KANIERE/McKAYS HEPS RECONSENTING...Its location is shown in Figure 1. It is situated on private property owned by Kaniere Farms Limited on the southern side of Lake Kaniere Road and

KANIERE/McKAYS HEPS RECONSENTING

McKays Creek Mitigation Area Prepared for TrustPower Limited

20 March 2012

Document Quality Assurance

Bibliographic reference for citation: Boffa Miskell Limited 2012. KANIERE/McKAYS HEPS RECONSENTING: McKays Creek Mitigation Area. Report prepared by Boffa Miskell Limited for TrustPower Limited.

Prepared by: Scott Hooson Senior Ecologist Boffa Miskell Limited

Reviewed by: Diana Robertson Senior Principal/Ecologist Boffa Miskell Limited

Status: FINAL Revision / version: 1 Issue date: 20 March 2012

Template revision: 20120313 0000

File ref: C09080_052_McKays_Mitigation_Site_Report_20120314 © Boffa Miskell Limited 2012

Cover photograph: Kahikatea and rimu-miro forest within the proposed mitigation site, © Scott Hooson, 2012

KANIERE/McKAYS HEPS RECONSENTING | McKays Creek Mitigation Area 1

1.0 Introduction

TrustPower Limited (TPL) commissioned Boffa Miskell to assess a proposed mitigation area for vegetation clearance associated with the proposed enhancements to the McKays Creek Hydro-Electric Power Scheme (HEPS).

1.1 Background Boffa Miskell prepared the Terrestrial Ecology Report “Kaniere Forks/McKay’s Creek Hydro-Electric Power Scheme: Terrestrial Ecology and Avifauna Assessment”1 that accompanied TrustPower Limited’s (TPL) Resource Consent Application (Resource Consents 100151 and 110075) for the re-consenting and enhancements of the Kaniere Forks/McKays Creek Hydro-Electric Power Scheme (HEPS).

In addition to the mitigation proposed in Section 9.3.1 of the Terrestrial Ecology Report, Section 9.5 of the report recommended that, following the mitigation hierarchy2, further off-site mitigation for the permanent loss of significant indigenous vegetation and habitats was required. The report provided further guidance as to the sorts of sites that should be considered.

The Terrestrial Ecology Report concluded that:

“Details of a potential ‘mitigation package’ for the proposed [[MKY and KNF enhancements have not been finalised. Without this detail, it is difficult to assess whether the balance of the potential effects against the proposed mitigation will result in a net positive or negative environmental outcome.”

Westland District Council responded to this conclusion as part of a letter to TPL (dated 9 December 2010. In relation to mitigation for vegetation clearance, Point 6 of the letter stated that:

“Details of proposed mitigation are required for the application along with the amended conclusions and recommendations from the ecological advisors to enable assessment of effects for the proposal.”

Recently, TPL has decided to place its proposed enhancements to the Kaniere Forks Scheme on hold. The change to the application has meant that mitigation for the proposed Kaniere Forks enhancements is no longer required at this time. However, TPL is still seeking resource consent to enhance the operation of the McKays Creek Scheme. The construction of the proposed tunnel deviation to the south of the existing tunnel will

1 Boffa Miskell Limited 2010. Kaniere Forks/McKay’s Creek Hydro-Electric Power Scheme: Terrestrial Ecology and Avifauna Assessment. Report prepared for Chancery Green on behalf of TrustPower Limited. November 2010.

2 Ministry for the Environment, 2011. Proposed National Policy Statement on Indigenous Biodiversity.

2 KANIERE/McKAYS HEPS RECONSENTING | McKays Creek Mitigation Area

result in the clearance of up to 1.2 ha of indigenous vegetation (of which 1.0 ha has been assessed as significant under section 6(c) of the RMA). Mitigation for the vegetation clearance associated with the McKays Creek HEPS tunnel deviation is still required.

TPL have now proposed a mitigation area for this vegetation clearance.

