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The Lake Eyre Basin (LEB) is the largest river basin in Australia covering around 1.2 million km2 in the arid region or 15% of the Australian landmass. The mean annual rainfall and runoff is the lowest of any major river basin in the world but periodic large and widespread flooding results in broad scale inundation of wetland habitats. This inundation drives some of the largest and most persistent wetlands in the country with slow moving floodwaters spreading across a low gradient catchment with extremely high floodplain to catchment area ratio.
Public concern about protection of the Basin’s water resources and aquatic ecosystems has risen with increasing pressure from development and tourism. Livestock grazing comprises approximately 80% of land-use, and around 10% of land is set aside for conservation. Extractive industries (e.g. gas and oil) and tourism are other significant industries in the LEB, although their land-use footprint is considerably less than livestock production. The LEB has a low population density with around half of the total population in the Basin (approx. 60,000) located in the urban centre of Alice Springs. There are a number of large iconic river systems within the LEB, notably Cooper Creek and the Diamantina River. The rivers within the LEB sub-catchments are largely unregulated, with minimal extraction and diversion of water bodies. Seasonal inundations and high variability in water flows are among the key features of the Basin. Disconnected waterholes play a critical ecological role during periods of no rainfall and have relatively high rates of primary production (mainly algae sustaining the food web). These waterholes are therefore important in supporting resident fauna and flora. Responsibility for assessing and on-going monitoring of the environmental condition of the LEB rivers lies with numerous agencies. These responsibilities include the monitoring of environmental indicators, monitoring and assessment of condition targets under regional natural resource management (NRM) plans, assessment of water affecting activities and the assessment and monitoring of water quality, biotic indicators and catchment condition under the SA EPA monitoring program.
The vastness and remoteness of the LEB region and the temporal response of flora and fauna to erratic environmental conditions make monitoring ecological condition in the region very difficult and expensive, which is borne out by the paucity of data for the region. This project explored a range of existing and novel techniques and approaches that could be considered to enhance the current monitoring programs in the region and that could be utilised to measure the connectivity and the adaptive diversity of organisms in the region.
Existing ecological and spatial datasets were combined and analysed to determine the best indicators to quantitatively assess environmental condition. The use of spatial analysis provided new research methods and knowledge about how to assess the spatial distribution of development impacts, land-use pressures and landscape vulnerabilities and their interactions with condition indicators and thresholds of potential concern.
Increasing concern about the protection of the LEB water resources and aquatic ecosystems led to the formation of the LEB Ministerial Forum under the LEB Intergovernmental Agreement. The LEB Rivers Assessment (LEBRA) was established in 2009-2010 to gain an understanding of the condition of the aquatic systems of the LEB. The LEBRA is central to the Ministerial Forum and aims to monitor and assess the environmental condition of the Basin’s waterways.
This project investigated a range of potential indicators of environmental condition including cultural, water and sediment quality parameters, genomic approaches and spatial data products and the findings are outlined below.
The project has provided research to underpin a world class approach and methodology for undertaking condition assessment that is based on well-defined and researched indicators and threshold values consistent with the Strategic Adaptive Management (SAM) approach endorsed by the LEB Ministerial Forum.
The project provided a platform for delivering targeted and highly applied research to progress the application of natural resource management evaluation in the LEB and provide a significant boost to the management and protection of a highly significant and vulnerable desert drainage system that is recognised on a global scale.
