Department of Integrative Biology, Oklahoma State University, Stillwater, Oklahoma, USA.
Department of Mathematics, Ohio State University, Columbus, Ohio, USA.
Ecol Lett. 2022 Feb;25(2):366-377. doi: 10.1111/ele.13925. Epub 2021 Nov 24.
Understanding mechanisms of coexistence is a central topic in ecology. Mathematical analysis of models of competition between two identical species moving at different rates of symmetric diffusion in heterogeneous environments show that the slower mover excludes the faster one. The models have not been tested empirically and lack inclusions of a component of directed movement toward favourable areas. To address these gaps, we extended previous theory by explicitly including exploitable resource dynamics and directed movement. We tested the mathematical results experimentally using laboratory populations of the nematode worm, Caenorhabditis elegans. Our results not only support the previous theory that the species diffusing at a slower rate prevails in heterogeneous environments but also reveal that moderate levels of a directed movement component on top of the diffusive movement allow species to coexist. Our results broaden the theory of species coexistence in heterogeneous space and provide empirical confirmation of the mathematical predictions.
理解共存机制是生态学的一个核心课题。对两种在不同扩散速度下在非均相环境中移动的同种生物进行竞争的模型的数学分析表明，较慢的移动者会排斥较快的移动者。这些模型尚未经过实证检验，也缺乏对指向有利区域的定向运动的包含。为了解决这些差距，我们通过明确包括可利用资源动态和定向运动来扩展之前的理论。我们使用秀丽隐杆线虫的实验室种群对数学结果进行了实验测试。我们的结果不仅支持了先前的理论，即在非均相环境中扩散速度较慢的物种占优势，而且还表明，在扩散运动之上加上适度的定向运动成分可以使物种共存。我们的结果拓宽了在非均相空间中物种共存的理论，并为数学预测提供了经验验证。
