生境破碎化对动物种群存活的影响

生境破碎是生物多样性下降的主要原因之一。通常以岛屿生物地理学、异质种群生物学和景观生态学的理论来解释不同空间尺度中生境破碎化的生态学效应。生境破碎化引起面积效应、隔离效应和边缘效应。这些效应通过影响动物种群的绝灭阈值、分布和多度、种间关系以及生态系统过程，最终影响动物种群的存活。野外研究表明，破碎化对动物的影响，因物种、生境类型和地理区域不同而有所变化，因此，预测物种在破碎生境中的存活比较困难。研究热点集中于：确定生境面积损失和生境斑块的空间格局对破碎景观中物种绝灭的相对影响，破碎景观中物种的适宜生境比例和绝灭阈值，异质种群动态以及生态系统的生态过程。随着3S技术的发展，生境破碎化模型趋于复杂，而发展有效的模型和验证模型将成为一项富有挑战性的任务。

Effects of habitat fragmentation on survival of animal populations

As one of major factors attributed to the loss of biodiversity, habitat fragmentation has become one of central issues in conservation biology and ecology. Although theories of island biogeography, metapopulation and landscape ecology have been developed to mainly explain effects of habitat fragmentation, it is still immature to get generally comprehensive insight on it. More recently, habitat fragmentation has mainly been used to strictly refer to the change in spatial configuration of fragmented patches. Simulation models and some statistical studies suggested that there might be a threshold in proportion of suitable habitat in landscape below which populations decrease very quickly. Distinguishing relative effects of habitat fragmentation and habitat loss on population extinction threshold has important implication for conservation, but empirical evidences are still of scarce in testing the effect of fragmentation on the population extinction threshold. Because edge effect, area effect and isolation effect can influence ecological relationships such as prey predation relationship, parasite host relationship and competition relationship among species in ecosystem, the effect of habitat fragmentation on population survival varies among species, habitats and regions. It is too early for predicting fate of populations in fragmented landscape. Future efforts will focus on relative effects of habitat loss and spatial configuration of fragmented patches on population survival, percentage of suitable habitat and population extinction threshold, metapopulation dynamics and ecological process of ecosystem under habitat fragmentation. With development of 3S technologies (global positioning system, geological information system and remote sensing), more data on habitat fragmentation will be available for spatially explicit models dealing with habitat fragmentation. However, working models are urgently needed and validation of models will become one of big challenges for understanding the effects of habitat fragmentation.