摘要
由于生物科学的进一步发展以及相互渗透，一些数学家和生态学家对采用数学模式来描述生物种群的生态规律愈来愈感兴趣。[1]中讨论了三个种群可解模式的生态系统，即一个被捕食种群N1(即被捕食的成员数为N1，或被捕食的种群密度为N1，其它情况类似，不另作说明)和二个捕食种群N2、N3；二个被捕食种群N1、N2和一个捕食种群N3；三步捕食者一食饵系统的食物链N1、N2、N3。
For the three-species ecosystems in a solvable model three different possibilities, namely, a one-prey-two-predator system, a two-prey-one-predator system and a three-step prey-predator food chain are consi-dered.Nalin Bhat and L.K Pande have made a study of the ecosystems, When the coefficients of mathematical models are all constants. The coefficients in this article are taken to vary periodically with time, Which are of apparent ecological significance and their sufficient conditions for the existence of unique positive periodic solutions of asymptotic stability in the large are given.
