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.