Inland Fisheries Ireland (IFI ) scientists are replicating natural wood structures in Irish rivers, including in Galway, 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.
Project locations include rivers in tributaries of Lough Corrib in Co. Galway; as well as in Dublin, Meath and Wicklow; and the Ballisodare river in Sligo.
Potential benefits to fish from reintroducing large wood into rivers includes the provision of:
Reef-like structures that act as foraging locations;
Refuge from predators;
Protection from low summer water flows or high winter floods;
Improved habitat complexity to support spawning;
Improved habitat complexity to support the development of fish species through their life cycle.
Fiona Kelly, Head of Research, Policy and Risk at IFI commented: “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 instream 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.”
IFI, in partnership with Coillte, has already completed habitat restoration works in the River Vartry, Devils Glen, Co. Wicklow, and on a tributary of the River Boyne, Co. Meath.
The 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.
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.
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.
