Diversity indices applied in desert grassland communities of Otero Mesa, New Mexico

摘要

To describe plant community (alpha) diversity on rangelands, managers are confronted with a variety of commonly used indices. The choice, performance, and interpretations of these indices are often not clear. Biodiversity indices were computed for a variety of plant communities in a desert grassland of southern New Mexico. Data consisted of reported importance values, range transect data for both grazed and ungrazed pastures, and search-and-find data specifically addressed to plant community diversity. Occurrence of threatened and endangered plants was considered by a weighting procedure. Performance of each diversity index was evaluated by ranking plant communities from low to high and comparing the rankings yielded by the various indices. Data based upon importance or dominance that omit plant species of lesser importance or dominance should not be the basis of comparisons for alpha diversity. Communities described by range transect data ranked differently depending upon the index used. The most practical measure of plant species diversity may be the number of species found by search-and-find procedures.