EXOTIC PLANT SPECIES INVADE HOT SPOTS OF NATIVE PLANT DIVERSITY

作者：Thomas J. Stohlgren, Dan Binkley, Geneva W. Chong, Mohammed A. Kalkhan, Lisa D. Schell, Kelly A. Bull, Yuka Otsuki, Greg Newman, Michael Bashkin, Yowhan Son · 发表于：Ecological Monographs · 年份：1999 · DOI：10.1890/0012-9615(1999)069[0025:epsihs]2.0.co;2 · 被引用次数：1083 · 研究领域：Ecology and Vegetation Dynamics Studies、Plant and animal studies、Botany, Ecology, and Taxonomy Studies

Some theories and experimental studies suggest that areas of low plant species richness may be invaded more easily than areas of high plant species richness. We gathered nested-scale vegetation data on plant species richness, foliar cover, and frequency from 200 1-m2 subplots (20 1000-m2 modified-Whittaker plots) in the Colorado Rockies (USA), and 160 1-m2 subplots (16 1000-m2 plots) in the Central Grasslands in Colorado, Wyoming, South Dakota, and Minnesota (USA) to test the generality of this paradigm. At the 1-m2 scale, the paradigm was supported in four prairie types in the Central Grasslands, where exotic species richness declined with increasing plant species richness and cover. At the 1-m2 scale, five forest and meadow vegetation types in the Colorado Rockies contradicted the paradigm; exotic species richness increased with native-plant species richness and foliar cover. At the 1000-m2 plot scale (among vegetation types), 83% of the variance in exotic species richness in the Central Grasslands was explained by the total percentage of nitrogen in the soil and the cover of native plant species. In the Colorado Rockies, 69% of the variance in exotic species richness in 1000-m2 plots was explained by the number of native plant species and the total percentage of soil carbon. At landscape and biome scales, exotic species primarily invaded areas of high species richness in the four Central Grasslands sites and in the five Colorado Rockies vegetation types. For the nine veget...