1.2 Purpose of report The purpose of this report is to:

a) Provide details on the mitigation area proposed for the clearance of indigenous vegetation associated with the proposed McKays Creek HEPS tunnel deviation;

b) Briefly describe the methods used to assess the mitigation area;

c) Describe the terrestrial ecology values of the mitigation area;

d) Discuss the value of the mitigation area and its suitability as a site for mitigating the adverse effects of the McKays Creek tunnel deviation;

e) Provide recommendations for the management of the area;

f) Conclude whether the potential effects of the overall proposal on terrestrial ecology values will result in a net positive or negative environmental outcome.

2.0 Methods

Several potential mitigation areas within the ecological district (ED) were identified from aerial photographs. Four of these sites were visited and assessed by Scott Hooson (Senior Ecologist, Boffa Miskell Limited) on 8 and 9 February and 8 March 2012.

The preferred mitigation area (also referred to as the site) was visited by Scott Hooson and Ms Carol Jensen on 8 March 2010.

The length of the entire site was walked and plant species and the vegetation communities were noted. All species of birds sighted or heard were recorded. Notes were made on the condition of the vegetation communities and the presence of weed and animal pests (including animal pest sign). Photographs and GPS waypoints were taken to assist with descriptions of vegetation types and habitats.

A list of the plant and bird species recorded are provided in Appendices 3 and 4, respectively.


Recce plots3 were measured in representative areas of the key vegetation communities (rimu-miro/kamahi-Quintinia forest and kahikatea forest) to obtain more detailed quantitative data (the Recce data sheets are held at Boffa Miskell and are available on request).

The adequacy of the site to mitigate for the loss of vegetation associated with the proposal was assessed by comparing the ecological values and sizes of the affected area and mitigation area. Biodiversity offsetting models, that use loss-gain calculations to quantify such comparative assessments, are still being developed in New Zealand. The Department of Conservation (DOC) is currently managing a programme funded by the Cross Departmental Research Pool (CDRP) that is investigating the feasibility of biodiversity offsetting4. Such models have not been used in this report given the stage of development of these models and the small scale of the proposed vegetation clearance.

3.0 Ecological Values of the Site

The site (shown in Photo 1, Appendix 2) is approximately 3.5 ha in area. Its location is shown in Figure 1. It is situated on private property owned by Kaniere Farms Limited on the southern side of Lake Kaniere Road and to the east of Blue Bottle Creek. It is approximately 700 metres south of the McKays Creek HEPS and is within the same catchment and ecological district (the Hokitika ED) as the proposed tunnel deviation and associated vegetation clearance. The elevation of the site is between approximately 80 – 95 m.a.s.l.

Primary rimu-miro/kamahi-Quintinia forest within the Kaniere Farm Conservation Area adjoins the site to the east and Blue Bottle Creek also flows close to the eastern boundary. To the west of the site is private land that has been cleared and is now in regenerating scrub dominated by gorse.

The vegetation within the site is almost entirely primary indigenous lowland forest comprised of kahikatea forest on the lower alluvial surfaces and rimu-miro/kamahi-Quintinia forest on the more elevated slope of a western facing moraine hill. Small areas of kahikatea/Carex/Sphagnum and wiwi/Sphagnum also occur in poorly drained situations.

The kahikatea forest (Photo 2) occurs on the moderately drained alluvial surfaces at the toe of the moraine hill below the rimu-miro/kamahi-Quintinia forest. The canopy is thick (75% canopy cover) and has an average top height of approximately 25 m). It is comprised almost entirely of kahikatea including some large (35 – 40 m) emergent trees. The sub-canopy (12 – 25 m tier) is also thick and includes putaputaweta,

3 Hurst J.M. Allen, R.B. 2007. The RECCE Method for Describing New Zealand Vegetation - Expanded Manual. Version 4. Landcare Research Contract Report LC0708/029.

