The potential of rapid assessment techniques as early warning indicators of wetland degradation: A review

in recent years, the need to develop assessment techniques that could provide advanced warning of significant wetland stress or degradation has been recognized. The goal of this paper is to identify rapid, yet realistic and reliable methods for the early detection of pollutant impacts on wetland ecosystems, particularly those in the wet-dry tropics of northern Australia. In doing so, it describes the ideal attributes of early warning indicators and their subsequent selection for wetland research. It then evaluates the potential of existing methods of assessment as early warning indicators of wetland degradation due to pollutant impacts. Particular attention is paid to rapid assessment techniques, covering a range of trophic levels and levels of biological organization. Due to a number of favorable characteristics, phytoplankton were considered to be potentially the most promising indicators of wetland degradation, and thus the scope of application of toxicity assessment and monitoring methods warrants further investigation. Rapid toxicity bioassays using invertebrates and vertebrates were also considered to be an essential part of an early detection program for wetlands, while biomarkers represented a promising tool for achieving true "early warning" of potential pollutant impacts. Given further refinement and development, rapid methods of monitoring aquatic community assemblages were also considered potentially useful tools for the early detection of wetland degradation. Finally, to gain effective use from an early warning system for wetlands, its incorporation into an ecological risk assessment framework was recommended. (C) 1998 by John Wiley & Sons,* Inc.