Effects Of Parasites On The Dynamics Of Biological Invasion

Biological invasions are global phenomena that threaten terrestrial, marine and freshwater biodiversity and wildlife conservation. Meanwhile, parasites might play a role in determining invasion outcomes. Recently, the role of the parasitic infection in the biological invasion has been developed rapidly, which has become a frontier and hot issue in the research of the invasion ecology and infectious diseases. This paper mainly focuses on the effects of parasites or pathogens on the species’invasion and coexistence, particularly in discussing the strategy of biological control based on analysis results. Here, the paper includes five chapters. First, we summarizes the concept, theory, research status of biological invasion; Second, the theory and model construction of biological invasion with parasitic regulation; Third, we established a spatially structured intraguild predation model with cellular automata method. Then we discussed the effects of parasite on biological invasion, where particularly explored how the indirect effects of parasitism (including density-mediated effects and trait-mediated effects) influence the spatial invasion dynamics of an exotic predator; Fourth, base on SI (susceptible-infected) model, we use pair approximation to discuss the effect of parasite on biological invasion under heterogeneous habitat; Finally, we illustrated the summary and outlook.Through the research, we mainly draws the following new results:(1) The introduction of parasite inhibits the invasion of exotic species with the three parasite-mediated indirect effects. (2) The impacts of trait-mediated indirect effect are more dramatic than density-mediated effect. Particularly, the inhibiting effect from the couple of density and trait effects is the most obvious among the three indirect interactions. (3) The density of invasive predator increases under the state of no parasite and parasite, but the density of native prey is reduced, and they will coexist at equilibrium. Local prey’ density is the smallest, but the density of invasive predator is the highest with no parasite, which indicates that the parasite can inhibit predator’s invasion. (4) Strong spreading of parasite will impede predator’s invasion. (5) Spatial heterogeneity is an important factor that effects biological invasion, and it is benefit for biological invasion under the invasive model with competitive relationship.