AN ASSESSMENT OF THE POTENTIAL EFFECT OF THE PROPOSED WAITAHA HYDRO SCHEME ON THE LIZARD FAUNA OF THE LOWER WAITAHA RIVER, WESTLAND

Transcription

1 WESTPOWER LIMITED: AN ASSESSMENT OF THE POTENTIAL EFFECT OF THE PROPOSED WAITAHA HYDRO SCHEME ON THE LIZARD FAUNA OF THE LOWER WAITAHA RIVER, WESTLAND Whitaker Consultants Limited 2013

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3 AN ASSESSMENT OF THE POTENTIAL EFFECT OF THE PROPOSED WAITAHA HYDRO SCHEME ON THE LIZARD FAUNA OF THE LOWER WAITAHA RIVER, WESTLAND A.H. Whitaker Whitaker Consultants Limited 2013

4 Bibliographic reference: Whitaker, A.H An assessment of the potential effect of the proposed Waitaha Hydro Scheme on the lizard fauna of the lower Waitaha River, Westland. Unpublished report by Whitaker Consultants Limited, Motueka, to Westpower Limited, Greymouth. ii + 18 pp. Photographs Tony Whitaker PREPARED BY: Whitaker Consultants Limited 270 Thorpe Orinoco Road Orinoco, RD 1, Motueka 7196 New Zealand Phone: whitaker@ts.co.nz FOR: Westpower Limited P.O. Box 375 Greymouth Phone: info@westpower.co.nz DATE: 12 August 2013 Cover illustration: Aerial view of the Waitaha River looking downstream (north) towards confluence with Macgregor Creek. The site of the proposed power station is on the floodplain on the true right of the river.

5 Summary o Westpower Limited is investigating the feasibility of a hydroelectric development on the lower Waitaha River. The preferred option as at May 2013 involves an intake weir at Kiwi Flat, situated just above Morgan Gorge, connected by a tunnel and penstock to a powerhouse on the true right of the river just upstream of Macgregor Creek (the project area ). o This assessment is based on a desk-based review of the literature and databases, and a brief field survey to assess the lizard habitats available. o There appear to be no records of lizards from within the project area. o Two gecko species (Mokopirirakau granulatus s.s., Naultinus tuberculatus) are expected to occur within the project area as these taxa are widespread in forest and shrubland habitats in northern and central Westland. o The effect of the proposed development on the gecko fauna will be negligible because forest and shrubland habitats that are similar to those within the project footprint occur widely in Waitaha catchment and throughout central Westland. o One skink species may occur in open habitats on forest margins and riparian areas within the project area as there are a few isolated and scattered records of small skinks (Oligosoma polychroma s.l.) in such habitats in the general region. o If skinks are present in the project area the potential effect of the development on their populations may be greater than for geckos as some riparian habitat may be affected in the construction of accessways and ancillary facilities associated with the powerhouse and tunnel, and at least in the short-term by changed water flows above the intake weir.. However, the total area likely to be affected is very small and the effects of this on the conservation status of skinks, if indeed any are present, cannot be predicted until their specific identity is known. o No mitigation for lizards is seen as necessary because the areas likely to be affected by the project are very small in comparison to the habitat available and the lizard taxa that are potentially present are expected to be widespread. However, should any lizards be found in the project footprint during the construction phase of the project they should be captured and given to the Department of Conservation. Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower i

6 Contents SUMMARY... i CONTENTS... ii 1 PREAMBLE LIZARD FAUNA Background Lizard Fauna Geckos:... 3 Forest geckos (Mokopirirakau spp.):... 3 Green Geckos (Naultinus spp.): Skinks:... 5 Common skink complex (Oligosoma aff. polychroma)... 5 Speckled skink complex (Oligosoma aff. infrapunctatum) CONSERVATION SIGNIFICANCE OF LIZARDS IN THE PROJECT AREA POTENTIAL EFFECT OF PROJECT ON LIZARDS, AND MITIGATION Potential Effect Mitigation REFERENCES:... 9 APPENDIX...11 Field Survey...11 FIGURES...13 Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower ii

