Scientists with Inland Fisheries Ireland (IFI) are replicating natural wood structures in Irish rivers to help nurture salmon, trout and lamprey.
The wood used is sourced from near rivers and includes trees that have fallen close to the channel, diseased trees expected to fall and non-native species growing along the banks.
Fiona Kelly, head of research, policy and risk at IFI said: “Reintroducing large wood back into rivers is increasingly used as a restoration approach in other countries.
“IFI’s new RiverWood project will provide important insights into the ecological value of large wood in Irish rivers, and its effectiveness as a habitat restoration tool for key species.
“The project will capture stakeholder perceptions and experiences of large in-stream wood in developing management guidance that balances ecological and societal needs.
“It will also highlight potential conflicts between ‘messy’ ecologically healthy rivers and the poor-quality habitat found in straight, tidy channels created by human engineering.”
In their natural state, many rivers are bordered by forests that deliver large amounts of woody material into the channel as fallen trees. This in turn shapes diverse habitats, resulting in high biodiversity and resilience to disturbance.
The potential benefits to fish from reintroducing large wood into rivers include:
- Providing reef-like structures that act as foraging locations
- Providing refuge from predators
- Giving protection from low summer water flows or high winter floods
- Improved habitat complexity to support spawning and the development of fish species through their life cycle
Project locations include rivers in Dublin, Meath and Wicklow, tributaries of Lough Corrib in Co Galway and the Ballisodare River in Co Sligo.
In partnership with Coillte, IFI has already completed habitat restoration works in the River Vartry at Devil’s Glen, Co Wicklow and on a tributary of the River Boyne in Co Meath. These target rivers are home to important populations of brown and sea trout, salmon and lamprey.
IFI, together with UCD staff, is monitoring fish species’ response to the restoration measures.
This RiverWood project is financed by the EPA Research Programme, and collaborations are taking place with Coillte, private landowners, the OPW, and South Dublin County Council.
