Bingara Gorge Wilton, NSW Threatened Frog Survey and Assessment

2015

Ross Wellington 5/5/2015

Bingara Gorge Wilton, NSW Threatened Frog Survey and Assessment

Ross Wellington ‐ Herpetologist

Introduction

The subject land is located in the Bingara Gorge area of Wilton, NSW. The area is proposed for a mixed development including residential and expansion of the existing golf course facility.

The subject land has been previously long used for agricultural purposes and existing part development of surrounding areas as low density residential development and part development as a golf course and associated tourism facilities.

The new areas proposed for similar development consist of areas previously utilised for agriculture that are largely cleared along with adjoining areas retaining remnant native vegetation, areas that area regenerating and other areas adjoining that are largely undisturbed native vegetation.

Approach

A desk top assessment was undertaken to determine herpetofaunal (reptile and amphibian) records from the subject land and a buffer area of 5km surrounding the area. Based on a search of available database records and an assessment of the known habitat in the area, terrain, previous survey efforts and habitat preference of the species with potential to occur, a species prediction table was developed (see Table 1).

On the basis of timing and budget constraints a site inspection and targeted survey was undertaken during the day and evening of the 5th May 2015. This survey, although undertaken during less than ideal seasonal conditions and activity periods of some species, was undertaken in an attempt to detect any species still active and identify the habitat potential and condition for certain threatened species with the highest potential to occur. Both parts of the subject Land’s components were inspected diurnally in the company of Steve House (ca 5 hours) and nocturnally in the company of Rodney Armistead (ca 2.5 hours).

Prevailing Habitat and Condition

The subject land is generally heavily disturbed with large areas of cleared agricultural land, areas with scattered paddock trees and small clumps of retained woodland remnants. Much of the site proposed for development is predominantly cleared, consisting of a largely grassy ground cover and with very little shrub/understorey layer across the majority of the plateau area and the potentially developable areas of the subject site.

It was determined from this single diurnal inspection that very little high quality habitat for frogs was present generally (although some frog species are able to occupy and forage within grassland). The exceptions being around the immediate vicinity of constructed farm dams (now naturalised) and in the vicinity of the headwaters of first order drainage lines (upper parts ephemeral) and that drain as ‘laterals’ from the plateau tops into the deeper main stream line gorges. Some of these lateral drainage lines had current flow following the heavy recent (at time of survey) rain events. But most of these are suspected to reduce to ephemeral pools and non‐flow stream lines during dryer

episodes. The deeper gorge areas are characterised by exposed/outcropping sandstone and it is these areas that are considered of varying but reasonable quality habitat for amphibians and have what appears to be somewhat typical sandstone benched geomorphology. These areas provide potential habitat for two threatened frog species – the Giant Burrowing Frog Heleioporus australiacus (NSW and Commonwealth listed) and the Red‐crowned Toadlet Pseudophryne australis (NSW listed) among a number of other potential/likely non‐threatened frog species (see predictive Table).

The diurnally inspected sites were then revisited at night for a period of approximately 2.5 hours and searched using spotlight/headlamp. All frogs observed or heard calling were recorded and compared against the predictive list of herpetofauna species considered likely in the locality on the basis of previous records within a 5 km radius, the habitat present and the known distribution and habitat preference of Sydney Basin herpetofauna species.

A composite predicted and actual herpetofauna species list was produced from the desktop assessment, previous survey experience in the general area and observations made during the current diurnal and nocturnal surveys of the site (see Table 1).

A map of the subject land depicts an area that includes the subject land and the prevailing landscapes. It also provides an indication of the areas traversed and assessed for the presence of amphibian habitat.

Figure 1 Locality Map depicting area of survey and assessment.

The diurnal and nocturnal site survey included inspection of a representative number of on‐site drainage lines (laterals) to ascertain and assess habitat suitability/condition as well as survey for the presence of herpetofauna species, particularly frogs and their larvae.