7 1 Preamble Westpower Limited, formed in 1994, is a community-owned West Coast electricity distribution company that is managed by the West Coast Electric Power Trust. In 1997 Westpower set up the wholly-owned subsidiary Electronet Services Limited to operate its electricity generation and transmission lines. Westpower is currently investigating the feasibility of a run of river, MW hydroelectric power scheme on the lower Waitaha River, in central Westland about 50 km south of Hokitika. The currently preferred design option (as at May 2013) involves a low intake weir at Kiwi Flat, immediately upstream of the Morgan Gorge, which would direct part of the river flow through a tunnel and penstock to a power house on the true right of the Waitaha River approximately 1.5 km upstream from the confluence of Macgregor Creek (see Figure 3). Access to Kiwi Flat for construction and servicing of the intake weir will be through the tunnel. The intake weir will initially create a small water impoundment but that should quickly fill with bed material as the channel regrades and result in a re-grading of the riverbed for several hundred metres upstream, perhaps as much as a kilometre, depending on the final weir design (Hicks 2013). Construction and maintenance of the tunnel, penstocks, power house, tail-race and transmission lines will involve some forest clearance and roading on the true right of the Waitaha River for approximately 2 km above Macgregor Creek and the clearance of a small area of riparian shrubland on the river terrace on the true right of the Waitaha River just upstream of Morgan Gorge. As part of the project investigation, Westpower has commissioned a series of studies including baseline assessments of the flora and fauna within the project area in order to determine the potential effects of this development on the environment and biota. The lizard fauna is one component of this assessment and is reported here. The Waitaha River flows northwest from the Main Divide to the Tasman Sea 14 km south of Ross. From the watershed at 2,000 m, the upper part of the river descends relatively steeply through a series of gorges before emerging into a broad alluvial valley below the confluence with Macgregor Creek. Kiwi Flat, lying between the Waitaha Gorge and the Morgan Gorge, is an alluvial floodplain at m and covering approximately 70 ha (2 km long by up to 0.5 km wide) (see Figure 1). Morgan Gorge is narrow, deeply-entrenched, winding and descends around 60 m over its one kilometre length, but between Morgan Gorge and Macgregor Creek the valley gradually widens again, with increasingly wider strips of alluvial floodplain. The surrounding slopes over the stretch of the river between Macgregor Creek and the Waitaha Gorge are steep to very steep with some bluffs and escarpments and they are densely covered with forest (see Figure 3). Downstream from Macgregor Creek the valley opens out to a wide (>3 km) alluvial floodplain that is completely cleared for farming. The vegetation and flora of the project area have recently been assessed in detail (TACCRA 2012). The vegetation cover is a mosaic of indigenous forest Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower 1

8 and shrubland types according to site factors, including the substrate, aspect and elevation. Overall the vegetation is regarded as relatively intact, having endured no significant historical anthropogenic effects apart from the impacts of introduced browsing mammals. Podocarp/hardwood forest predominates, in which rimu, miro, totara and southern rata are the main emergents and the canopy is largely kamahi and quintinia. The canopy and subcanopy is floristically rich; tree ferns and ground ferns are abundant. On old floodplains and along forest margins on low river terraces there is a dense hardwood shrubland dominated by divaricating Coprosma spp., Olearia spp., broadleaf and Dracophyllum. In the wetter floodplain sites toitoi is abundant; elsewhere there is a dense ground cover of indigenous and exotic sub-shrubs, herbs and grasses. The project area is within the Wilberg Ecological District (ED 50.04) of the Whataroa Ecological Region (McEwen 1987) and lies almost on the southern boundary of the Department of Conservation (DOC) Hokitika Area. The entire project area is on Crown Land under the stewardship of DOC. Apart from a brief field survey to assess the suitability of the habitat for lizards (see Appendix 1), this assessment of the lizard fauna has been a desk-based exercise. For the purposes of this assessment: o project area is defined as extending from the confluence of the Waitaha River and Macgregor Creek to the Waitaha Gorge at the upstream end of Kiwi Flat, and up to approximately the 400 m contour (see Figure 1). This includes the project footprint (see below) plus areas where any direct effects may occur (e.g. aggradation), the abstraction reach and where the ecological surveys have been undertaken. o project footprint is defined as the area that would encompass the proposed temporary and permanent installations, infrastructure and access ways. The expected lizard fauna of the project area was determined from existing literature and database records, from personal knowledge of the West Coast lizard fauna in general, and from interviews with people who have worked in or near the Waitaha catchment. Should any aspects of the final development depart significantly from those provided by Westpower to August 2013 (summarised above) the interpretation of the potential effects on the lizard fauna given here may no longer be valid. 2 Lizard Fauna 2.1 BACKGROUND The extant New Zealand native lizard fauna is currently recognised as comprising 97 endemic species of geckos (F. Diplodactylidae) and skinks (F. Scincidae), of which 40 are still to be formally described (Hitchmough et al 2013). This number of species is expected to change through both the recognition and discovery of new taxa and the rejection of others. Nonetheless, Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower 2

