Department of Biology, McGill University, 1205 Docteur Penfield, Stewart Biology Building, Montreal, Quebec, Canada.
School of Biological and Behavioural Sciences, Queen Mary University of London, Fogg Building, Mile End Road, London, UK.
Proc Biol Sci. 2023 Sep 13;290(2006):20230841. doi: 10.1098/rspb.2023.0841.
Aquatic ecosystems offer a continuum of water flow from headwater streams to inland lakes and coastal marine systems. This spatial connectivity influences the structure, function and dynamics of aquatic communities, which are among the most threatened and degraded on the Earth. Here, we determine the spatial resolution of environmental DNA (eDNA) in dendritic freshwater networks, which we use as a model for connected metacommunities. Our intensive sampling campaign comprised over 420 eDNA samples across 21 connected lakes, allowing us to analyse detections at a variety of scales, from different habitats within a lake to entire lake networks. We found strong signals of within-lake variation in eDNA distribution reflective of typical habitat use by both fish and zooplankton. Most importantly, we also found that connecting channels between lakes resulted in an accumulation of downstream eDNA detections in lakes with a higher number of inflows, and as networks increased in length. Environmental DNA achieves biodiversity surveys in these habitats in a high-throughput, spatially integrated way. These findings have profound implications for the interpretation of eDNA detections in aquatic ecosystems in global-scale biodiversity monitoring observations.
水生生态系统提供了从源头溪流到内陆湖泊和沿海水域系统的连续水流。这种空间连通性影响着水生群落的结构、功能和动态，而水生群落是地球上受威胁和退化最严重的群落之一。在这里，我们确定了树枝状淡水网络中环境 DNA (eDNA) 的空间分辨率，我们将其作为连接的复合群落的模型。我们的密集采样活动包括在 21 个相连的湖泊中采集了超过 420 个 eDNA 样本，使我们能够在多种尺度上分析检测结果，从一个湖泊内的不同栖息地到整个湖泊网络。我们发现，eDNA 分布的湖泊内变化具有很强的信号，反映了鱼类和浮游动物的典型栖息地利用情况。最重要的是，我们还发现，湖泊之间的连接通道导致流入湖泊的下游 eDNA 检测积累，而随着网络长度的增加，这种情况也会增加。环境 DNA 以高通量、空间综合的方式在这些生境中进行生物多样性调查。这些发现对在全球生物多样性监测观测中解释水生生态系统中的 eDNA 检测结果具有深远的影响。