4 Biodiversity Offsets Programme Update. September 2011. Department of Conservation, Wellington.


broadleaf, kaikomako, kamahi and young miro. The 5 – 12 m tier is comprised of similar species but also includes soft tree-fern, weeping matipo and Coprosma species. The 2-5 m tier is more open but is very similar in terms of its composition and structure. The understorey (0.3 – 2 m) is also relatively open but is very diverse. It is characterised by red horopito, white rata, several species of Blechnum ferns hook grass, and numerous other saplings, seedlings, shrub and fern species. The ground-cover is similarly diverse (36 vascular plant species were recorded within the 20 x 20 Recce plot) and is comprised of vegetation (70%) and moss (5%) with the remainder being leaf-litter. Epiphytes are moderately diverse and dominated by ferns. The understorey and ground tiers have been modified by deer and cattle with several species showing moderate to high levels of browse. Introduced plant species are largely absent, except where cattle have disturbed the soil. With the exception of deer and cattle damage, no other human modifications were observed in this vegetation community.

The rimu-miro/kamahi-Quintinia forest (Photo 3) occurs on the well drained slopes of a low west facing moraine hill. It is characterised by large emergent rimu and miro and a relatively thick canopy (75% canopy cover, average top height of 20 m) dominated by kamahi and Quintinia. Mountain toa toa is occasionally common in the canopy and southern rata is also present but rare. Lancewood, along with the canopy species, is present in the sub-canopy. The 5 - 12 m tier is dominated by kamahi, Quintinia, rimu and mountain toa toa but includes all of the species present in the sub-canopy as well as soft and rough tree-ferns and broadleaf. The 2 - 5 m tier is relatively open and is comprised largely of broadleaf, Coprosma species, rohutu and red horopito with some kahikatea saplings. The understorey (0.3 – 2 m) cover is also relatively open and contains numerous saplings and seedlings and both shrub and fern species. The ground-cover is also very diverse (37 vascular plant species were recorded within the 20 x 20 Recce plot), but is open and dominated by leaf-litter (70 %) with the remainder being vegetation (20%) and moss (10 %). Epiphytes are numerous and diverse and include several fern species, three species of rata and bamboo orchid. While the upper tiers appear to be in good condition, and no possum sign was observed, the understorey and ground tiers have been modified by deer. The levels of browse on broadleaf in particular, was high. With the exception of a few small gorse seedlings, introduced plant species were entirely absent.

Indigenous plant diversity is high, with over 100 indigenous vascular plant species recorded during the 5 hour site inspection. Several species of moss were also observed.

The site provides good quality habitat for forest birds. The composition of the avifauna is likely to be fairly typical of similar indigenous forest habitats on the West Coast (e.g. Spurr et al. 1992) and the forests surrounding the Kaniere Forks and McKays Creek HEPS (as described in the Terrestrial Ecology Report, Boffa Miskell 2010). The bird species seen or heard during the site investigation are listed in Appendix 4.

No threatened plant species were recorded within the site, and it is unlikely any occur in here given the vegetation communities present. Western weka (Declining) were observed and a small number of other ‘Threatened’ or ‘At Risk’ bird species such as Kea (Naturally uncommon), long-tailed cuckoo (Naturally Uncommon) and possibly New Zealand falcon (Nationally Vulnerable) and South Island kaka (Nationally Endangered) may use the site, at least from time to time, as they are known to occur in the forest nearby.


Although it appears that the site has not been logged, other signs of modification were observed. These included a disused earth water race, a boundary fence and associated vegetation clearance between the site and the adjoining Kaniere Farms Conservation Area and modification by cattle and deer.

Cattle disturbance is causing modification to the understorey and ground tiers of the kahikatea forest in the southern part of the site (Photo 4). Ongoing disturbance to the soil (through pugging) has resulted in the introduction of exotic plant species such as selfheal and creeping buttercup. It does not appear that cattle have accessed the rimu-miro/kamahi-Quintinia forest on the more elevated slopes.

Deer sign (browse, faeces, prints and antler rubbings) was abundant and deer numbers are likely to be high. Deer will be adversely affecting the structure and composition of the understorey and ground tiers and limiting the recruitment of the more palatable plant species.

In summary, the site is of high ecological value despite its small size. Kahikatea forest on alluvial surfaces is now under-represented in the ED5. Floodplains which previously supported extensive stands of kahikatea forest have been developed for agriculture and the remaining remnants on private land are small and isolated. Although rimu forest is well represented on Public Conservation Land within the ED, lowland rimu forest has been disproportionately cleared and modified compared to that on adjacent hill slopes.

