Aspiration for a beaver recovery network

That some riparian environments on the Isle of Wight afford entirely suitable beaver habitat while in tandem others would provide for successful long-term colonisation.

The high degree of suitability would allow beavers from an unfenced release or series of releases on Trust reserves to colonise and establish the lower catchment, with permitted natural spread over time spreading the benefits of enhanced biodiversity and ecosystem service provision. This scenario could be successfully implemented in conjunction with well adopted beaver management strategies.

Existing collaborative partnership conservation and land-management projects on the Island already recognise and promote objectives such as managing scrub woodland, habitat connectivity, promotion of sustainable tourism, developing high value green spaces, woodland replanting and flood prevention. These activities all readily lend themselves to beaver reintroduction. 

This would shape a potential license application to Natural England to release beavers within the framework of a specified release strategy.

Hampshire & Isle of Wight Wildlife Trust have also been contributing to a national Wildlife Trust working group, representative of many Wildlife Trusts, with both existing and pending beaver projects. Part of the purpose of this group is to:
- Inform national-level engagement with government to clarify the legal status of beaver.
- To adopt a national beaver management framework.
- To explore ways of incentivising beaver presence and management within the new Environmental Land Management Scheme (ELMS).

The Beaver Trust has also been a close consultee of the Trust’s emerging plans and we are grateful for the support and advice provided to date.

In the Summer of 2021 a beaver recovery project officer for the Isle of Wight was appointed. Her first steps will be engaging the Island community and stakeholders about beavers and how important they are for restoring healthy wetland ecosystems. As part of this she will also be seeking local opinions to help inform our license application to reintroduce beavers to the Isle of Wight. 

The Eastern Yar is the largest river on the Island (24km) and is classed as being of moderate ecological quality. The catchment is typically lined by low willow scrub and interconnected by numerous drainage channels, floodplain grasslands and reedbed, much of which is owned or occupying by conservation organisations, notably Hampshire & Isle of Wight Wildlife Trust. We own 300 acres of linked land in the catchment that spans 4.5km of the river channel and consists of prime habitat suitable for a beaver release.  

While the ground water quality is classed as good, high levels of nitrogen and pesticide pollution can be an issue by the time the outflows reach the Solent, partly exacerbated by past modification to the river through built impoundments, dredging and drainage of the floodplain.

Newchurch Moors Nature Reserve was deemed to provide exceptionally good habitat for beaver. Within the reserve are a series of interconnecting freshwater ponds, heavily lined by woody vegetation including shrubby willow and range of mature tree species. These ponds also possess a good coverage and range of semi-emergent and aquatic plant species. All of which would provide beavers with rich, year-round forage, presenting a highly suitable release location.

With excellent resources for foraging and shelter creation, beavers could be readily released directly into the Eastern Yar where they might be expected to flourish. The long-term goal of this prospect would be to create a best practice example to promote both positive habitat restoration through beaver activity and to ensure a targeted approach to the selection of founder stock sufficient to maximise complete genetic diversity.

A keystone species is a species which plays a unique and critical role in the way an ecosystem functions, or in the structure and health of a habitat. The presence of keystone species determines the types and numbers of other species found in that environment. Without keystone species, the habitat is dramatically different, usually far less healthy, and in many cases, ceases to exist. An analogy is the keystone in a brick arch. If you remove the keystone then the arch collapses. When beavers were removed from Britain, the habitats they supported collapsed.

Beavers do modify the habitats and landscapes they live in through coppicing, feeding and in some cases damming (beavers living on lakes or large rivers have little need of constructing dams). In the first instance, these changes can markedly alter the appearance of the local environment but these modifications mostly have a positive effect on biodiversity.  

Beaver adaptations can bring enormous benefits to other species, including otters, water shrews, water voles, birds, invertebrates especially dragonflies, and breeding fish. In effect, beavers naturally create and maintain diverse habitats. Their dams can hold water in periods of drought, can regulate flooding and improve water quality by holding silt behind dams or onto the floodplain. They also provide an important role by intercepting acidic and agricultural run-off. 

