Research On The Stability Of Complex Food Web Based On Niche And Bioenergetics Model

Food web is a complex network that describes the interactions between species based on nutrient relationships.It is a channel of material circulation and energy flow in an ecosystem,and has an important impact on the function of the ecosystem.The influence of complex food web structure on stability is a core issue for ecologist.In this paper,niche models were used to generate complex near-nature food webs with different species diversity and connectance.The kinetic model of food web was constructed based on bioenergetics.Based on the ecological metabolism theory,the model parameters were calculated according to the species size and metabolic type,and the effects of species diversity and connectance on the main topological properties and stability of the food web were studied by numerical simulation,and the influencing mechanism was explored.The main results and conclusions are summarized below.(1)The dynamic model of complex food web based on the principle of bioenergetics showed that the larger the size of food web(the more species),the proportion of basal species and top predator species decreased,while the proportion of intermediate predator species increased;This further leads to a decrease in the proportion of connections between top predators and basal species,and an increase in the proportion of connections between intermediate predators;The average nutrient level,maximum nutrient level and nutrient similarity of food web increased significantly.At the same time,with the increase of the number of food web species,the community biomass increased and the variance of community biomass decreased,which resulted in the improvement of the stability of time series.In addition,the persistence of the food web decreased gradually as the number of species increased.(2)The effects of connectance on the persistence of food webs and the stability of time series were inconsistent under different species numbers.With the increase of connectance,the proportion of basal species decreased,while the proportion of intermediate predator species increased.This further leads to a decrease in the proportion of connections between top predators and basal species,and an increase in the proportion of connections between intermediate predators;The average nutrient level,maximum nutrient level and nutrient similarity of food web increased significantly.At the same time,the biomass of large-scale food webs decreases,which leads to the stability of time series.In addition,the sustainability of the medium-scale food web decreased with the gradual increase of connectance,while that of the large-scale food web decreased first and then increased.(3)Under the gradient of species diversity,the maximum trophic level,average prey number per species,and average trophic level are important indicators affecting the stability of complex food webs.Under the connectance gradient,the maximum trophic level,average prey number per species,and the proportion of the number of top predators are important indicators affecting the stability of complex food webs.The results and conclusions of this paper are helpful to deepen the understanding of nature complex ecosystem,explore how species coexist in nature,and then provide certain support and solutions for improving the stability of ecosystem and maintaining the function of ecosystem.