具有食饵群体抵御力作用影响的捕食系统

对一类食饵种群具有群体抵御力的二维捕食食饵系统进行了定性研究。证明了解的正有界性。在鞍结分岔条件下，得到了正平衡点附近的轨线结构和全局的轨线结构。结果表明捕食种群的生存或绝灭依赖于食饵种群的内部增长率：若内部增长率较小，捕食者最终绝灭；若内部增长率增加，捕食种群的持续生存区也增大：但若内部增长率较大时，食饵的群体防御能力使得捕食者很难捕食，捕食种群的持续生存区减小。

A predator system affected by collectively defensive capability of the predator population

A predator system of 2 dimension was qualitatively investigated,where the prey population having the collectively defensive capability. The positive boundness of the solutions was proved; and at the condition of the fold bifurcation, the portraits structure near the positive equilibrium and the global structure of the portraits were obtained. The results showed that whether the predator persist on or perish out depends on the intrinstic increasing rate of the prey population: If it is lower, the predator will perish out; Increasing it, the predator's persist region extends; But if it is higher, the collectively defensive capability of the prey population make the predator difficult, and the predators persist region contracts.