Josh Griffiths1, Matt Stephenson2, Caroline McGuinn2, John Black1, Anthony van Rooyen1, Sue Song1, Andrew Weeks1,3
1EnviroDNA, Brunswick, Australia, 2East Gippsland Landcare Network, Bairnsdale, Australia, 3The University of Melbourne, School of BioSciences, Parkville, Australia
Introduced foxes have been implicated in the decline of a range of Australian wildlife and continue to have significant impacts. Despite significant investment, control programs may have limited long-term impacts due to learned avoidance by ‘smart’ individuals or influx of surplus foxes from surrounding areas.
We used genotyping and metabarcoding of environmental samples (scats) to assess local fox abundance and their potential impacts on threatened species, particularly migratory shorebirds, within a Gippsland Lakes Reserve. Fox scats (n = 103) were collected from walking transects with assistance from detection dogs.
Fox DNA was successfully amplified from surface swabs of 48 samples with microsatellite analysis identifying 23 individuals (10 females, 13 males). Individual foxes were considered transient if only identified from a single scat (17) or resident if identified from multiple scats (6). The ability to identify individual foxes from scats allows robust estimates of population size and quantitative assessments of control strategies.
Vertebrate metabarcoding of all scats identified at least 43 species (2 fish, 1 frog, 21 birds, 14 mammals, 5 reptiles), highlighting the broad and opportunistic diet of foxes, including native, introduced and domestic species. While no migratory bird species were identified (Covid restrictions inhibited sampling during migratory bird season), the results suggest foxes may impact these populations in season.
Fox scats are shown as a useful aggregation of genetic material from a broad area that can provide an estimate of local biodiversity or a novel method to determine the presence of cryptic threatened species through eDNA analysis.
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