Beavers forage close to water with activity usually concentrated within 20m of the water’s edge. Beavers do fell broad-leafed trees and bushes in order to eat the bark during the winter and to construct their lodges. Most trees will be coppiced and will regenerate, which diversifies the surrounding habitat structure. Coppicing has been practiced by foresters throughout history as a method to manage bankside trees. The actions of beavers are very similar meaning the woodlands will be naturally maintained. 

Beavers are a species that occasionally require the need for direct management intervention, if their activities result in undesirable localised flooding or tree felling. Any occasional problems are usually overcome by simple actions, such as overflow piping and electric fencing. In rarer instances beaver dam activity can be cleared, often forcing the beaver to move on. 

Evidence from Europe and elsewhere in the UK shows that beaver damage is, in the vast majority of cases, small-scale and localised. The presence of beavers across large parts of Europe has become more common place, including in farmed landscapes and more urban environments. Where beavers are considered a problem it is usually treated as a manageable issue with many effective techniques available. These include the removal of dams, the introduction of overflow piping, tree protection or the installation of fencing (as one does for deer and rabbits). 

Beavers rarely build dams in main rivers downstream where there is sufficient depth of water, and so many of the concerns about flooding are unfounded. However, in low lying floodplains where agricultural activities depend on land drains and deep ditches, beaver dams can have more significant impacts. They can obstruct culverts and “restore wetlands” in places that are not compatible with the existing land-uses and therefore create real, and perceived conflicts. In some cases mitigation measures will not be successful, and beavers may need to be moved on. 

Evidence from elsewhere in Europe shows that instances of beaver dams creating undesirable flooding are uncommon, localised and usually small-scale. In these situations dams are simply removed or pipes (‘beaver deceivers’) are placed through them to manage water levels. 

Beavers can make rivers less prone to flash floods, reducing flooding by holding water in ‘the right place’ in river headwaters, and enabling the slower release of water in drier periods. 

A project with the University of Exeter in the River Otter has studied the impacts of beavers on water flows and hydrology in great detail. The results are remarkable and show that beavers tend to decrease flooding overall. 

It is important to differentiate between the storage of water by beavers in river headwaters, and the impact of beavers on low lying land. In some places, culverts and drainage systems, some of which are critical to reducing flood risk, need to be kept clear of beaver debris. 

In order to create habitat for themselves, and to store water upstream, beavers need to temporarily and seasonally flood areas of land to create beaver ponds. This can be managed so that they do this in areas where flooding is wanted. 

Beavers are a native species to Britain and were lost from our wetlands a few hundred years ago. They were hunted to extinction for their fur, meat and castoreum. Many places derive their names from the presence or influence of beaver activity on the local areas. We have perhaps lost the recent cultural memory and association from living among these animals but many river catchments today still exhibit signs of beaver activity from hundreds of years prior. 

In Hampshire fossil evidence has been discovered on the Test & Itchen catchments ranging from Bronze Age to Medieval eras. Evidence is limited for the Isle of Wight but this should not be deemed as evidence of absence. The locality of the island to the mainland coupled with the once extensive floodplain wetlands that would have been prevalent, makes it likely that beavers would have been present. Furthermore, the beaver’s appeal to early human settlers and the island’s isolation would have made them susceptible to early extinction, relative to their mainland counterparts. The impact of early human arrival relating to the demise and extinction of many species has been well documented. 

A study on the economic impacts of the beaver by the University of Oxford's Wildlife Conservation Research Unit concluded that "with forethought, prior consultation and planning, a beaver reintroduction should bring significant monetary benefits within the local economy and communities that could greatly outweigh any potential negative impacts.” 

