Koala Habitat Suitability Model for North East NSW

A habitat suitability model at a 250 m resolution for the Koala Phascolarctos cinereus in north-eastern New South Wales using ‘presence only’ records and MaxEnt modelling. Model extent was based on the extent of Crafti vegetation mapping for north east NSW. Substantial spatial clustering of records in coastal urban areas was reduced using a 2 km spatial filter and by modelling separately two sub-regions divided by the 500 m elevation contour. An average of 1086 occurrence records was used to develop models. A bias file was prepared that accounted for variable survey effort, including the concentration of Koala records along sealed and unsealed roads. A reduced set of 14 variables was used in model building. The models were evaluated using a test set of 25 % of the records, with a resulting good fit for each model, as measured by AUC. Frequency of wildfire, Australian Soil Classification, floristic mapping and elevation had the highest relative contribution to the model, whilst a number of other variables made minor contributions. The model was field validated at 65 ground-truth sites.