is probably an unending process, in that all that isreally being said is that with more data more could be achieved. But with incorporationof the traits data into the decision tree the available data files would be by and large usedup. If the type of approach to employment of faunas in environmental assay enshrined inthe FAP used here is to develop, and become usable for answering more than rather basicquestions, there is considerable need for resources to be allocated for autecological workon the target organisms - without better knowledge of them their use as tools cannotprogress beyond a certain level, which is approaching all-too-rapidly. That said, the

62

existing database is proving a remarkably powerful tool and interest in its use should helpto stimulate the generation of data which will increase its capacity and versatility.

5.2. Use of the database in general site management

For a site manager, a site list of birds, mammals or flowering plants has rather differentimplications from a site list for some group of invertebrates. For one thing, the speciesare usually big enough to find, unaided. For another, getting to know most of themsufficiently well to be able to recognise them is usually a practical proposition, becausethere are not too many of them. Thirdly, there is usually someone within reach to providebasic information about the species. Failing that, there is normally reasonably accessiblerelevant literature. Certainly, invertebrate species lists are not generally so amenable tointerpretation. Various attempts have been made to make invertebrate lists more usable,primarily by developing systems for indexing species, so that each has a particular valuefor a given type of analysis. A range of examples, mostly based on Coleoptera, can befound in Eyre (1996). Decleer and Verlinden (1992) provide an example based onSyrphidae. The Syrph the Net database represents an attempt to provide a role for allrecorded syrphid species in site assessment/ management procedures, rather thanconfining attention to some particular subgroup(s) of species, as in more traditional “bio-indicator” work. It is hoped that, armed with relevant species lists of Syrphidae, a sitemanager knowing little or nothing about syrphids will be able to interrogate the syrphiddatabase as illustrated in the following pages, thus transforming syrphid species listsfrom collections of meaningless names into valuable information.

The site used in this demonstration is beside the Old Kenmare Road, in the KillarneyNational Park, Co.Kerry (Ireland) and is referred to in this text as the OKR site. Attemptsare being made by the National Park Authority to improve the quality of the OKR site. Itis on a north-east facing slope, at 300- 400 metres altitude. It is covered in moorland anddegraded blanket bog, with areas of poorly-drained Molinia grassland maintained by deerand sheep. In the valley bottom it incorporates an oligotrophic stream flanked by a smallfloodplain, covered by Myrica/Schoenus bog. This stream has occasional, isolated scrubSalix along its length, augmented by a few old, planted Larix and one or two trees ofQuercus, Ilex and Betula, where it passes through a steep-sided gulley. Malaise trapswere installed on this site for 3 periods of 20 days during 1995: 1-21 June, 1-21 July and

63

1-21 August. Traps were installed in pairs at each trapping station, a total of 9 trappingstations being used in all.

In this instance, use of the database involves comparison between observed and predictedfauna at many levels and using many different combinations of categories, combinedfrom different data files. The utility of any particular comparison depends upon thequestions being asked of the database. In the present context two general questions willbe addressed. Firstly, in what ways might the character of the site be most usefullymodified in order to improve the representation of species associated with the habitatspresent on the site now? Secondly, in what ways might the composition of the fauna ofthe site be expected to change in response to introduction of other habitats there? Inaddressing these questions, a step-wise process is adopted, in which attributes of a sitefauna recognised as demanding further investigation at one stage are further investigatedat the next stage, the stages of the process being characterised by a progressive filteringof the fauna into ever-more closely defined sub-groups. In these features, this processclosely resembles the process followed in the site evaluation procedure detailed inprevious pages. Site components are defined in habitat and microhabitat terms, andrequirements of missing species predicted for the site are identified through theirbiological traits.

Examination of the site fauna commences using the entire observed fauna (i.e. sitespecies list, which is in this case based on inventory rather than a sampling programme)and the entire predicted fauna.

The first filter used with the predicted fauna is geographic, so that prediction operateswithin the preferred geographic context, be it international, national or regional.The first filter used with the observed fauna relates to the habitats observed on-site.Inevitably, since the adults of Syrphidae are flighted organisms, some of the observedspecies will be derived from habitats not present on-site, but from somewhere in thesite’s vicinity. Segregating the observed species into those associated with habitatsobserved on-site and those not associated with habitats on-site is thus the first actionperformed on the site list within the computer. The observed species associated with thehabitats observed may then be compared with the predicted species associated with thosehabitats, to establish whether there is a reasonable representation on-site of the speciesexpected for those habitats.

64

The concept of a “reasonable” representation of the expected species is centred on the50% level. In other words, if 50% or more of the regionally-occurring species associatedwith a particular habitat are present on the site, the fauna of that habitat is taken to bereasonably represented. If less than 50% of the predicted species are present, the fauna ofthat habitat is regarded as under-represented. Contrasting situations illustrated by 3different habitats on the OKR site are shown in Fig.5.1. The syrphid fauna of the poorly-drained, unimproved pasture present on the site is represented by 40% of the Atlantic-zone species for that habitat, 42% of the Irish species for that habitat, 44% of theCo.Kerry species for that habitat and 60% of the Killarney National Park species for thathabitat. So, only in the context of representation of the National Park fauna would thefauna of poorly-drained unimproved pasture be regarded as reasonable on the OKR site.All of the species associated with the general surface of blanket bog in the Atlantic zoneare, however, present on the OKR site, so for this habitat category the site fauna wouldbe regarded as reasonable at all four regional levels.

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Pasture

Bog surface

Stream

Fig. 5.1.: The OKR species associated with three different habitats, shown as a percentage of thespecies associated with those same habitats in the species lists for various geographical areas. Thusthe first histogram column shows that 40% of the AZ species associated with poorly-drained, unimprovedpasture occur on the OKR site, and the fourth column shows that these species represent 60% of the KNPspecies associated with this habitat. Abbreviations: AZ = Atlantic zone of Europe; IRL = Ireland; Kerry =Co.Kerry; KNP = Killarney National Park; OKR = Old Kenmare Road site.

