Determining environmental factors that influence the occurrence of Sarcoptic Mange in bare-nosed wombats (Vombatus ursinus) using citizen science data

Sarcoptic mange is a significant welfare and conservation issue in a diverse range of mammalian species, wombats being some of the most impacted. Cases have been observed in bare-nosed (Vombatus ursinus) and southern hairy-nosed (Lasiorhinus latifrons) wombats but not the northern hairy-nosed wombat (Lasiorhinus krefftii). Here, we map the prevalence and model habitat suitability for sarcoptic mange that infests wombats across Australia. Presence-only data was isolated from wombat observation records entered into the citizen science project Wombat Survey and Analysis Tool (WomSAT). Environmental variables were collated from publicly available databases and prepared for analysis in ArcGIS Pro. Maxent modelling software was used to generate the habitat suitability model for wombat sarcoptic mange infestations. Sarcoptic mange contributed to 26.2% of all observations and were most frequent in Victoria (VIC) followed by New South Wales (NSW). The most important factors (percent contribution) in our model were Interim Biogeographic Regionalisation for Australia (IBRA; 25.7%), land use (24.5%), maximum summer temperature (15.1%), rain in summer season (10.7%), Collaborative Australian Protected Areas Database (CAPAD; 7.6%) and the hourly relative humidity at 3 pm (7.3%). All remaining environmental variables had very low to zero effect on the model. Our predictive presence model identified 73 local government areas (LGAs) across NSW (n = 20; 79.27 km²), VIC (n = 27; 265.46 km²) and Tasmania (TAS; n = 26; 21.52 km²) that had ‘highly suitable’ conditions and 79 that had ‘suitable’ conditions (3467.12 km²) for sarcoptic mange occurrence. In Queensland (QLD), only one LGA had ‘suitable’ (0.61 km²) habitat for sarcoptic mange and no areas that were ‘highly suitable’. SA had four LGAs that were ‘moderately suitable’ (74 km²) for sarcoptic mange, while the remaining LGAs were ‘not suitable’. The habitat in the ACT was predominantly ‘not suitable’ for sarcoptic mange. Predictive models, such as this can be used to help plan management strategies and support treatment efforts by carers.