Beaver Translocation Consultation - River Beauly Catchment Environmental Report

Published: 2023

1. Background

An update to the Beavers in Scotland Strategic Environmental Assessment (SEA) produced in 2017 was published in 2022 as an Environmental Report Addendum 2022 (ER). The ER Addendum brings up to date to our knowledge of beavers in Scotland, their impacts and management since the 2017 report. The ER Addendum supports the new policy position announced by Scottish Ministers in November 2021 to enable the proactive movement of beavers to new areas of Scotland and the publication of Scotland’s Beaver Strategy. It provides a national overview of the environmental effects that are likely to be important in informing where beaver translocation benefits are likely to out-weigh the risks. Socio-economic impacts are not part of the SEA process, but socio-economic costs and benefits are also recognised.

NatureScot have set out that we will assess the effects of beaver releases into new areas at a catchment scale. The assessment of catchments will be subject to prioritisation based on their suitability for beavers and other factors including where there is an interest in beaver translocations. The River Beauly and Beauly Coastal catchments have been selected for assessment because of the relatively high ranking in terms of the extent of suitable beaver habitat (taken together the catchments are ranked 9th nationally) and the potential for ecosystem benefits combined with the relatively low assessment of risk factors. In addition, there is expressed interest in beaver translocation within these river catchments. The purpose of this environmental report is to assess the risk and benefits that are particularly pertinent to these catchments rather than to review the entire range of potential effects that have been assessed previously. The report is accompanied by a Habitats Regulations Assessment of the potential effects on Natura sites in the catchment.

Ecologically the river catchment is the logical extent that beavers will disperse to in the medium-long term if released into a particular catchment. Hence NatureScot have proposed to assess the environmental effects of beaver translocations at the scale of main river catchments. We will assess the likely routes of movement to other catchments and the need for impacts in other catchments to also be assessed. The proposed catchment by catchment approach does not incorporate any population modelling to assess the likely time taken to colonise different parts of the catchment, but assumes that all areas that are ecologically accessible could be colonised by beavers in due course and aims to assess the likelihood and significance of such effects.

However, population modelling tools are now available that allow such projections to be made and we explore this in section 1.1 below. The boundaries of both the River Beauly and Beauly Coastal Catchment are illustrated in Figure 1 and are otherwise treated as a single catchment in this report. A previous analysis of catchment permeability (Stringer et al., 2015)* suggests most catchments are likely to be permeable to beaver dispersal. This analysis indicated that 33% of the catchment boundary for both the River Beauly and Beauly Coastal catchments is likely to be permeable to beaver movement to adjacent catchments. This analysis did not account for colonisation of freshwater via coastal routes. Both catchments offer potential linkage with the Ness catchments via several tributaries that are located near to Tomich that flow in to the Ness system as well as a route through the Beauly Firth and Caledonian canal.

1.1 Beaver presence and predicting their spread

There are records of beavers living wild in the Beauly catchment from 2012. The first record was thought to be an escaped animal. Attempts to trap it failed, but a beaver later struck by a train on the Inverness-Dingwall line was assumed to be the same animal. In 2015, an additional report of fresh beaver activity was recorded on the river. In 2017, a Trees for Life survey found beaver activity at three separate locations along the main river between Eskadale Moor and the Aigas Dam, with breeding recorded at one location that year. A decision was made to trap and translocate beavers from the unauthorised population on the River Beauly to the official trial release site in Knapdale, with trapping taking place in 2017-2018. Five individuals, including two adults and a kit were trapped during this process from one location. A follow-up survey in 2019 found evidence of fresh beaver activity around Carnoch, Struy (both upstream of the hydro dams) and the town of Beauly (downstream of the dams). This indicated at least two animals remaining in the catchment, though likely there were 3-4 individuals. An additional survey by NatureScot staff in November 2021 found continuing presence of beavers at these locations. Using a similar territory assessment method as for the Tayside surveys, the survey estimated there were two territories, separated by the hydro dams. Public reports of an additional beaver near Cannich were confirmed by the survey, but with no evidence that an animal was resident at that time. Two captive groups of beavers are known within the catchment with enclosures in the Beauly and Beauly Coastal catchments.  Since 2020, three beaver carcasses have been reported and collected from the catchment, though one of those had likely recently escaped from one of the captive groups.

