Biological invasions: process, mechanism and prediction
外来种入侵的过程、机理和预测

Biotic invasions can occur when organisms are trans ported to new, often distant, ranges where their descendants proliferate, spread , and persist. Biological invasions have been causing major environmental and ec ological damage, few areas remain sheltered from these immigrations in today's w orld, and they have become a priority concern for conservation biologists and la nd managers. In this paper, we discuss the process of invasions, the mechanism o f alien species displacing native species, and the predicting of biological inva sions. Humans have served as both accidental and deliberate dispersal agents for alie n species immigrations worldwide. The fate of immigrants is decidedly mixed, few survived the hazards of chronic and stochastic forces, and only a small fractio n became naturalized. In turn, some naturalized species do become invasive. The potential reasons why some immigrant species prosper may be related with t he biological and /or ecological characters of nonindigenous species, and the vu lnerability of the communities that they invade. Invasive species usually have h igher competition ability and they fit the environment of invaded ecosystem bett er than native species, many invasive species can even wreck havoc on ecosystems to which key native species are not adapted. Some alien species escape from the constraints of their native predators or parasites, community diversity and sta bility might affect its invasibility, and sudden, radical disturbances in enviro nment may encourage invasions. The predicting of biological invasions include identifying which species will become future invaders, where alien species would invade landscape and what impa ct they bring to native ecosystems, and how the geographic range of the invasive species population expand. Every kind of related models has its advantage and l imitation, their association may heighten our understanding to the expanding mec hanism of invader species.cies p