Increasing fire severity negatively affects greater glider density

Abstract

Context Fire severity and frequency is predicted to increase over the remainder of the 21st century in Australia’s temperate forests; therefore, the effects of fire severity on forest-dependant species is of major conservation concern. Aims Determining the short-term (<1 year) effect of fire severity on a forest-dependant species, the greater glider, Petauroides volans, in Monga National Park, south-eastern New South Wales. Methods Three fire-severity classes were investigated, namely, low (canopy unburnt), moderate (partial canopy burn) and high (complete canopy consumption). Fifteen randomly allocated sites were visited in total, with five sites in each fire-severity class being visited on three separate occasions. Spotlighting of two off-track transects per site was completed over a 4-week period by using multi-covariate distance sampling (MCDS) to estimate greater glider densities at each fire-severity class. Key results An overall mean greater glider density estimate of 0.456 ha−1 (95% confidence interval (CI) 0.256–0.654 ha−1) was calculated across all sites in Monga National Park. Density estimates varied among fire-severity classes; low 0.779 ha−1 (95% CI 0.358–1.692 ha−1), moderate 0.472 ha−1 (95% CI 0.262–0.848 ha−1), and high 0.077 ha−1 (95% CI 0.0142–0.414 ha−1). Conclusions Distance sampling estimates suggested that areas affected by high-severity fire have lower densities of greater gliders. Implications The importance of areas experiencing low fire severity as a source of greater glider refugia during wildfire events is evident. Under a changing climate, frequent major wildfire events may significantly affect population viability of greater gliders if insufficient time between fires allow for population recovery.

Fire severity has lasting effects on the distribution of arboreal mammals in a resprouting forest

“…2015; May‐Stubbles et al . 2022). Our results demonstrate that high‐severity fires can have lasting effects on the greater glider, even in these highly fire‐resilient, resprouting eucalypt forests.…”

“…2015; May‐Stubbles et al . 2022), as well as parts of landscapes that remain long unburnt (>30 years; McLean et al . 2018).…”

Conservation genomics of an endangered arboreal mammal following the 2019–2020 Australian megafire

“…Greater gliders are extremely susceptible to population decline and extinction, particularly in response to fire that partially or completely consumes the canopy 97 . Lindenmayer et al 36 reported low greater glider abundances in high severity burn sites in the Central Highlands of Victoria, and May-Stubbles et al 37 observed the same pattern within high severity burn sites of Monga National Park, NSW. This is due to the species' specialist eucalypt diet and sensitivity to high temperatures [29][30][31]37,45,98 .…”

“…Lindenmayer et al 36 reported low greater glider abundances in high severity burn sites in the Central Highlands of Victoria, and May-Stubbles et al 37 observed the same pattern within high severity burn sites of Monga National Park, NSW. This is due to the species' specialist eucalypt diet and sensitivity to high temperatures [29][30][31]37,45,98 . Fire has also caused significant declines in the past, with greater gliders considered locally extinct after a fire burnt 90% of the Royal National Park (NSW) before they were rediscovered in 2012 99 .…”

“…Greater gliders are highly dependent on eucalypt forests, as they have specialist eucalypt diets 29 – 31 and are reliant on large hollows for sheltering and raising offspring 28 , 32 , 33 . The species has experienced significant decline as a result of habitat loss 34 , 35 , wildfire 36 , 37 and the effects of climate change 38 – 40 . Over the past 20 years, long-term studies have identified rapid declines in populations 38 , 41 – 43 as well as local extinction, such as at Booderee, New South Wales (NSW) 42 .…”