An index of plant community integrity: development of the methodology for assessing prairie wetland plant communities

We developed an Index of Plant Community Integrity (IPCI) for quantitatively assessing the quality of seasonal wetland plant communities. In 1998 and 1999, we sampled the plant communities of 46 seasonal wetlands in the Prairie Pothole Region (PPR) of central North Dakota, USA. We selected wetlands that represented a range of disturbance from well-managed native rangeland to heavily disturbed cropland. We delineated plant data into metrics of the data set (e.g. species richness, percentage of introduced and annual plants) and analyzed these metrics using principal components (PCs) and cluster analyses. Through analyses, five quality classes (Very good, Good, Fair, Poor, and Very poor) were determined. We then assigned ranges and scores for each metric based on the statistical analyses. By using this classification system, the plant communities of additional seasonal wetlands in the PPR can now be assessed and placed in quality classes for mitigation or ecological purposes, such as tracking the improvement of restored or reclaimed wetlands, wildlife habitat evaluation, hydrogeomorphic (HGM) assessment, and evaluation of other ecological functions.