A new approach to assessing ecosystem condition across spatial scales: vertical linkages among indicators of wetland condition.
Morgan, Steven *,1, Cherr, Gary1, Groholz, Edwin1, Anderson, Susan, Higashi, Rick1, Green, Peter1, 1 University of California, Davis, CA
ABSTRACT- A unique interdisciplinary approach using a suite of traditional and novel measures was developed to address the challenging problem of evaluating the condition of wetland ecosystems across multiple spatial scales. Chemists documented the concentrations of various contaminants in the five West Coast salt marshes and a key inhabitant (lined shore crab, Pachygrapsus crassipes), toxicologists detected damage to cells and vital organs, and ecologists determined survival and reproductive performance of individuals, surveyed population densities and are linking all of these indicators. This integrated approach revealed that contaminant exposure and bioavailability may be related to 1) DNA damage of blood cells from crabs exposed to metals; 2) detoxifying enzymes in gills and embryos exposed to organic contaminants, 3) diminished reproductive performance, including reduced clutch sizes, increased abnormalities of developing embryos, reduced weight and size of embryos, reduced hatching and reduced larval survival; and 4) reduced population densities and size of adults. The existence of a vertical linkage between exposure to different types of contaminants across levels of biological organization and life stages to population density promises to provide a reliable set of indicators that not only can identify the individual and combined effects of multiple contaminants on wetland condition but that can be applied quickly, easily and inexpensively across broad stretches of our coastlines by resource managers that are charged with evaluating the state of our wetlands.
Key words: indicators, spatial scales, wetland, ecosystem condition
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