Impact of the 2019–20 drought, heatwaves and mega-fires on Greater Gliders ( <i>Petauroides volans</i> ) in the Greater Blue Mountains World Heritage Area, New South Wales

Summary

This field study quantifies the severe impact of the 2019–20 Australian drought, heatwaves and mega-fires on Greater Gliders (Petauroides volans) in the Greater Blue Mountains World Heritage Area. Post-fire surveys of burnt and unburnt transects reveal that survival was dependent on the presence of eucalypt trees with abundant unburnt foliage; populations were extirpated from high-extreme severity burn areas but persisted at reduced levels (mean 43% decline) where low-moderate foliage damage occurred. The study further documents that 84% of known Greater Glider sites across the World Heritage Area burnt during the 2019–20 fires, with significant population declines evident even on unburnt transects, suggesting that drought and heatwave stress independently compromised population viability.

UK applicability

This paper documents climate extremes and their ecological consequences in an Australian context and has limited direct applicability to UK farming systems or soil health research. However, it may inform UK policy discourse on climate resilience and species conservation under increasing drought and heat stress scenarios.

Key measures

Greater Glider population counts on 16 transects (eight burnt, eight unburnt) pre-2019 and post-fire (2020–2021); fire severity classification (high-extreme versus low-moderate); percentage of eucalypt foliage killed in canopy and understorey; proportion of trees with unburnt foliage; fire severity mapping across 773 known Greater Glider recording sites within the World Heritage Area

Outcomes reported

The study quantified Greater Glider population declines following the 2019–20 drought, heatwaves and mega-fires across the Greater Blue Mountains World Heritage Area, using pre- and post-fire transect surveys to measure species persistence relative to fire severity and eucalypt foliage availability. Population declines of 43% were recorded on low-moderate severity burnt transects, whilst complete absence was documented on high-extreme severity transects; additional declines of 34% occurred on unburnt transects, attributed to drought and heatwave impacts.

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