9 lizard species richness is far greater than that of the terrestrial indigenous birds, and lizards are a significant though often neglected component of the extant native fauna. Many of the New Zealand lizard species have naturally restricted ranges and occur in only a small part of the country. Further, since the arrival of humans in New Zealand, widespread habitat loss and degradation coupled with predation by and competition from introduced species, has led to the extinction of two species and the decimation of most others. Many species now survive only as highly-fragmented or localised populations. Nationwide DOC regards 32 lizard species as Threatened, another 49 to be At Risk, and 4 to be so poorly known that they are listed as Data Deficient (Hitchmough et al. 2013). Only 12 taxa are listed as Not Threatened (Hitchmough et al. 2013). For many lizard taxa basic information on distribution, ecology and conservation status is largely lacking, particularly so in some regions of which the West Coast is one. Information on the lizard fauna of central Westland has been derived from a series of field surveys largely undertaken in the 1990s (Aviss & Lyall 1995; Miller 1999; Miller et al. 1999; van Mierlo 1998; Lettink 2013). Lizard nomenclature used here follows Greaves et al.(2008), Liggins et al. (2008), Chapple et al. (2009), Neilsen et al.(2011) and Hitchmough et al. (2013). 2.2 LIZARD FAUNA Seventeen lizard species (7 geckos, 10 skinks) are currently recognised from the West Coast region (as defined by boundaries of the DOC West Coast/Tai Poutini Conservancy) and there are unverified records of two others, both geckos (Whitaker & Lyall 2004; BioWeb Herpetofauna 2013) 1. Of these, five species (2 geckos, 3 skinks) occur only on the West Coast. Eight lizard species (3 geckos, 5 skinks) occur in central Westland, defined by the DOC Hokitika and Franz Josef Areas that encompass the project area (see Table 1), with one taxon confined to the Hokitika Area. It is expected that three, or possibly four of these species will occur in the project area GECKOS: Forest geckos (Mokopirirakau spp.): Two Mokopirirakau species are known from central Westland i) Mokopirirakau granulatus s.s. (Gray 1845), which occurs in the North Island and north-western South Island, to a southernmost genetically-confirmed record from Ross, 22 km NE of the project area, and ii) Mokopirirakau sp. Okarito, which is known only from Okarito State Forest, 48 km SW of the project area, and the Douglas Range in south Westland. Like other taxa in the Mokopirirakau granulatus species-complex, these two species are expected to be allopatric. Between Ross and Okarito there are a wide scattering of records of forest geckos but none have been genetically tested to confirm their identity (Whitaker & Lyall 2004; BioWeb Herpetofauna 2013). The nearest of these records to the project area are at Pukekura and in Ianthe and Wanganui State 1 Molecular data have subsequently shown that two putative taxa included by Whitaker & Lyall 2004 Oligosoma Paparoa and Oligosoma Denniston to be conspecific with Oligosoma infrapunctatum (Greaves et al. 2008). Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower 3

10 TABLE 1: Lizard taxa known from the Hokitika and Franz Josef Areas, central Westland, listed according to likelihood they will occur in the project area, together with their national DOC Threat Classification (Hitchmough et al 2013), priority for conservation within the West Coast/Tai Poutini Conservancy (Whitaker & Lyall 2004), and a subjective assessment of the significance of their occurrence to the proposed Waitaha Hydro Scheme. Likely Occurrence DOC Threat Category Conservancy Priority Significance of Occurrence Mokopirirakau granulatus s.s. High At Risk (Declining C2/1) Low Naultinus tuberculatus Moderate Threatened (Nationally Vulnerable C2/1) Low Oligosoma polychroma s.s. Moderate Not threatened Moderate Low Oligosoma infrapunctatum s.s. Low At Risk (Declining B2/1) Moderate Moderate Mokopirirakau sp. Okarito Data Deficient Moderate Low Oligosoma aff. polychroma Clade 4 At Risk (Declining C2/1) n/a* Moderate O. aff. infrapunctatum crenulate At Risk (Relict B) n/a Moderate O. aff. infrapunctatum Chesterfield Threatened (Nationally Critical A2) n/a High * not assessed. Forests, between km to the west. The morphology of the forest geckos found in the Harihari/Whataroa area suggests that the taxon that is expected to occur in the Waitaha catchment is most likely Mokopirirakau granulatus s.s. Mokopirirakau spp. are diurno-nocturnal, arboreal taxa that occur in forest and shrubland habitats throughout New Zealand except for the eastern South Island (roughly Kaikoura to Dunedin). They are very widespread on the West Coast, where they have been recorded in coastal forest, pakihi shrublands, podocarp/broadleaf forest, beech forest, subalpine shrubland and montane vegetation to at least 1400 m. Although they are expected to occur more or less continuously through these habitats, the West Coast populations are generally at low density and the geckos are difficult to locate because they largely live in the forest canopy (e.g. Whitaker 1997, 1998 & 1999). Indeed, almost all the records from the Harihari/Whataroa area originate from the period of legal indigenous logging of State Forests when the geckos were recovered from the crowns of podocarps that had just been felled or were taken from podocarp logs at sawmills. The podocarp/hardwood forest throughout the project area, and its associated shrubland margins, provide ideal habitat for Mokopirirakau granulatus s.s. and, although it was not detected during the field survey, it will unquestionably be present. Green Geckos (Naultinus spp.): The only green gecko species confirmed from central Westland is Naultinus tuberculatus (McCann 1955), which is well documented to at least as far south as the Hokitika district (Whitaker & Lyall 2004; BioWeb Herpetofauna 2013). The closest verified record of this species to the project area is at Kaniere State Forest, 48 km NE. The sparse scattering of green gecko records from south of Hokitika (to at least Haast) are unsupported by photographs or vouchers so their specific identity is unclear. However, it is thought they are more likely to represent a southern extension of the range of Naultinus tuberculatus than a Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower 4

