To effectively monitor, manage and protect aquatic species and understand their interactions, knowledge of their spatiotemporal distribution is needed. In this study, we used a fine-scale spatiotemporal water sampling design, followed by environmental DNA (eDNA) 12S metabarcoding, to investigate occupancy patterns of a natural community of fish and amphibian species in a lentic system. In the same system, we experimentally estimated the spatial and temporal dispersion of eDNA by placing a community of different fish and amphibian species in cages at one side of the pond, creating a controlled point of eDNA emission. Analyses of this cage community revealed a sharp spatial decline in detection rates and relative eDNA quantities at a distance of 5–10 m from the source, depending on the species and its abundance. In addition, none of the caged species could be detected 1 week after removal from the system. This indicates high eDNA decay rates and limited spatial eDNA dispersal, facilitating high local resolution for monitoring spatial occupancy patterns of aquatic species. Remarkably, for seven of the nine cage species, the presence of a single individual could be detected by pooling water of subsamples taken across the whole water body, illustrating the high sensitivity of the eDNA sampling and detection method applied. Finally, our work demonstrated that a fine-scale sampling design in combination with eDNA metabarcoding can cover total biodiversity very precisely and allows the construction of consistent spatiotemporal patterns of relative abundance and local distribution of free-living fish and amphibian species in a lentic ecosystem.

中文翻译：

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使用环境 DNA 监测静水水生系统中鱼类和两栖动物物种的时空占有模式

为了有效监测、管理和保护水生物种并了解它们的相互作用，需要了解它们的时空分布。在这项研究中，我们使用了精细尺度的时空水采样设计，然后是环境 DNA (eDNA) 12S 元条形码，以研究 lentic 系统中鱼类和两栖动物物种的自然群落的占用模式。在同一系统中，我们通过将不同鱼类和两栖动物群落放置在池塘一侧的网箱中来实验估计 eDNA 的空间和时间分散，从而创建 eDNA 发射的受控点。对该网箱群落的分析显示，在距源 5-10 m 的距离处，检测率和相对 eDNA 数量在空间上急剧下降，具体取决于物种及其丰度。此外，从系统中移除 1 周后，没有检测到任何笼养物种。这表明高 eDNA 衰减率和有限的空间 eDNA 扩散，促进了用于监测水生物种空间占用模式的高局部分辨率。值得注意的是，对于九个网箱物种中的七个，可以通过汇集整个水体中采集的子样本的水来检测单个个体的存在，这表明所应用的 eDNA 采样和检测方法具有高灵敏度。最后，我们的工作表明，与 eDNA 元条形码相结合的精细采样设计可以非常精确地覆盖总生物多样性，并允许构建一致的时空模式，即在静水生态系统中自由生活的鱼类和两栖动物物种的相对丰度和局部分布。