Data from: Tradeoffs and coexistence in fluctuating environments: evidence for a key dispersal-fecundity tradeoff in five nonpollinating fig wasps

The ecological principle of competitive exclusion states that species competing for identical resources cannot coexist, but this principle is paradoxical because ecologically similar competitors are regularly observed. Coexistence is possible under some conditions if a fluctuating environment changes the competitive dominance of species. This change in competitive dominance implies the existence of tradeoffs underlying species' competitive abilities in different environments. Theory shows that fluctuating distance between resource patches can facilitate coexistence in ephemeral patch competitors given a functional tradeoff between species dispersal ability and fecundity. We find evidence supporting this tradeoff in a guild of five ecologically similar nonpollinating fig wasps, and subsequently predict local among patch species densities. We also introduce a novel `colonization index' to estimate relative dispersal ability among ephemeral patch competitors. We suggest that a dispersal ability-fecundity tradeoff and spatiotemporally fluctuating resource availability commonly cooccur to drive population dynamics and facilitate coexistence in ephemeral patch communities.

竞争排斥原理（competitive exclusion principle）指出，为相同资源竞争的物种无法共存，但该原理看似存在矛盾——生态位相似的竞争者常被观测到共存。在部分条件下，若波动环境改变物种的竞争优势，物种便可实现共存。这种竞争优势的变化意味着，不同环境下物种的竞争能力背后存在权衡（tradeoff）。理论研究表明，若物种扩散能力与繁殖力之间存在功能权衡，那么资源斑块间的距离波动可促进短暂性斑块竞争者的共存。我们在包含5种生态位相似的非传粉榕小蜂（nonpollinating fig wasps）的同资源种团（guild）中，找到了支持该权衡的证据，并据此预测了斑块间物种的局部密度。此外，我们提出了一种全新的“定殖指数（colonization index）”，用以估算短暂性斑块竞争者间的相对扩散能力。我们认为，扩散能力-繁殖力权衡与时空波动的资源可利用性通常共同存在，以此驱动短暂性斑块群落的种群动态并促进物种共存。