Exploring The Factors Behind Species Extinction-from The View Of Habitat Loss,Species Characteristics And Specie Richness

With an increasing number of species at risk of extinction because of habitat loss,more and more precious species are in danger,even at risk of extinction,and thus species protection and the maintenance of biodiversity are facing more and more challenges.To cope with this situation,this paper investigates how species characteristics and community specie richness affect species survival in the face of habitat loss.To build appropriate communities,spatially heterogeneous resource landscapes are first generated,and then communities are generated in these landscapes throughout both the gradual evolution of body size using a food-web model with spatial structure.Finally,build two types of habitat loss models,including random and contagious habitat loss model.When the communities reach ecologically and evolutionarily stable state,this paper investigates how species characteristics affect species survival in the face of habitat loss,and how species richness affect species survival in the face of habitat loss.The results about how species characteristics affect species survival in the face of habitat loss show that:(1)large species or species at high trophic level are more vulnerable to habitat loss;and random habitat loss is more dangerous than contagious habitat loss for these species.(2)Species with small energy output,low ratio of energy output to intake,low diversification of energy output,but high diversification of energy intake,are more vulnerable to habitat loss;and for these species,random habitat loss is more dangerous than contagious habitat loss.Though,the species with small energy intake are also more vulnerable to habitat loss,there are no obvious difference in the effect of habitat loss on these species between random and contagious.(3)Species with small body size or low trophic level,lose more individuals and distribution area for contagious habitat loss than for random habitat loss,especially between an intermediate and significant fraction of lost habitat.(4)Species with large energy intake or output,high ratio of energy output to intake,highdiversification of energy output,but low diversification of energy intake,lose more individuals and distribution area for contagious habitat loss than for random habitat loss,especially between an intermediate and significant fraction of lost habitat.(5)Species with intermediate energy intake or output,low diversification of energy intake,high diversification of energy output,and high ratio of energy output to intake,can grow population size in a long period of habitat loss process,especially for random habitat loss.The results about how species richness affect species survival in the face of habitat loss show that:(1)Species extinction occurs earlier in communities with greater species richness in the face of habitat loss,especially for random habitat loss.(2)Species richness does not affect the extinction time of the last extinct heterotrophic species in the communities.(3)For species-richer communities,the mean extinction time of all heterotrophic species is shorter in the face of habitat loss,especially for random habitat loss.(4)Under contagious habitat loss,species-poorer communities have a shorter extinction duration between the first and last extinct species;however,for random habitat loss,there are no similar phenomenon.(5)For species-richer communities,the mean extinction time of all top species in the food web is longer in the face of habitat loss.(6)When random habitat loss occurs,the intermediate species in the food web are easier to become extinct than that when contagious habitat loss occurs.(7)For contagious habitat loss,a community loses more individuals,but for random habitat loss,a community loses more species,especially between an intermediate and significant fraction of lost habitat.