Investigating semi-arid vertebrate communities from different quality habitats using eDNA derived from soils

Abstract

Since European settlement, many arid and semi-arid Australian vertebrates have suffered declines, with a disproportionally high number also going extinct. This can be attributed to introduced animals, e.g. feral cats, as well as habitat modification and loss. Native species in arid and semi-arid zones rely on refugia during dry periods, where the greenness of vegetation is linked to refugia availability. To preserve and manage native species populations, accurate biomonitoring data is crucial. Traditional techniques, e.g. camera and live trapping, are labour intensive, costly and biased towards large, common species. New techniques are being developed to improve the accuracy and reliability of biomonitoring data. One such technique is environmental DNA (eDNA). This study aimed to use soil-derived eDNA to examine the preferences of vertebrates for three different environments, as determined by a greenness index, in semi-arid zones in New South Wales, Australia. One hundred and sixty-two soil samples were collected and amplified using the 12S5V vertebrate primer. Sixteen unique taxa were detected: four reptiles, four birds and eight mammals, of which five were non-native mammals. Of these, twelve were assignable to the level of species. There was no significant difference in species richness and community composition for the different classes of greenness. However, sampling site location did have a significant effect on the community composition but not on the species richness. This suggests that greenness levels might not be the dominant driver for habitat preference, with other factors, e.g. plant community composition or water accessibility also influencing the preference of vertebrates. However, it is emphasised that this study was a pilot study and was restricted to one region over a short period. Hence, further studies are required to determine whether soil-derived eDNA can be used to determine the composition of vertebrates within arid and semi-arid regions.