What type of rainforest burnt in the South East Queensland's 2019/20 bushfires and how might this impact biodiversity

Abstract

Bushfires burnt over 18 million hectares across Australia's east coast, including rainforests, over the spring and summer 2019/2020 period. Rainforest harbours a large percentage of Australia's biodiversity and does not usually burn and therefore understanding the extent and biodiversity implications was a priority. The National Indicative Aggregated Fire Extent Dataset (NIAFED) combined with detailed regional ecosystem (RE) mapping was used to estimate the perimeter and area of each of the burnt rainforest types within South East Queensland (SEQ). Previous biodiversity estimates for each rainforest regional ecosystem type combined with remnant ecosystem mapping data then enabled an assessment of the potential biodiversity impacts of the fires for SEQ rainforest. We found that 12% of the rainforest estate in SEQ was within the burn footprint (29 031 ha) including parts of the UNESCO World Heritage Gondwana Rainforests of Australia. Fifty per cent of the total remnant area of the Endangered rainforest type, semievergreen vine thicket on Mesozoic to Proterozoic igneous rocks (RE: 12.12.17) was potentially burnt. This rainforest type has high diversity. Burn severity analysis found that the rainforest primarily burnt with low severity, however, there were patches of high severity. Accuracy assessment of severity mapping resulted in a weak correlation (0.57) due to the underestimation of ground fires in rainforest. As expected, we found rainforest-suppressed fires. However, in contrast to expectations, we found the wettest rainforest types and putative past refugia burnt more than other rainforest types. These results suggest that given drought conditions any rainforest could burn, and we can expect that the area of rainforest will contract if both incidences of drought and wildfires increase due to climate change.

The ability to resprout basally enables the endangered 'Macadamia jansenii' to survive fire

“…It appeared that the fires had burnt the leaf litter layer and seedling layer, with evidence of charring mostly within the first 30 cm above the ground (evidenced by charring on tree trunks) indicating low fire intensity (Hayward 2020b). Additionally, remote sensed fire severity mapping confirmed the fire was low severity, with some high intensity areas, within Bulburin National Park (Thorley 2020). Where high severity fires occurred, adult trees were killed.…”

Are species richness and endemism hotspots correlated within a biome? A test case in the fire-impacted subtropical rainforests of Australia

“…This distributional pattern is suggestive of past range contractions, and some inherent vulnerability to climate change and potentially changing distributions of re sensitive dry rainforest or vine thicket habitats (Schneider et al 1998). These habitats are both naturally and unnaturally fragmented, and at greater risk from edge effects and disturbances (including re) than larger rainforest patches (Laurance 1991;Shapcott et al 2017;Thorley et al 2023).…”

“…These rainforest areas largely occur as a series of habitat 'islands' centred upon the eastern edge of Australia's Great Dividing Range (Fig. 1) and support a high alpha diversity and endemism in many taxa (Williams et While most remaining subtropical rainforests in Australia are protected, recent severe droughts and res of unprecedented extent and severity have impacted large areas of these re-sensitive communities (Ward et al 2020;Godfree et al 2021;Beranek et al 2022;Thorley et al 2023). Regeneration of rainforests burnt at higher severities is likely to take many decades and is impeded by invasion of ecosystem changing weeds that further exacerbate re risk (Hines et al 2020;Ross et al 2023), particularly for small rainforest patches or those fragmented through vegetation clearing (Driscoll et al 2021).…”

The relative importance of precipitation change and temperature sensitivity in determining the population viability of a threatened sub‐tropical rainforest endemic plant Triunia robusta (Proteaceae)

“…Threatened rainforest species in fragmented landscapes are of particular concern because of their potentially narrow thermal tolerances, small population sizes, restricted distributions and limited dispersal (Bell et al., 2010; Hilbert et al., 2001). The sub‐tropical rainforest communities of the southeast Queensland region (SEQ) in Australia are thought to have functioned as refugia during historical climate change cycles and contain many endangered and vulnerable endemic species (Shapcott et al., 2017; Thorley et al., 2023; Weber et al., 2014). However, the region has become highly fragmented due to intensive land clearing and many species in the remaining rainforest fragments are now thought to be under risk of extinction (Powell et al., 2005).…”