Specifically, two threatened species were the focus of this survey and assessment, the Red‐crowned Toadlet Pseudophryne australis (RCT) and the Giant Burrowing Frog Heleioporus australiacus (GBF). Both species are known to occupy similar habitat types and have a similar pattern of distribution, quite often occupying the same streamlines but usually with some micro separation; with RCT generally occupying the upper most and more ephemeral sections of the drainage line. A summary/profile of both these species ecology, distribution and environmental impact assessment can be found within several readily available publications (see references Recsei, 1997; Thumm and Mahony, 1997; Thumm and Mahony, 1999; NPWS 2001a; NPWS 2001b; DECC, 2010)

Neither of these species were detected during the survey and given the heavy rain events immediately preceding the survey it would have been reasonably expected that RCTs would be detected if present in any significant numbers as this species generally displays an opportunistic pattern of breeding activity. Conditions were also suitable for detecting activity of the GBF although timing for breeding activity likelihood was more equivocal in May but the species can often been detected at this time of the year and even later, due to the frequent occurrence of over‐wintering tadpoles, even when adult activity is likely reduced or absent. Therefore, it is not possible to rule out presence of either species on the basis of an inability to detect them during such a brief survey. However, the detection of a pair of active Stony Creek Frogs Litoria lesueurii was indicative that conditions were warm enough for frog detection generally but the prevalence of calling Verreaux’s Frogs Litoria verreauxii, a known autumn/winter calling species was also indicative of the prevailing seasonal influence.

In lieu of undertaking extended and regular interval, repeated surveys to confirm presence of either species or to be confident of actual absence from the site altogether, a preferred option is to assume presence and identify/categorise areas with highest likelihood of providing habitat for the species based on their known habitat preference.

By so doing, the areas identified include all the ephemeral drainage lines flowing from the plateau top that still retain natural vegetation. (Description of the two drainage line features demarcating the two species microhabitat differentiation).

By protecting and buffering these areas from the direct impacts of development by excluding them from the proposed developable areas would be a first step in the precautionary protection of this assumed potential habitat for both species.

However, to further protect this habitat from the known potential indirect impacts of the development may well prove more problematic. Both species are highly sensitive to changes in hydrology and water quality and their disappearance from downstream areas of urbanised development has been well documented (see references).

Urbanised impacts on flow regimes generally include such things as:

 rapid and high volume flow events from increased extent of hardstand surfaces;  reduced infiltration that contributes to maintained or lengthened stream flows following rain events.

Water quality is generally influenced by such factors as:

 bituminous road surfaces, particularly immediately following road surfacing;  the use of ‘blue‐metal’ aggregate as road base and the runoff from fresh and curing concrete  elevated nutrient levels from urban run‐off such as gardens, putting greens and fairways as well as the removal of ground covers during construction that can exacerbate erosion and sedimentation of streamlines.

Consequently, innovative measures to reduce these potential impacts and include measures that ensure flow regimes are maintained, water quality of runoff is not altered or returned/filtered/treated to natural water quality measures, are essential to ensure any local populations of these two threatened species are maintained in an un‐impacted state. To achieve this outcome in an area adjacent to typical urbanisation is not simple and likely will require some new and creative measures to be developed and implemented.

A map of the areas containing habitat for these species is depicted in Figure 2. The area covers the area of the terrain within the subject land that most reasonably approximates the area containing potential breeding areas for both Red‐crowned Toadlets (RCTs) and Giant Burrowing Frogs (GBFs). The defined area does not necessarily contain all possible habitat for either species as both are known to occupy areas away from their breeding sites and move between foraging and shelter sites to their breeding areas during favourable conditions (NPWS 2001a; Thumm & Mahoney 1997;1999; Stauber 2006; Penman et al. 2008).

Figure 2 Potential Habitat Map depicting area likely to contain habitat of the Giant Burrowing Frog and Red‐crowned Toadlet.

