大丰自然保护区麋鹿种群密度制约增长的模型

Model of the growth restricted by the density of Milu population in Dafeng Nature Reserve Region

建立了关于大丰自然保护区麋鹿种群在密度制约下增长的数学模型,导出了不同危害强度下种群数变化的平衡值和确保种群可持续生存的危害强度临界值。运用MATLAB软件绘制了在不同危害强度下模型解(麋鹿种群数)在方向场中的动态趋势图。研究表明:危害强度越大,平衡值越低。当危害强度低于临界值时,平衡值大于基础种群数,麋鹿种群的生存是可持续的;当危害强度高于临界值时,平衡值将小于基础种群数,这意味着麋鹿种群生存的可持续性将受到威胁。

A mathematic model of the growth restricted by the population density of Milu population in Dafeng National Reserve Region in this paper and derived the equilibrium values of the population under different intensity of damage. In the meantime, the critical value of the intensity of damage for keeping the population to survive sustainable was preen- ted. It draws the portrait, in the direction field, of solutions （Milu populations） of the model under different intensi^y of damage by MATLAB software. It was showed that the greater the intensity of damage is, the lower the equilibrium value is. When the intensity of damage was less than the critical value, the equilibrium value would become greater than the basic population, and the Milu population would survive sustainable. However, the equilibrium value will less than the basic population when the intensity of damage was greater than the critical value. This means that the sustainability of Milu＇s survival will be threatened.