Freshwater connectivity transforms spatially integrated signals of biodiversity

Abstract

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 earth. Here, we determine the spatial resolution of eDNA in dendritic freshwater networks, which we use as a model for connected metacommunities. Our intensive sampling campaign comprised over 430 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.Raw sequence files are .gz format; can be opened with WinZip or similar. R and R studio for opening statistical analysis scriptsFunding provided by: Canada Research ChairsCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100001804Award Number: 230517Funding provided by: Canada Research ChairsCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100001804Award Number: 237170Funding provided by: MitacsCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100004489Award Number: IT08003Funding provided by: Quebec Centre for Biodiversity Science *Crossref Funder Registry ID: Award Number: Funding provided by: WSP Montreal Environment Department *Crossref Funder Registry ID: Award Number: Funding provided by: Natural Sciences and Engineering Research Council of CanadaCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100000038Award Number: 2016-04016Funding provided by: Natural Sciences and Engineering Research Council of CanadaCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100000038Award Number: 04331-201