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

Abstract

Wildfire severity is assumed to be an important driver of habitat availability and species' distributions in forest ecosystems. Many studies have focused on the immediate or short‐term effects of fire severity in fire‐prone ecosystems, with much less focus on how long the effect of fire severity may persist. We examined the effect of fire severity on the distribution of arboreal mammals at 3 and 10 years post‐fire, in a temperate forest ecosystem dominated by eucalypts that have strong resistance and resilience to low and high severity fire, respectively. The study took place within areas affected by the 2009 Kilmore East‐Murrindindi wildfires in south‐eastern Australia. Sites were established across a gradient of fire severity (unburnt through to canopy consumption) and surveyed at 3 and 10 years following fire. Owing to low detection rates for many species, analyses were limited to greater glider (Petauroides volans) occurrence and arboreal species richness. At both 3 and 10 years post‐fire, the greater glider was restricted to unburnt forest or sites affected only by understorey fire, which acted as fire refugia. Greater gliders were absent from sites affected by high severity, canopy‐consuming fires at both points in time. Greater glider occurrence was associated with high levels of canopy cover (>50%), which were typically those areas that were unburnt or burnt at low severity. The richness of arboreal mammals increased over time and was greater in unburnt or minimally affected forest. Our findings emphasize: (i) that fire severity is an important driver of the distribution of arboreal mammals; and (ii) the importance of recognizing longer‐term effects of fire severity in assessing species distributions, even in highly resilient forest communities. Recent advances in mapping fire severity provide new opportunities to assess the effects of fire severity on the distributional patterns of fauna in eucalypt forests.

Increasing fire severity alters the species composition and decreases richness of seeds potentially dispersed by small mammals

“…The combination of low functional redundancy and the absence (or at least reduced abundance) of forest‐specialist species in the most disturbed areas could lead to a decline in the seed dispersal function performed by small mammals. The persistence of these impacts could be long‐lasting, as fire‐affected animal populations might not revert to pre‐fire conditions even after 10 years following high‐severity fire events (Campbell‐Jones et al., 2022).…”

“…Particularly for small mammals, certain species thrive while others decline, resulting in a turnover of species over the post‐burn period (Briani et al., 2004; Chia et al., 2016; Fox, 1982; Vieira, 1999). In forested ecosystems that experience infrequent fires, the post‐fire recovery of small mammal communities is slow, taking years for populations of some fire‐sensitive species (mostly arboreal or scansorial species) to reestablish themselves (Campbell‐Jones et al., 2022; Cazetta & Vieira, 2021; Mendonça et al., 2015). This longer recovery period is likely a consequence of the lower resilience and longer post‐fire regeneration of forest plant communities (Armenteras et al., 2021; González et al., 2021; Hoffmann et al., 2009).…”

Priority areas for conserving greater gliders in Queensland, Australia

“…Among other things, local populations can be extirpated (i.e. locally extinct) due to the impacts from catastrophic bushfires, disease or other stochastic processes, and habitat connectivity provides the means for re-colonisation from neighbouring populated habitat locations (Andrew et al 2014;Campbell-Jones et al 2022). Habitat connectivity can maintain meta-population connectivity, thereby reducing inbreeding and genetic drift associated with small, isolated populations.…”

Patchy prescribed fire has variable effects on invasive predators and their native prey

“…Fire can increase the activity invasive predators, such as feral cats (hereafter 'cat') and European red foxes (hereafter 'fox'), by removing vegetation which normally provides prey with refuge (McGregor et al 2015;Leahy et al 2016;Hradsky 2020;Miritis et al2023). Climate change is increasing the occurrence of fire in many parts of the world (Canadell et al, 2021;van Oldenborgh et al, 2020;Jones et al 2022) and may facilitate range expansions for both cats and foxes (Aguilar et al 2015;Elmhagen et al 2017), thus increasing the likelihood of negative impacts on native fauna. This highlights the need for well-informed management strategies that account for the effects of fire, vegetation, and anthropogenic features on the activity of cats, foxes, and native mammals, so the effectiveness of protected areas for conservation can be optimised.…”