References

Campbell, A. (1999) Editor Declines and Disappearances of Australian Frogs. Australian Government, Canberra. http://www.environment.gov.au/system/files/resources/7de68015-f93b-4064-bed6- b2e21d16b5bd/files/frogs.pdf Department of Environment and Climate Change (2010) Recovery Plan (Draft) Giant Burrowing Frog Heleioporus australiacus DECC, Sydney

Laxton, J.A. (2007) Effect of Blue Metal (Basalt) Chips on Rainwater Runoff. (unpublished Report to Gosford City Council).

NSW NPWS (Wellington, R.) (2001a) Environmental Impact Assessment Guideline Red-crowned Toadlet Pseudophryne australis (Gray, 1835). Hurstville, NSW. http://www.environment.nsw.gov.au/resources/nature/RedcrownedtoadletEia0501.pdf

NSW NPWS (Wellington, R.) (2001b) Environmental Impact Assessment Guideline Giant Burrowing Frog Heleioporus australiacus (Shaw & Nodder 1795). Hurstville, NSW. http://www.environment.nsw.gov.au/resources/nature/Giantburrowingfrogeia0501.pdf

Penman T., Lemckert, F. and Mahony, M (2008) Spatial ecology of the Giant Burrowing Frog (Heleioporus australiacus): implications for conservation prescriptions. Australian Journal of Zoology, 56: 179–186

Recsei, J. (1997) The Eastern Owl Frog, Heleioporus australiacus pp 59-68; In: Threatened Frogs of NSW - Habitats, Status and Conservation Ed. Harald Ehmann, published by the Frog and Tadpole Study Group of NSW Inc.

Stauber, A. (1999) Geographic variation in Pseudophryne australis: morphological and genetic differences. BSc (Honours) Thesis, UTS Sydney

Stauber, A. (2006). Habitat requirements and habtiat use of the Red-crowned Toadlet Pseudophryne austalis and the Giant Burrowing Frog Heleiopourus australiacus in the Sydeny Basin. Department of Environmental Sciences. Sydney, University of Technology, Sydney. Doctorate. https://opus.lib.uts.edu.au/research/bitstream/handle/2100/890/Whole02.pdf?sequence=2

Thumm, K. and Mahony , M., (1997) The Red-crowned Toadlet, Pseudophryne australis: pp. 143-156; In: Threatened Frogs of NSW - Habitats, Status and Conservation Ed. Harald Ehmann, published by the Frog and Tadpole Study Group of NSW Inc.

Thumm, K. and Mahony, M. (1999) Loss and Degradation of Red-Crowned Toadlet Habitat in the Sydney Region. Pp 99-108 In: Campbell, A. (Editor) Declines and Disappearances of Australian Frogs. Biodiversity Group Environment Australia, Canberra

Thumm, K. and Mahony, M. (2002a). Hatching dynamics and bet-hedging in a temperate frog, Pseudophryne australis (Anura: Myobatrachidae). Amphibia-Reptilia 23, 433-444

Thumm, K., Mahony, M. (2002b): Evidence for continuous iteroparity in a temperate zone frog, the Red-crowned Toadlet, Pseudophryne australis (Anura: Myobatrachidae). Aust. J. Zool. 50: 151-167.

Appendix A

Table 1. Composite known and predicted Herpetofauna Species List for the Locality

Predicted Bionet on basis of Records EPBC NSW locality within Previous This Group Family Scientific Name Common Name Act Comment Status and known vicinity of Study Study Status distribution the Locality Heleioporus Amphibia Limnodynastidae Giant Burrowing Frog V,P V australiacus *

