Mountain ash and alpine ash forests in the Central Highlands of Victoria provide habitat for a range of threatened and rapidly declining species. The mountain ash forest ecosystem itself has also been assessed as Critically Endangered by the International Union for the Conservation of Nature’s (IUCN) Red List of Ecosystems. Fragmentation and disturbance of habitat is a well-documented threat to forest ecosystems. We quantified the extent of forest disturbance, fragmentation and edge effects resulting from logging and fire in mountain ash and alpine ash forests over the past 20 years (1999–2019).
We found that disturbance and proximity to disturbance increased significantly over the 20-year period and that by 2019, approximately 70% of the mountain ash estate and 65% of alpine ash forest estate, was either disturbed or within 200 m of a disturbed area. Despite large areas of habitat burning during the 2009 and 2019 wildfires, clear-felling has continued since the wildfires. Logging planned under the April 2019 Timber Release Plan will increase the proportion of land that is disturbed or within 200m of a disturbed area to 72% for mountain ash and 70% for alpine ash. While the extent of core areas (i.e. those places >1000 m from a disturbed area) will decrease. Increasing forest disturbance, fragmentation and edge effects has negative consequences for the remaining ash forest ecosystem and threatened forest-dependent species.