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Presented at the NABS Annual meeting, Athens, Georgia, 2003
in Food Webs
Effects of catchment management on the food web ecology of Intermittently Closed and Open Lakes and Lagoons (ICOLLs) in Coastal New South Wales, Australia
A.H. Arthington and W.L. Hadwen. Centre for Catchment and In-Stream Research, CRC for Sustainable Tourism, Griffith University, Nathan QLD 4111, Australia
Along the eastern coast of Australia, Intermittently Closed and Open Lakes and Lagoons (ICOLLs) occur naturally in a variety of physical and chemical states ranging from freshwater closed systems (similar to lakes and lagoons) to saline tidal systems (similar to estuaries). However, local management strategies strongly influence the state of ICOLLs. To investigate the effects of management strategies on the ecological health of ICOLLs, food web structure and energy processing were characterised using stable isotope analyses in seven representative systems along the northern coast of New South Wales, Australia. There was considerable variability in food web structure and species diversity, presumably owing to differences in opening and closing regimes and catchment characteristics. Sites with excessive nutrient inputs (typically from sewage treatment plants) had producers and consumers with elevated δ15N signatures (relative to those for pristine coastal waterways). Regardless of nutrient status, food webs were fueled by autochthonous production. A range of conceptual models have been developed to predict the long-term consequences of excessive nutrient inputs, fish and crustacean extraction through recreational fishing and increasing tourism and coastal development on the ecological health of ICOLLs along the northern New South Wales coastline.
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