65

It is possible to identify whether the fauna of some particular microhabitat is under-represented in a particular habitat, or whether species-representation is poor for allmicrohabitats associated with that habitat. The OKR site representation of speciesassociated with various microhabitats of the poorly-drained, unimproved pasture isshown in Figs.5.2a and 5.2b. Fig.5.2a shows that predicted species with larvae living onherbaceous plants in poorly-drained, unimproved pasture are well-represented on the site,whereas predicted species with larvae living in plant stems or bulbs in this habitat areentirely absent. Examination of the biological traits of these species shows that theformer group have aphid-feeding larvae, whereas the larvae of the latter group feed onplant tissues. The plant feeders are much influenced by which plant species are present,while the aphid feeders are more dependent upon vegetation structure. The flora of theMolinia grassland on the OKR site is species poor, so an absence of plant-feedingsyrphids there is not surprising. Fig.5.2b shows that the representation of species withlarvae inhabiting litter-layer microhabitats is more as predicted for species whose larvaelive free in the litter than for species with larvae living in sub-aqueous microhabitats ofdecomposing vegetable debris and cow-dung. More or less the same suite of absenteespecies is involved in respect of both decomposing vegetable matter and cow-dung, sincetheir larvae may use either microhabitat. Examination of their biological traits shows allare microphages/ saprophages as larvae. Since there have been no cows on this site, thegrazing animals there being deer (Cervus elephas) and sheep, absence of syrphids withcow-dung- feeding larvae would be expected. However, the absence of these samespecies also indicates that supplies of wet, decomposing vegetable matter in general areinadequate or in an inappropriate condition for them, on the OKR site.

The same, step-wise process may be used to identify which site components arefunctioning most effectively for the fauna of the habitats represented on a site. Theimplication then being that, for these site components, existing management practicesshould be continued. The entire procedure can be re-run considering only threatenedspecies, or only threatened European endemic species, or whichever target group of thefauna requires to receive separate attention.

66

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%On herbaceous plants

In herbaceous plants(stem s) In herbaceous plants(bulbs)

Fig. 5.2a: The OKR species associated with three larval microhabitats of poorly-drained,unimproved pasture, expressed as a percentage of the species associated with these samemicrohabitats in various geographical areas. Thus the first histogram column shows that more than 80%of the Atlantic zone species occurring as larvae on herb layer plants in poorly-drained, unimproved pasture,occur on the OKR site. The eight vacant columns show that none of the species with larvae living in planttissues or bulbs, in this habitat, occur on the site. Abbreviations: as in Fig.5.1.

0%

10%

20%

30%

40%

50%

60%

70%

80% Plant litter

W et/subm erged plant litter

Cow dung

Fig. 5.2b: As Fig.5.2a, but for different microhabitats.Abbreviations as in Fig.5.1.

67

5.2.1. Use of the database in site restoration

Two potential components of site restoration activity will be considered here:replacement of missing components of existing ecosystems and replacement of oneecosystem by another.

5.2.1.1 Replacement of missing ecosystem components

Replacement of missing components of a system implies the existence of somemechanism for identifying which components are missing. Comparison between the listof species observed and the list predicted for a site can aid in identifying missingcomponents, just as it can in identifying poorly-functioning components.Use of thesyrphid database follows the same general procedure in both instances, but in identifyingmissing components the predicted fauna is drawn not only from the species associatedwith habitats observed on the site, but from all habitats typical for the ecosystemsobserved on the site. Thus, in the case of the OKR site, in identifying missing ecosystemcomponents the species predicted for blanket bog would include not only those for thehabitats of blanket-bog surface, flushes, springs and streams, all of

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Stream Spring Flush Pool edge

All b.bog habs.

Blanket bog habitats

Fig. 5.3: The predicted Irish syrphid fauna of habitats that are typical constituents of blanket bog,compared with the observed fauna for these habitats in selected geographic areas. Thus the firsthistogram column shows that 70% of the stream-associated blanket-bog species known in Ireland occur on

68

the OKR site. The second column shows that the same proportion of these species occurs in the KillarneyNational Park in general. Abbreviations: All b.bog habs. = all blanket-bog habitats; others as in Fig.5.1.

which were observed on-site, but also for pools, which were not observed. The result ofcomparing observed fauna with predicted fauna are shown in Fig.5.3. It is apparent fromFig.5.3 that there is, indeed, a group of syrphid species associated with pools in blanketbog in Ireland, only 45% of which are found on the OKR site, making this the poorest-represented group of blanket bog species occurring there. These histograms also showthat whereas more than 90% of the Irish species in this group occur in Kerry, only justover half of them are present in the Killarney National Park. Further investigation ofthese missing species shows they all have larvae which are either predatory (on aphids)or aquatic/subaquatic saprophages.

5.2.1.2 Replacement of one ecosystem by another

Replacement of an ecosystem existing on a site by another ecosystem implies somemethod for deciding which alternative ecosystem would be the preferred option. On theOKR site, active consideration is being given to replacement of the poorly-drained,unimproved Molinia grassland by some form of forest. This proposition requiresconsideration of what is the potential for establishment on-site of a representative faunaof the alternative forest types. An approach to evaluating the relative merits ofestablishing Quercus forest or Alnus/Salix forest there is illustrated in Fig.5.4. Inconducting this comparison, all species observed on the OKR site are included - thespecies recorded on the OKR site, but not associated with existing habitats there, may bederived from Quercus or Alnus/Salix forest somewhere in the vicinity, and would soindicate a capacity for species from these forest types to reach the OKR site. Fig.5.4shows that the existing site fauna contains few species associated with either Quercus orAlnus/Salix forest, and that, except for species associated with scrub, the existing faunawould contribute somewhat more to Alnus/Salix forest than to Quercus forest. The faunaof the Killarney National Park in general would also have a greater capacity to contributeto the fauna of Alnus/Salix forest, were it established on the OKR site, than to the faunaof any Quercus forest established there, again with the exception of scrub fauna. Thesame is true of the fauna of Kerry, the County within which the Park is located. Overallthen, Alnus/Salix forest established on the OKR site might be expected to have a morecomplete fauna than Quercus forest established there.

69

��

��

��

��

��

��

��

��

��

��

��

��0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

��Series1 Series2

Scrub Clearings M ature Overm ature

Salix Q uercus

Fig. 5.4: Syrphid fauna predicted for selected habitats typical of two forest types, Quercus andSalix/Alnus, if established on the OKR site, based on the known fauna of these forest types in areasof different geographic extent. Thus, the first histogram column shows that c.20% of the Irish speciesassociated with scrub Salix would be predicted to occur on the OKR site if Salix forest were establishedthere, basing prediction on the existing OKR site fauna. The third column similarly shows that c.45 % ofthe Irish scrub Salix fauna would be expected, basing prediction on the fauna of the National Park ingeneral. Abbreviations: as in Fig.5.1.

