The movement of water between freshwater bodies can transport eDNA

This highlights the potential of eDNA to provide a comprehensive view of freshwater biodiversity.

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The water flow in aquatic habitats ranges from headwater streams to inland lakes and coastal marine systems. The structure, operation, and dynamics of aquatic communities—some of the planet’s most endangered and damaged ecosystems—are influenced by this spatial connection.

A new study determined the spatial resolution of environmental DNA (eDNA) in dendritic freshwater networks, which scientists used as a model for connected metacommunities. Scientists used environmental DNA (eDNA) metabarcoding to analyze fish and zooplankton communities.

The study discovered that freshwater connectivity—water movement between freshwater bodies—can carry eDNA. This demonstrates how eDNA has the potential to offer a thorough picture of freshwater biodiversity.

The study was conducted at the IISD Experimental Lakes Area in Canada’s Boreal Forest. Dr. Joanne Littlefair, a lecturer in biological sciences at Queen Mary University of London, directed it. It examined three lake networks with a total of 21 lakes. The researchers discovered that while some eDNA was carried into downstream lakes, most within-lake eDNA primarily represented the species’ environmental preferences. There were more eDNA detections in lakes with higher connectivity levels that could not be accounted for by standard monitoring methods.

Dr Littlefair said, “eDNA can be used to detect the presence of species that are not easily monitored using conventional methods, including invasive species, or for monitoring the presence of rare or endangered species.”

“But it’s not all bad news. Our study showed that eDNA surveys can be carefully designed to consider the connectivity of the freshwater system being studied. In systems with high levels of connectivity, collecting samples from multiple locations is important, which will allow us to build a complete picture of the present biodiversity.”

The results have implications for using eDNA to track biodiversity in freshwater ecosystems. While eDNA is a promising technique for monitoring biodiversity, data must be evaluated in the context of landscape connectivity.

The study also emphasizes the need for greater investigation into the elements influencing the spatial resolution of eDNA detection, such as the impacts of water movement. For instance, it could be necessary to gather more samples if the water in an environment moves swiftly to enhance the likelihood of finding eDNA. This study will advance our knowledge of how eDNA can be utilized to monitor and protect aquatic biodiversity.

Journal Reference:

  1. Joanne E. Littlefair, Jase Hleap, et al. Freshwater connectivity transforms spatially integrated signals of biodiversity. Proceedings of the Royal Society B. DOI: 10.1098/rspb.2023.0841
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