Competitive and exclusion and oscillation phenomena of an eco-epidemiological model: An invasive approach

Eco-epidemiological model plays a crucial role in maintaining ecological balance and biological invasions.In this paper,we propose a predator-prey model where the predator population is infected by the disease.The non-negativity and boundedness of the solution are addressed.The existence and stability of equilibrium are discussed by an invasive approach.Numerical simulations are used to demonstrate the competitive and exclusion,and oscillation behaviors of the model.Interestingly,the predation rate of the infected predator is shown to have far-reaching implications for the structure and stability of ecological communities.

Global Asymptotically Stable of a Generalized Discrete Ricker Competition System

The purpose of this article is to investigate the sufficient conditions for the global asymptotic stability of one equilibrium point of a generalized Ricker competition system,……which appears as a model for dynamics with one extinct species, by applying the technique of average functions and the new principle of competitive exclusion.

Big plants--do they limit species coexistence?

Aims According to conventional theory,larger plant species are likely to inflict more intense competition on other(smaller)species.We tested a deducible prediction from this:that a larger species should generally be expected to impose greater limits on the number of species that can coexist with it.Methods Species richness was sampled under plant canopies for a selection of woody species(‘host’species)that display a wide range of adult sizes(from small shrubs to large trees),growing within natural vegetation of the Interior Douglas-fir zone of southern British Columbia,Canada.These data were compared with species richness levels sampled within randomly placed plots within the host species habitat.Important Findings A prominent host species size effect on species richness was detected but only narrowly at the small end of the species size range.Across most(90%)of the increasing size range of host species,the number of species residing under the host canopy showed no significant decrease relative to the number expected by random assembly,based on species richness within randomly defined equivalent areas within the habitat of the host species.This apparent‘null effect’,we suggest,is explained not because these larger species have no effect on community assembly.We postulate that larger species are indeed likely to be more effective in causing competitive exclusion of some smaller species(as expected from conventional theory),but that any potential limitation effect of this on resident species richness is offset for two reasons:(i)larger species also generate niche spaces that they cannot exploit under their own canopies and so have minimal impact(as competitors)on smaller species that can occupy these niches and(ii)certain other small species—despite small size—have effective competitive abilities under the severe competition that occurs within host neighbourhoods of larger species.These and other recent studies call for re-evaluation of traditional views on the role of plant size in affecting competitive ability and community assembly.

Invasion reproductive numbers for discrete-time models

Although invasion reproductive numbers(IRNs)are utilized frequently in continuous-time models with multiple interacting pathogens,they are yet to be explored in discrete-time systems.Here,we extend the concept of IRNs to discrete-time models by showing how to calculate them for a set of two-pathogen SIS models with coinfection.In our exploration,we address how sequencing events impacts the basic reproductive number(BRN)and IRN.As an illustrative example,our models are applied to rhinovirus and respiratory syncytial virus co-circulation.Results show that while the BRN is unaffected by variations in the order of events,the IRN differs.Furthermore,our models predict copersistence of multiple pathogen strains under cross-immunity,which is atypical of analogous continuous-time models.This investigation shows that sequencing events has important consequences for the IRN and can drastically alter competition dynamics.