Mature forest habitat mitigates the decline of an endangered greater glider population through a widespread disturbance event

Globally, forests support more than two-thirds of extant mammal species. Land clearing, logging and fire are prevalent disturbance mechanisms that reduce forest cover. However, impacts from severe storm events may also seriously impact forests and the mammals they contain. Despite predictions that storms may become more frequent and severe under anthropogenic climate change, little is known about how these disturbance events impact mammal species. In Victoria, Australia, the Wombat Forest supports a population of the endangered arboreal marsupial, the southern Greater Glider (Petauroides volans), which is isolated from the main part of the species’ distribution. A major storm event in June 2021 felled large swathes of trees, significantly impacting the Wombat Forest. We sought to investigate the effect of key habitat components on the abundance of Greater Gliders, and which factors exacerbate or mitigate the impact of the storm event on Greater Glider abundance. We monitored forty-two sites pre- and post- storm through double-observer spotlighting and applied a mark-recapture distance-sampling (MRDS) model to calculate detection probability and abundance-level parameters. The abundance of the Greater Glider was higher with increased levels of mature forest, including dead trees, and higher basal areas of food trees (Eucalyptus dalrympleana/cypellocarpa and Eucalyptus radiata). Wetter microclimates (e.g. gullies) as well as the lack of recent fire (in the preceding 40 years) also corresponded to higher abundance. The storm led to a decline in abundance of approximately a third (-39.0 % [90 % CI: −49.1 %, −27.1 %]) within sampled areas. This change in abundance is predicted to have reduced the population from 13,549 [90 % CI: 10,495, 17,776] to 8560 [90 % CI: 6489, 11,565] individuals within the Wombat Forest study area (374.6 km2). However, mature forest habitat (as indicated by the median DBH of trees) had a mitigating effect on the decline in Greater Glider abundance between pre- and post-storm surveys. This means that mature habitat not only increases Greater Glider abundance but also enhances their ability to persist through disturbance events. The predicted impacts of the storms and changing climates place the Wombat Forest population at risk of further decline. Retention of mature forest can be a strategy to maintain the density of Greater Glider populations facing future disturbance events. •Endangered greater gliders suffered large population declin