11 western extension over the Southern Alps of Naultinus gemmeus (which occurs in Canterbury and Otago) or a new Naultinus taxon (Whitaker & Lyall 2004). Naultinus spp. are diurnal, arboreal inhabitants of forest and shrubland habitats throughout New Zealand, from coastal scrub to at least the tree-line. The highly cryptic colouration and behaviour of green geckos makes them difficult to locate. They are best known from shrubland habitats such as seral manuka and kanuka, lowland grey scrub (divaricating shrubs including Coprosma spp., matagouri, etc.), pakihi fernlands and montane shrublands but whether this is because foliage/twig density confers an ecological advantage or the low stature of the vegetation makes them easier to find is unknown. They are particularly difficult to locate in tall forests where they primarily inhabit the canopy. Naultinus tuberculatus is expected to occur semi-continuously through indigenous forest and shrubland habitats on the West Coast but, apart from at a few specific locations (e.g. the Stockton and Denniston Plateaux), their populations appear to be at low density. The tall podocarp/hardwood forest in the project area is expected to provide suitable habitat for green geckos but the shrubland margins, and in particular the divaricating Coprosma scrub on the floodplains (e.g. at Kiwi Flat), appear ideal. Notwithstanding the doubt about the specific identity, there is highly likely to be a Naultinus species present in the project area SKINKS: All the skink species that occur on the West Coast are in the genus Oligosoma, and they are diurnal, heliothermic and terrestrial. As such they require open or relatively open habitats in which they can find basking sites. None of them occur in closed forest habitats but they can occupy open shrublands and forest margins. Within the project area the only suitable habitats for skinks are on the flood-plains and old flood channels, in the riparian zones (provided they are not repeatedly subject to flooding), and perhaps on slip margins. Molecular studies have revealed that Oligosoma infrapunctatum (sensu Hardy 1977) and Oligosoma polychroma (sensu Chapple et al. 2009) are both cryptic-species complexes comprising, respectively, at least four and five clades (Greaves et al. 2008; Liggins et al. 2008). In each case these clades are now accepted as distinct species but all currently remain undescribed except for the type species (Hitchmough et al. 2013). These are the only skink taxa known from central Westland. Common skink complex (Oligosoma aff. polychroma) Two species in the polychroma-complex occur in central Westland Oligosoma polychroma s.s. and Oligosoma aff. polychroma Clade 4 (Liggins et al. 2008). These taxa can only be reliably differentiated by genetic testing. Oligosoma polychroma s.s. occurs in the southern North Island, Nelson and the northern West Coast, to a southernmost genetically-confirmed record at Blaketown, 80 km NE of the project area. Oligosoma aff. polychroma Clade 4 has a limited range on the eastern side of the Southern Alps in North and Mid-Canterbury and is genetically confirmed from a single site on the West Coast, on pakihi terraces along the Oneone River 26 km W of the project area. However, between Blaketown and Oneone River there are a number of records of Oligosoma polychroma s.l., of which the closest to the project area are Hendes Ferry, 10 km SW, and Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower 5