The vegetation communities in the site are relatively intact and support a diverse range of indigenous species. Several ‘Threatened’ or ‘At Risk’ bird species may use the site, although given its size, it is unlikely to be particularly important for these species. The site adjoins and plays a buffering role to the Kaniere Farms Conservation Area to the east and probably to some extent, to Blue Bottle Creek.

4.0 Suitability for Mitigation

There are a limited number of suitable mitigation areas in private ownership within the ED and finding a suitable site is difficult. This site is considered suitable as a mitigation area because:

a) Its ecological values are higher than that of the forest TPL is proposing to clear to construct the tunnel deviation;

b) It is within very close proximity to, and within the same ED as the area proposed for clearance;

c) The site represents a ‘like-for-like or better’ scenario. The rimu-miro/kamahi-Quintinia forest on the more elevated eastern side of the mitigation site is very

5 Miller, C. 2002. Conservation of riparian forest remnants, West Coast, New Zealand. Landscape Research, 27 (2): 125-140.


similar forest to that that will be cleared, but is of higher value. In addition, the site supports ecologically valuable kahikatea forest.

d) The mitigation area is on private land, and given the extent of forest clearance on private land in the wider area, the threat of clearance is high. Its protection will ensure its biodiversity values are not lost.

e) Recommended fencing to exclude cattle and deer will rapidly improve the condition of the understorey and ground tiers of the forest and increase the sites overall ecological value.

At 3.5 hectares the proposed mitigation area is approximately three times the size of the indigenous vegetation that will be permanently lost. This is appropriate given that the vegetation clearance associated with the proposed enhancements will also have indirect effects on the adjacent forest, for example edge effects and because the proposed mitigation involves protection and enhancement of existing forest (i.e. it is not resulting in a net increase in the area of forest).

5.0 Recommendations for Management

We understand that TPL has an agreement with Kaniere Farms Limited whereby if TPL decides to proceed with the tunnel deviation it will purchase the mitigation area. Ownership would then be transferred to DOC6 or the land would be protected through a covenant (i.e. a QEII or DOC covenant).

In addition to this protection, the following management actions are required to improve and maintain the condition of the site, and to ensure a net positive environmental outcome:

a) Deer fencing of the boundary;

b) Fence inspections and maintenance;

c) Weed surveillance; and

d) Weed control.

The rationale for each of these is briefly discussed below.

Deer and cattle are currently adversely affecting the condition of the understorey and ground tier as discussed in Section 3 above. Deer fencing the boundary of the site would exclude red deer and domestic stock and result in marked and rapid improvements to forest health. It would allow palatable species to regenerate and improve the structure of the forests understorey and ground tiers. The eastern fence line in particular should be erected without using machinery such as a bulldozer to minimise damage and the introduction of plant pests. Once erected the fence should be

6 This is the preferred option, however it will need to be approved by DOC.


checked regularly to ensure it is stock and deer proof. Fence maintenance should be undertaken as and when required.

A small number of introduced plant species occur within the site. Most of these are not considered to be weeds and do not require management. Some of the weed species, including Himalayan honeysuckle, marsh thistle, ragwort, blackberry and foxglove, are generally considered to be weeds and could be controlled manually. However, in this situation they do not threaten the ecological values of the site and are unlikely to cause problems. It is preferable that gorse on the forest margin is not controlled as native forest species will regenerate through it at this site. Surveillance for, and control of other ecological weeds that could potentially establish should be undertaken regularly in conjunction with fence inspections.

A range of introduced animal pests such as possums, stoats, rats, cats and hedgehogs are likely to be present within the site and will be adversely affecting its indigenous ecological values. However, animal pest control is unlikely to be cost effective and is not recommended given the small size of the site, the high likelihood of re-invasion and the cost of undertaking effective predator control for a range of animal pest species.