Another line of enquiry concerns the extent to which an introduced ecosystem type mightbe expected to support particular groups of target species, for instance threatened species.In considering this question it is necessary to address such issues as what threatenedspecies are available for colonisation of the site, what microhabitats they occupy and forhow long it would be necessary to monitor the site in order to evaluate the success of theundertaking. As an example, Quercus-forest syrphids threatened in Ireland are consideredin Fig.5.5. The first set of three histogram columns shows that no species in this categoryoccur on the site at present, that only 10% of them occur in the Killarney National Parkand only 30% of them have been recorded from Co.Kerry in general. The majority of thethreatened Irish Quercus forest syrphids cannot, therefore, realistically be regarded asavailable for colonisation of the OKR site. The second set of three histogram columnsshows that most of the threatened species in this category are saproxylics, so that anyQuercus forest established on the OKR site would have to be of adequate size to providefor all age classes of trees up to and including overmature and senescent trees, in order tomaintain these species on-site, were they to establish themselves there. The third set of

70

three columns shows that most of these threatened species would not be expected toestablish themselves on-site in less than 50-100 years, so that long-term monitoringwould be necessary to find out whether establishment of Quercus forest on the OKR siteled to establishment of these species. The spreadsheet used in production of this set ofhistograms has as yet only been coded for the Irish species and does not form part of thepublished version of the database.

0%

10%

20%

30%

40%

50%

60%

70%

80%

O ak forest syrphids threatened in Ireland

establishm ent tim e

m icrohabitat

IRL spp. in diff.lists

Fig. 5.5: Threatened Irish Quercus forest syrphid species categorised in three different ways: asrepresented on selected lists (three columns at left); as associated with three different larvalmicrohabitats (three columns at centre); according to potential rate of establishment on-site (fourcolumns at right). For explanation, see text. Abbreviations: as in Fig.5.1.

5.3. Comparisons between regional lists.

To illustrate this potential application of the database, syrphid species lists for variousparts of the Atlantic zone of Europe are compared. The lists are derived from Ireland,Great Britain, North France, Central France and the Atlantic Zone in general, these partsof Europe being defined as in Speight (1996b), where this comparison was firstpresented.

The syrphid list used for North France comprised 228 species, while the list for GreatBritain included 251 and the list for Ireland 171. The list compiled for the Atlantic zonein general comprised 345 species when this comparison was carried out. The species may

71

first be categorised according to which general habitat categories they utilise. Thedistribution of the species between general habitat categories is indicated in thehistograms presented in Fig.5.6, with the species complement for each of the five listsbeing considered separately. It should be noted that because the habitat associations ofspecies are not necessarily exclusive, some species occur in more than one of the habitatcategories employed. In consequence, summing the percentages shown by a set ofhistograms for a particular species list does not give a total of 100%.

��

��

��

��

��

��

��

��

��

��

��

��

0%

10%

20%

30%

40%

50%

60%

Deciduous forests Coniferous forests W etland Open ground

Series1

Series2�� Series3�� Series4��

Series5

CFR

NFR

GB

IRL

AZ

Fig. 5.6: Representation of syrphids associated with major habitat categories in various parts of theAtlantic zone of Europe, expressed as the percentage of each regional list associated with each category.Example: column 1 shows that approximately 54% of the syrphid fauna of Central France is associatedwith deciduous forest habitats.Regional lists used: AZ = Atlantic zone, general; CFR = Central France; GB = Great Britain; IRL =Ireland; NFR = North France.

Fig.5.6 shows that the major component of the Central France fauna is deciduous forestspecies, and the similar preponderance of deciduous forest species in the lists for NorthFrance and Great Britain suggests this is not unusual for parts of Atlantic Europe. In thepast, the natural vegetation types predominating in these parts of Europe were alldeciduous forest of one sort or another (Ozenda, et al, 1979), so the dominance ofwoodland syrphids in these faunas is not surprising. But, given the considerable influenceof man’s activities in Europe over the past 5000 years, particularly in removing forestfrom most of the continent, the dominance of woodland syrphids in these lists might quitereasonably be regarded as a “fossil” feature, reflecting the past rather than the present.

72

The case of Ireland, where forest removal by man has been most extreme and wetlandsyrphids predominate, might simply be interpreted as being as much a consequence of theland-use history of the island as of climatic influences. The increasing diversity ofindigenous, deciduous forest types represented locally, as you travel from Ireland throughto Central France, will also increase the capacity of Central France to support deciduousforest syrphids, in comparison with Ireland. For instance, beech (Fagus) forest is notindigenous to Ireland, whereas it is indigenous to the parts of Europe covered by theother lists used in Fig.5.6, and 5% of the deciduous forest syrphids listed for GreatBritain, North France and Central France are species which occur almost exclusively inbeech forest.

Fig.5.6 shows there is a progressive increase in the proportion of deciduous forestsyrphids in each list as you pass towards Central France, but does not address thequestion of the number of deciduous forest species in these lists. Contrasting the Irish andCentral France lists, Fig.5.6 indicates that there is either a lesser diversity of wetlandspecies represented in the Central France list, or a considerable increase in the deciduousforest species in that list, as compared with Ireland. Examination of the lists themselvesshows that both processes are occurring.

The general habitat grouping with the smallest component of species in the CentralFrance list is conifer forests, in stark contrast to the situation for deciduous forests. Onceagain, comparison with the other species lists shows this is not an exceptional condition.Indeed, comparing the situation with the species lists for the entire Atlantic zone showsthat syrphids which utilise conifer forest habitats are but a minor constituent of the entireregional fauna. Presented as in Fig.5.6, the conifer forest contingent of syrphid speciesincludes species shared with deciduous forest, i.e. species which utilise either conifer ordeciduous forests as habitat. If syrphids which use only conifer forest habitats areconsidered separately, an even more extreme situation is revealed. More than half of theconifer forest syrphid fauna consists of species shared with deciduous forest - the speciesoccurring only in conifer forest comprise only 8% of the lists for Central France andNorth France, 9% of the list for Great Britain and 6% of the Irish list. The most extremecase is again that of Ireland. Indigenous conifer forests (of Pinus sylvestris) are believedto have been almost entirely eradicated from Ireland for 500 years or more, so the 6% ofthe fauna made up of strictly conifer forest syrphids is believed to be of very recentorigin, namely syrphids which colonised the island subsequent to introduction of

73

commercial plantations of introduced conifers, which began on a large scale only duringthe present century.

