A CLIMATE-DRIVEN EXPLORATION OF ENAMEL STABLE ISOTOPES AND DENTAL MICROWEAR TEXTURES WITHIN THE SWAMP WALLABY (WALLABIA BICOLOR)

Australia is currently facing extreme aridification, droughts, and bushfires due to its rapidly changing climate. Along with direct anthropogenic influences, these changes have led to decreased biodiversity and increased wildlife endangerment throughout the country. Researching how modern mammals record their local climate and environment in their teeth can inform paleoecological reconstructions and clarify mammalian responses to climate change through time. Dental microwear texture analysis (DMTA) and stable isotopes (δ18O and δ13C) are tools used to understand the ecology and paleoecology of animals. Stable isotopes preserved in tooth enamel can indicate an animal’s diet, contemporaneous vegetation, water consumption, and local climate, while dental microwear can indicate the textural properties of an animal’s diet. This study analyzed the relationship between annual climate variables and dental microwear/stable isotope variables for members of Macropodidae on a species level. Wallabia bicolor is this study’s focal species and is commonly considered to be a generalist mixed-feeder, with observational studies indicating evidence of grazing, browsing, and mycophagy. Univariate and multivariate linear regressions were run using climate, dental microwear, and stable isotope variables for W. bicolor. Similar to other macropodids, W. bicolor records relative humidity in both δ18O and δ13C isotopes from tooth enamel (reflecting negative and positive relationships, respectively). No other independent climate variables are recorded by δ18O isotopes. Conversely, δ13C isotopes are positively correlated with: mean annual temperature, mean maximum and minimum annual temperature, mean annual precipitation, and negatively correlated with δ18O precipitation. The best model (lowest AIC value) is the multivariate model including annual relative humidity and mean annual precipitation (AIC = 88.726, R2 = 0.542, and p < 0.0001). None of the dental microwear variables significantly predict local climate, consistent with DMTA tracking textural properties of food and not environmental conditions. Moving forward, this process will be repeated for other macropodid species to improve understanding of how a diversity of marsupials record local climate parameters in their teeth.