Research into the impact of beavers on the local economy around Knapdale Forest was carried out as part of the Scottish Beaver Trial and its results are currently being assessed by the Scottish Government. Local businesses reported an upturn in business due to interest in the Trial increasing visitor numbers to the area. There is also increasing evidence of growing beaver tourism to the River Otter in Devon. 

Beavers are entirely vegetarian (herbivorous) and don’t eat fish. Their presence is generally very positive for most fish species. The natural wetland habitats that beavers create often help to increase natural fish populations. 

Concern is expressed by some, about the ability of salmon and sea trout to get over dams. The science is stark in demonstrating that long term benefits generally outweigh any localised short term impacts. 

Natural woody material is a natural part of river systems and fish have migrated through these natural obstructions for millennia. Woody debris also provides essential cover for for fish of all sizes, as well as providing a ctitical habitat for invertebrates, which in turn provide prey for fish. Man-made obstructions to fish passage have a far greater impact on migrating fish populations. 

Beaver are entirely herbivorous, eating only plants and woody material.  Not just trees but they’ll be eating brambles and other plants too. They’re big fans of Himalayan balsam, which is an invasive non-native species that can spread easily and become problematic for our native wildflowers.  

In summer, beavers graze mostly on riverside plants and grasses. In winter they feed mostly on tree bark and shoots. They like to eat willow and aspen trees, and to a lesser extent, alder. They will take fruit trees (particularly apple) and poplar trees if these are close to watercourses. If required, these tress can be effectively protected. 

Beavers tend not to move far from fresh water so impacts are often very close to the riverbank, generally within 20m.  

Beavers coppice trees to create dams. Many of the trees beavers cut for damming, are species like willow which will grow and re-root where they are ‘planted’ by the beaver.  

Beavers have a definite preference for certain trees. Preferred tree species include alder, aspen, apple, birch, cherry, cottonwood, poplar and willow. Aspen/poplar and apple are their favourite. If the supply of their preferred trees is low they will harvest oaks and some maples. Conifers such as pines, hemlocks, etc. are their least favourite.  

Most native trees will naturally re-sprout when cut (coppicing). However, browsing by deer and livestock has a far more detrimental impact on regrowth. Special trees can easily be protected from beaver activity. 

Beavers are often known as eco-engineers, they are only doing what our team of reserve officers would be doing on our wetland reserves to provide the best habitat for wildlife, but they will be doing it far better than we can!  

There tends to be a large initial cut when beavers first arrive in their new enclosure, which can be alarming for some people to see. As beavers settle in for the first few months you may notice trees being cut as they build shelters and dams. Most of this is coppicing, so they will grow back and provide more spaces for wildlife.  Tree coppicing can look bare in winter, but that it will promote lush regrowth in the spring – a way of beavers helping to regenerate their own food supply. 

You may notice that beavers cut down more trees in late autumn. This is because they are stockpiling a food cache of sticks for the winter.  

Beavers are well adapted to water and evolved over millennia to use water as a defence from predators. While surprisingly fast over short distances, beavers do not like to travel too far from the water to cut down a tree, and most of the trees that beavers cut down are within 30 metres of the water.  

As beavers deplete the supply of food trees close to the pond’s edge they may raise the height of the beaver dam to bring the pond closer to more distant trees, or create a series of further dams to access other areas for foraging.  

Another engineering method beavers employ is to excavate canals from the pond in the direction of the trees they wish to harvest. Once a tree is toppled they are able to cut off and transport the branches easier and more safely to the pond using their canal. 

On main rivers or where there is adequate depth beavers do not typically build dams. Beavers tend to build dams to create lagoons in which they can better protect themselves from predators and in which they often build their family lodges which are accessed from underwater. The ideal depth of water a beaver seems to seek behind these dams is around 70cm (28”).   

