arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1507.05337q-bio.PEcond-mat.stat-mechphysics.bio-ph
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大型生态系统中共存的几何学

The geometry of coexistence in large ecosystems

Jacopo Grilli, Matteo Adorisio, Samir Suweis, György Barabás, Jayanth R. Banavar, Stefano Allesina, Amos Maritan

摘要:

物种之间的相互作用在控制生态系统的稳定性和生物多样性之间的相互作用的作用仍然没有得到很好的理解。生态群落在物种丰度受到小扰动后恢复的能力(局部渐近稳定性)已经得到了很好的研究,而当相互作用发生变化时,群落持续存在的可能性(结构稳定性)受到的关注要少得多。我们的目标是了解多样性,相互作用强度和生态网络结构对参数空间体积的影响,从而导致可行的平衡,即,所有种群的丰度都是正的我们开发了一个几何框架来研究可行的共存互惠和消费资源系统的必要条件的范围。使用分析和数值方法,我们表明,可行性是由少数数量描述的相互作用,产生一个非平凡的复杂性可行性关系。通过分析100多个经验网络,我们发现互惠系统中共存条件的范围可以通过随机相互作用的零模型进行分析预测,而食物网的特征在于比随机预期的共存域更小。最后,我们描述了可行域的几何形状,从而确定了更有可能引起扰动的扰动方向。有趣的是,互惠互动的结构导致了对扰动的非常异质的反应,使这些系统比预期的更脆弱。

英文摘要:

The role of species interactions in controlling the interplay between the stability of an ecosystem and its biodiversity is still not well understood. The ability of ecological communities to recover after a small perturbation of the species abundances (local asymptotic stability) has been well studied, whereas the likelihood of a community to persist when the interactions are altered (structural stability) has received much less attention. Our goal is to understand the effects of diversity, interaction strenghts and ecological network structure on the volume of parameter space leading to feasible equilibria, i.e., ones in which all populations have positive abundances. We develop a geometrical framework to study the range of conditions necessary for feasible coexistence in both mutualistic and consumer-resource systems. Using analytical and numerical methods, we show that feasibility is determined by just a handful of quantities describing the interactions, yielding a nontrivial complexity-feasibility relationship. Analyzing more than 100 empirical networks, we show that the range of coexistence conditions in mutualistic systems can be analytically predicted by means of a null model of random interactions, whereas food webs are characterized by smaller coexistence domains than those expected by chance. Finally, we characterize the geometric shape of the feasibility domain, thereby identifying the direction of perturbations that are more likely to cause extinctions. Interestingly, the structure of mutualistic interactions leads to very heterogeneous responses to perturbations, making those systems more fragile than expected by chance.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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