The response of mammal populations to abrupt changes in fire regimes in montane landscapes of south-eastern Australia
Loading...
Citations
Altmetric:
Altmetric::
Download
Associated Records
Authors
File Licence
Editors
Date
2024-10
Source Title
Journal Title
Journal ISSN
Volume Title
Publisher
Melbourne Authors
Affiliation
School of Agriculture, Food and Ecosystem Sciences
Document Type
PhD thesis
Subject Code
Citation
Access Status
This item is embargoed and will be available on 2027-01-24.
DOI
Access URL
Open Access URL
Open Access at PMC
Linked Resource URL
NHMRC Grant Code
ARC Grant Code
Description
© 2025 Jeremy Paul Johnson
Abstract
This thesis explores the causes and impacts of altered fire regimes on mammal populations in montane forest ecosystems of south-eastern Australia. Through a series of empirical studies, it examines how and why fire patterns are changing, the implications of these changes for vegetation dynamics, and the roles of both habitat and fire in shaping mammal occurrence.
It begins by exploring the roles of climate, land use, topography, and past fire in shaping contemporary fire patterns. 40 years of spatial data revealed that drought is a primary driver of fire occurrence, increasing fire likelihood through its influence on fuel availability. This relationship is mediated by recent fire history and topography, while land use had a minimal effect on fire patterns.
Subsequent chapters explore how altered fire regimes reshape habitats and impact mammalian diversity. Mammals were classified into three groups based on their response to fire: species which preferred fire-affected areas, fire-sensitive specialists, and generalist species. These groups displayed different levels of resilience to fire-driven habitat changes. Species with adaptations to fire, such as the eastern pygmy-possum (Cercartetus nanus), thrived in habitats shaped by high severity fires, which create open canopies and promote diversity in the shrub layer. These conditions generate essential resources for this semi-arboreal mammal, including fruiting plants and dense mid-storey vegetation for movement and nesting. In contrast, species that were sensitive to fire, such as the dusky antechinus (Antechinus swainsonii) relied on dense cover and abundant foraging resources provided by long-unburnt areas. Generalists, such as the agile antechinus (A. agilis), were more resilient to variations in fire patterns, likely due to a flexible diet and behaviour that enable them to thrive in both fire-affected and long-unburnt habitats.
The spatial arrangement of fire patterns also played a critical role in determining mammal occurrence. To capture these patterns, I developed the concept of "fire syndromes" that included measuring the combined influence of fire frequency and severity on fire patterns and mammalian populations. The value of this combined metric was demonstrated by the response of the mobile and arboreal yellow-bellied glider (Petaurus australis). In this case, empirical data indicates that the yellow-bellied glider selects complex fire mosaics dominated by low severity fire that provide the structural complexity required for nesting and the resources needed for foraging. These preferences suggest that understanding the distribution of mobile mammalian species requires the consideration of multiple components of the fire regime.
This research highlights the importance of promoting variability in fire characteristics across montane landscapes, with that variation defined by the species and forest ecosystem of interest. Different mammalian species are adapted to particular fire patterns and the habitats generated by these patterns. Maintaining a mix of fire frequencies and severities will ensure that diverse forested habitats are available to support a wide range of species. Overall, this study provides valuable insights into how fire regimes affect mammal species in montane forests, offering critical guidance for future conservation and fire management strategies aimed at preserving biodiversity in fire-prone ecosystems under a changing climate.
Notes
Terms of Use
Keywords
Australia, Fire, Ecology, Mammal, Montane forests