The small size of the conifer forest syrphid fauna in these various parts of the Atlanticzone of Europe shows that the current practice of replacing native deciduous forests withconifers, whether the conifers are of European or other origin, must result in a netdecrease in the diversity of the syrphid fauna. Furthermore, Fig.5.6 shows that these partsof the Atlantic zone are also typical of the Atlantic zone in general, in the relativeinsignificance of the conifer forest fauna. At a time when European nations areattempting to grapple with the problems of maintaining biological diversity, following onfrom the provisions of the Biodiversity Convention, the potential influence ofconiferisation on the diversity of forest faunas perhaps requires to be given greaterprominence. If other taxonomic groups are similar to the syrphids, forest faunas willprogressively change from being the largest group of species in a local fauna to itssmallest group of species, as an area’s forests are converted from deciduous trees toconifers, to judge from the information provided by the comparison of species listspresented here. Admittedly, with enormous hectarages of conifers now establishedoutside their natural range, from the Atlantic to the Urals, some influx of conifer forestfauna from outside Europe, from Siberia, might be expected. To-date, this invasion haslargely resulted in the appearance of a number of conifer pest species and their associatedpredators - some of them syrphids - which has in no way counteracted theimpoverishment of forest faunas caused by coniferisation itself.

Fig.5.7 demonstrates that syrphids with predatory (aphid-feeding) larvae are predominantin the conifer forest fauna of the Atlantic zone of Europe, and that this dominance isexpressed in its most extreme form in the Irish list. Managed, commercial coniferplantations lack both the associated ground flora and the overmature trees of indigenous,natural forest. In consequence, the syrphids associated with both ground flora and oldtrees are almost entirely absent in Irish conifer plantations and hence absent from theIrish syrphid list. In contrast, the presence of more extensive areas of less intensivelymanaged indigenous forest, both conifer and deciduous, in both North and CentralFrance, is reflected in the reduced dominance of forest syrphids with predatory larvae

74

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

d.predators c.predators d.herbivores c.herbivores d.saproxylics c.saproxylics

Fig. 5.7: Representation of syrphids with predatory, plant-feeding or saproxylic larvae in thedeciduous forest and coniferous forest faunas of various parts of the Atlantic zone of Europe, expressed asa percentage of the relevant forest fauna of each species listCoding of columns as in Fig.5.6; prefix c = coniferous forest; prefix d = deciduous forest e.g. dpredators =deciduous forest syrphids with predatory larvae. Example: column 9 shows that 90% of the Irish coniferforest syrphids are species with predatory larvae.

there, the species with saproxylic (dependent upon old/senescent trees) or plant-feeding(leaf, stem or root-mining) larvae becoming increasingly evident components of thefauna. The fauna for Central France again represents the opposite extreme to the Irishfauna, in this regard. The percentage of predatory species in the Central France list mostclosely resembles that for the Atlantic zone in general, in respect of both deciduous andconifer forests. It is noticeable that in both conifer and deciduous forest,

Syrphids with predatory larvae are the dominant component in all lists. However, even inthe list for the Atlantic zone in general, the predatory species comprise a greaterproportion of the conifer forest fauna than the deciduous forest fauna - in deciduousforest, the saproxylics and plant-feeding species combined represent as great a proportionof the fauna as the predators, while in conifer forest there are twice as many predatoryspecies as the combined total for plant-feeders and saproxylics.

75

��

��

��

��

��

��

��

��

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

peatlands other wetlands dry, unim proved pasture hum id, unim proved pasture

Fig. 5.8: Proportion of the Atlantic zone syrphid fauna of particular habitat types represented in variousspecies lists, expressed as the percentage of the Atlantic zone fauna of each habitat type represented oneach list. Example: column 3 shows that 90% of the Atlantic zone syrphid species associated withpeatlands are represented in Great Britain.Coding of columns as in Fig.5.6.

Turning to the wetland and open ground groups of habitats, the most evident differencebetween the species lists lies in the high proportion of wetland species in the list forIreland. But this is more because of an absence from Ireland of forest species representedon the other lists, than because more wetland species are present in Ireland than in theother lists. This can be recognised from considering the proportion of Atlantic zonewetland species on each list. Subdividing wetland habitats into two groups, peatland (fenand bog) and non-peatland habitats, produces the results shown in Fig.5.8, whichindicates that for both sub-groups of wetland habitats a smaller proportion of theassociated Atlantic zone fauna occurs in Ireland than in Great Britain, despite the factthat deciduous forest species are the dominant component of the British fauna andwetland species predominate in the Irish fauna. Another characteristic of these wetlandfaunas, indicated in Fig.5.8, is that peatland species are somewhat better represented inboth Ireland and Great Britain than are the species associated with other wetland habitats,whereas the converse is true in both Northern and Central France. A similar relationshipexists between the species complement of humid and dry unimproved pasture, which,between them, comprise the vast majority of the open ground species. Thus, species

76

associated with humid, unimproved pasture, are better represented on the Irish andBritish lists, while species associated with dry, unimproved pasture are better representedon the two French lists. The list for Central France represents the extreme of thiscondition, with the lowest representation of peatland-associated syrphids and the bestrepresentation of syrphids associated with dry, unimproved pasture. The character of theclimate is presumably to a significant extent responsible for these features of the syrphidfauna.

Indubitably, a myriad influences have combined to shape the syrphid fauna of Atlanticparts of Europe as we find it today. But this overview shows that some features ofregional syrphid faunas are probably in large part a consequence of the history of man’sactivities in the area, just as others are most easily understood by considering parametersof the local climate. Whatever the precise reasons may be for some particular feature of afauna, the ecological balance of regional species lists, as employed here, is demonstrablya tool of potential value in environmental interpretation.

