Research On The Mechanism And Numerical Simulation Of Species Competing For Resource

The classical research approaches and theories of species competition in ecology are based on the Lotka-Volterra competition model, and many competition models of species have been put forward in ecological literature since 20's in 20 centuries. On this foundation, a new kind of theory of resources competition, which are based on resources consumption, was developed in 70's in 20 centuries. A great deal of different consumer-resource models have been designed at that time. After that, the studies of resources competition theories have been developed quickly. But the resources competition theories in earlier period have mainly come from chemostat model. Up to 90's in 20 centuries, a large numbers of species inhabit patchy environments due to fragmentation of landscape resulting from unreasonable economic activities by man. And hence islands biogeography and metapopulation concept are in ecological theories, and the resources competition theories, which correlate with that, have had a fast development synchronously, and mathematical models of resources competition of species in metapopulation appear. In particular at recent years, with the extensively applications of computer technology, the research on spatial and numerical simulation experiment of resources competition is in imposing conditions. For all that, because of the complexity of competition, there still have no perfect resources competition theories up to now. Some obvious shortages have been found in theoretical study and experimental examination, for example, resources competition of multi-patch and multi-species have been studied less correspondingly, also the same situations include the study of explicit spatial theories, the influence of spatio-timporal heterogeneity of resources on consumers, the practical examination of theory models, the influence of man's activities on resources competition. Based on the former works, a popular resources competition model was built, and with that we study the dynamical mechanism of different species competing for resources in different patches, we have the following conclusions via the analysis of various situations.1) Apart from analyzing and verifying the traditional resources competition theories of R*-rule, we also have the conclusion that there exist the possibility that species having different R* value can coexist, even the species with higher R* value can also outcompete the species having lower R* value, the conclusions have indetermination.2) When multi-species compete single resource, if there exist non-negative steady E*=(R*, N₁*,…, N_n*), then , if R*>R_n*, then E* is the global attractor, this is the sufficient and essential conditions of species coexistence.3) With the increasing of intraspecific competition, the density of superior species descends gradually, but the density of inferior species increases gradually, they have reached the equilibrium state gradually at last, and they realize stable coexistence of multi-species.4) With the same population demography, the bigger the difference of resources growth rate is, the more disadvantageous in the coexistence of the consumer species there are, if the demography are not same, under the same resources growth rate, the coexistence of species are impossible.5) The dispersals of species between patches can result in a source-sink structure and net single directional flow. This spatial heterogeneous structure can promote coexistence of competing species.6) We have examined the competition-dispersal trade-off theories and the negative correlation relationship between competition and dispersal. We also obtain another conclusion, that is the species with superior competition ability need high dispersal ability, then it can coexist with species having inferior competition ability, but low dispersal ability.7) After restoration of habitat, the occupancy rates to habitat of all odd species increase clearly, becoming the superior species, and occupancy rates of even species decrease, which becoming the inferior species. Species undergo three evolution stages of growth, oscillation and stability.