12 Kowhitirangi, 34 km NE. At Hendes Ferry the skinks are allegedly relatively common in a farmland environment in rank grass and rough pasture. There are two older skink specimens from central Westland that appear to be in the polychroma species-complex but neither has been specifically identified as such. One is from Mystie Flat, at Hendes Creek on the Wanganui River, 9 km S of the project area. Given the proximity of this site to the location for Oligosoma polychroma s.l. at Hendes Ferry, just 7 km downstream, it is probably the same taxon. The habitat at Mystie Flat is likely to be very similar to that at Kiwi Flat. The other unidentified specimen is allegedly from Mt Spencer, on the Burster Range, 6 km E of Franz Josef and 50 km SW of the project area. There is also a sight record of small brown skinks from Ross, 22 N of the project area. Oligosoma polychroma s.s. and Oligosoma aff. polychroma Clade 4 are expected to be allopatric and their distributions are likely to be patchy and localised. It is highly likely that a species in the polychroma species-complex will be present in the project area but until skinks from there (or nearby) are genetically tested it is not possible to say which one. However, the most likely taxon to occur in the Waitaha catchment is Oligosoma polychroma s.s. Speckled skink complex (Oligosoma aff. infrapunctatum) Three taxa in the infrapunctatum-complex occur in central Westland Oligosoma infrapunctatum s.s., Oligosoma aff. infrapunctatum Chesterfield and Oligosoma aff. infrapunctatum crenulate 2 (Greaves et al. 2008). These taxa are not easy to distinguish on morphological characters alone. Oligosoma aff. infrapunctatum Chesterfield is a very rare species known from just a few sites over several hundred hectares on the coast at Chesterfield, 63 km NE of the project area, and an isolated population near Reefton. Oligosoma aff. infrapunctatum crenulate has a disjunct distribution that includes the central North Island and a few sites in north Westland, with the southernmost genetically-confirmed locality being Hokitika, 46 km NE of the project area. All populations of Oligosoma aff. infrapunctatum crenulate are on or adjacent to the coast. The range of Oligosoma infrapunctatum s.s. extends from Stephens Island (Cook Strait), through Nelson to central Westland. It is the most widely distributed of these species on the West Coast, being known from a relatively large number of sites between Kahurangi National Park and Okarito, including many that are well inland. The closest genetically-confirmed locations to the project area are at Hokitika, 46 km NE, but records from Takutai (44 km NE) and Okarito Forks (44 SW) appear to be this taxon. The distributions of these three taxa clearly indicate that the most likely one to be in the Waitaha area is Oligosoma infrapunctatum s.s. However, south of Greymouth it is presently known only from lowland locations, generally on or close to the coast 3, suggesting its occurrence in the project area is unlikely. 2 It has been suggested that the name Oligosoma robinsoni (Wells & Wellington 1985) might be applied to this taxon (Jewell & Morris 2011) but this is not generally accepted (Hitchmough et al. 2013). 3 North of Greymouth Oligosoma infrapunctatum s.s. also occurs at locations that are well inland and at higher elevation, including montane sites on the Paparoa Range, the Stockton/Denniston Plateaux, and in Kahurangi National Park. Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower 6

13 3 Conservation Significance of Lizards in the Project Area The subjective assessments that follow for the conservation significance of the lizard taxa in the project area are based on the assumption that their presumed identities are correct (see above and Table 1). Obviously these identifications require verification and it is therefore crucial that any lizards found in or near the project area are examined by specialists and preferably genetically tested. The two gecko species expected from the project area (Mokopirirakau granulatus s.s.; Naultinus tuberculatus) are not of conservation significance in relation to the project development despite their DOC threat listings of At Risk Declining and Threatened Nationally Vulnerable, respectively because both are widespread on the West Coast and their habitat is so extensive, and the area of their habitat that might be affected or lost should the project proceed is inconsequential. However, in the unlikely event that the forest gecko in the project area proves to be Mokopirirakau sp. Okarito then its conservation significance increases, but not markedly so as the available habitat for it across what would then become its known range (Waitaha River to Douglas Range, 130 km) is still extensive. The expected occurrence of a taxon in the common skink species-complex is of somewhat greater concern than for geckos because the occurrence of these skinks on the West Coast is patchy and localised and areas of potential habitat for them within the project area are restricted. The most likely taxon to be present, Oligosoma polychroma s.s., has a very wide national distribution and is listed by DOC as Not Threatened (Hitchmough et al. 2013), and would therefore be of only low conservation significance. On the other hand, if the taxon in the project area proves to be Oligosoma aff. polychroma Clade 4, its conservation significance to the development would be a lot higher than for Oligosoma polychroma s.s. as its national range is relatively restricted, its DOC threat listing is At Risk Declining, and its occurrence on the West Coast is presently based on a single locality (Oneone River). The potential habitat in the project area for taxa in the speckled skink speciescomplex is very restricted. If Oligosoma infrapunctatum s.s. is present it would be of moderate conservation significance because, although it has a relatively large national range, its occurrence in central Westland is very patchy and localised and it has a DOC threat listing of At Risk Declining. It is highly improbable that either of the other taxa in the speckled skink species-complex is present in the project area. However, should they occur Oligosoma aff. infrapunctatum crenulate would be of moderate conservation concern because although relatively widespread and locally abundant in north Westland, it has a DOC listing of At Risk Relict and the project area is well south of its known range. The occurrence of Oligosoma aff. infrapunctatum Chesterfield would be of high conservation concern as it is a very rare and poorly known species with an extremely restricted range, with the sites at Chesterfield under extreme threat from agricultural development through dairy conversions. Reflecting this, it has a DOC threat listing of Threatened Nationally Critical. Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower 7

