USING SPACE FOR TIME SUBSTITUTIONS AND COMPARISONS BETWEEN FOSSIL AND MODERN SPECIMENS TO ASSESS IMPACTS OF EUROPEAN ARRIVAL ON MARSUPIAL MAMMALS

European arrival into Australia, more than 200 years ago, had large scale impacts on the local flora and fauna. Most notably, Europeans brought with them numerous non-native species. Among these species was the red fox, to allow for traditional English sport. The downstream consequences of foxes and feral cats in Australia has decimated native mammals, causing some to exist largely on islands. Here, we examined the dietary ecology of native marsupial mammals during the Pleistocene and today (i.e., petrogales in Western Australia) and also compared the dietary ecology of the quokka (Setonix brachyurus) across space, today (i.e., island vs. mainland populations). Dental microwear textures of both petrogales and quokkas are largely indistinguishable across space and through time and consistent with the consumption of woody browse. In contrast, quokkas have significantly greater carbon isotope values (from tooth enamel) on islands as compared to mainland Australia in Western Australia. These data suggest that quokkas feed in slightly more open environments on islands where foxes and feral cats are not present, suggesting that predation pressure may be less intense on islands. However, similarities of dental microwear textures and highly negative carbon isotope values (all values range from -20.6‰ to -15.5‰) suggest their dietary ecology was largely conserved through time and across space, respectively. Similarities in the dietary ecology of these taxa across space and through time suggests that their restricted ranges today are primarily a result of predation of non-native carnivorans and/or other human influences.