Mallee fire and biodiversity

The Mallee Fire and Biodiversity Project was a large, four-year collaborative project which commenced in March 2006. It was jointly led by Associate Professor Mike Clarke (La Trobe University) and Professor Andrew Bennett (Deakin University).

The project aimed to identify the properties of habitat mosaics produced by fire that enhance the persistence and status of a broad range of taxonomic groups (birds, mammals, reptiles, key invertebrates and plants) in eucalypt-dominated mallee habitats across three states (VIC, SA, NSW). Seven PhD students researched the respective taxonomic groups.

Project aims

To identify the properties of habitat mosaics produced by fire that enhance the persistence and status of a broad range of taxonomic groups (birds, mammals, reptiles, key invertebrates and plants) in eucalypt-dominated mallee habitats.

Key Research Questions

What are the properties of fire-induced vegetation mosaics that enhance the status of different taxonomic groups (birds, mammals, reptiles, selected invertebrates and plants) in eucalypt mallee vegetation?

How do these favoured properties vary between different taxonomic groups, and between different species or guilds within groups?

What are the site-level attributes that influence the status (presence/absence, abundance) of different species and taxonomic assemblages?

Are fire mosaics and sites that are suitable for plant species identified as 'key fire-response species' also suitable for faunal groups (i.e. are the fire-response plants reliable surrogates for biodiversity planning?)

Study Area

The study was carried out in the Murray Mallee region of south-eastern Australia, encompassing parts of Victoria, New South Wales and South Australia (see map). Study locations included:

  • Victoria: Murray Sunset National Park, Hattah-Kulkyne National Park
  • SA: Billiatt Conservation Park, Gluepot Reserve, Danggali Conservation Park
  • NSW: Tarawi Nature Reserve, Scotia Sanctuary, Mallee Cliffs National Park, Petro Station and Lethero Station

Selection of study mosaics

Figure 2 Characteristics of the 28 mosaics selected for the study.Twenty-eight landscape mosaics were selected for study; each a circular area of 2 km radius (12.56 km^2). These mosaics were selected based on three major criteria.

Geographic position. Mosaics were selected in the northern part of the study region (Gluepot, Tarawi, Scotia, Danggali) and in the south (Murray-Sunset, Hattah, Billiatt, Mallee Cliffs).

Percentage of long unburnt mallee. Mosaics were chosen to represent a gradient in the proportion of long unburnt mallee, from 100% down to 0%. Long-unburnt mallee was subjectively defined as mallee not having been burned for >40 years (Figure 2).

Number of post-fire age classes present. Mosaics were chosen to represent variation in the number of post-fire age classes present, from 1 to 6 age classes (Figure 2). This represents a measure of the heterogeneity of the 'visible' mosaic. (It also offers the opportunity to investigate the 'invisible' mosaic because mosaics with multiple fires have a history of a sequence of burns over the last 40 years.) We will develop measures to quantify the temporal pattern of burns on each mosaic.

Figure 3 Example of sampling scheme within a mosaic.Mosaics were also selected such that there was a minimum of 2 km between the boundaries of adjacent mosaics, and they were generally established in pairs to allow survey teams to service two mosaics simultaneously.

Surveys

Modelling

Data gathered by the team in the field was used to develop mathematical models which identify the most powerful predictors of biodiversity responses to fire. Insights gained from these models will then be combined with GIS data layers to generate further models to predict flora and fauna responses to fire. These GIS-based models will then be used to produce spatially explicit models and maps for the region that identify areas of high biodiversity value.

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