Limnodynastes Eastern Banjo Frog P dumerilii grayi * *

Limnodynastes peronii Brown-striped Marsh Frog P * *

Limnodynastes Spotted Marsh Frog P tasmaniensis * * *

Myobatrachidae Crinia signifera Common Eastern Froglet P * * *

Mixophyes balbus Stuttering Frog E1,P,2 V *

Paracrinia haswelli Haswell’s Frog P * *

Pseudophryne australis Red-crowned Toadlet V,P *

Pseudophryne bibronii Bibron’s Toadlet P * *

Uperoleia laevigata Smooth Toadlet P * *

Green and Golden Bell Pelodryadidae Litoria aurea E V Frog *

Litoria caerulea Green Tree Frog P *

Litoria citropa Blue Mountains Tree Frog P * *

Litoria fallax Eastern Dwarf Tree Frog P * *

Litoria freycineti Freycinet's Frog P *

Litoria jervisiensis Jervis bay Tree Frog P *

Litoria latopalmata Broad-palmed Frog P * * *

Litoria lesueurii Lesueur’s Tree Frog * * *

Litoria littlejohni Littlejohn's Tree Frog V,P V *

Litoria peronii Peron's Tree Frog P * *

Litoria phyllochroa Leaf-green Tree Frog P *

Litoria tyleri Tyler’s Tree Frog P * *

Litoria verreauxii Verreaux's Frog P * * *

Reptilia Chelidae Chelodina longicollis Long Necked Turtle P *

Nepean Short-necked Emydura dharuk P Turtle *

Carphodactylidae Phyllurus platurus Broad-tailed Gecko P *

Underwoodisaurus milii Thick-tailed Gecko P *

Diplodactylidae Amalosia lesueurii Lesueur's Velvet Gecko P *

Diplodactylus vittatus Wood Gecko P *

Predicted Bionet on basis of Records EPBC NSW locality within Previous This Group Family Scientific Name Common Name Act Comment Status and known vicinity of Study Study Status distribution the Locality Pygopodidae Lialis burtonis Burton's Snake-lizard P *

Pygopus lepidopodus Common Scaly-foot P *

Scincidae Acritoscincus platynota Red-throated Skink P *

Concinnia tenuis Barred-sided Skink P *

Cryptoblepharus Elegant snake-eyed Skink P pulcher *

Ctenotus robustus Robust Striped-skink P *

Ctenotus taeniolatus Copper-tailed Skink P *

Cyclodomorphus She-oak Skink P michaeli *

Egernia cunninghami Cunningham's Skink P krefftii *

Eulamprus quoyii Eastern Water-skink P *

Dark-flecked Garden Lampropholis delicata P Sunskink * *

Lampropholis Pale-flecked Garden P guichenoti Sunskink *

Liopholis whitii White's Skink P *

Lygisaurus foliorum Tree-base Litter-skink P *

Saiphos equalis Three-toed Skink P *

Tiliqua scincoides Eastern Blue-tongue P *

Amphibolurus Agamidae Jacky Lizard P muricatus *

Intellagama lesueurii Eastern Water Dragon P *

Pogona barbata Bearded Dragon P *

Rankinia diemensis Mountain Dragon P boylani *

Varanidae Varanus rosenbergi Rosenberg's Goanna V,P *

Varanus varius Lace Monitor P *

Ramphotyphlops Typhlopidae Blackish Blind Snake P nigrescens *

Boidae Morelia spilota Diamond Pythons P *

Colubridae Boiga irregularis Brown Tree Snake P *

Dendrelaphis Green Tree Snake P punctulatus *

Elapidae Acanthophis antarcticus Common Death Adder P *

Cacophis squamulosus P *

Cryptophis nigrescens Eastern Small-eyed Snake P *

Drysdalia rhodogaster Mustard-bellied Snake P *

Furina diadema Red-naped Snake P *

Black-bellied Swamp Hemiaspis signata P Snake *

Hoplocephalus Broad-headed Snake E1,P,2 V bungaroides *

Notechis scutatus Tiger Snake P *

Pseudechis Red-bellied Black Snake P porphyriacus * *

Pseudonaja textilis Eastern Brown Snake P *

Vermicella annulata Bandy-bandy P *