14 In the extremely unlikely event that any lizard species other than those listed in Table 1 are detected in the project area they would be of high conservation significance. However, any comment on the relevance of their occurrence is impossible until their identity and the location and extent of their population(s) are known. 4 Potential Effect of Project on Lizards, and Mitigation 4.1 POTENTIAL EFFECT As presently defined, the proposed Waitaha Hydro Scheme in the lower Waitaha catchment will have no detrimental effect on the broader conservation status of the lizard fauna known from central Westland. At a local scale, the project is expected to have very little adverse effect on the lizard fauna of the project area, though clearly those lizards living within the final project footprint will be lost or displaced. The loss or displacement of Hoplodactylus granulatus s.s. and Naultinus tuberculatus from within the project footprint through the clearance of forest and shrubland habitats for the construction of roads, access ways and sites for the power station and ancillary structures will have essentially no conservation effect. The area of habitat likely to be involved is minimal, contiguous with it there are vast tracts of similar habitat, and suitable habitat for these two species extends throughout the region. The situation for skinks is a little different. Within the project area, habitat suitable for skinks is very limited in extent and almost entirely restricted to herbaceous vegetation and open shrubland in riparian areas and old flood channels along the Waitaha River. The extent to which this habitat will be affected in the in the vicinity of the access road, power house and tail race is unknown. However, at Kiwi Flat some loss of riparian habitat for skinks may occur above the intake weir as the river establishes a new gradient but this will affect a very small area in relation to the available habitat in the catchment as a whole. On the other hand, forest clearance and earthworks associated with the development could inadvertently create new forest margin or open rocky areas that may be habitable by skinks. Changed flow regimes in the Waitaha River resulting from the project will not affect lizards. 4.2 MITIGATION At this stage mitigation for potential effects of the scheme on lizards appears unnecessary. However, in order get better information on the lizards of the project area, any lizards detected during environmental and engineering surveys for this power project and if it proceeds during the construction phase, must be captured and forwarded to DOC staff at Hokitika so that their identity can be confirmed by genetic testing. It is only with additional information and Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower 8

