Theory predicts that species engaged in intraguild predation (IGP) can only coexist under limited conditions, yet IGP is common in nature. Habitat complexity can promote coexistence by reducing encounter rates, but little information is known about the contribution of differential habitat use. We hypothesized that differential use of alternative habitats promotes coexistence of an intraguild (IG) predator and prey. We evaluated predictions of this hypothesis with an experimental introduction of an IG predator fish into four natural stream communities that previously contained only the IG prey fish. We monitored the development of this IGP over the course of four years to determine how each species used alternative stream habitats. The introduced species preferred pool habitats while the resident species was more evenly distributed across pools and riffles. The density of the resident decreased in the pool habitat preferred by the invader, accompanied by a local increase in the mean of the resident size distribution. Selective predation by the invader on hatchling residents appears to impact the residents’ demographic response. The continued recruitment of resident juveniles in riffles, where the introduced species is rare, facilitated the persistence of the resident. This differential use of habitats was not accompanied by a change in the resident’s growth rates in either habitat. Our results showed that differential habitat selection and recruitment promoted persistence during an invasion involving IGP, which helps to bridge the gap between theory and observation in explaining coexistence in IGP systems.

中文翻译：

---

不同的栖息地使用和招募促进了公会内部捕食的社区共存

理论预测，从事行内捕食（IGP）的物种只能在有限的条件下共存，而IGP在自然界中很常见。栖息地复杂性可以通过降低遭遇率来促进共存，但关于不同栖息地利用的贡献的信息知之甚少。我们假设对替代栖息地的不同使用促进了公会内 (IG) 捕食者和猎物的共存。我们通过将 IG 捕食鱼实验性地引入四个以前仅包含 IG 猎物鱼的自然溪流群落来评估对这一假设的预测。我们在四年的时间里监测了这个 IGP 的发展，以确定每个物种如何使用替代溪流栖息地。引入的物种更喜欢水池栖息地，而常驻物种更均匀地分布在水池和浅滩上。在入侵者偏好的水池栖息地中，居民的密度下降，同时居民规模分布的平均值局部增加。入侵者对孵化居民的选择性捕食似乎影响了居民的人口反应。在引进的物种很少见的浅滩中继续招募常驻少年，促进了常驻的持久性。这种对栖息地的不同利用并未伴随居民在任一栖息地的增长率的变化。我们的研究结果表明，在涉及 IGP 的入侵期间，不同的栖息地选择和补充促进了持久性，