GLOBAL PATTERNS OF PLANT INVASIONS AND THE CONCEPT OF INVASIBILITY

摘要: With a simple model, I show that comparisons of invasibility between regions are impossible to make unless one can control for all the variables besides influence exotic richness, including rates immigration species and characteristics invading themselves. Using data from literature 184 sites around world, found nature reserves had one-half fraction outside reserves, island nearly three times mainland sites. However, number exotics were also dependent on site area, this be taken into account valid The native was used as surrogate area habitat diversity. Nearly 70% variation in accounted by multiple regression containing following predictors: species, whether an or mainland, not it reserve. After controlling scale, there significant differences among biomes, but continents, their level invasion. Multiple biome temperate agricultural urban most invaded deserts savannas least. considerable within-group mean degree Scale-controlled analysis showed New World is significantly more than Old World, only when richness (probably diversity) factored out. Contrary expectation, communities richer more, fewer, exotics. For sites, invasion increased with latitude, no such relationship islands. Although islands apparently because low set less rich similar area. increases visitors. difficult draw conclusions about relative invasibility, potential, roles dispersal disturbance any these results. Most observed patterns here could potentially explained properties, ecosystem propagule pressure.