基于复杂网络的生态系统稳定性与生态多样性

Ecological system stability and diversity based on complex networks

生态多样性和稳定性之间的内在机理一直是研究热点。本文利用复杂网络理论,根据具体的阔叶混交林生态系统,把物种看成是节点,物种间的捕食关系看成是有向边,物种之间捕食依赖程度看成是边权,构建食物网的复杂有向加权网络。在随机或有选择地移除网络节点的情况下,利用相关指标,计算系统的稳定性和多样性,研究它们之间的关联性。结果表明,在阔叶混交林生态系统中,特定物种的丧失使生态多样性降低,影响了生态系统中能量供求的平衡关系,引起相关物种生活习性的改变,转而对其他物种加大捕食力度,使原本稳定的捕食关系逐渐破裂。捕食关系的不断破裂最终促使生态系统的稳定性下降。因此,在阔叶混交林生态系统中,生态多样性的丧失会降低系统的稳定性,多样性与稳定性呈正相关。

The internal mechanism between the ecological diversity and stability has been a research hotspot. Based on the theory of complex networks,considering the species as a node,prey relationships among species as directed edges,prey on dependent predation among species as edge weight,the directed and weighted complex networks of food web are constructed in a specific broad-leaved mixed forest ecosystem. Under the condition of randomly or selectively removing network nodes,the diversity and stability of system is calculated using related indicators and the correlation between them is studied. The result shows that in the broad-leaved forest ecosystem,the loss of a particular species reduces the biodiversity and influences the balance of energy supply and demand in the ecosystem,causes the change of related species＇ life habits,then increases the strength of predation on other species which makes the originally stable feeding relationship gradually broken. The constant rupture of prey relationships between species finally prompts the decline of the stability of the ecosystem. As a result,in the broad-leaved mixed forest ecosystem,the loss of ecological diversity will reduce the stability of the system,and the diversity and stability is positively correlated.