International Conference of Ecology 2009
The 10th International Conference of Ecology was recently held in Brisbane, the 1st time it has been held in the southern hemisphere. Tom Barrett from the Great Eastern Ranges Initiative gave a presentation on 'effective habitat area' modelling. His focus was how to achieve habitat connectivity in the challenging Hunter River catchment region.
Why the Hunter?
Agricultural, urban and infrastructural development has led to the loss and fragmentation of many natural ecosystems in eastern Australia. The Hunter River catchment is an area where there has been a great impact on natural systems due to agriculture, coal mining, power generation and associated infrastructure.
How was it done?
Vegetation communities are an important proxy for fauna habitat, so a major obstacle to undertaking analysis in the study area was the lack of a seamless vegetation map.
Models of habitat quality were produced for 3 broad habitat types – moist forest, dry forest and woodlands – using raster-based geographic information system modelling techniques and remotely-sensed measures of vegetation canopy density and greenness derived from satellite imagery. These 2 measures of vegetation structure were used to model broad Vegetation Structural Classes (VSCs) to produce habitat suitability surfaces for moist forest, dry forest and woodland/grassland fauna species.
The VSC suitability surfaces were used as inputs into 'effective habitat area' modelling to provide a measure of fragmentation and identify 'core' habitat more likely to support species populations. They were also used as a surrogate for species movement ability in a 'links' analysis that modelled potential corridors within and between habitat patches, using a least-cost-path approach.
Connectivity values across the intervening matrix were calculated at regional and interregional scales. These models of landscape-scale ecological processes and the conceptual framework they are based on provide invaluable decision support and visualisation tools and have helped facilitate regional-scale conservation planning decisions in the Hunter River catchment.
Results and Conclusion
The broad landscape scale patterns identified in the study allowed a steering committee to decide on 4 'areas of interest' (AOIs). Each AOI represents regions with similar habitat and connectivity values, as well as common land uses and threats to biodiversity. A profile was generated for each AOI, listing known threatened species and threats to biodiversity, as well as opportunities for biodiversity conservation within the AOI.
