Thesis abstract:

Mountain and highland ecosystems are considered some of the most sensitive to the compounding impacts of climate and land use change. While future species- to community-level responses to these stressors have been projected with relative confidence, prognoses of broader ‘systemic’ change – that is, incorporating both abiotic and biotic phenomena – remain poorly constrained. This knowledge gap is particularly vast in the context of the High Country of south-eastern NSW, Australia, which demands urgent research in this area due to ongoing postcolonial degradation reducing its regional resilience to anthropogenic climate change. To constrain the long-term past and future sensitivity of the High Country, this study will reconstruct millennial-scale paleoenvironmental change for high-altitude catchments over the Holocene epoch. This will be achieved through a multi-proxy analysis of lake and mire sediments from sites within the alpine, subalpine, montane and tablelands zones. Through comparison of these records between sites and existing paleoecological data, it will be possible to infer systemic sensitivity to past perturbations, while also evaluating how this varies with altitude and between abiotic and biotic agents. By employing these histories as paleo-analogues for future change, the direction, rate and magnitude of ‘whole of system’ responses to stressors can be more confidently projected. It is anticipated that these prognoses can be incorporated into existing conservation strategies for threatened and deteriorating ecological communities that exist within these catchments, informing actors on how their various earth surface and ecological processes can be moderated to enhance biophysical resilience and in turn maximise critical environmental services.