6.0 Conclusions

In our opinion the protection and management of the proposed mitigation area would provide sufficient mitigation for the adverse effects of the construction of the proposed tunnel deviation.

Other mitigation measures are included in the draft conditions of the resource consent application. When considered in conjunction with the proposed mitigation area as described in this report, the potential effects of the overall proposal on terrestrial ecology values is likely to result in a net positive environmental outcome.


7.0 Appendices

7.1 Appendix 1: Maps

Kaniere/McKays Re-consenting

Figure 1: Location Map

| Date: 19 March 2012 | Revision: 0 |

Plan Prepared for TrustPower Limited by Boffa Miskell Limited

Author:[email protected] | Checked: XX

File Ref: C09080_017_McKays_Mitigation_Site_20110919.mxd

www.boffamiskell.co.nz

0 500 m

Projection: NZTMData Sources: Aerial photography sourced from Gooogle Earth. © Google 2011

1:25,000@ A3

Leg

en

dThese plans and drawings have been produced as a result ofinformation provided by the client and/or sourced by orprovided to Boffa Miskell Limited by a third party for thepurposes of providing the services. No responsibility is takenby Boffa Miskell Limited for any liability or action arising from

any incomplete or inaccurate information provided to BoffaMiskell Limited (whether from the client or a third party).These plans/drawings are provided to the client for thebenefit and use by the client and for the purpose for which itis intended. © Boffa Miskell Limited 2010

°N

Proposed Off-site Mitigation Area

Kaniere Farm Conservation Area

Lake Kaniere Scenic Reserve

Kaniere Farms Ltd (Private)

Kaniere Farm Conservation Area

Kaniere/McKays Re-consenting

Figure 2: Proposed Off-Site Mitigation Area

| Date: 19 March 2012 | Revision: 0 |

Plan Prepared for TrustPower Limited by Boffa Miskell Limited

Author:[email protected] | Checked: XX

File Ref: C09080_017_McKays_Mitigation_Site_20110919.mxd

www.boffamiskell.co.nz

0 150 m

Projection: NZTMData Sources: Aerial photography sourced from Gooogle Earth. © Google 2011

1:7,500 @ A3

Leg

en

dThese plans and drawings have been produced as a result ofinformation provided by the client and/or sourced by orprovided to Boffa Miskell Limited by a third party for thepurposes of providing the services. No responsibility is takenby Boffa Miskell Limited for any liability or action arising from

any incomplete or inaccurate information provided to BoffaMiskell Limited (whether from the client or a third party).These plans/drawings are provided to the client for thebenefit and use by the client and for the purpose for which itis intended. © Boffa Miskell Limited 2010

°N

Mitigation Area

Property Boundaries

Public Conservation Land


7.2 Appendix 2: Site Photographs

Photo 1: Looking east across gorse scrub on private land towards the kahikatea and rimu-miro/kamahi-Quintinia forest within the proposed off-site mitigation area.

Photo 2: Typical understorey under the kahikatea forest


Photo 3: Typical understorey under the rimu-miro/kamahi-Quintinia forest

Photo 4: Cattle damage to the understorey and ground tiers in the southern part of the site.


