Animals and plants engineer their physical environment by building structures that create or modify habitat. Biotic effects on physical habitats can influence community composition, trophic dynamics, and ecosystem processes; however, the scales and mechanisms regulating the importance of biotic engineering effects are not well documented. We used a laboratory experiment with common and abundant silk net-spinning caddisflies (Trichoptera:Hydropsychidae) to investigate how biotic structures built in riverbeds influence fluid dynamics at micro spatial scales (1 cm) over 2 months. We made velocity measurements with acoustic doppler velocimetry around caddisfly silk structures to test how they influence flow velocity and whether these effects are maintained after the structure is abandoned. We found that caddisfly retreats reduced flow downstream by 85% and upstream by 17% compared to gravels without caddisfly retreats. We also found that experimentally abandoned caddisfly retreats could persist for at least 60 days, suggesting legacy effects of the structures. Although aquatic insects are rarely accounted for in hydrological models, our study suggests that small, but numerous caddisfly larvae could have substantial hydraulic effects. Future work could address variation in the magnitude and duration of biotic engineering among different silk-producing species, densities through space or time, and hydrologic regimes.

中文翻译：

---

退却不投降：网纺石蚕（Hydropsychidae）丝对河道水力学具有持久影响

动物和植物通过建造创造或改变栖息地的结构来设计它们的物理环境。生物对自然栖息地的影响会影响群落组成、营养动态和生态系统过程；然而，调节生物工程效应重要性的尺度和机制并没有得到很好的记录。我们使用常见且丰富的丝网纺石蛾（毛翅目：Hydropsychidae）实验室实验来研究在 2 个月内建立在河床中的生物结构如何影响微观空间尺度（1 厘米）的流体动力学。我们使用声学多普勒测速仪在 caddisfly 丝结构周围进行了速度测量，以测试它们如何影响流速以及在放弃结构后这些影响是否仍然存在。我们发现，与没有石蝇撤退的砾石相比，石蝇撤退使下游的流量减少了 85%，上游减少了 17%。我们还发现，实验性废弃的石蛾撤退可以持续至少 60 天，表明这些结构的遗留影响。尽管在水文模型中很少考虑水生昆虫，但我们的研究表明，虽然数量不多但数量众多的石蛾幼虫可能具有显着的水力效应。未来的工作可以解决不同产丝物种之间生物工程的大小和持续时间、空间或时间密度以及水文状况的变化。尽管在水文模型中很少考虑水生昆虫，但我们的研究表明，虽然数量不多但数量众多的石蛾幼虫可能具有显着的水力效应。未来的工作可以解决不同产丝物种之间生物工程的大小和持续时间、空间或时间密度以及水文状况的变化。尽管在水文模型中很少考虑水生昆虫，但我们的研究表明，虽然数量不多但数量众多的石蛾幼虫可能具有显着的水力效应。未来的工作可以解决不同产丝物种之间生物工程的大小和持续时间、空间或时间密度以及水文状况的变化。