带有捕食作用的随机CKTW模型维持物种多样性的研究

Maintenance of Species Diversity by Stochastic CKTW Models with Predation

摘要: 在海洋生态系统中，消耗细菌种群数量的因素包括原生动物的非选择性捕食与噬菌体的裂解。本文在具有共同进化机制的随机CKTW模型基础上，引入原生动物非选择性捕食作用，建立基于个体水平的带有非选择性捕食作用的随机CKTW模型。利用随机模拟算法对种群数量有限的随机模型进行数值模拟，捕捉到丧失物种多样性的三种灭绝路径与维持物种多样性的现象，并通过模拟实验计算出这些现象发生的概率。这里使用的随机模拟算法为Gillespie算法。最后以香农熵作为物种多样性的评价指标，对两类随机模型的物种多样性进行对比分析，说明共同进化可以在一定程度上维持物种多样性。

Abstract: In Marine ecosystems, factors that deplete bacterial populations include non-selective predation by protozoa and phage lysis. In this paper, based on the stochastic CKTW model with coevolutionary mechanism, we introduce the non-selective predation of protozoa and establish the stochastic CKTW model with non-selective predation based on individual level. The stochastic simulation algorithm was used to simulate the stochastic model with limited population to capture the three extinction paths that lost species diversity and the phenomena that maintained species diversity, and the probability of occurrence is calculated by a large number of simulation experiments. The stochastic simulation algorithm used here is Gillespie algorithm. Finally, Shannon entropy was used as the evaluation index of species diversity, and the species diversity of the two stochastic models was compared and analyzed, indicating that coevolution could maintain species diversity to a certain extent.