Terrestrial Biodiversity Theme

The Great Southern is in the South West Botanical Province. This has been listed as one of the international biodiversity hotspots and as such is not only high in biodiversity but also subject to a range of threatening processes. Terrestrial biodiversity in the Great Southern is under threat from the ongoing impacts of agricultural clearing through fragmentation; weed invasion; salinity; and rising water tables. Many species and ecosystems are highly localized and under threat from feral animals; inappropriate fire regimes; and fungal pathogens such as Phytophthora cinnamomi.

Fragmentation

Background

Fragmentation of vegetation results in changes in ecosystem processes and function long after agricultural clearing. Even where there is remaining vegetation, biodiversity values can decrease due to edge effects from nutrients, and weed and feral animal invasion. Hydrological changes also continue to impact. Isolation of small populations and distance for pollination or seed dispersal can reduce the long-term viability of remnants. Poor connectivity of remnants can impact on faunal movements and breeding.

NRM problem: Small areas of remnant vegetation are not necessarily viable. It is important to understand the impact of fragmentation on management and restoration of remnants.

Research objectives

  • Developing methods to measure and monitor fragmentation
  • Using genetics to understand fragmentation of populations
  • Understanding the impact of fragmentation on population dynamics
  • Understanding the interactions of fragmentation with other threatening processes

Fungal pathogens eg. Phytophthora cinnamomi

Background

The fungal pathogen Phytophthora cinnamomi is widespread in the region. Phytophthora dieback not only threatens susceptible species but also has indirect impacts by causing major changes to habitat and ecosystem function. It spreads by soil movement and so the threat increases with increases in people and vehicle movement and erosion after fire.

NRM Problem: Phytophthora dieback is having an increasing impact on biodiversity in the region.

Research objectives

  • Improving eradication and containment methods for dieback
  • Understanding the interaction of phosphite treatments with soil and plant systems

Feral Animals

Background

The European red fox, the feral cat, rabbit and feral pig are the main feral vertebrates in the Great Southern. The fox is an adaptable predator with a wide dietary range and a major threat to native fauna. Broadscale baiting with 1080 has been found to be the only effective control. Rabbits damage vegetation, inhibit regeneration, cause soil erosion and compete with native mammals. Feral cats are also a major predator and more difficult to bait than foxes. The Department of Environment and Conservation in the Great Southern has a research program to improve the success of cat baiting. The importance of monitoring prey/predator interactions between foxes, rabbits and cats in any control program has been demonstrated with the likely effect of fox baiting on increasing cat predation (mesopredator effect). Feral pigs are a threat to biodiversity through predation, and habitat damage as well as disease transmission. Feral bees are also a threat to hollow nesting/dwelling fauna.

NRM problem: Feral animals are a major threat to biodiversity.

Research objectives

  • Increasing understanding of feral vertebrate predator ecology, interactions and population dynamics
  • Developing methods for more effective feral animal control
  • Developing effective measurement/monitoring of both feral vertebrate and invertebrate populations

Weeds

Background

Exotic plants from other parts of Australia and overseas can invade native vegetation and are a major threat to biodiversity. They are also a threat to agriculture and have a very high economic impact. Some of the worst environmental weeds in the Great Southern are Acacia species from the eastern states and Victorian Tea Tree. Improving eradication methods for weeds of regional significance and understanding invasiveness are priority areas for research.

NRM problem: Invasive weeds are an economic and environmental problem. Environmental weeds impact on ecosystem structure and function and can change susceptibility to fire.

Research objectives

  • Improving control and eradication methods for weeds
  • Increasing knowledge of the ecology of weeds and improve understanding of why and how they become invasive
  • Increasing understanding of the interactions of weeds and biodiversity

Fire Ecology

Background

Although there is no single optimum fire regime for maintaining biodiversity, finding the most appropriate diversity of fire regimes, preventing destructive wildfires and understanding the interaction of fire with other threatening processes are important research goals. In order to develop appropriate fire regimes there is a need for a better understanding of the responses of species and habitat to a diversity of fire regimes.

NRM problem: Inappropriate fire regimes are a threat to biodiversity and human settlement.

Research objectives

  • Increasing knowledge on the responses of species and communities to fire, eg. plant community and structure, inter-fire recruitment, impact of senescence
  • Understanding the relationship between fauna habitat and fire regime

Landscape Scale Biodiversity Distribution and Conservation Planning

Background

Although there is more remnant vegetation in the Great Southern than in other regions in WA, much of the vegetation of the Great Southern is highly fragmented. Landscape scale re-vegetation and protection of remnant vegetation are recognized as important in conserving ecosystem function. A major problem for conservation and restoration of biodiversity is how to determine priorities. It is also essential to be able to measure the impact of landscape restoration on ecosystem function and to incorporate such monitoring into adaptive management. Knowledge of historical patterns and processes can increase understanding of fragmented landscapes.

NRM problem: Determining priorities for landscape scale restoration.

Research objectives

  • Understanding the landscape processes that have driven diversity
  • Biodiversity distribution, mapping, vegetation mapping, threatened species/communities mapping
  • Development of predictive models for threatened species
  • Improving conservation planning methods
  • Development of decision support methods

Ecological Processes

Research objectives

  • Measuring the impact of restoration on ecological processes
  • Improving understanding of historical patterns and processes
  • Further understanding of the ecology of malleefowl and other focal species in determining the integrity of ecological processes
  • Better understanding of role of invertebrates and fauna and fungi in nutrient cycling
  • Understanding ecological patterns and processes in specific landscapes

Climate Change and Terrestrial Systems

Background

Reductions in rainfall and increases in temperature are likely to impact on some terrestrial ecosystems and species more than others. Relictual Gondwana fauna and montane communities are particularly at risk.

Research objectives

  • Understanding the effect of climate change on seeds
  • Increasing knowledge of longevity in preserving species through seedbanks
  • Predicting the impact of climate change on fauna
  • Predicting vulnerable species/ecosystems
  • Finding strategies that will enable species/systems to adapt such as identifying refuges, increasing connectivity and reducing other threats
  • Predicting the impact of plantations/carbon plantings on terrestrial systems
  • Improving silviculture, the design of carbon plantings to maximize biodiversity
  • Development of methods for measurement of carbon sequestration