Beavers create a mosaic of habitats, from small and large ponds, canals, vegetated margins, wet meadows and areas of mud and silt trapped behind dams. They are ecosystem engineers, and experts in wetland management, creating more diverse habitat for inhabitants, from the smallest invertebrates to large mammals. Evidence from across their European range is compelling in that beaver habitats are not only rich environments, but also support an array of rarer species. 

Beavers are herbivorous, so do not eat fish. Habitat modification by beavers, however, can have impacts on fish populations in some circumstances, and fisheries groups are often concerned about the potential impact of beaver dams on the movement of migratory fish. Beaver dams range from temporary to more permanent and influence conditions around them in a variety of ways. Typically beaver dams will create diverse bypass features enabling passage around the structures in many cases. Where beavers are deemed to be problematic management can be put in place to address the issue. 

Beaver activities may have both positive and negative impacts on different fish species, although migratory salmon and sea trout cause most concern. Beaver dams may act as barriers to migratory species in some years and cause localised siltation upstream of dams affecting spawning habitat. Understanding the overall impact is complex and it could be argued that further scientific assessment is required from an England context to quantify this effect. On the other hand, positive impacts may include an increase in habitat for fish rearing and overwintering, an increase in refuge areas during high and low flow periods and an increase in aquatic invertebrate prey species.  The balance of scientific literature weighs in favour of the benefits overall. 

Our aspiration is that the proposal for the Isle of Wight would support an open, wild beaver introduction. The details of this will be determined as the project progresses. The implementation plan might require a phase approach, inclusive of enclosed release for time period. 

This is yet to be determined. Most projects in England source their beavers from Scotland. 

Any beavers released are health checked by veterinarians to make sure that they do not carry any infectious parasites or diseases, and that they are fit for release both from a disease and a welfare perspective. This process is thorough and adhering to strict conditions required as part of any translocation programme. 

There is no evidence from Europe to suggest that Eurasian beavers carry bovine tuberculosis bTB. As most mammals can be infected by bTB it is theoretically possible for beavers to become infected if they are exposed in English landscapes. The risk is thought to be low. 

Beavers only breed at 2-3 years old, they breed once a year, and have an average of 3 kits. The kits are vulnerable to predation by foxes, birds of prey and maybe otters – so not all kits survive.  

When first released, adult beavers initially colonise relatively rapidly over large distances. Once territories are established, population numbers only rise slowly. Beavers live in strict family groups, with only the dominant pair breeding.  

Beaver numbers and the resources available to them will be monitored throughout the project to ensure animal welfare. If the territories become saturated, we may need to re-home older offspring several years down the line.  

Beavers live in burrows dug into river and pond banks. They also live in lodges built out of sticks and mud, which can be seen above ground. They are mostly nocturnal (they are active at night). They can be seen emerging or returning to their lodges at dusk and dawn, times when they are actively feeding, grooming and patrolling their territories.  

As part of our proposed Beaver release, we have a full time Beaver Recovery Project Officer. Should we be successful in our licence application their role will be to monitor and manage the beaver project and provide mitigation for potential beaver impacts where necessary.  For example, if the beavers started building dams in areas that may cause issues, a mitigation hierarchy would be employed to manage the dam and the beaver activity. This could be a range of options from dam modification to dam removal. This mitigation hierarchy forms part of the requirement for our licence application.

Beavers are very territorial so will self-regulate numbers with young beavers dispersing to find new territories. As carrying capacity is reached Beaver numbers will be managed where needed, with beavers caught and translocated to other areas if needed. Our potential release would be a carefully managed one as opposed to just leaving them to it and the Trust would commit to management in perpetuity. It is also worth noting that the North American beaver and European beaver are different species and have differing behavioural traits.

Any project looking to introduce/re-introduce a species requires a large amount of research and assessment. In 2020 the Trust commissioned a feasibility study to assess the suitability of the Island for a beaver release. This was carried out by the UK’s leading experts and the Isle of Wight was found to have highly suitable habitat and was deemed an excellent release area for beaver. This report looks at habitat suitability and dam capacity within the river catchments as well as a wide range of other factors. The Trust have enhanced this report with further data and supporting evidence.

