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Taft, J. B. Wilhelm, G. S. Ladd, D. M. and L. A. Masters. Floristic quality assessment for vegetation in Illinois, a method for assessing vegetation integrity. Pp. 3-95.
Abstract: Floristic quality assessment (FQA) is proposed as a method to assess floristic integrity in Illinois. For the application of FQA, each taxon in the Illinois vascular flora was assigned an integer from 0 to 10 termed a coefficient of conservatism (C). Two basic ecological tenets that the coefficients represent are that plant species differ in their tolerance to disturbance and disturbance types, and that plant species display varying degrees of fidelity to habitat integrity. With these principles as a guide, the coefficient applied to each taxon represents a rank based on observed behavior and patterns of occurrence in Illinois plant communities and our confidence that a taxon is remnant (natural area) dependent. Species given a C value of 0-1 are taxa adapted to severe disturbances, particularly anthropogenic disturbances, occurring so frequently that often only brief periods are available for growth and reproduction. Species ranked with a C value of 2-3 are associated with somewhat more stable, though, degraded, environments. Those species with coefficients 4-6 include many dominant or matrix species for several habitats; they have a high consistency of occurrence within given community types. Species with C values 7-8 are taxa we associate mostly with natural areas, but that can be found persisting where the habitat has been degraded somewhat. Those species with coefficients 9-10 are considered to be restricted to high-quality natural areas. A floristic quality index (FQI) and a mean coefficient of conservatism © are two of the values derived from floristic inventory data. Other derived parameters include species richness, relative importance, percent of taxa that are native and adventive, number of rare species, and guild diversity (including wetness and conservatism ranks, and physiognomic classes). We suggest that FQA is a promising tool that can be used to discriminate natural quality of vegetation on the Illinois landscape and to make time-series comparisons in ecological studies. We suggest the use of certain parametric and nonparametric statistical tests, such as analysis of variance, mean-separation techniques, and goodness-of-fit tests, that can aid in distinguishing nonrandom differences in floristic quality.
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