A skink out of water: impacts of anthropogenic disturbance on an Endangered reptile in Australian highland swamps S ARSHA G ORISSEN,MATTHEW G REENLEES and R ICHARD S HINE Abstract The Blue Mountains water skink Eulamprus Habitat loss and degradation are key causes of extinction leuraensis is an Endangered swamp specialist known from of threatened wildlife worldwide (Gibbons et al., ; , sites and restricted to the rare, threatened and frag- Hibbitts et al., ). Research into the impacts of disturb- mented habitat of Temperate Highland Peat Swamps on ance on herpetofauna has focused on the global amphibian Sandstone. Understanding the species’ ecology, notably its decline (e.g. Collins & Storfer, ). A similar global de- vulnerability to threatening processes such as hydrological cline may also be underway in reptiles but has attracted disturbance, is essential if we are to retain viable populations less research (Gibbons et al., ; Böhm et al., ), al- of this Endangered reptile. We examined the impact of an- though localized declines and extinctions have been well thropogenic disturbance (longwall mining practices, devel- documented (Cogger et al., ; Hecnar & M’Closkey, opment (industrial, urban, infrastructural) and damage by ; Shine et al., ; Reading et al., ; Sinervo et al., recreational vehicles) on this species, other herpetofauna ). Specialist, fragile or low-mobility species may be at and the swamp by surveying six paired undisturbed and dis- greatest risk when environments change (Steffen et al., turbed sites in south-eastern Australia. The abundance of E. ). One such imperilled species is the Endangered Blue leuraensis was severely affected by disturbance. The species Mountains water skink Eulamprus leuraensis (ARASG, was absent from disturbed swamps, where it was replaced by ). its congener E. heatwolei and other woodland reptile spe- This iconic reptile is known only from , isolated sites cies. Disturbance was associated with a halving of soil mois- within the montane regions of south-eastern Australia (Blue ture content and a loss of surface water; the dense, live Mountains and Newnes Plateau; Gorissen, ). It is understorey was replaced by a sparser, drier habitat with endemic to a unique peat-swamp habitat, Temperate dead vegetation, logs, rocks and bare ground. In effect, dis- Highland Peat Swamps on Sandstone, which is also rare turbance eliminated the distinctive features of the swamp (c. , ha in extent; Hensen & Mahony, ) and feder- habitat, transforming it into an area that resembled the ally listed as Endangered (TSSC, ). Genetic studies surrounding habitat in terms of fauna, flora and physical show low rates of lizard dispersal, and thus gene flow, be- characteristics. Our surveys suggest that hydrological dis- tween these swamps (Dubey & Shine, ), and even less turbance (groundwater loss or alterations in surface water genetic connectivity between the two main regions where chemistry) extirpates E. leuraensis. This species’ dependence such swamps occur (i.e. Blue Mountains water skinks on on groundwater renders it sensitive to habitat degradation the Newnes Plateau are genetically distinct from those in through hydrological disturbance. The conservation mes- the Blue Mountains; Dubey & Shine, ). Climate change sage for management authorities is clear: to protect the is expected to cause hotter and drier weather conditions skink, protect the habitat. in the area, reducing water availability (CSIRO & BOM, ; IPCC, ). Longwall mining is an immediate Keywords Conservation, groundwater, hydrology, mining, and landscape-scale threat, given its detrimental and often mire, threatened ecosystem, threatened species, water severe impacts on swamps in this region (Aurecon, ; pollution Goldney et al., ; Enforceable Undertaking, ) via groundwater loss through subsidence (and chemical pollution from mine-water discharge), and is listed as a Introduction Key Threatening Process in protective legislation (NSW n essential first step in understanding the level of threat Scientific Committee, ). Development (industrial, Ato a species is to determine its response to disturbance urban) and damage by vehicles are other threatening pro- (Shine et al., ; Pike et al., ; Böhm et al., ). cesses affecting swamps of the region (Hensen & Mahony, ; Fryirs et al., ; Belmer et al., ) and may potentially degrade habitat quality for this Endangered rep- SARSHA GORISSEN (Corresponding author), MATTHEW GREENLEES and RICHARD tile. We surveyed swamps exhibiting habitat degradation SHINE School of Life and Environmental Sciences, University of Sydney, Sydney, NSW 2006, Australia. E-mail [email protected] (and thus altered hydrological regimes), to