7.3 Appendix 3: Plant Species List

Species name Common name

Acaena anserinifolia Red bidibid Agrostis capillaris* Browntop Agrostis stolonifera* Creeping bent Aristotelia serrata Wineberry Asplenium appendiculatum subsp. appendiculatum Spleenwort Asplenium flaccidum Drooping spleenwort Asplenium gracillimum Hen and chicken fern Astelia grandis Swamp astelia Blechnum discolor Crown fern Blechnum fluviatile Kiwikiwi Blechnum minus Swamp kiokio Blechnum novaezelandiae Kiokio Blechnum penna-marina subsp. alpina Little hard fern Blechnum procerum Small kiokio Cardamine sp. Carex flaviformis Yellow sedge Carex geminata Cutty grass Carex ovalis* Oval sedge Carex sinclairii Sinclair's sedge Carex virgata Swamp sedge Carpodetus serratus Putaputaweta Centella uniflora Centella Cirsium palustre* Marsh thistle Clematis paniculata Small white clematis Coprosma areolata Thin-leaved coprosma Coprosma foetidissima Stinkwood Coprosma grandifolia Kanono Coprosma propinqua var. propinqua Mingimingi Coprosma rigida Coprosma rotundifolia Coprosma tayloriae Coprosma tenuicaulis Swamp coprosma Cordyline australis Cabbage tree Cortaderia richardii Toetoe Corybas sp. Ctenopteris heterophylla Comb fern Cyathea medullaris Black tree fern Cyathea smithii Soft tree fern Dacrycarpus dacrydioides Kahikatea Dacrydium cupressinum Rimu Dianella nigra Turutu Dicksonia squarrosa Rough tree fern Digitalis purpurea* Foxglove Earina aestivalis Bamboo orchid Earina autumnalis Easter orchid Elaeocarpus dentatus Hinau Elaeocarpus hookerianus Pokaka Gahnia rigida Gahnia Gaultheria antipoda Bush snowberry


Grammitis billardierei Common strap fern Griselinia littoralis Broadleaf Hebe salicifolia Koromiko Hedycarya arborea Porokaiwhiri Histiopteris incisa Water fern Hoheria glabrata Mountain lacebark Hydrocotyle heteromeria Waxweed Hydrocotyle novae-zeelandiae var. novae-zeelandiae Hymenophyllum demissum Drooping filmy fern Hypolepis ambigua Hypolepis millefolium Thousand leaved fern Juncus edgariae Wiwi Juncus effusus* Leafless rush Leptecophylla juniperina Prickly mingimingi Leptopteris superba Heruheru Leptospermum scoparium var. scoparium Manuka Leycesteria formosa* Himalayan honeysuckle Libertia pulcella Lotus pedunculatus* Lotus Lycopodium scariosum Creeping clubmoss Manoao colensoi Silver pine Melicope simplex Poataniwha Metrosideros diffusa White rata Metrosideros fulgens Rata Metrosideros perforata White rata Metrosideros umbellata Southern rata Microlaena avenacea Bush rice grass Microsorum pustulatum subsp. pustulatum Hound's tongue Myrsine australis Red mapou Myrsine divaricata Weeping matipo Neomyrtus pedunculata Rohutu Nertera depressa Nertera Nertera villosa Nertera Parsonsia heterophylla New Zealand jasmine Pennantia corymbosa Kaikomako Phormium tenax Lowland flax Phyllocladus alpinus Mountain toatoa Pittosporum tenuifolium Kohukohu Pneumatopteris pennigera Gully fern Podocarpus acutifolius Westland totara Podocarpus cunninghamii Mountain totara Podocarpus totara var. totara Totara Persicaria decipiens Polystichum richardii Polystichum vestitum Punui Prumnopitys ferruginea Miro Prumnopitys taxifolia Matai Prunella vulgare* Selfheal Pseudopanax crassifolius Horoeka Pseudowintera colorata Red horopito Pteridium esculentum Bracken Pterostylis sp. Greenhood orchid Pyrrosia eleagnifolia Leather-leaf fern Quintinia serrata Tawheowheo Ranunculus repens Creeping buttercup Ripogonum scandens Supplejack


Rubus australis Tataramoa Rubus cissoides Tataramoa Rubus fruticosus agg.* Blackberry Schefflera digitata Pate Senecio jacobaea* Ragwort Sticherus cunninghamii Umbrella fern Trichomanes reniforme Kidney fern Ulex europaeus* Gorse Uncinia uncinata Hook grass Urtica urens Nettle Weinmannia racemosa Kamahi

7.4 Appendix 4: Bird Species Recorded

Common Name Threat Status

Bellbird Not Threatened Fantail Not Threatened Grey warbler Not Threatened Silvereye Not Threatened Tomtit Not Threatened Tui Not Threatened Western weka Declining Wood pigeon Not Threatened

Documents

KANIERE/McKAYS HEPS RECONSENTING...Its location is shown in Figure 1. It is situated on private property owned by Kaniere Farms Limited on the southern side of Lake Kaniere Road and