The genetic history of the resident population is not known. However, given the very low numbers of individuals from the outset, and an additional genetic bottleneck from removal of some animals in 2017-2018, low genetic diversity in the current population is highly likely. Reinforcing the population with animals from elsewhere would increase its genetic diversity. Because the 2019 and 2021 surveys found similarly low levels of activity, indicative of little change in numbers, the current population in the Beauly catchment may not be sustainable without reinforcement. In contrast, the Tayside beaver population showed a c.30% annual increase over the same period. Formalising the Beauly population could improve the genetic diversity of the Scottish population because the founders of the Beauly population could contain alleles not found elsewhere in Tayside and Knapdale. Not reinforcing the existing wild population could be viewed as an opportunity lost in terms of restoring beavers to their former range.

The long-term monitoring of the beaver population is an action in Scotland’s Beaver Strategy 2022-2045. Post-release monitoring of the beaver population in new catchments will be expected to enable appropriate monitoring of effects. Hence the likely spread of beavers to further catchments could be used to trigger the assessment of effects in new catchments where they have not already been assessed.

We can use the pilot population modelling tool produced by the University of Newcastle in partnership with NatureScot to run simulations based on the current estimated wild population and modelled release scenarios and thereby predict the likelihood of the beaver population expanding and having a continued presence in the area.

The model works by simulating beaver population spread based on a range of known life history parameters (breeding and recruitment, survival, territories (size and features) within a landscape of three habitat suitability classes (informed by habitat mapping); ‘suitable’ to support territories, ‘dispersal’ habitat and ‘unsuitable’ habitat.

While the pilot modelling tool is designed for the assessment of new releases (of known composition) in to catchments without beaver presence, we have used it here to provide an indication of potential population change in the lower catchment. We have assumed that the beaver families are of equivalent composition to new releases (pairs or families with 1-4 offspring) and acknowledge that we do not have any data on the current family structures.

Using what is believed to be an approximation of the current wild living population in the lower Beauly (here based on 3 families), the modelling tool suggests that the beaver population should be stable, but only marginally increasing. This seems to reflect what has been observed and suggests the population would benefit from reinforcement. For example, we know the beaver territories are likely isolated from one another either side of the dams on the Aigas gorge, a factor which is not currently built into the pilot version of the population modelling tool. 

Table 1. Results of simulations of population growth after 10 years starting from estimated current beaver populations in the Beauly catchments.

year after release	number of families average (min-max)	number of families median	predicted probability of at least 3 families	predicted probability of number of territories having at least doubled	number of adults average (min-max)	number of adults median	predicted probability of at least 6 adults	predicted probability of abundance having at least doubled
0	3(3-3)	3	100%	0%	6(6-6)	6	100%	0%
1	4.5(3-5)	5	100%	0%	6.9(6-8)	7	100%	0%
2	7.1(3-14)	7	100%	67%	9.2(5-17)	9	80%	20%
3	7.7(3-16)	7	100%	80%	9.6(5-20)	9	93%	20%
4	8.1(4-16)	8	100%	87%	9.7(4-18)	10	87%	27%
5	8.4(4-18)	8	100%	87%	10.4(4-22)	10	93%	40%
6	8.1(3-18)	8	100%	80%	9.9(3-21)	10	93%	33%
7	8.6(3-19)	8	100%	80%	10.4(3-24)	9	87%	33%
8	8.7(3-20)	8	100%	80%	10.5(3-26)	9	80%	40%
9	8.1(2-17)	8	93%	60%	9.7(2-23)	9	67%	33%
10	8(2-18)	7	93%	60%	9.7(2-24)	8	67%	33%

 

If we model a similar release in the upper catchment, involving 3 family groups released into Lochs Beinn á Mheadhoin and Affric, it is likely that beavers will settle and persist in the area, with a strong probability that the number of territories will have doubled within 5 years; as young beavers (from 2 years old) disperse and establish new territories. However, again the population growth is relatively modest relating to the small number of founders. In some model runs the model predicts movement into the Abhainn Deabhag across the watershed which is likely an artefact of the scale of habitat mapping suggesting there is connectivity between ‘dispersal habitat’.

The simulated release shown in Table2 and Figure 3, includes 3 initial groups of beavers (some adult pairs, some families), where the initial (settled) population contains 3 groups, or a total of 7 beavers (6 adults + 1 young), one group is with one young.