clarify the impact Received March . Revision requested April . of hydrological disturbance on E. leuraensis and its swamp Accepted April . First published online September . habitat. Oryx, 2017, 51(4), 610–618 © 2016 Fauna & Flora International doi:10.1017/S0030605316000442 Downloaded from https://www.cambridge.org/core. IP address: 170.106.202.8, on 30 Sep 2021 at 16:15:35, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605316000442 A skink out of water 611 FIG. 1 Locations of the swamp sites surveyed in the Blue Mountains and Newnes Plateau areas of south-eastern Australia (NPWS, ; Table ). BS, MS and XFC have both undisturbed and disturbed areas. (Adapted from Gorissen et al., ) Study area Table ), c. ,–, m in extent, with mean elevations of –, m. Three swamps were pristine at one end but The Newnes Plateau and Blue Mountains areas of south- disturbed at the other (BS, MS, XFC; Plate a), providing eastern Australia, c. km north-west of Sydney (Fig. ), both control and treatment sites. We therefore sampled have a temperate climate, with mean monthly temperature sites in total (selected based on their level of disturbance), – – of . °C (BOM, ), mean annual rainfall of comprising six pairs of undisturbed and disturbed sites, , mm (Keith & Benson, ; Whinam & Chilcott, paired by proximity and availability. All disturbed sites ex- ; DEC, ), and an underlying sandstone geology hibited hydrological degradation, in terms of ground- and/ (Keith & Benson, ). or surface-water quantity (loss through subsidence from longwall mining practices at EWS, (Plate b) and JS (Plate Methods c,d)), damage by recreational vehicles (XFC (Disturbed); Hensen, ) or development of infrastructure (MS Study sites (Disturbed); Fryirs et al., ). Surface-water quality was also affected (physical and/or chemical properties) by pollu- The swamps sampled included Blue Mountains sedge tion and/or sedimentation as a result of industrial (BS swamps and Newnes Plateau shrub swamps (Keith & (Disturbed); N. Belmer et al., unpubl. data) or urban devel- Benson, ; Benson & Baird, ). Islands within a matrix opment (BRS; Belmer et al., ). Eight of the study sites of sclerophyll woodland and open forest, these swamps are were on the Newnes Plateau, mainly within State Forests, dominated by sedge, shrub and grass vegetation growing on at c. , m elevation, and four were in the Blue peaty soils (Keith & Benson, ; TSSC, ; Benson & Mountains, on land managed by the Blue Mountains City Baird, ). The swamps contain one or more drainage Council, at c. m elevation. lines, and many are elongate in shape (Benson & Baird, These swamp sites span the entire known distribution- ). Nine such swamps were selected for surveys (Fig. , al range of the Blue Mountains water skink, which is the sole Oryx, 2017, 51(4), 610–618 © 2016 Fauna & Flora International doi:10.1017/S0030605316000442 Downloaded from https://www.cambridge.org/core. IP address: 170.106.202.8, on 30 Sep 2021 at 16:15:35, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605316000442 612 S. Gorissen et al. TABLE 1 Features of the six paired swamp sites in the Blue Mountains and Newnes Plateau areas of south-eastern Australia (Fig. ), with swamp type, disturbance, hydrological impact, year of disturbance, elevation and area (Aurecon, ; Goldney et al., ; Belmer et al., ; M. Hensen, pers. comm., ). Swamp site (Type) Swamp name Disturbance Hydrological impact Year disturbed Elevation (m) Area (m2) Pair 1 PNP4 (Undisturbed) Upper Dinner Gully 973 42,400 JS (Disturbed) Junction Longwall mining; Water loss 2003–2004 1,170 4,111 subsidence Pair 2 SS (Undisturbed) Sunnyside 1,135 83,000 EWS (Disturbed) East Wolgan Longwall mining; Water loss 2002–2009 1,120 40,400 subsidence; mine- water discharge Pair 3 XFC1 (Undisturbed) Happy Valley 1,075 119,018 XFC1 (Disturbed) Happy Valley Vehicles Water loss Prior to 2006 1,085 2,922 (recreational) Pair 4 BS (Undisturbed) Browns 1,100 108,200 BS (Disturbed) Browns Development Water pollution Prior to 2008 1,120 9,057 (industrial); sedimentation Pair 5 MS (Undisturbed) Marmion Road 945 22,413 MS (Disturbed) Marmion Road Development Water loss 2003–2004 960 1,925 (infrastructure) Pair 6 SL (Undisturbed) South Lawson 685 21,749 BRS (Disturbed) Boronia Road Development Water pollution 2011–2012 755 3,790 (urban); concrete contamination endemic vertebrate of the region (Fig. ). Prior to surveying, trapping effort in surrounding woodland , m from the pilot trapping established presence of the lizard in all undis- swamp boundary; Gorissen et al., ). These scincid lizards turbed swamps. Of the three disturbed sites, the species was are medium-sized (total length to . cm, c. g), vivip- recorded