In a second example of comparison between regional species lists, Speight (2000b)compares attributes of the regional species lists for conifer plantation syrphids fromvarious parts of Europe, from Ireland to Switzerland. This comparison demonstrates thatconifer plantations are unlikely to function as "ecological corridors" for the transport ofall elements of the European syrphid fauna of Abies/Picea/Pinus forests, into/throughthose parts of Europe where conifer forest is not indigenous. The only element of theconifer forest syrphid fauna which seems generally able to make use of these plantationsis the species which feed on conifer foliage aphids, and even these species show littlecapacity for rapid spread through conifer plantations. For instance, in Ireland, where noneof these conifers are indigenous (Pinus sylvestris did occur in Ireland during the post-glacial, but became extinct some hundreds of years ago), only one Picea-associatedspecies, Eriozona syrphoides, is recorded so far, although the "ecological corridor"provided by conifer plantations has now been in place for nearly 100 years.

77

Chapter 6. PROGRESS AND LIMITATIONS

A primary objective of the FAEWE project was to make progress toward establishmentof an expert system, to apply in particular to functional analysis of river margin wetlands.The studies on invertebrates incorporated into the project adopted the spirit of thisobjective, in attempting, wherever possible, to set up and test mechanisms which wouldenable non-experts to gather, handle and interpret data relating to the taxonomic groupsof invertebrates addressed by the project. For syrphids, selection of field techniqueswhich would allow maximal involvement of non-experts in the sample-collection processproved reasonably easy. Ways of transferring the necessary laboratory work to non-experts proved an obdurate problem. In particular, the identification of material collectedremains firmly in the hands of experts and all evidence points to this being an immutablerequirement for the foreseeable future, whatever taxonomic group of invertebrates isinvolved. The procedure developed is entirely dependent upon identification of the targetorganisms to species, correctly.

At the outset of the FAEWE project there was no mechanism in existence which allowedthe interpretation of terrestrial invertebrate faunas to be carried out by non-experts, otherthan those which treated the organisms simply as integers. The project saw thedevelopment, testing and use of a novel system which, at this point in time, can alreadybe used by non-experts to interpret species lists for certain invertebrates, makingmaximal use of available biological data about the species. Indisputably, more incisiveand comprehensive interpretations can be obtained by use of the system for the samepurposes by specialists in the taxonomic groups concerned. However, procedures, likethe FAP run through here, can be conducted by someone who has no knowledge of theorganisms involved, armed just with species list and habitat data collected from the targetsites.

The problems encountered during course of this work nearly all relate to the process ofsetting up a system whereby non-experts might interpret species lists. These problemswere encountered every step of the way, right from the point in time at which it wasnecessary to decide which taxonomic groups of invertebrates would be the mostappropriate to use as tools in this endeavour. The criteria employed in the selectionprocess were enumerated in the Introduction to this volume. One of these criteria was

78

that adequate biological information should be available for the organisms chosen, suchthat it would be possible to deal with entire faunas, rather than having to restrict attentionto a few so-called bio-indicators which had been studied in depth. Following decision onwhich groups to use it was rapidly discovered that, despite an apparent wealth ofpublished information, the published data sources all-too-frequently lacked necessaryingredients. Much reliance then had to be placed upon consultation of experts to obtainmissing data, much of which had never been published. In the case of the syrphids, thismeant contacting experts in many different countries.

The files which constitute the database have undergone considerable evolution since theywere first set up. The fuzzy coding system was introduced at the outset and has provedinvaluable, but the categories coded were for some years in a state of almost continuousflux. Originally envisaged as paired files, one coding habitat data and the other codingbiological traits data, both the number of categories of data included in the files and thenumber of files, increased with experimentation in their use. In large part, theproliferation of categories and files related to attempts to refine the prediction process onwhich depended provision of a reliable standard, with which to compare observed faunas.Initial prediction attempts resulted in over-prediction of species, so that additional datawere then needed to provide filters allowing of more successful exclusion of wronglypredicted species. The outcome of this evolution was the use of the macrohabitats files asthe basis for prediction of the expected fauna of a site, with the supplementary habitatcategories and certain additional files, developed from the original traits file, introducedspecifically to shape the prediction process. The flight period file used in predicting thesyrphid fauna of a site is one such additional file. Other elements of the original traits filedeveloped into the microsite features file, used not in prediction, but for investigation ofdifferences between predicted and observed faunas. Similarly, it became apparent thatsome way had to be found to deal with threatened species as a distinct issue, since otherapproaches to evaluation of site faunas almost inevitably explored the use of the threatstatus of the observed species, even if the rest of the fauna was entirely ignored. Thisresulted in production of the range and status file. The relative availability of data on thedifferent species, for coding them in these various files, has already been referred to.Suffice it to say that, even when relevant information existed, it proved difficult toencapsulate in ways that made possible the construction of a common reference system ofcategories for the three taxonomic groups employed on the FAEWE project. Essentially,each author or expert used their own terminology for describing habitat, habits, ecology

79

etc. Given that large projects had been in place for some years to set up Europe-widesystems for classifying habitats, it might be assumed that, for macrohabitats at least,delineation of categories to use would have been relatively simple, just by adopting theCORINE system, for instance. This was attempted, and where possible CORINE“habitat” categories are used in the macrohabitats file. But the CORINE “habitats” havelittle in common with invertebrate habitats (see Speight et al, 1997a) and it provednecessary to generate a complementary system of categories to “fill in” the invertebratehabitats not recognised by CORINE. In the process it was discovered that eachtaxonomic group required to have macrohabitat categories defined for it alone, a processwhich would be magnified further with addition of each supplementary taxonomic groupof invertebrates one might wish to incorporate into the system. This problem proved evengreater, when it came to defining microsite feature categories which were meaningful.The number of microsite feature categories not shared by the three taxonomic groupsstudied is greater than the number that is shared. This has produced a complicationevidenced in the FAP decision tree calculations included in this text, namely that thereare surprisingly few contact points between the microsite feature results for the threegroups. While it might be argued that it is inevitable that organisms with such differentevolutionary history and strategies would provide different types of input to such adecision tree and should thus provide different sorts of information about a site, there arecircumstances in which it would nonetheless be helpful if the results from the threegroups were more directly comparable!

A whole range of issues await exploration with the syrphid database, few of which havebeen referred to in this text. The database may be used to predict impacts upon the faunaof specified changes in macrohabitat occurring on a site/in a region, for predictingfaunistic change likely to occur accompanying initiatives in restoration ecology, or forinvestigating many aspects of the inter-relation between groups of species and theirattributes. Recently, the focus of exploration of applications of the database has switchedfrom macrohabitats to microhabitats, with recognition of the direct link that existsbetween microhabitats and impact of land management operations (Speight, 2000a). Thishas resulted in addition of an additional file to the database, in which the degree ofadverse impact of a range of animal farming management practices upon the species arepredicted (Speight et al, 2000). The full range of potential applications of the database isstill not defined.