Table 2. Results of simulations of population growth after 10 years following the release of 3 families in the upper (Affric) sub-catchment.

year after release	number of families average (min-max)	number of families median	predicted probability of at least 3 families	predicted probability of number of territories having at least doubled	number of adults average (min-max)	number of adults median	predicted probability of at least 6 adults	predicted probability of abundance having at least doubled
0	3(3-3)	3	100%	0%	6(6-6)	6	100%	0%
1	3.7(3-4)	4	100%	0%	5.9(5-7)	6	73%	0%
2	5.2(2-8)	5	93%	33%	7.7(5-13)	7	87%	7%
3	7.5(3-12)	7	100%	73%	9.9(6-16)	9	100%	33%
4	8.4(4-12)	8	100%	87%	10.7(7-16)	11	100%	33%
5	9(4-14)	9	100%	80%	11.3(6-19)	11	100%	47%
6	9.5(4-17)	10	100%	87%	11.7(5-19)	12	93%	60%
7	10(4-19)	10	100%	80%	12(4-21)	11	93%	40%
8	9.6(3-17)	10	100%	87%	11.7(3-22)	12	87%	53%
9	10.1(2-23)	10	93%	80%	12.5(2-29)	12	87%	53%
10	9.3(1-20)	9	93%	73%	11.1(1-23)	11	73%	40%

 

*Summary values include 15 simulations considering similar initial territories.

The modelling tool is a simplification of reality and makes assumptions about habitat suitability based on the habitat classes assigned and does not account for barriers to movement such as dams. The underlying beaver habitat suitability layer (Potential Core Beaver Woodland) is designed to be relatively conservative, highlighting better quality habitat – but it is likely beaver territories may be established in poorer quality habitat, especially in the longer term. These types of factors will be incorporated into improved versions of the modelling tool. Predicted population changes over time and space will also vary depending on the specific details fed into the modelling tool, such as the precise location of releases, and beaver family structures. However, it provides a useful basis to explore predicted beaver occupancy and about the potential rate of spread based of different modelled founder populations.

2. Environmental Characteristics of the River Beauly and Beauly Coastal catchments

General description of the catchment

The habitats and species in these catchments are likely to continue on current trajectories in the absence of further beaver releases, noting that wild beavers are already present and will be having some albeit localised impact on riparian woodland and wetlands in the lower Beauly and coastal catchment.

Aligned with the increasing interest in rewilding in the catchment, the formal establishment of beavers would be expected to provide benefits for ecotourism business and associated accommodation and service sectors, for recreational wildlife watching, as an educational resource and cultural ecosystem services more generally.

3. Key environmental issues to consider in the Beauly and Beauly coastal catchments.

This section includes an assessment of the potential environmental effects (including cumulative effects) that may arise with a focus on receptors (interests) identified in the national spatial analysis (in the ER Addendum) and drawing on the 2017 ER, those effects that are considered to be the most important within each catchment. An updated review of beaver mitigation approaches is included in the 2022 ER Addendum.

3.1 Biodiversity, flora and fauna

An appropriate assessment (HRA) of potential effects on Natura sites (Special Protection Areas (SPAs) and Special Areas of Conservation (SACs)) is available alongside this Environmental Report. The conclusions regarding the likely significant effects and effects on site integrity are considered by making an appropriate assessment for each of the Natura sites in these catchments (River Beauly and River Beauly Coastal) and the need for mitigation and management is outlined. To avoid duplication, these effects are not included in this Environmental Report.

The potential impacts on Sites of Special Scientific Interest (SSSIs) features (not already covered by HRA or equivalent interests) is included as Annex 1. In assessing impacts on SSSIs, we have scoped out those where beavers are unlikely to have an effect due to a lack of ecological connectivity or geographical overlap. The hydrology of raised bog interests are likely to be independent of beaver effects. Lochs and fen features are most likely to benefit from beaver presence through improvements to water quality. The introduction of/or release into the site of any wild, feral or domestic animal, plant or seed is an Operation Requiring Consent (ORC) for many of the SSSIs.

A comprehensive assessment of observed and potential biodiversity interactions is included in the ‘Beavers in Scotland’ report, which covered each major habitat type and each major taxonomic group. This emphasises that on balance, beaver cumulative effects are expected to be largely positive for biodiversity. Again this evidence is not systematically repeated here, but consequently the information presented is somewhat biased towards where there is the potential for negative effects. Further research is ongoing that for example may be able to model and thereby quantify likely benefits in terms of wetland creation or flood attenuation in the future. 

The biodiversity text below also includes notable conservation interests in this catchment in the wider countryside.

