Habitat Degradation
When we surveyed the upper Wye in 1995/6 we found that the tributaries were no longer in a sufficiently good state to produce the densities of juvenile fish stocks of former years. A huge increase in animal stocking densities had taken place since the early 1980's and the historic practice of coppicing had ceased many decades earlier. Overgrazing and poaching by sheep and cattle destabilised the riverbanks and denuded the riparian vegetation, causing streams to widen and become shallow. Combined with heavy shading as a result of overgrown multistem alders, fish densities in the majority of tributaries streams were only 20% of their potential and Rannunculus weed had disappeared completely from sites where it had been abundant.
We were not surprised to find large parts of the Usk in a similar condition when we surveyed the catchment in 2004 and again in the Lugg and Arrow in 2006. For further details of this work please see the sections on UP! , Phish and WHIP and Lugg and Arrow projects.
The remedy is to fence out stock, coppice over-shaded sections and repair accelerated erosion. With over 1000km in the catchments, our resources need very careful targeting. Research by O' Grady and others suggest that fully restored habitats can very significantly increase survival rates of salmon and trout.
Severe habitat degradation, mostly through bank erosion and over shading, along with pollution from abandoned cars had led to the Llynfi Dulas, an upper Wye tributary, becoming almost uninhabitable for juvenile fish. Just one year after the completion of restoration work in 2003 the stream started to revert back to its natural state and is now one of the more productive in the Wye system.
2007 - Foundation revetment work to correct severe erosion problems on the River Lugg, a few miles upstream of Mortimers Cross.
The results of revetment work by the Foundation on the Clywedog, an upper Wye tributary.