80

REFERENCES

Aubert, J., Aubert, J.-J., and Goeldlin P. 1976. Douze ans de captures systématiques deSyrphides (Diptères) au col de Bretolet (Alpes valaisannes). Bull.Soc.ent.Suisse 49:115-142.

Bournaud, M., Richoux, P., Usseglio-Polatera, P. (1992). An approach to the synthesis ofqualitative ecological information from aquatic Coleoptera communities. RegulatedRivers. 7: 165-180.

Brunel, C., Brunel, E. and Frontier, S. 1990. Structure spatio-temporelle d’un peuplementde Diptères Dolichopodidés le long d’un transect culture / coteau calcaire / valléehumide (Vallée de la Somme). Bull. Ecol. 21: 97-117.

Bradescu, V. (1991) Les Syrphides de Roumanie (Diptera, Syrphidae), Clés dedétermination et répartition. Trav.Mus.Hist. nat. Grigore Antipa, 31: 7-83.

Brunel, C., Brunel, E. and Frontier, S. (1990) Structure spatio-temporelle d'unpeuplement de Diptères Dolichopodidés le long d’un transect culture/coteaucalcaire/vallée humide (Vallée de la Somme). Bull.Ecol., 21: :97-117

Castella, E. & Speight, M.C.D. (1996) Knowledge representation using fuzzy-codedvariables: an example with Syrphidae (Diptera) and the assessment of riverinewetlands. Ecological Modelling, 85: 13- 25.

Castella, E., Speight, M.C.D., Obrdlik, P., Schneider, E. & Lavery, T. A (1994)methodological approach to the use of terrestrial invertebrates for the assessment ofalluvial wetlands. Wetlands Ecology and Management, 3: 17-36.

Chemini, C., Daccordi, M. and Mason, F. 1983. Ditteri Sirfidi raccolti in due siti forestalipresso Ala (Provincia de Trento). Studi Trentini di Scienze Naturali, Acta Biologica60: 125-139.

Chessel, D. and Mercier, P., 1993. Couplage de triplets statistiques et liaisons espèces -environnement. In: J.D. Lebreton and B. Asselain (Editors), Biométrie etEnvironnement, Masson, Paris, pp.15-44.

Chevenet, F., Dolédec, S., Chessel, D. (1994). A fuzzy coding approach for the analysisof lomg-term ecological data. Freshwater Biology. 31: 295-309.

Day, K.R. (1987). The species and community characteristics of ground beetles(Coleoptera: Carabidae) in some Northern Ireland nature reserves. Proc. R. Ir.Acad. 87: 65-82.

81

Decleer , K. (1990). Faunistic and ecological study of the invertebrate fauna of the naturereserve “De Gultke Putten” (Prov. Western Flanders, Wingene). 1. Hoverflies(Diptera: Syrphidae) with a discussion on Malaise traps. (in Dutch with Englishabstract). Phegea 18: 71-88.

Decleer, K. & Verlinden, L. (1992) A standard method for site evaluation and indicationof “Red Data Book” species, using distribution data of invertebrates. An examplebased on the hoverfly fauna (Diptera, Syrphidae) of Belgium. In: Van Goethem,J.L. & Grootaert, P. (eds.) Faunal inventories of sites for cartography and natureconservation. Proc.8th.Int.Colloq.EIS, Brussels, 1991: 115-132.

Diday, E., Lemaire, J., Pouget, J. and Testu, F., 1982. Eléments d'analyse de données.Dunod, Paris, 462pp.

Digby, P.G.N. and Kempton, R.A., 1987. Multivariate Analysis of EcologicalCommunities. Chapman & Hall, London, 206pp.

Disney, R.H.L. (1986). Assessment using invertebrates: posing the problem. In: UsherM.B. (ed), Wildlife Conservation Evaluation. Chapman and Hall, London. pp. 271-293.

Dolédec, S. and Chessel, D., 1993a. Programmathèque ADE. Analyse multivariée etexpression graphique des données environnementales. Version 3.6. (5. Ordinationlinéaire). URA CNRS 1451. Université Lyon 1. F-69622 Villeurbanne Cedex.France.

Dolédec, S. and Chessel, D., 1993b. Programmathèque ADE. Analyse multivariée etexpression graphique des données environnementales. Version 3.6. (6. Ordinationsimultanée de deux tableaux). URA CNRS 1451. Université Lyon 1. F-69622Villeurbanne Cedex. France.

Dolédec, S., Chessel, D. (1994). Co-inertia analysis; an alternative method for studyingspecies-environment relationships. Freshwater Biology. 31: 277-294.

Eyre, M.D. (ed.) (1996) A bibliography of work relating to environmental monitoring,environmental surveillance and conservation using invertebrates. 1-80. EMSPublications, Newcastle-u.-Tyne.

Eyre, M.D. and Rushton, S.P. (1989). Quantification of conservation criteria usinginvertebrates. J. Appl. Ecol. 26: 159-171.

Eyre, M.D., Rushton, S.P., Luff, M.L., Ball, S.G., Foster, G.N. and Topping, C.J. (1986).The use of invertebrate community data in environmental assessment. AgriculturalResearch Group, Faculty of Agriculture, The University, Newcastle-upon-Tyne,UK. 16pp.

82

Foeckler, F. (1991). Classifying and evaluating alluvial flood plain waters of the Danubeby water mollusc associations. Verh. Internat. Verein. Limnol. 24: 1881-1887.

Gatter, W. and Schmid, U. 1990. Wanderungen der Schwebfliegen (Diptera, Syrphidae)am Randecker Maar. Spixiana Supplement 15: 1-100.

Greenacre, M.J., 1984. Theory and applications of Correspondence Analysis. AcademicPress Inc., London, 364pp.

Haslett, J.R. 1988. Qualitätsbeurteilung alpiner Habitate: Schwebfliegen (Diptera:Syrphidae) als Bioindikatoren für Auswirkungen des intensiven Skibetriebes aufalpinen Wiesen in Österreich. Zool. Anz. 220: 179-184.

