The exploration of mechanisms that enable species coexistence under competition for a sole limiting resource is widespread across ecology. Two examples of such facilitative processes are intraspecific competition and spatial self-organisation. These processes determine the outcome of competitive dynamics in many resource-limited patterned ecosystems, classical examples of which include dryland vegetation patterns, intertidal mussel beds and Sub-alpine ribbon forests. Previous theoretical investigations have explained coexistence within patterned ecosystems by making strong assumptions on the differences between species (e.g. contrasting dispersal behaviours or different functional responses to resource availability). In this paper, I show that the interplay between the detrimental effects of intraspecific competition and the facilitative nature of self-organisation forms a coexistence mechanism that does not rely on species-specific assumptions and captures coexistence across a wide range of the environmental stress gradient. I use a theoretical model that captures the interactions of two generic consumer species with an explicitly modelled resource to show that coexistence relies on a balance between species’ colonisation abilities and their local competitiveness, provided intraspecific competition is sufficiently strong. Crucially, the requirements on species’ self-limitation for coexistence to occur differ on opposite ends of the resource input spectrum. For low resource levels, coexistence is facilitated by strong intraspecific dynamics of the species superior in its colonisation abilities, but for larger volumes of resource input, strong intraspecific competition of the locally superior species enables coexistence. Results presented in this paper also highlight the importance of hysteresis in understanding tipping points, in particular extinction events. Finally, the theoretical framework provides insights into spatial species distributions within single patches, supporting verbal hypotheses on co-existence of herbaceous and woody species in dryland vegetation patterns and suggesting potential empirical tests in the context of other patterned ecosystems.

中文翻译：

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空间自组织和种内竞争的相互作用促进了资源有限的模式生态系统中物种的共存

在生态系统中，探索使物种在竞争唯一限制资源的情况下共存的机制已广为人知。这种促进过程的两个例子是种内竞争和空间自组织。这些过程决定了许多资源受限的模式生态系统中竞争动态的结果，其中经典的例子包括旱地植被模式，潮间带贻贝床和亚高山带状森林。先前的理论研究通过对物种之间的差异做出强有力的假设（例如，对比不同的分散行为或对资源可用性的不同功能响应）来解释模式生态系统内的共存。在本文中，我表明，种内竞争的不利影响与自我组织的促进性之间的相互作用形成了一种共存机制，该机制不依赖于特定物种的假设，并且可以在广泛的环境压力梯度中捕获共存。我使用一种理论模型捕获了两个通用消费物种与一个显式建模资源的相互作用，以表明共存依赖于物种定殖能力与其本地竞争力之间的平衡，前提是种内竞争足够激烈。至关重要的是，对于物种共存的自我限制的要求在资源投入范围的相反两端是不同的。对于低资源水平，拥有强大的定居能力的物种具有较强的种内动态，从而促进了共存，但是对于大量的资源投入而言，本地优势物种的强大的种内竞争可以实现共存。本文介绍的结果还强调了滞后在理解临界点（尤其是灭绝事件）中的重要性。最后，该理论框架提供了对单个斑块内空间物种分布的见解，支持了关于旱地植被模式中草本和木本物种共存的口头假设，并提出了在其他模式生态系统背景下的潜在经验检验。本文介绍的结果还强调了滞后在理解临界点（尤其是灭绝事件）中的重要性。最后，该理论框架提供了对单个斑块内空间物种分布的见解，支持了关于旱地植被模式中草本和木本物种共存的口头假设，并提出了在其他模式生态系统背景下的潜在经验检验。本文介绍的结果还强调了滞后在理解临界点（尤其是灭绝事件）中的重要性。最后，该理论框架提供了对单个斑块内空间物种分布的见解，支持了关于旱地植被模式中草本和木本物种共存的口头假设，并提出了在其他模式生态系统背景下的潜在经验检验。