Objectives
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Develop new conceptual models of post-fire succession, and expand knowledge of mechanisms underlying plant and animal responses to fire regimes, using detailed biological information.
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Use novel applications of genetic techniques and traditional ecological methods to determine the sources of colonists after fire and their dispersal distances.
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Provide a strong data-base for future simulation modelling (phase 3).
Reptile Ecology and Genetics
Project leader: Annabel Smith
Supervisors: Don Driscoll, Michael Gardner, Michael Bull
Objectives
Investigate the relationship between dispersal parameters and post-fire succession. Do early successional species have a greater dispersal ability than late successional species, allowing them to colonise a habitat more quickly?
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Determine the mode of post-fire recolonisation. Are post-burn habitats colonised by surviving individuals or migrants from surrounding unburnt habitat?
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Compare demographic parameters among burn ages to understand their relationship with succession. Do early successional species have higher growth rates, fecundity and population densities?
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Examine mechanisms behind fire responses with studies of habitat use. Do late successional species use a more specific habitat than early successional species?
Outline
Fire is an intergral part of many ecosystems but human induced changes in land use and climate mean
that new ways of managing fire in natural habitats are necessary. Many animal
species are sensitve to fire, with some relying on
old-growth unburnt habitat, while others are more abundant in recently burnt
sites. Biodiversity may be at risk if fire regimes are not implemented at
scales which incorporate the complexity of fire responses in animal
communities.
There are clear models to explain how
plant species respond to fire but the mechanisms behind animal responses are
not well understood. Most studies of post-fire succession in animals have
attributed fire responses primarily to vegetation changes in the habitat.
However, other factors relating to the biology of an animal species may also
determine its successional response. We aim to build
on simple habitat-use models which have previously been used to explain
succession in reptiles by including detailed information on demography, ecology
and dispersal. This project will go beyond a documentation of community level
patterns of post-fire succession by describing the mechanisms behind the
response of fire-sensitive reptile species.
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Ctenotus atlas (the striped skink)
Photo A. Smith |
Nephrurus stellatus (the starred knob-tailed gecko)
Photo A. Smith
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Amphibolurus norrisi (the mallee tree dragon)
Photo A. Smith |
The focus species are: Ctenotus atlas (the striped skink), Nephrurus stellatus (the starred knob-tailed gecko) and Amphibolurus norrisi (the mallee tree dragon). Each of these species have contrasting fire responses, specialising in different successional stages.
We aim to produce results that will have
practical applications in land management while also strengthening succession
theory. In particular, the findings from this study will assist land managers
in planning the optimal temporal and spatial scales for prescribed burning.
Results
Bird Ecology and Genetics
Project leader: Simone Dalgairns
Supervisors: Sonia Kleindorfer, Steve Donnellan, Don Driscoll
Objectives
- Use detailed biological data to examine the response of native bird populations to fire disturbances and fire regimes in the mallee,
- To develop a better understanding of biological mechanisms driving observed recovery patterns in birds,
- Use genetic methods to estimate gene flow and dispersal ability of bird populations in order to examine how populations re-establish after fire,
- Assess the likely impacts of increased fire frequency due to climate change on bird populations.
Outline
The loss and decline of a number of species of birds in Australia can be directly attributed to adverse fire regimes resulting from changes in the patterns of burning and habitat fragmentation. In mallee habitats, fire plays a critical ecological role and has major impacts on the survival of bird populations. Despite this there have been few detailed studies examining the response of bird populations to fire, and our knowledge of bird responses to fire is limited.
This study will be conducted within remnant mallee patches on the Eyre Peninsula, with sampling from replicated sites representing three different times since fire (burnt >20, 5-10, and 1-2 years ago). At each site three bird species, the Blue-breasted Fairy-wren (Malurus pulcherrimus), Inland Thornbill (Acanthiza apicalis) and Western Yellow Robin (Eopsaltria griseogularis), will be monitored. Target species were chosen on the basis that they represent different functional groups and show contrasting post-fire age class preference.
Results to date
Preliminary studies conducted by Driscoll and Plimer (unpublished study) suggest that both the Blue-brested Fairy-wren and Inland Thornbill show a preference to early successional fire stages, with highest average population densities in 5-10 year burns. In contrast the Western-yellow Robin is most abundant later in the post-fire succession (20+ years).
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| PhD students Annabel Smith and Simone Dalgairns |
Plant Ecology
Project leader: Rebecca Gibson
Supervisors: Ross Bradstock, David Keith, Meredith Henderson, Don Driscoll
Using selected species covering a range of life-history and fire responses, the project will estimate population structure, survival, fruit production and recruitment in locations with contrasting fire histories. Seed bank longevity has a critical influence on recovery after fire and so the dynamics of seed banks will be explored using a range of experimental approaches. Experiments may also be undertaken to derive estimates of seed dispersal.
Plant Genetics
Project leader: Bianca Dunker
Supervisors: Michael Bull, Andrew Lowe, Steve Donnellan, Don Driscoll
This PhD will use new genetic methods to measure dispersal of plant species in relation to time since fire. Good measures of dispersal are essential to effectively predict recovery after fire. Plants will be sampled in a spatially explicit design addressing boundaries of populations and fire to develop robust models of propagule dispersal and establishment. A combination of chloroplast and nuclear DNA will be used to distinguish pollen from seed dispersal. This rapidly developing field provides an exciting opportunity for a student to master lab techniques and reveal patterns of dispersal by plants after fire.
Reptiles in Fragmented Mallee
Project leader: Juliana Lazzari
Supervisors: Don Driscoll, David Lindenmayer, Geoff Cary
In fragmented landscapes, fire suppression is the dominant management regime and this may disadvantage fire-loving species. When remnants do burn, they are entirely incinerated, so any fire-sensitive species will not have the benefit of unburned refuges from where they can recolonise. Cycles of fire suppression followed by a large fire could therefore ratchet down biodiversity in fragmented landscapes. The aim of this PhD is to test the effect of fragmentation and fire by examining the fire history and distribution of native species in fragmented landscapes.
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