Hutcheson, J. 1990. Characterisation of terrestrial insect communities using quantified,Malaise-trapped Coleoptera. Ecol.Ent. 15: 143-151.

Kassebeer, C.F. 1993. Die Schwebfliegen (Diptera: Syrphidae) des Lopautals beiAmelinghausen. Drosera 93: 81-100.

Keddy, P.A. (1992). Assembly and response rules: two goals for predictive communityecology. Journal of Vegetation Science. 3: 157-164..

Lebreton, J.D. and Yoccoz, N., 1987. Multivariate analysis of bird count data. ActaOecologica, Oecol. Gener., 8: 125-144.

Lozek, V. (1964): Quarter Mollusken der Tschechoslowakei. Rozpravy UstredníhoUstavu Geologickeho, 31, 374 pp, 32 Tafel.

Lozek, V. (1992): Mekkysi (Mollusca). In: L. Skapec (ed.): Cervená kniha ohrozenych avzacnych druhu rostlin a zivocichu CSFR. 3. Bezobratli. Príroda, Bratislava, 155pp.

Luff, M.L. (ed). (1987). The use of invertebrates in site assessment for conservation.Agricultural Research Group, Faculty of Agriculture, The University, Newcastle-upon-Tyne, UK.

Maibach, A., Goeldlin de Tiefenau, P. & Speight, M.C.D. (1994) Limites génériques etcaractéristiques taxonomiques de plusieurs genres de la Tribu des Chrysogasterini(Diptera: Syrphidae) 2. Statut taxonomique de plusieurs des espèces étudiées etanalyse du complexe Melanogaster macquarti (Loew). Ann.Soc.Entomol.Fr.(N.S.), 30: 253-271.

Maltby, E., Hogan, D.V. & McInnes, R.J. (eds.) (1996) Functional analysis of Europeanwetland ecosystems, Phase 1 (FAEWE).: the function of river marginal wetlandecosystems. Ecosysyems Research Report No.18, 408pp. Directorate General XII,Science, Research and Development, European Commission, Brussels.

83

Marcos-Garcia, M.A, 1990. Catalogo preliminar de los Syrphidae (Diptera) de laCordillera Cantabrica (Espana). Eos 66: 83-100.

Muirhead-Thomson, R.C. 1991. Trap responses of flying insects: the efficiency of trapdesign on capture efficiency. Academic Press, London.

Murphy, K.J., Castella, E., Clément, B., Hills, J.M., Obrdlik, P., Pulford, L.D., Schneider,E. & Speight, M.C.D. (1994) Biotic indicators of riverine wetland ecosystemfunctioning In: Mitsch, W.J. (ed.) Global Wetlands: Old and New, 659-682.Elsevier, Amsterdam.

Ökland, F. (1929). Methodik einer quantitativen Untersuchung der Landschneckenfauna.Arch. Moll. 61: 121-136.

Ozenda, P., Noirfalise, A. & Trautmann, W. (1979): Vegetation map of the Council ofEurope member states. Nature & Environment no.61: 1-99. Council of Europe,Strasbourg.

Peck, L.V. (1988) Syrphidae. In: Soos, A. & Papp, L. (eds.) Catalogue of PalaearcticDiptera, 8: 11-230. Akad.Kiado, Budapest.

Penka, M., Vyskot, M., Klimo, E. and Vasicek, F. (1985). Floodplain forest ecosystem. 1.Before water management measures. Developments in Agricultural and ManagedForest Ecology, 15A. Elsevier Science Publishers. 466pp.

Penka, M., Vyskot, M., Klimo, E. and Vasicek, F. (1991). Floodplain forest ecosystem. 2.After water management measures. Academia Praha. 629pp.

Precht, A. & Cölln, K. (1996a). Schwebfliegen (Diptera, Syrphidae) einer Feuchtweisebei Stadtkyll (Eiffel) - methodische Bemerkungen und Ergebnisse. Verh. Westd.Entom. Tag 1995. Löbbecke-Mus., Düsseldorf: 165-175.

Precht, A. & Cölln, K. (1996b). Zum Standortbezug von Malaise-Fallen. EineUntersuchung am Beispiel der Schwebfliegen (Diptera: Syrphidae). Fauna FloraRheinland-Pfalz 8: 449-508.

Refseth, D. (1980). Ecological analyses of Carabid communities. Potential use inbiological classification for nature conservation. Biological Conservation 17: 131-141.

Rotheray, G.E. (1994) Colour guide to hoverfly larvae (Diptera, Syrphidae) in Britainand Europe. Dipterists Digest, (1993), No.9: 1-156.

Rotheray, G.E. (1999) Phylogeny of Palaearctic Syrphidae (Diptera): evidence fromlarval stages. Zool.J.Linn.Soc., 127: 1-112.

Siepel, H. (1989). Objective selection of indicator species for nature management.Comptes Rendus du Symposium “Invertébrés de Belgique”: 443-446.

84

Sladecek, V. (1973). System of water quality from the biological point of view. Arch.Hydrobiol. Suppl. 7. 218pp.

Southwood, T.R.E. (1978). Ecological Methods. Chapman and Hall, New York.Speight, M.C.D. (1986a). Criteria for the selection of insects to be used as bio-indicators

in nature conservation research. Proc. 3rd. Eur. Cong. Ent. Amsterdam pt.3: 485-488.

Speight, M.C.D. (1993) Révision des syrphes de la faune de France: 1 - Listealphabétique des espèces de la sous-famille des Syrphinae (Diptera, Syrphidae).Bull.Soc.ent.Fr., 98: 35-46.

Speight, M.C.D. (1994) Révision des syrphes de la faune de France: II - LesMicrodontidae et les Syrphidae Milesiinae (in part.) (Diptera, Syrphoidea).Bull.Soc.ent.Fr., 99: 181-190.

Speight, M.C.D. (1996a) Cheilosia psilophthalma and Odinia boletina, insects new toIreland and Sapromyza sexpunctata confirmed as an Irish species (Diptera:Syrphidae, Odiniidae and Lauxaniidae). Ir.Nat.J., 25: 178-182.

Speight, M.C.D. (1996b) Syrphidae (Diptera) of Central France. Volucella, 2: 20-34.Speight, M.C.D. (1997) Invertebrate species lists as management tools: an example using

databased information about Syrphidae (Diptera). Proc.Coll. on Conservation,Management and Restoration of Habitats for Invertebrates: enhancing BiologicalDiversity., Environmental Encounters Series, No.33: 74-83. Council of Europe,Strasbourg.

