Carlisle Heath: Refuge provision for small mammals in a changing climate

One in five Australian mammal species is currently threatened with extinction. Climate change and resulting increases in droughts and wildfires will place further pressure on many species. To avert losses, urgent conservation is required focusing on areas in the landscape that can buffer these disturbances. These areas, known as refuges, offer unique properties that species can retreat to and expand from during unsuitable conditions that may otherwise cause displacement or mortality. So that we might begin protecting refuges, we require knowledge about what features constitute them for different species and ecosystems. This study aimed to investigate if Carlisle Heath functions as a refuge for the Otways region in Victoria by determining small mammal abundance and diversity as well as measuring attributes that influence these values. Small mammals were surveyed across sites of wet heathland, heathy woodland and ecotonal vegetation communities, and environmental values fire history, vegetation productivity, topography and habitat structure were assessed. Distance-based linear modelling was used to establish factors influencing small mammal assemblages. Differences in composition were found in the two vegetation communities but both offered strong habitat for small mammals. The transitional ecotone between the two was important to the threatened Swamp Antechinus (Antechinus minimus). A major driver of diversity and abundance was length of time since fire, with medium to long intervals since fire supporting much higher numbers of native species than early years post fire. Abundance of mammals was also positively influenced by high vegetation productivity and low-lying dense vegetation of heath and shrubs in wet heath and ecotone areas. This supports the importance of having vegetation with structural value, which can offer protection from predation. It is critical that prescribed burns are enacted with thorough consideration of important refuge areas and connectivity to ecotones that may offer important habitat in the landscape.<p></p>