基于元胞自动机的濒危植物明党参种群数量动态研究

Studies of Population Quantity Dynamics of an Endangered Plant Based on Cellular Automata

根据3年来积累的和峨参野外实验数据,利用元胞自动机模型在计算机上模拟了濒危植物明党参(Changium smyrnioides)的种群生长动态,并选取同科的峨参(Anthriscus sylvestris)作为对照种进行比较分析。模拟结果显示,两个物种在种群中的个体数量均随生殖率m和可利用生境比率h的增大而增加,当生殖率大于0.6732时明党参种群才可在模拟时间尺度上(100年)保持不衰退;峨参生殖率的变化则不会使种群衰退,当m】9.15时,种群密度就不再增加。明党参的最小生境需求值小于峨参。明党参在h大于0.7%时,种群密度不再增加,即明党参最多只能利用生境的0.4%,峨参则可占据生境中位置的81.9%。综合分析模拟参数和结论,我们认为:明党参偏向于K策略,峨参偏向于r策略。本文相关资料对于确定明党参相应的保护措施有重要参考价值。研究元胞自动机在生态学上的初步模拟可以为将来进行更加深入的研究奠定基础。

Cellular automaton was a new technology developed in the 50’s of 20 century. Now it becomesan important technique in modern scientific field, because the cellular automaton could simulate various physical, chemical and biological phenomenons commendably. This article gives a brief review of its application in the field of the population ecology, and using this technique to simulate the growth dynamics of population of the endangered species Changium smyrnioides Hoff. and compare it with another similar species Anthriscus sylvestris. According to the results of the simulations, the critical point, which may accurately describe the population dynamics, can be made out. During our simulations, we choose the Reproductive Rate (m) and the Proportion of Inhabitable Sites as two main variables. The conclusions indicate that the quantity of these two species will increase while their reproductive rates (m) or the proportion of inhabitable sites (h) increase, and from the results, we can make decision that the reproduction rate is the main cause of C. smyrnioides being in danger. C. smyrnioides can keep surviving only when m > 0.6732 plant/year. Comparatively, with the reproduction rate from 6.15 to 10.75 plant/year, A. sylvestris won’t decline, but when m > 9.15 plant/year, the density of population can’t be increase any more, so it suggests that there is excess reproduction in population of A. sylvestris. The proportion of cell that C. smyrnioides takes up can not rise up with h beyond a certain value-0.7%, so its maximum percentage of cell occupation only can achieve 0.4%, while A. sylvestris may reach at 81.9% of all the inhabitable cells. The requirement of minimum patch occupancy of C. smyrnioides is smaller than that of A. sylvestris. The following conclusions are: C. smyrnioides tends to be the K strategy; while A. sylvestris is tending to be the r strategy. With these simulations, the corresponding measures of the protection on this endangered species can be identified. More profound research in future is still based on its elementary simulation on the ecology by cellular automaton.