Performance of rapid floristic quality assessment indices for increasing cost-effectiveness of wetland condition evaluation

Abstract

This project tested whether rapid floristic quality indices can be used in North Carolina’s diverse wetland types, given the many cost-saving benefits that can be realized from using such indices. Vegetation plot data from 2030 North Carolina wetland plots were analyzed to test how well two floristic quality assessment indices, based on cover-dominant species and based on non-graminoid species, were correlated with full index values based on a comprehensive species list.Dominance based indices (Mean C and FQI) significantly correlated with Mean C and FQI using all species, but Mean C was more strongly correlated than FQI. Mean C of cover-dominant species correlated with the Ohio Rapid Assessment Method, but could only distinguish the lowest and highest North Carolina Wetland Assessment Method ratings. Removal of graminoids as a group, which are difficult to identify, did not appear to affect Mean C, even in herbaceous wetlands, though some wetlands were comprised of only graminoids; a dominance based index would still be useful in graminoid marshes. The availability of this cost-saving assessment tool will benefit researchers and practitioners looking for more expedient ways of assessing wetland quality or validating rapid assessments with direct measurements.