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Nature recovery

2 Letting nature lead

2.1 Case study



When dead wood is left in rivers, it serves as a vital component of the ecosystem by providing resting and observation spots for birds and dragonflies, as well as egg-laying sites for insects, fish, snails, and dragonflies. It forms the base of complex food webs that include myriad wildlife species, such as diatoms, insect larvae, fish, ospreys, herons, and otters.

Bryozoans (simple aquatic invertebrates), sponges, and caddisflies attached to the wood enhance water quality. Deadwood offers numerous hiding places for young fish and helps to create variation in the river bed.

An illustration depicting the ecological role of riparian woody debris (dead trees in rivers) as a foundation for aquatic and terrestrial ecosystems. The image shows a submerged tree in a river, surrounded by diverse species such as pike, nose carp, otter, and kingfisher. Smaller organisms like diatoms, midge larvae, caddis worms, and bryozoan colonies are attached to or near the debris. Juvenile fish use the debris for shelter, while insects and birds rest and lay eggs above the water. Text explains how the debris supports food chains, provides attachment surfaces for plants and animals, filters water, and influences sediment deposition.

The key role of dead trees in rivers. Credit: Jeroen Helmer / ARK Rewilding Netherlands.

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