Testing the Efficacy of Species Richness and Floristic Quality Assessment of Quality, Temporal Change, and Fire Effects in Tallgrass Prairie Natural Areas

Abstract

Abstract Despite extensive use, few studies have thoroughly tested competency of the Florist Quality Index (FQI) to assess vegetation quality by comparing it with alternative statistics and with independent measures in large data sets. We compared the efficacy of species richness and floristic quality indices in detecting temporal change and fire effects on quality within and among tallgrass prairie remnants. We calculated species richness at small (1/4-m2 plot) and large (total sample) scales, as well from a Species Richness Index (SRI) that integrates these measures. These statistics were compared with FQI, which assesses quality by integrating species richness with estimates of species conservatism (C values) to undisturbed natural vegetation. We made within-site comparisons of temporal change in dry-mesic and mesic prairie vegetation following 22 years of fire exclusion and then after five years of fire management. The among-site comparisons used 33 prairies that were graded as A or B quality and samp...