Welsh Beaver Project
Alicia Leow-Dyke, Welsh Beaver Project Officer with Wildlife Trusts Wales attended the launch of Pembrokeshire Rivers Trust’s “Adopt-A-Riverbank” project at Treffgarne Angling Centre on 30th April 2016. She presented information about the state of the current European beaver projects in other parts of the UK – both deliberate along the West Coast of Scotland with the licensed reintroduction trial at Knapdale, and unintended along the River Tay, and the River Otter in Devon, which is now a licensed reintroduction trial.
According to Alicia, research in Norway and elsewhere has generally shown that beavers improve river catchments for fish, by increasing invertebrate life, slowing down the flow of water, trapping silt and pollution, and creating refuges (pools) etc. It is likely that any problems caused by beavers will be relatively small compared to those long-term problems that have led to the decline of migratory fish runs since well after the beaver was killed off in the UK. The negative effects would be more localised – i.e. beavers might construct dams which pose a barrier to migrating fish in low-water conditions, or they may construct them in spawning areas. The important message to get across here is that beaver dams can be removed (and often are in flash floods), and any beaver reintroduction in Wales would include a mitigation strategy for such incidents, whereby problem dams could be removed by the statutory body or local Wildlife Trust, or advice given so that landowners or angling groups can remove the obstructions themselves. This is a model that has been successfully employed in other countries where beavers are present and they can be found living alongside thriving angling industries, such as in Norway and North America. Beavers and salmonids evolved alongside each other and coexisted successfully for millennia. If we reintroduce the beaver we are helping to restore the sort of habitat in which salmonids once thrived.
Beavers are strictly herbivorous. They do not eat fish and the evidence so far is that they help indigenous brown trout in particular with breeding. Research is currently being conducted on migratory fish in Scotland and the results so far are proving positive. If gravel beds are cleaner and less silted as a result of upstream beaver activity, it may be that this will also help migratory fish. Anglers are naturally anxious not to make already threatened fishing worse – particularly on migratory rivers, and the debate will continue. Possibly a pilot reintroduction will occur on smaller less fished streams. Beavers do breed and will spread through catchments (and in the very long-term, across catchments) so this is an important debate – whether to reintroduce a former native species. However, population growth and expansion rates of beavers are slow and it can take decades before there is any noticeable expansion of beaver populations. Beavers tend to move along banks, staying within 20 meters of a waterway, and coppicing the trees on the banks before moving on. Riverside corridors of vegetation will help both beavers and agricultural run-off, and will be naturally coppiced in cycles by any beavers present in any occupied territory. If over time beavers began to cause problems within any catchment, management would need to occur including lethal control as a last resort. The population size in a catchment river system is naturally capped by habitat availability, which is determined by the abundance of food and suitable habitat conditions, such as water depth and speed of water.
Noxious weeds are an interesting aspect and beavers may assist in the control of non-native invasive plant species; using rhododendron stems in the construction of their lodges and dams and eating Himalayan balsam. A few years ago a beaver kit in Scotland was spotted eating Japanese knotweed. North American beavers also eat skunk cabbage.
Article written by Dr R Burns & Alicia Leow-Dyke
(The photo shows a portly, somewhat over-stuffed beaver.)
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