Am Nat. 2022 Aug;200(2):193-201. doi: 10.1086/720269. Epub 2022 Jun 27.
AbstractResource competition theory predicts coexistence and exclusion patterns based on species' *s, the minimum resource values required for a species to persist. A central assumption of the theory is that all species have equal access to resources. However, many systems are characterized by preemption exploitation, where some species deplete resources before their competitors can access them (e.g., asymmetric light competition, contest competition among animals). We hypothesized that coexistence under preemption requires an *-preemption trade-off-that is, the species with the priority access should have a higher * (lower "efficiency"). Thus, we developed an extension of resource competition theory to investigate partial and total preemption (in the latter, the preemptor is unaffected by species with lower preemption rank). We found that an *-preemption trade-off is a necessary condition for coexistence in all models. Moreover, under total preemption, the trade-off alone is sufficient for coexistence. In contrast, under partial preemption, more conditions are needed, which restricts the parameter space of coexistence. Finally, we discuss the implications of our finding for seemingly distinct trade-offs, which we view as special cases of the *-preemption trade-off. These trade-offs include the digger-grazer trade-off, the competition-colonization trade-off, and trade-offs related to light competition between trees and understories.
摘要资源竞争理论基于物种的最小资源值（维持物种生存所需的最低资源值）预测共存和排斥模式。该理论的一个核心假设是所有物种都平等地获得资源。然而，许多系统的特征是抢占性开发，其中一些物种在其竞争对手能够获得资源之前就耗尽了资源（例如，不对称的光竞争，动物之间的竞争竞争）。我们假设，在抢占性开发下的共存需要一种 *-抢占权衡-也就是说，具有优先访问权限的物种应该具有更高的 （更低的“效率”）。因此，我们开发了资源竞争理论的扩展版本来研究部分和完全抢占（在后一种情况下，抢占者不受抢占等级较低的物种的影响）。我们发现， - 抢占权衡是所有模型中共存的必要条件。此外，在完全抢占的情况下，权衡本身足以共存。相比之下，在部分抢占的情况下，需要更多的条件，这限制了共存的参数空间。最后，我们讨论了我们的发现对看似不同的权衡的影响，我们认为这些权衡是 *-抢占权衡的特殊情况。这些权衡包括挖掘者-食草动物权衡、竞争-殖民化权衡，以及与树木和林下层之间的光竞争相关的权衡。