Any release would require a licence from Natural England and we are currently working up the required information to submit an application for an open release.  A large amount of information is required and we are consulting with Isle of Wight residents, landowners, stakeholders and statutory bodies to determine views and opinions and to understand any concerns there may be. This will inform key aspects of the licence application around monitoring, beaver management and mitigation. Currently Natural England are not accepting Licence Applications whilst DEFRA are reviewing the Beaver Reintroduction and Management in England. We hope to be able to submit a licence application later this year.

In the future, we may look for locations in Hampshire that could benefit from Beavers.

We would ensure that Rights of Ways were protected and that we worked with people to ensure Beavers could live alongside our community in a way that is positive for both people and wildlife.

Any beavers released would be  health checked by veterinarians to make sure that they do not carry any infectious parasites or diseases, and that they are fit for release both from a disease and a welfare perspective. This process is thorough and adhering to strict conditions required as part of any translocation programme

We have no records or fossil evidence for when beavers were last present on the Island. But, there is evidence from both the Test and Itchen Rivers in Hampshire; The Island separated from the mainland about 7000 years ago, but prior to this the Island would have been covered with extensive wetlands so beaver would have been utilising habitats across the land mass that we now recognise as the Island. As with most Islands once separated large fauna were quickly eradicated by the actions of early settlers.  

It is worth stressing that the beaver is a native species to the UK and the strength of the species lies in its abilities as an eco-engineer and Keystone species. The potential for improvements for nature and benefits to people and local communities are huge. Beavers can happily co-exist alongside people as shown throughout Europe.

If Beavers were released we would stress that dogs are kept on leads in the areas where Beavers are present to avoid distressing them and other wildlife. We would encourage dog owners to keep their dogs out of the water to minimise disturbance to all wildlife. Many wetland species such as Water Voles, Beavers, and birds are highly sensitive to disturbance. By keeping your dog on a lead, you are much more likely to get a glimpse of some of these amazing species. Signage and more information will be available if our license application is successful. 

The Trust would like to carry out a wild release of beavers along the Eastern Yar catchment, where the Trust owns over 300 acres of floodplain along Newchurch Moors, Alverstone Mead, Sandown Meadows and Morton Marsh nature reserves. 

We would hope to introduce a few pairs along the lower Eastern Yar, to support a healthy and genetically diverse population to allow breeding. Beavers breed once a year, and typically have between 2 and 6 kits, averaging 3. The babies stay with their parents until they're two years old, at which point they leave to establish territories of their own. These juvenile beavers would likely disperse and move further up into the headwater streams of the Eastern Yar, and may eventually colonise other rivers. In fact we think it quite likely that beavers would be able to move into the Medina, since the two catchments are so close to each other.  

Over the longer term as carrying capacity is reached, and as the suitable habitat is colonised by existing beaver territories, we imagine that there will need to be some translocation to allow the population to remain healthy long term. This could include translocation of individuals off the Island to other projects in England looking to diversify their genetics, but also could work as an exchange, to allow for fresh blood in the island population, to prevent our beavers from becoming inbred. 

Since beavers are territorial and defend their food resources fiercely against each other, there would be a natural limit to the population, and beaver territorial aggression can be a leading factor of mortality. Mortality also occurs as the two years olds disperse, especially if they decide to swim out to sea. The babies are also vulnerable to predation, particularly by otters. 

Culling of beavers would be legal under licence from Natural England, and culling does occur in Scotland where landowners in prime agricultural land along the floodplain can suffer economic loss due to beaver activity. The Trust would aim to work with our landowners on the Island to prevent having to resort to culling, and would offer a number of management options including tree protection, and dam removal to resolve conflicts over beaver foraging and localised flooding, as well as live trapping and translocation services. But culling would be available as a last resort to landowners in the absence of any other viable alternative.