Speight, M.C.D. (2000a) Syrph the Net: a database of biological information aboutEuropean Syrphidae (Diptera) and its use in relation to the conservation ofbiodiversity. In: Rushton, B.S. (ed.) Biodiversity: the Irish dimension, 156-171.R.Ir.Acad., Dublin.

Speight, M.C.D. (2000b) Some thoughts on corridors and invertebrates: the hoverfly(Diptera: Syrphidae) fauna of Abies/Picea forests in temperate west/central Europe.Proc. Workshop on ecological corridors for invertebrates: strategies for dispersaland recolonisation in today's agricultural and forestry landscapes. Neuchatel, May2000, 129-135. Environmental Encounters, no.45. Council of Europe, Strasbourg.

Speight, M.C.D. & Castella, E. (1995) Bugs in the system: Relationships betweendistribution data, habitat and site evaluation in development of an environmentalassessment procedure based on invertebrates. In: Valovirta, I., Harding, P.T.andKime, D. (eds.) Threatened species and bioindicators at the pan-European level, 1-7. Proc.9th.Internat.Colloq. EIS, Helsinki. WWF Finland, Helsinki.

85

Speight, M.C.D. & Nash, R. (1993) Chrysotoxum cautum, Ctenophora ornata,C.pectinicornis, Helophilus trivittatus and Mesembrina mystacea (Diptera), insectsnew to Ireland. Ir.Nat.J., 24: 231-236.

Speight, M.C.D., Anderson, R. & Luff, M.L. (1983) An annotated list of the Irish groundbeetles (Col., Carabidae + Cicindelidae). Bull.Ir.Biogeog.Soc., No.6, 1982: 25-53.

Speight, M.C.D., Castella, E., Obrdlik, P. & Schneider, E. (1997a) Are CORINE habitatsinvertebrate habitats? In: Schreiber, H. (ed.) The importance of chorology toinvertebrates, 193-200. Proc.10th.Int. Colloq.EIS, Saarbrucken.

Speight, M.C.D., Claussen, C. & Hurkmans, W. (1998) Révision des syrphes de la faunede France: III - Liste alphabétique des espèces des genres Cheilosia, Eumerus etMerodon (Diptera, Syrphidae). Bull.Soc.ent.Fr., 103: 403-414.

Speight, M.C.D., Good, J.A. & Sarthou, J.-P. (2000) Impact of Farm Managementoperations on European Syrphidae (Diptera): species of the Atlantic, Continental &Northern Regions. In: Speight, M.C.D., Castella, E., Obrdlik, P. and Ball, S. (eds.)Syrph the Net, the database of European Syrphidae , vol.19, 162 pp., Syrph the Netpublications, Dublin.

Speight, M.C.D., McLean, I.F.G. & Goeldlin de Tiefenau, P. (1992) The recognition ofsites of international importance for protection of invertebrates. EnvironmentalEncounters series, no.14: 39-42. Council of Europe, Strasbourg.

Speight, M.C.D., McLean, I.F.G. & Goeldlin de Tiefenau, P. (1992 ) The recognition ofsites of international importance for protection of invertebrates. EnvironmentalEncounters series, no.14: 39-42. Council of Europe, Strasbourg.

Stork, N.E. (ed) (1990). The role of Ground Beetles in ecological and environmentalstudies. Intercept Ltd. Andover, Hampshire, England. 424pp.

Stubbs, A.E. & Falk, S.J. (1983) British hoverflies: an illustrated identification guide.Br.Ent.Nat.Hist.Soc., London, 253pp.

Torp, E. (1994) Danmarks Svirrefluer (Diptera: Syrphidae). Danmarks Dyreliv, 6: 1-490.Apollo books, Stenstrup.

Trautner, J. & Müller - Motzfeld, G. (1995 a): Faunistisch - ökologischerBearbeitungsstand, Gefährdung und Checkliste der Laufkäfer. Eine Übersicht fürdie Bundesländer Deutschlands.- In. Naturschutz und Landschaftsplanung, 27,3:96-105

Van der Goot, V.S.(1981) De zweefvliegen van Noordwest - Europa en EuropeesRusland, in het bijzonder van de Benelux. KNNV, Uitgave no.32: 275pp.Amsterdam.

86

Verlinden, L. (1991) Fauna van Belgie: Zweefvliegen (Syrphidae). 1-298. Inst.Roy.Sci.Nat.Belg., Brussels.

Verlinden, L. and Decleer, K. 1987. The hoverflies (Diptera, Syrphidae) of Belgium andtheir faunistics: frequency, distribution, phenology. Inst. Roy. Sci. Nat. Belgique,Documents de Travail. 39: 1-170.

Verneaux, J., Galmiche, P., Janier, F. and Monnot. (1982). Une nouvelle méthodepratique d'évaluation de la qualité des eaux courantes. Un indice biologique dequalité générale (IBG). Ann. Sc. Univ. Franche-Comté, Biol. Anim. 4: 11-21.

Violovitsh, N.A. (1986) Siberian Syrphidae (Diptera). Translation by van der Goot, V.S.& Verlinden, L. Inst.Taxon.Zool. (Zool.Mus.),Amsterdam, Verslagen enTechnische Gegevens, No.43: 1-228.

Vockeroth, J.R. & Thompson, F.C. (1987) Syrphidae. In: McAlpine, J.F. (ed.) Manualof Nearctic Diptera, 2: 713-743. Agriculture Canada, Ottawa.

Wartenberg, D., Ferson, S. and Rohlf, F.J., 1987. Putting things in order: a critique ofdetrended correspondence analysis. The American Naturalist, 129: 434-448.

Wright, J.F., Moss, D., Armitage, P.D. and Furse, M.T. (1984). A preliminaryclassification of running-water sites in Great-Brittain based on macro-invertebratespecies and the prediction of community type using environmental data. FreshwaterBiology 14: 221-256.

87

Appendix 1: HABITAT SURVEY FORM

SITE NAME:

-------------------------------------------------------------------------------------------------------LOCATION:

-------------------------------------------------------------------------------------------------------SITE NUMBER:DATE OF SURVEY:

CODE NUMBER OFHABITAT OBSERVED

CODE NUMBERS OF ASSOCIATEDSUPPLEMENTARY HABITATS

NOTES