Development and testing of a rapid appraisal wetland condition index in south-eastern Australia

Abstract

The high costs and lengthy time commitments associated with traditional monitoring, and the remoteness of many wetlands have necessitated the development of techniques for rapid wetland appraisal. A rapid appraisal condition index based on four attributes of wetlands, soil, fringing vegetation, aquatic vegetation and water quality, was developed for assessing the health of permanent floodplain wetlands in the Murray-Darling Basin of south-eastern Australia. The index, composed of 13 indicators related to wetland function, was tested in the field for scientific validity relative to an independent long-term monitoring data set, replicability of indicator scores by different investigators and the responses to the seasonality in wetland processes. Indicator values were based on a mixture of visual estimates and measurements using simple instruments or procedures and all data could be collected in the field in less than 3 h. There was a significant positive correlation between rankings of the condition of 10 wetlands based on an independent long-term monitoring data set and the wetland condition index. There were also highly significant positive correlations between indicator scores collected by different investigators. Indicator scores for physical factors and fringing vegetation did not differ between autumn and winter, but winter rainfall had a significant impact on aquatic vegetation and water quality indicators. The results indicate that the wetland condition index is a valuable and reliable tool for the rapid surveying of the condition of permanent floodplain wetlands.