Patterns of niche contraction identify vital refuge areas for declining mammals

Aim Investigation of realised niche contraction in declining species can help us understand how and where threats are being either mediated or tolerated across landscapes. It also provides insights into species’ sensitivity to environmental change that are unable to be identified through analysis of declines in range size or abundance alone. Here, we apply the recently proposed ‘niche reduction hypothesis’ to investigate relationships between trends in niche breadth and geographic distribution of declining species. Location Northern Australia Methods We compare and contrast contemporary and historical datasets to examine the relationship between extent of occurrence (EOO) and realised niche hypervolume, and investigate changes in species’ utilisation of environmental space through time via generalised linear modelling and bootstrapping of historical values. We also use the ‘Maxent’ algorithm to create and stack contemporary and historical ecological niche models (ENMs) an...