Designated interests

In this catchment many of the designated interests are included in the Natura interests (SACs and SPAS). Hence the only additional SSSI interests for these sites not considered in the Habitats Regulations Assessment that need to be considered are as follows:

Crested tit and lichens both occurring in – Glen Strathfarrar SSSI and Glen Affric SSSI.

Crested tit was assessed as having the potential for likely significant effects. Crested tit nest almost exclusively in holes in dead pine trees. Hence whilst there is the potential for trees with nests to be felled, pine is not the preferred food of beavers and hence felling on a scale that would have any impact on nest site availability seems unlikely.

Glen Strathfarrar is considered to be the most significant pinewood in Britain for its lichen flora and, including areas of birch with oak and alder, is currently known to host over 300 species, including 28 rarities. These include the nationally rare forked hair-lichen Bryoria furcellata and the nationally scarce Fuscopannaria ignobilis, Alectoria sarmentosa subsp. sarmentosa and Collema nigrescens. This assemblage is internationally important and differs from those found in Scandinavian pinewoods due to its oceanic and continental components.

Glen Affric is outstanding for the lichen flora that grows on its trees, with a significant number of nationally rare or scarce lichens, including Bryoria furcellata, B. capillaris and Calicium parvum.

The lichen interests related to broadleaves and pinewood components and both sites are currently regarded to be in favourable condition. NatureScot undertakes Site Condition Monitoring on a rolling basis. However, some additional monitoring post-release of sensitive sites/ individual trees would be advised to assess beaver tree species preferences in the local context and any impacts on lichen assemblages that may warrant further consideration of mitigation. This could be part of a wider programme of monitoring of biodiversity effects in the catchment.

The following potential beaver interactions with biodiversity interest were highlighted by the national spatial analysis in the 2022 SEA Addendum.

Riparian woodlands

As noted in section 2.1. the total extent of Potential Core Beaver Woodland in the catchments is high (Map 1). In terms of the total extent and connectivity of the woodland the resource is extensive, particularly along the River Affric and lower reaches of the Beauly. There are however, stretches of the river network where the woodland cover is low or where the age-class of the woodland poses a threat to its continuity.

During the NatureScot survey of the rivers Glass and Beauly in November 2021 the existing pressures on riparian woodland on some sections of the river Glass were noted, with areas with few or moribund trees lining the river, some of which were already subject to beaver impacts.

The woodland in the catchment mostly sits within the eastern half of the country and as such is not considered to be ‘rainforest’ in character, although specialist lichen and bryophyte interests are noted above.

See Map 2. for the distribution of all riparian woodland in the Beauly catchments. The establishment of beavers in this system could present an additional pressure on riparian woodland. The analysis of Potential Core Beaver Woodland with Native Woodland Survey of Scotland data on herbivore impacts, (which is now more than 10 years old) highlights that 97-99% of Potential Core Beaver Woodland was classed as subject to Moderate or High herbivore impacts.

The HRA examines the potential effects on SAC woodland interests, but more widely there is a need to assure that beaver impacts in combination with other herbivores, are not adversely affecting the condition of riparian woodlands. This is likely to require a regular review of herbivore impacts through existing woodland management plans and schemes and consideration of impacts.  In general, beaver impacts on woodlands are expected to be patchy in space and over time. Broadleaved species are adapted to beaver impacts and would be expected to recover via coppicing. Hence the focus is expected to be on other herbivore impacts being at a level that will allow beavers to be present and not adversely affect the woodland condition in the medium to long term.

There are many drivers for increasing riparian woodland from improving nature networks, moderating water temperature and flood mitigation. The presence of beavers could also provide a catalyst for riparian woodland regeneration and there appear to be existing opportunities to enhance the connectivity and resilience of the riparian woodland in the catchment. The highest priority areas for riparian woodland establishment from a water temperature perspective are in the upper catchment.

There is 14.6 ha of woodland with >25% aspen canopy cover (based on Native Woodland Survey of Scotland data) in the River Beauly catchment and none in the coastal catchment. Of this, 4.5 ha is within Potential Core Beaver Woodland, i.e. and estimated third would be accessible to beaver foraging, although as aspen is a preferred species beavers may forage further from freshwater to access it.

Aspen may be a focus for felling activity due to a preference for this high nutrient species, but it normally coppices and produces suckers allowing for rapid recovery. It is likely that beaver impacts on aspen specialist invertebrates will be mixed. By providing an opportunity for a mix of aspen life stages it will benefit those species by having a range of habitats available. However, if all of the aspen in an area is the same life stage it may have an impact on those species and so some stands of aspen may benefit from early intervention if beavers impacts are detected. If there are stands that are of particular conservation value, these should be identified prior to release.

