Using genetics to understand how species will be affected by changing fire regimes.
Northern Australia is often considered a haven for biodiversity, however, the numbers of native mammals in this part of the country have alarmingly declined in recent years. The reasons for this decline have perplexed scientists, as the usual culprits, like land clearing and habitat fragmentation, don’t seem to be responsible.
Recent research rather, has implicated changes in fire regimes as a probable cause for the mammal species decline. The patterns of ecological disturbance (including fires, floods, and more mundane events like wave action on rocky shores) are globally changing, producing major implications for biodiversity. To anticipate the effects of these changes, an understanding of the fundamental biology, relating to how natural populations interact with disturbances like fire, is required.
Genetic effects of disturbance can occur through natural selection because the frequency or severity of fires can shape the evolution of traits that help species persist in fire-prone landscapes.
Genetic diversity is also strongly influenced by the effects of fire on the distribution and abundance of animal populations. This is because fire can drive extinction-re-colonisation process; or the natural patchiness of populations caused by the effects of fire on habitat, which can shape the genetic diversity within populations and the genetic differences between them. The flipside of this is that we can use genetics to study the dynamics of animal populations in response to fire patterns.
Sam works with a number of scientists and land managers to integrate this information into conservation practice. A collaboration with Fenner colleagues Ian Davies and Geoff Cary; and Erin Landguth from the University of Montana, uses computational modelling to predict how changes in disturbance regimes will affect the viability and genetic diversity of natural populations.
Work with David Lindenmayer (Fenner), combines field ecology with genetics to understand the recovery of the mountain ash forest ecosystem from the 2009 Black Saturday fires. A long-term aim is to predict future responses of mountain ash trees, and the animals dependent on them, and to anticipate the consequences of changing fire patterns.
A practical outcome of this research has been the development of new tools to study how animals respond to fire management.
Robyn Shaw recently started a PhD with Sam and others and aims to understand how declining native rodents in the Kimberley region of Western Australia recover from bushfires. She is using new computer simulation tools, field and lab work, to determine the genetic signatures of different population recovery processes. She aims to understand the importance of animal survival and movement for post-fire population recovery to inform conservation management.
Sam, Robyn and others collaborate with scientists from the Australian Wildlife Conservancy (AWC), and this research aims to complement the AWC’s large-scale EcoFire program which focusses on developing and applying pro-active fire management strategies for mammal conservation in the Kimberley.
Sam’s research in this area tells us a lot about genetic diversity in natural populations, and is starting to provide a new understanding of what is actually causing the declines of species under changing disturbance regimes.
This has outcomes for conservation in northern Australia, and also in other parts of the world where natural disturbance regimes are changing. This is a good example of fundamental biological research being essential for effective biodiversity conservation.