环境污染对生物种群持续生存的影响

THE EFFECTS ON SURVIVAL OF POPULATION IN A POLLUTED ENVIRONMENT

本文系统地综合了我们近年来关于环境污染对生物种群生存影响的一系列研究成果。在建立和改进模型的基础上对单种群和两种群相互作用的群落都得到了种群持续生存的阈值;提出了种群在有限时间段内存在与绝灭的概念,对单种群给出了有限时间内生存与绝灭的分界线,对两种群构成的群落给出了在有限时间内生存或绝灭的若干充分条件;研究了群落的一致持续生存问题;证明了在某类模型中,时滞对持续生存和一致持续生存均是无害的;得到了种群的成员数量波动与已知参数间的关系式;还得出了个体生存和绝灭的条件,其中的大部分研究成果有着明显的生态意义。

In this synthetical article. a series of studies on this topic in recent years are introduced. One of the main problems of those work is to find the threshold between persistence and extinction for some population or community models invaded by toxicants. From mathematical point of view, the problem is to in- vestigate the asymptotic behavior of the solutions for some non-linear and non- autonomous systems. For a single population and a community consisting of two species the thresholds have been obtained. On the basis of the conceptions of persistence and extinction at a finite time i e, β-persistence and β-extinc- tion, which were proposed by us, the separatrix between β-persistence and β-extinction for a population and some sufficient conditions about β-persistence and β-extinction for two species model have also been obtained. In addition, we have studied the uniform persistence of Volterra model invaded by toxicants and got some sufficient conditions and proved that the time delay is harmless for both persistence and uniform persistence of Volterra model. We have also got a formula linking the fluctuation of the members of a community with the parameters of the model. Besides, we have investigated a toxicant-individual model, some conditions under which the individual will be persistent or extinct have been obtained. All of our results have remarkable ecological meaning.