生境片断化对植物的遗传影响

生境片断化指大片连续的生境被分割成空间隔离的小生境的现象。通常认为，生境片断化使植物残遗种群由于经历随机遗传漂变和高水平的近交以及基因流的下降，而发生遗传侵蚀，遗传多样性下降，遗传结构改变，变得更加分化。但近期的研究证明，并不是所有的片断化事件都导致植物种群遗传变异丧失，且种群问的基因流甚至有可能增加了。片断化对植物种群的遗传作用还受到诸如世代长短的种间差异、片断化前的丰富度、有性和无性繁殖系统的多样性、种子库以及和传粉媒介及种子传播者的相互作用等的影响。

The Genetic Consequences of Habitat Fragmentation on Plants

Habitat fragmentation is the phenomenon of the reduction of large, continuous habitat into several smaller spatially isolated remnants. It is generally thought that habitat fragmentation will lead plant population to experience an erosion of genetic variation, reduction of genetic diversity and change of genetic structure, and make plant population more divergent due to random genetic drift, high level of inbreeding and reduced gene flow. Empirical studies, however, suggest that not all fragmentation events lead to losses of genetic divergence, even increase gene flow among remnant populations, breaking down local genetic structure. Other studies also exhibit that many other factors such as interspeeifie differences in longevity, prefragmentation abundance, their variety of sexual and asexual reproductive systems, the storage of genetic material as seed, and their interactions with animal pollination and dispersal vectors will also influence the genetic consequences of habitat fragmentation on plant populations.