生境破碎化对动植物遗传多样性的影响研究进展

Effects of habitat fragmentation on genetic diversity of plants and animals

生境破碎化是生物多样性降低的主要原因之一,此前研究多集中在生境破碎化对物种和生态系统多样性的影响.综述了生境破碎化的成因、度量和理论基础,以及对动植物遗传多样性的影响机理和生态学效应.生境破碎化主要通过增加种群间隔离程度和降低有效种群大小等途径限制种群间基因交流,提高遗传漂变频率,从而影响动植物遗传多样性;但是影响效应取决于植物繁殖策略和动物迁移能力,以及传粉方式、种群大小、生命周期、生境的景观特性等因素;而且生境破碎化对动植物遗传多样性的影响大多存在滞后效应.由此可见,生境破碎化对动植物遗传多样性的影响因素多且复杂,而且不易及时发现,从而忽略生境破碎化对遗传多样性的负面影响;未来应加强生境破碎化对动植物遗传多样性的影响研究,特别是在更长时间尺度上的生境破碎化研究.

Habitat fragmentation(HF) is a key factor in the decrease in biological diversity. Previous studies focused on species and ecosystem diversity, whereas the effects of HF on genetic diversity and its mechanism remains unclear. Here we reviewed the causes, measurements, and theoretical foundations of HF, and the ecological consequences and effects of HF on genetic diversity of plants and animals. Habitat fragmentation affects genetic diversity through increasing isolation distance among populations and decreasing effective population size, with the alteration of gene flow frequency among populations and genetic drift within populations. However, the HF effects depend on the reproductive strategy of plants and the mobility of animals, which interact with other factors, such as mating patterns, population size, life cycle, landscape attributes, and so on. For example, HF significantly affects animals with low mobility, such as small mammals and amphibians, whereas animals with high mobility, such as birds, are less sensitive to HF. Trees can buffer the effects of the genetic drift because of their longevity, but grasses and shrubs with short life cycles cannot. Moreover, there is often a time-delayed effect of HF on genetic diversity. These results indicate that the mechanism of HF on genetic diversity is complicated, and its negative effects are likely to be ignored because of the time-delayed phenomenon. Hence, it is important to study the effects of HF on genetic diversity,especially at a longer time scale.