Study Of The Impact Of Different Invasion Methods Of Species On Omnivorous Food Web

To explore the impact of invaders on species in a simple omnivorous food web in landscapes characterized by habitat loss and habitat fragmentation,a simple omnivorous food web model was first developed to study the effects of habitat loss and habitat fragmentation on omnivorous food web.The simulation results of this model further confirm that the simple omnivorous food web does not follow the trophic rank hypothesis.In habitat loss and habitat fragmentation,simple omnivorous food webs can see the first species to go extinct are intermediate predators rather than omnivorous predators of the highest trophic level.The effects of changes in predation preference/predation pressure and species dispersal patterns on simple omnivorous food webs were also investigated.Based on this model,a model framework of a post-invasion omnivorous food web was constructed to describe the patch occupancy of each species in the post-invasion omnivorous food web.The effects of different invasion patterns on the post-invasion omnivorous food web were explored.The simulation results of the model show:(1)Compared with the invasive as predator,the invasive specie is prey more likely to succeed in the omnivorous food web;When invasive species invade omnivorous food webs as prey,they can tolerate more habitat loss and habitat fragmentation than when they invade omnivorous food webs as predators.(2)When invasive species are predators of species with different trophic levels on omnivorous food web,they show different coexistence patterns.The degree of habitat loss and habitat fragmentation also affects the habitat patch occupancy rate of invasive species.In most habitat structures,the lower the trophic level of the invasive location,the more successful the invasion.(3)When the invasive species are the prey of the species in the omnivorous food web,no matter what trophic level the invasive species invade,the invasion is easier to succeed.(4)The degree of habitat loss and habitat fragmentation,together with the colonization rate of species,has certain influence on the invasion results under different roles and trophic levels.Finally,the simulation results of the model are compared with several intrusion examples in nature to illustrate the reliability and accuracy of the simulation results,and some subjective suggestions are put forward for the future model building to make the simulation results of the model more accurate and real.In a word,this study provides some theoretical thinking for biological invasion and has certain guiding significance for biological control.