Genetic diversity and structure of the threatened striped legless lizard, Delma impar: management implications for the species and a translocated population

Abstract

The striped legless lizard, Delma impar, is a specialist grassland species restricted to south-eastern Australia. Anthropogenic influences have seen the destruction of much of its habitat and the species is threatened with extinction. Known populations of D. impar in Canberra (Australia) have recently been cleared for urban development. In 2015, Bush Heritage Australia translocated 41 individuals from these populations to Scottsdale Reserve. In this study, we completed the first population genetics analysis of D. impar in Canberra, providing a baseline for assessment of the genetic success of the translocation to Scottsdale Reserve. We analysed 154 D. impar individuals from six populations in Canberra, assessing levels of genetic diversity and differentiation within and between populations, using eight highly polymorphic microsatellite loci. High levels of genetic diversity and negligible levels of genetic differentiation were observed. Measures of allelic diversity were lower in the translocated population compared to the Canberra populations and Bayesian analysis revealed a disproportionate representation of two genetic clusters identified by STRUCTURE between the Scottsdale Reserve and Canberra populations, indicating that the initial genetic capture failed to ‘capture’ recommended levels of genetic diversity to support an ongoing population. If the species successfully establishes itself at Scottsdale Reserve, the data suggests that the population should be augmented with individuals from other sites in Canberra, with the aim of increasing genetic diversity to recommended levels (i.e. > 95% genetic variation). This will maximise resilience, adaptability and long-term survival potential of the Scottsdale Reserve population of striped legless lizards from a genetic context.