Species Diversity Responses To The Spatio-temporal Heterogeneity Of Habitat Destruction

Habitat loss and fragmentation is the primary cause of population, metapopulation and species extinction worldwide. The speeds of habitat destruction and species extinction reach the climax during the past 200 years because of rapid human population growth and advances in technology. The growing rates of this destructive process urge the development of a conceptual framework aiming at understanding the responses of ecosystems to habitat destruction. Many metapopulation models have simulated the consequences of habitat destruction on species diversity and gained many developments. However, those models, spatially implicit models, or spatially explicit models, focus on the effects of instantaneous destruction on species extinction and metapopulation dynamics. They have not studied the temporal heterogeneity of habitat destruction, and the interaction of temporal heterogeneity and spatial heterogeneity. Furthermore, no universal index of species diversity has been used to study the responses of species diversity to habitat destruction. Although many studies indicate there is a close relation between species extinction and habitat destruction, it is usually hard to determine whether the cause of extinction of a particular species is habitat destruction or interspecific competition.Firstly, we have modified multiple species competition-coexistence model advanced by Tilman, developed a new universal non-autonomous dynamical model of multiple species competition-coexistence, and simulated the responses of species diversity to the temporal heterogeneity of habitat destruction at different rates. Secondly, we have simulated the responses of species diversity to spatial and spatio-temporal heterogeneity of habitat destruction by the integration of cellular automata and fractal geometry. Thirdly, Shonn diversity index has been used to study the responses of species diversity to the spatio-temporal heterogeneity of habitat destruction. Finally, we have simulated the direct and indirect effects of habitat destruction, and the effects of competition on species extinction under spatio-temporal heterogeneity of habitat destruction.Seven conclusions can be drawn from the above analysis:1) There is not only the extinction of superior competitors ranked from the best to the poorest, but also the extinction of inferior competitors from the poorest to the best. Moreover, extinction of inferior competitors can be further classified into two types: one is the short-time and mass extinction of inferior competitors, the other is the long-time extinction of inferior competitors from the poorest to the best. Contrastingly, when taking spatial patterns into consideration, species extinction can also be classified into two types: extinction of superior competitors and extinction of inferior competitors. Howerver, the extinction debt is greater than that of spatially implicit model. Furthermore, only under random habitat destruction, will the responses of species diversity be similar to those of spatially implicit model. So, the order of species extinction is dependent not...