Adapting to climate change: A risk assessment and decision making framework for managing groundwater dependent ecosystems with declining water levels. Supporting document 5: The impact of declining groundwater levels on stygofauna communities in the Leeuwin Naturaliste Ridge Cave systems
Author: Stacey Chilcott
Loss of groundwater depth, rather than water quality, is the primary threat to stygofaunal communities in the caves of Leeuwin Naturaliste Ridge, home to a number of Threatened Ecological Communities (TECs). This project examined the structural changes of the animal communities living within the groundwater dependent ecosystem of Leeuwin Naturaliste Ridge (LNR) and Yanchep, Western Australia, as well as water quality of each of these cave systems. Multidimensional scaling, Simper analysis and BIOENV techniques were used to characterise and compare water quality, quantity and community structure. It was found that each cave contained a distinct faunal community contribution and that three caves were distinct in their ionic compositions. Factors that may have contributed to the biological and physical differentiation of these caves include the extensive evolutionary and hydrogeological development of each cave. Threats to cave systems were also identified, including climate change induced rainfall decline and anthropogenic stressors. The loss of groundwater from the cave systems appears to be the primary threat to stygofauna communities as there is little evidence of a decline in water quality as a result of groundwater decline in the caves over time. This report uses the research findings to generate informed recommendations on management strategies for future conservation of TECs in this area.