Figure 1

Trajectories of model (4) with \(b=0.4\), \(b_{1}=0.2\), \(T(t)=0.25+0.1\sin t\), \(\xi =0.3\), \(\lambda =0.2\), \(\rho =0.1\), \(\beta _{2}^{2}=0.1\), \(\beta _{3}^{2}=0.2\). (a) \(\beta _{1}^{2}=0.36\), which reflects the extermination of the species. (b) \(\beta _{1}^{2}=0.3\), which reflects the nonpersistence in mean of the species. (c) \(\beta _{1}^{2}=0.25\), which reflects the weak persistence of the species. (d) \(\beta _{1}^{2}=0.04\), which reflects the permanence of the species