Mitigation and Management
Beavers aren't problem free but the majority of these problems can be mitigated using the practical solutions below.We appreciate that sometimes beaver come into conflict with human land use and mitigation may be needed. However, in the majority of circumstances, mitigation can take place to solve issues so that beavers and humans can live in harmony. In the rare circumstances that mitigation does not work then translocation should be the next protocol. The Scottish Wild Beaver Group believes the ban on translocation outside their current natural range should be lifted so that we can take advantage of the 105,586ha of potential core beaver habitat as outlined by Nature Scot. Lethal control should only be an option as a very last resort.
Common Issues and their mitigation
Damage caused by fluctuations in water levels
Issues
In areas where beavers have created dams, average water levels are often changed from their pre-dammed states. This can create new and extremely important habitats, slow down downstream flows in times of high rainfall, reduce drought extremities and create breeding habitats for fish such as salmon. However, when in close vicinity of human land use there can be issues of flooding immediately above a dam where a beaver pond has been created and water levels have risen. Other issues can arise when dams break, increasing the possibility of floods downstream.
Mitigation
A simple short-term solution to impacts from beaver dams are to remove them, releasing water up stream and allowing water levels to return to their previous state. However, the term “busy beaver” doesn’t come lightly, as a beaver may rebuild a dam within days. In these circumstances a pond leveller or beaver deceiver can be used as a long-term solution to alleviate issues that come about due to water level fluctuations. A simple pipe is places through the beaver dam running 10ft on either side of the dam. This allows water to pass freely through the dam, whilst tricking the beavers into thinking their dam is sufficient as they do not hear or see any breaks or flows in the dam.
Ring barking and felling of trees
Issues
Seen by some as the creation of an “untidy” riverbank, it is no secret that beavers can and will gnaw at and fell trees. It is understandable that landowners may not want certain trees to be damaged in such ways and tree felling can also lead to accidental property damage. However, if beavers have already ring-barked any trees to the extent that the trees are dead, the upside of this is that they will provide wonderful habitat for woodpeckers, owls and many other species. Large standing deadwood is an important but rare habitat in Scotland.
Mitigation
To prevent damage to trees, mitigation can be put in place using often cheap and simple techniques. Trees can be wrapped in wire mesh, reaching 1 metre up the tree. This leaves space for the tree to breathe and grow but prevents beavers from doing any damage. Alternatives include painting trees with sand and PVA glue, a good deterrent that puts beavers of gnawing at the bark. We have found that certain trees, such as beech are surprisingly robust and protection may work even after a substantial amount of bark has been stripped.
Riverbank damage and the re-meandering of rivers
Issues
It is not always the case that beavers build their homes in large visible dams made of wooden debris on the water’s edge or in a flooded margin. Beavers are also incredible diggers and will build a burrow within the side of a riverbank with an entrance below the average water level. Over time, and especially where heavy external land pressures are apparent, for example from farming machinery, burrows may collapse in on themselves. This can lead to increased sediment in the water for a brief period but also damage to the riparian land, which may include private or commercial land. Also, due to the effect beavers have on hydrology in certain areas when creating habitats, rivers can begin to re-meander. Although this is more beneficial from an ecological and hydrological sense, this can have impacts on commercial land, where land use has been fixed around a straight river system.
Mitigation
Unfortunately, this can be one of the more tricky situations to try and manage. However, there are still options. In the short term, beavers can be translocated from “conflict areas” so that rivers can stay straight and fast flowing. But the real success is when we learn to live alongside beavers. From studies across the globe, it is evident that when you give beavers breathing space, sometimes as low as 5 meters from the water’s edge, over 90% of issues can be fixed. There are also numerous countries that encourage landowners to bring beavers onto their land through initiatives and compensation schemes. In some cases, once infertile riparian land can be more profitable to landowners when given back to the beaver, improving water quality, water and carbon storage and biodiversity.
Slowing down migrating fish species
Issues
Contrary to the belief of some, beaver dams do not halt the migration of fish. Beaver dams have adapted and evolved alongside migrating fish for centuries and so although we agree this may impact the speed of migration, fish will not be halted in reaching their goal. In fact, studies find that many species of fish actually improve in beaver enriched habitats.
Mitigation
In certain areas where fish migration may need to be prioritised, fish steps can be installed into beaver dams. By creating small pools for fish to jump and rest whilst ascending a beaver dam, the effects of blockage can be reduced.
Parasite risk
Issues
There is a very small chance that one of the handful of imported beavers to Scotland could have carried the parasite Echinococcus multilocularis. However, all screened beavers seemed to carry no evidence of this parasite. Consequently, since 90% of the Tay beavers were born in Scotland they will be guaranteed free from this parasite. For updated information on the parasite risk and health of Scottish beavers click here.
Mitigation
This parasite was carefully risk assessed by experts and a strategy for further risk reduction has been agreed upon.
The parasite, which cycles between rodents and canids cannot be passed directly from beavers to humans. This risk occurred as a result of lack of knowledge in the past when beavers were brought legally into the UK and quarantined for use in zoos, wildlife parks etc. The Scottish Government scientists have already advised the Ministry that culling the beavers, for this reason, is not appropriate
The North Americans have a great deal of experience in this field and the Martinez Beavers website is one of the best on this topic. As problems arise in Scotland, we will post photographs of the solutions that we have used.
If you plan to protect your own trees through wire mesh, ensure that the wire goes one metre up the trunk and is secured at the top. Otherwise the beaver may stand on its hind legs and reach up to pull the wire down! (Remember that they may be helped in this venture when snow raised the ground level.) It is best to secure it to a post knocked in next to the tree, to avoid marking the tree, and to prevent the wire getting embedded in the tree as it grows.
Simple and effective way to protect trees from damage