Bioindicator snake shows genomic signatures of natural and anthropogenic barriers to gene flow
MetadataShow full item record
Funding and Sponsorship
Urbanisation alters landscapes, introduces wildlife to novel stressors, and fragments habitats into remnant ‘islands’. Within these islands, isolated wildlife populations can experience genetic drift and subsequently suffer from inbreeding depression and reduced adaptive potential. The Western tiger snake (Notechis scutatus occidentalis) is a predator of wetlands in the Swan Coastal Plain, a unique bioregion that has suffered substantial degradation through the development of the city of Perth, Western Australia. Within the urban matrix, tiger snakes now only persist in a handful of wetlands where they are known to bioaccumulate a suite of contaminants, and have recently been suggested as a relevant bioindicator of ecosystem health. Here, we used genome-wide single nucleotide polymorphism (SNP) data to explore the contemporary population genomics of seven tiger snake populations across the urban matrix. Specifically, we used population genomic structure and diversity, effective population sizes (Ne), and heterozygosity-fitness correlations to assess fitness of each population with respect to urbanisation. We found that population genomic structure was strongest across the northern and southern sides of a major river system, with the northern cluster of populations exhibiting lower heterozygosities than the southern cluster, likely due to a lack of historical gene flow. We also observed an increasing signal of inbreeding and genetic drift with increasing geographic isolation due to urbanisation. Effective population sizes (Ne) at most sites were small (< 100), with Ne appearing to reflect the area of available habitat rather than the degree of adjacent urbanisation. This suggests that ecosystem management and restoration may be the best method to buffer the further loss of genetic diversity in urban wetlands. If tiger snake populations continue to decline in urban areas, our results provide a baseline measure of genomic diversity, as well as highlighting which ‘islands’ of habitat are most in need of management and protection.
Showing items related by title, author, creator and subject.
The Broad-Scale Analysis of Metals, Trace Elements, Organochlorine Pesticides and Polycyclic Aromatic Hydrocarbons in Wetlands Along an Urban Gradient, and the Use of a High Trophic Snake as a BioindicatorLettoof, Damian C. ; Bateman, Bill ; Aubret, F.; Gagnon, Marthe Monique (2020)Wetlands and their biodiversity are constantly threatened by contaminant pollution from urbanisation. Despite evidence suggesting that snakes are good bioindicators of environmental health, the bioaccumulation of contaminants ...
Investigating the role of urbanisation, wetlands and climatic conditions in nematode parasitism in a large Australian elapid snakeLettoof, Damian; von Takach, B.; Bateman, Bill ; Gagnon, Marthe Monique ; Aubret, Fabien (2020)Tiger snakes (Notechis scutatus) in wetlands of South-West Western Australia (SW WA) are commonly parasitised by the nematode Ophidascaris pyrrhus. Host-parasite interactions are complex and can potentially be impacted ...
Tiger snakes, Notechis scutatus, as a Bioindicator of Wetland Health across the urban matrix of Perth, Western AustraliaLettoof, Damian Christopher (2021)Urbanisation frequently degrades wetlands via physical modifications, novel stressors and the introduction of pollutants. The health of wetlands can be measured through the use of bioindicators - such as top predators. ...