Environmental DNA at Capeenpuro – A Major Opportunity for the Benefit of Stream Ecosystems

Monitoring the biodiversity of streams is a key part of practical nature conservation and the sustainable management of aquatic ecosystems. Traditionally, fish population monitoring has been conducted through methods such as test netting and electrofishing, both approaches being labor-intensive and can disturb sensitive or endangered species.

At Capeenpuro and Juurikkapuro in Laukaa, a new approach has been introduced alongside traditional methods: the state of fish populations is being monitored using environmental DNA (eDNA). Puro Analytics is responsible for the monitoring studies, employing advanced eDNA methods that enable efficient mapping of species without disturbing the environment.

Background of the Capeenpuro Project

Capeenpuro is a former water intake channel for a fish farm that has been undergoing naturalization since 2020, transforming it into a near-natural stream ecosystem. The main goal of the project is to improve habitat conditions for the endangered lake trout (Salmo trutta lacustris) and to create a thriving stream environment that also supports broader biodiversity.

The main funder of the project is the R. Erik and Bror Serlachius Foundation, which also owns the land in the restoration area. Additional support comes from the Centre for Economic Development, Transport and the Environment of Central Finland (ELY Centre), the University of Jyväskylä, the University of Helsinki, the Finnish Environment Institute, and the Finnish Freshwater Foundation. One of the key aims of the project is to monitor how quickly nature recovers and when trout and other stream-dwelling species begin to spread into the newly created, human-made stream channel.

The Capeenpuro project is unique in many ways. It is hoped to serve as an example for other stream restoration efforts and to inspire various stakeholders to improve the condition of valuable aquatic habitats.

What Is Environmental DNA and Why Is It Ideal for Monitoring Biodiversity?

Environmental DNA (eDNA) refers to genetic material that organisms leave behind in their surroundings for example, in skin cells, mucus, feces, or other biological traces. This DNA can be collected from the environment without the need to capture or directly observe the organisms themselves. By processing the samples in a laboratory and applying bioinformatics, a comprehensive picture of the species present in an area can be formed.

Puro Analytics uses a metabarcoding sequencing approach, which allows the identification of hundreds of species from a single eDNA sample. The method is fast, accurate, cost-effective, and environmentally friendly.
The use of environmental DNA is not limited to streams as it can be applied to monitor nearly all groups of organisms across diverse environments, from forests and wetlands to marine areas. eDNA technology thus opens a new era in biodiversity monitoring.

How the Monitoring Is Conducted at Capeenpuro and Juurikkapuro

During 2025, three rounds of environmental DNA sampling will be carried out in Capeenpuro. The first samples were collected in April and are being analyzed through metabarcoding to identify all fish species in the area. The next sampling rounds are planned for autumn and early winter.

eDNA monitoring has also been expanded to Juurikkapuro, which is a previously dammed stream west of Capeenpuro. Here, the fish community is being surveyed before restoration work begins, providing valuable baseline data that will make it possible to evaluate how the aquatic life changes as a result of the restoration.

First results have been analyzed during the summer 2025, and Puro Analytics will continue monitoring throughout the year, aiming to establish environmental DNA as a standard method for long-term monitoring in stream restoration projects. This enables a continuous, reliable, and cost-efficient way to assess restoration impacts over time.

Conclusion

Capeenpuro is an excellent example of how traditional restoration techniques and modern environmental DNA technology can come together to support biodiversity.
The data collected, and the growing understanding of how species compositions change, make it possible to plan, target, and evaluate conservation actions more effectively.

Through environmental DNA, we can contribute to building more sustainable, evidence-based solutions that promote the recovery and preservation of biodiversity for future generations.