The role of climate and tree nutrition on the occurrence of the southern greater glider (Petauroides volans) and its implications for conservation planning

© 2021 Benjamin WagnerThe southern greater glider (Petauroides volans) is southeastern Australia’s largest gliding marsupial and widely distributed, but the species has recently experienced drastic declines in population numbers. Its association with hollow-bearing trees, used for nesting, has made it an important flagship species for the conservation of old-growth forest ecosystems. Stand replacing or altering wild- or planned fires and timber harvesting have been identified as major threats to the greater glider, but individuals and populations have over time disappeared from areas that have experienced neither, raising questions about the role of other factors in their decline. Habitat suitability is determined by three distinct factors: A narrow thermotolerance makes greater gliders vulnerable to high ambient temperatures. A specialised diet consisting entirely of nutrient-rich Eucalyptus leaves confines them to certain forest types and the need for multiple large tree hollows for denning confines populations to mature forests. Therefore, different spatial scales need to be considered when determining likelihood of occupancy and habitat suitability for greater gliders. Using high spatial and temporal resolution climate data, I identified that climate is driving greater glider occupancy across the landscape. At a stand scale, I developed new methods of remotely sensing feeding and nesting resources using field sampling and multispectral imagery collected by an unoccupied aerial vehicle (UAV). My findings have important implications for greater glider management and conservation of their habitat and associated forest types. At the landscape scale, I identified climatic refugia that may allow greater gliders to persist into a future under climate change if properly protected. At a stand scale, remotely sensed estimates of feeding and nesting resources may enable forest managers to better retain highly suitable habitat or assess remaining habitat suitability and likelihood of persistence after disturbance. The gathered knowledge enables us to spatially extrapolate field observations and model findings to test how different landscape, resource and disturbance configurations affect population density and persistence, which should further enhance our ability to protect southern greater gliders in southeastern Australia