15 confirmed identities that the true significance of the lizard fauna can be determined and put into regional context, and informed management decisions relating to its welfare can be made. 5 References: Aviss, M.E., and Lyall, J Survey for the Chesterfield skink (Leiolopisma sp.) near Hokitika on the West Coast, 7 9 March Threatened Species occasional publication No 8. 8 pp. + figures BioWeb Herpetofauna Amphibian and Reptile Distribution Scheme database. Department of Conservation, Wellington. (output dated 4 February 2013). Chapple, D.G., Ritchie, P.A., and Daugherty, C.H Origin, diversification, and systematics of the New Zealand skink fauna (Reptilia: Scincidae). Molecular phylogenetics and evolution 52: Greaves, S.N.J., Chapple, D.G., Daugherty, C.H., Gleeson, D.M., and Ritchie, P.A Genetic divergences pre-date Pleistocene glacial cycles in the New Zealand speckled skink, Oligosoma infrapunctatum. Journal of biogeography 35: Hicks, M Potential for aggradation at Kiwi Flat with a weir at Morgan Gorge. Unpublished report, by NIWA, Christchurch, to Westpower Limited/Electronet Services Limited, Greymouth. 4 pp Hitchmough, R., Anderson, P., Barr, B., Monks, J., Lettink, M., Reardon, J., Tocher, M., and Whitaker, T Conservation status of New Zealand reptiles, New Zealand Threat Classification series No pp. Jewell T, and Morris, R A photographic guide to reptiles and amphibians of New Zealand (2 nd edition). New Holland, Auckland. 143 pp. Lettink, M Determination of conservation status of Okuru skink (Oligosoma aff. inconspicuum Okuru ) and Chesterfield skink (Oligosoma aff. infrapunctatum Chesterfield ). Unpublished Report prepared for the Department of Conservation National Office, Wellington. 11 pp. + appendices. Liggins. L., Chapple, D.G., Daugherty, C.H., and Ritchie, P.A A SINE of restricted gene flow across the Alpine Fault: phylogeography of New Zealand common skink (Oligosoma nigriplantare polychroma). Molecular ecology 17: McEwen, W.M Ecological regions and districts of New Zealand; third revised edition in four 1: maps (Part 3). New Zealand Biological Resources Centre publication No. 5. xxii pp. + map Miller, C Genetic diversity and management units for conservation of West Coast Oligosoma (Reptilia: Lacertilia: Scincidae). Unpublished MConSci, Victoria University of Wellington, Wellington. 51 pp. Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower 9

16 Miller, C., Affeld, K., and Adams, L West Coast lizard survey: taxonomy, distribution and habitat requirements. Unpublished report, West Coast Conservancy, Department of Conservation, Hokitika. 27 pp. Nielsen, S.V., Bauer, A.M., Jackman, T.R., Hitchmough, R.A., and Daugherty, C.H New Zealand geckos (Diplodactylidae): cryptic diversity in a post-gondwanan lineage with trans-tasman affinities. Molecular phylogenetics and evolution 59: 1 22 TACCRA Limited Proposed Waitaha Hydro Scheme Development: vegetation description /assessment. Unpublished report by TACCRA Limited, Greymouth, to Westpower Limited/Electronet Services Limited, Greymouth. 66 pp. + maps van Mierlo, R West Coast skink (Oligosoma sp.) survey: September 1997 May Unpublished report, West Coast Conservancy, Department of Conservation, Hokitika. [unnumbered] Wells, R.W.; Wellington, C.R A synopsis of the amphibia and reptilia of New Zealand. Australian journal of herpetology supplementary series No. 1: Whitaker, A.H Timberlands West Coast Limited: The herpetofauna of Beech Working Circles 1 and 3, Grey Valley and Maruia Valley, north Westland. Unpublished report, Timberlands West Coast Limited, Greymouth. iv + 31 pp Whitaker, A.H Pike River Coal Company Limited: The herpetofauna of the lower Pike Stream catchment, eastern Paparoa Range, north Westland. Unpublished report, Pike River Coal Company, Auckland. iv+14 pp. Whitaker, A.H Timberlands West Coast Limited: The herpetofauna of the Inangahua Working Circle (BWC2), north Westland. Unpublished report, Timberlands West Coast Limited, Greymouth. iv + 22 pp. Whitaker, T., and Lyall, J Conservation of lizards in West Coast/Tai Poutini Conservancy. Department of Conservation, Wellington. vii + 93 pp. Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower 10

17 Appendix FIELD SURVEY A brief site familiarisation and field survey for lizards in the proposed Waitaha Hydro Scheme project area was undertaken by two people 4 from February The objectives of this survey were to assess the suitability of the habitats for lizards, and if possible confirm the occurrence of lizards. Authorisation to capture and handle lizards for the purpose of identification was granted under the following DOC permits issued to Rhys Buckingham, Wildlife Surveys Limited: o Low Impact Research and Collection Permit No RES o Wildlife Act Authority No DOA. Based on knowledge of the lizards present on the West Coast and in central Westland in particular two arboreal gecko taxa and at least one skink species are expected to occur in the Waitaha catchment. Both the gecko species inhabit forest and shrubland habitats, and population densities are expected to be equivalent in both habitats. Searching for them within forest is impractical because they generally occur in the canopy where they are difficult to detect and impossible to identify, but searches in shrublands are effective. The primary search technique for geckos was spotlighting at night with specialised equipment capable of detecting their eyereflections at up to 80 m. Additionally, Mokopirirakau geckos were sought by investigating appropriate retreat sites during the day (e.g. beneath logs or loose bark) and active Naultinus geckos were sought during sunny weather by visually searching shrubs and low vegetation for basking animals. Oligosoma skinks are diurnal and terrestrial and they inhabit open herbaceous areas, rocky sites, open shrubland and forest margins. They were sought by investigating potential retreat sites (e.g. beneath logs or rocks) for inactive animals or sign of their occurrence (e.g. faeces), and during sunny weather by visually searching appropriate microsites to detect basking or foraging animals. To optimise search effort in the brief time available, two sites were selected for the field survey based on the quality of the habitat available, the ease with which it could be searched for lizards, their proximity to the project footprint and which were representative of the habitat within the project area and were contiguous with it. These sites were: o An area of approximately 30 ha of cut-over podocarp/hardwood forest at the head of Robinson Slip (see Figures 1, 2, & 4 6). This site had old logging tracks through it that provided ready access for spotlighting and extensive scrub margins to the forest that provided habitat for skinks. The southern edge of this area was along the terrace edge with 4 A.H. Whitaker and V.A. Whitaker Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower 11

