Restricted dispersal and genetic diversity in populations of an endangered montane lizard (Eulamprus leuraensis, Scincidae)

Abstract

Many alpine species are under threat from global climate change, as their geographic ranges become increasingly fragmented and unsuitable. Understanding rates and determinants of gene flow among such fragmented populations, over historical as well as recent timescales, can help to identify populations under threat. It is also important to clarify the degree to which loss of local populations reduces overall genetic diversity within the taxon. The endangered Blue Mountains Water Skink (Eulamprus leuraensis) is restricted to <40 small swamps in montane south-eastern Australia. Our analyses of seven microsatellite loci of 241 animals from 13 populations show strong geographic structure, with major genetic divergence even between populations separated by <0.5 km. Dispersal between populations is scarce, and appears to involve mostly males. Our analyses suggest potential recent bottleneck events in all the identified populations, and lower genetic diversity and population size parameter at lower-elevation sites than at higher-elevation sites. Management of this endangered taxon thus needs to treat most populations separately, because of their genetic distinctiveness and low rates of genetic exchange.

Geographic variation in the age of temperate-zone reptile and amphibian species: Southern Hemisphere species are older

“…Although causal mechanisms remain unclear, 'older' species consistently are less resilient to the challenges imposed by human activities [9]. Hence, all else being equal, Southern Hemisphere ectothermic vertebrates may be less able to cope with threats (such as those driven by changes in climate, habitat quality, invasive species and habitat fragmentation [11][12][13]) than are ecologically analogous taxa from the Northern Hemisphere. Understanding such broadscale geographical biases in species vulnerability may help us to understand why extinction rates are so much higher in some parts of the world than others [14], and to allocate conservation and management efforts to regions where endemic taxa may be at particular risk [15].…”

Fine-scale population genetic structure and sex-biased dispersal in the smooth snake (Coronella austriaca) in southern England

“…In this instance, the dispersing sex is likely to have a larger vAIc value than the philopatric sex because of increased probability of both resident and immigrant individuals being present in the sampled populations (Dubey et al, 2008). Because of the inequality in the number of males and females sampled at each site, we used a random re-sampling procedure to create five new data sets (n ¼ 110) with an equal sex ratio (male ¼ 55 females ¼ 55) and calculated the mean statistic and probability values for each test (sensu Dubey and Shine, 2010) Results A total of 149 individual smooth snakes were captured within Wareham Forest. Samples from two individuals failed to amplify any of the eight loci and so were excluded from further analyses.…”

Vegetation, fauna and groundwater interrelations in low nutrient temperate montane peat swamps in the upper Blue Mountains, New South Wales.

“…Dubey and Shine (2010) have highlighted the genetic divergence among swamp populations of Eulamprus leuraensis, recommending that most populations be treated as discrete conservation units, with clear implications in the event of extirpation of individual swamp populations. The distinctiveness of individual swamp populations is also supported by Hose's (2009) work on stygofauna in swamps on the Woronora Plateau.…”

“…In addition to identified threats (urban development, pollution, sedimentation, alteration to hydrological regimes, weed invasion, visitor disturbance, cat predation) (NPWS 2001), climate change has been identified as a potential threat to this stenotopic, patchily distributed reptile (Dubey & Shine 2010). A recent genetic study has identified low rates of genetic exchange and high genetic divergence between discrete swamp populations, and recommended that most populations be treated separately as discrete conservation units (Dubey & Shine 2010). The species is listed as Endangered under the TSC Act 1995 and the EPBC Act 1999.…”

“…The Blue Mountains water skink, Eulamprus leuraensis (Scincidae) is endemic to mid to upper elevation BMSS and to NPSS (Dubey & Shine 2010;LeBreton 1996;NPWS 2001). The species is viviparous and grows to 64 (-72) cm (SV) long (Swan et al 2004).…”