两种种群动态模型的比较研究

A Comparative Research on Two Models of Population Dynamics

对两种种群动态模型，逻辑斯蒂种群动态模型（简称ＬＭＰＤ）和可变资源下的种群动态模型（ＭＰＤＶＲ），在微机上进行了数值分析，比较了两种模型在１）没有资源输入２）具有不同初始资源状态３）有资源输入４）具有不同的资源消耗水平等四种情况下种群动态的差异。在ＬＭＰＤ中，种群的比增长率为种群大小的线性函数，而在ＭＰＤＶＲ中则为非线性函数。在ＬＭＰＤ，种群增长速率到达最大值（ｄＮ／ｄｔ）＿（ｍａｘ）的时间ｔ＿ｍ比在ＭＰＤＶＲ中要短，但种群到达稳态的时间ｔ＿ｓ要比在ＭＰＤＶＲ中长，对于ＬＭＰＤ。随环境负荷能力的提高，ｔ＿ｍ、ｔ＿ｓ和（ｄＮ／ｄｔ）＿（ｍａｘ）随之提高，而在ＭＰＤＶＲ中，ｔ＿ｍ、ｔ＿ｓ和（ｄＮ／ｄｔ）＿（ｍａｘ）还依赖于环境负荷能力提高的具体途径。

The numerical analysis about two models of population dynamics,theLogistic model of population dynamics(the LMPD)and the model of population dynamicsunder variable resource(the MPDVR),is given in micro-computer;the different behavioursof population dynamics between the two models are discussed in four cases,a)without re-source input; b)with different initial resource state,c) with a constant resource input, d)with different resource consumption. In the LMPD,the relative growth rate of population isa linear function of population size (N),but in the MPDVR,it is a nonlinear function.t_m,the time for population to reach its maximum of growth rate(dN/dt)max is lower in the LM-PD than in the MPDVR,but t_s,the time for population to reach its steady state is greater inthe LMPD than in the MPDRV. The indexes,t_m,t_s and (dN/dt)max increase with the carry-ing capacity of environment(K),but they depend on the detail process which the carryingcapacity of environment (K)increases by.