18 Macgregor Creek that had extensive areas of boulders that also provided potential habitat for skinks. o An area of approximately 25 ha of shrubland and herbaceous vegetation on the flood plain at Kiwi Flat (see Figures 1, 2, and 7 10). The old flood channels across this area provided ready access and visibility for spot-lighting the extensive scrub margins. There were also stable boulderfields in the old flood channels and along eroding terrace margins that provided potential habitat for skinks, as did logs and other flood debris. o Brief searches were also made inside closed podocarp/hardwood forest on the elevated terrace above Kiwi Flat Hut and on Doughboy Hill. Kiwi Flat was surveyed from February for a total of 21.7 person hours of day search and 12.0 person hours of night search. The day search on 18 February was in heavily overcast condition but it was fine and sunny on February. Night time conditions at Kiwi Flat were good for searching with high humidity and little or no wind, but a little cooler than desirable (10 14 C). Robinson Slip was surveyed from February for a total of 11.0 person hours of day search and 9.5 person hours of night search. The day search on 21 February was in partly cloudy conditions, with some long fine spells. Night time conditions at Robinson Slip were initially good for searching with temperatures between C, high humidity and little or no wind. However, the search on 21 February had to be terminated just after midnight because thick mist had developed. No lizards or any sign (e.g. sloughed skinks, faeces) were found during this survey. Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower 12

19 Figures FIGURE 1: Map of Waitaha River in the vicinity of the proposed Waitaha Hydro Scheme showing the location of the sites at Robinson Slip and Kiwi Flat (red dots) at which searches were undertaken for lizards in February Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower 13

20 FIGURE 2: Detail of the areas searches for lizards: Upper: Area of cut-over podocarp/hardwood forest with extensive forest margins on shingle fan at Robinson Slip. Also open shrubland and boulder fields on alluvial terraces along Macgregor Creek. Lower: Alluvial floodplain and old flood channels on Kiwi Flat with extensive areas of herbaceous vegetation and grassland, divaricating Coprosma shrubland, hardwood shrubland and podocarp/hardwood forest margin. The open flats also had bouldery areas on eroding terrace margins and some flood debris (logs) that provided potential cover for skinks. Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower 14

21 FIGURE 3: Aerial view of Waitaha River looking north towards confluence with Macgregor Creek. The proposed power station will be on the floodplain on the true right of the river. The Robinson Slip survey site is on the edge of farmland at the upper right. FIGURE 4: Margin of cut-over podocarp/hardwood forest on Robinson Slip, with thick growth of divaricating Coprosma that is ideal habitat for Naultinus species. Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower 15

22 FIGURE 5: Margin of cut-over podocarp/hardwood forest on Robinson Slip, with piles of boulders and dense fern growth that provide good habitat for Oligosoma species. FIGURE 6: Extensive boulder banks on stable terrace of Macgregor Creek provide good habitat for Oligosoma species. Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower 16

23 FIGURE 7: Overview of Kiwi Flat looking north from the ridge above the Kiwi Flat Hut showing areas of herbaceous vegetation and hardwood scrub on flood plain and in old flood channels. FIGURE 8: Mixed hardwood scrub on Kiwi Flat flood plain is good habitat for geckos, with the divaricating Coprosma on left being particularly good for Naultinus species. Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower 17

24 FIGURE 9: Stable bouldery area in old flood channel on Kiwi Flat flood plain, good habitat for Oligosoma species. FIGURE 10: Talus on eroding terrace margin on Kiwi Flat. Boulder bank and flood debris (logs) are good habitat for Oligosoma species. Whitaker Consultants Limited 2013 Waitaha Hydro Scheme: Westpower 18