Atlantic salmon/fish

None of the rivers in the catchment are designated for the fish or other freshwater species, but nonetheless the rivers are important for fish and fisheries. Atlantic salmon, sea trout and eels are found in the catchment, (with a few local records of lamprey) marking the river as of conservation importance.

The complex evidence around the potential effects on fish populations is reviewed extensively elsewhere (‘Beavers in Scotland’ see 3.4.7, CREW report), and highlights the potential for positive as well as potentially negative effects. For example the variability of damming effects on migration depending on flow regimes, the spatially variable effects on temperatures, and predation risks, the beneficial effects of an increase in woody debris and for sediments, water quality and invertebrate populations.

Existing obstacles to fish passage, both natural and man-made are illustrated in Figure 4. The three hydro dams in the catchment have been fitted with fish passes.

NatureScot commissioned the University of Exeter to produce a ‘Beaver Dam Capacity’ (BDC) layer for the whole of Scotland based on the methods of Graham et al. 2020. The model infers the density of dams that can be supported by stream reaches (111.1m ± 52.5) across a catchment⁴. Each reach is classified for dam capacity using five categories ranging from ‘none’ (defined as no capacity for damming) to ‘pervasive’ (defined as having a maximum capacity of 16-40 dams in 1 km of channel) assuming the beaver population is at carrying capacity, i.e. a maximum value. MAP 3 shows the beaver dam capacity modelling for both catchments and Map 4 shows the Beaver Dam Capacity Modelling (‘occasional’ to ‘pervasive’ categories) overlaid with salmon presence. This suggests the potential for beaver dams to affect salmon are relatively restricted with the main rivers being too wide and many upland burns being too steep and rocky or having limited suitable habitat for beavers. Hence the potential for beaver interactions with salmon are most likely in the Abhainn Deabhag, tributaries of the Glass above Cannich, Eskadale Burn, Belladrum burn and Bruiach Burn.

The Beauly District Salmon Fisheries Board have highlighted the small tributaries in the Belladrum sub-catchment as being important for sea trout and brown trout. They have raised concerns around the potential of seasonal damming affecting fish passage and the prevalence of salmon fry habitat. They have also highlighted a potential tension between beaver presence, riparian native woodland restoration and therefore water temperature.  

In the Loch Lomond catchment where beaver release has recently been approved, salmon and lamprey spp. are notified interests of the Endrick Water SAC. A risk-based approach to monitoring and management is proposed, informed by information about beaver presence and the likelihood of beaver damming. Hence where beavers are established, it is proposed to carry out surveillance for the presence of dams in key locations at the critical times of year for the spring (smolts) and autumn runs (adults) to locate any beaver dams. Where dams are identified, they would be assessed for pass-ability and, where necessary, agreed dam removal/notching criteria implemented under licence. Removal of dams that are less than two weeks old can take place at any time without a licence from NatureScot.

Whilst not linked to designated sites in the Beauly catchments, a similar programme of dam surveillance at key locations could be implemented. Going forward it is anticipated that we will acquire greater knowledge of beaver and fish interactions (further research is an action in Scotland’s Beaver Strategy) and the need for ongoing monitoring can subsequently be reviewed.

There is small stretch of the river Beauly that supports freshwater pearl mussels with some potential for beaver dams, which should be included in dam surveillance.

3.1 Water quality, resource and ecological status

The Beauly catchments have water courses that fall into all of the classifications of Scottish river types and characteristics from mountain streams, to meandering reaches to modified rivers in agricultural and urban settings. The water quality in ground water and bedrock are already classed as good in the Beauly catchments (SEPA waterbody classification 2018).

It is anticipated that with the rapid fluctuation of the water levels near to hydro dams that beavers will avoid these areas, however there may be localised impacts from beaver on the hydro infrastructure and more frequent inspections of the dam intakes may be required.

Beaver burrowing and damming are the main activities that may influence water resource management. The range of influences have been reviewed by CREW and are considered to be largely positive with beaver presence likely to bring improvements in water quality and, beaver dams to provide benefits in terms of flood attenuation, nutrient and sediment capture.

Beaver’s effect on channel form will likely vary depending on existing physical processes and the location in the system. There is evidence of dams leading to significant deposition of sediment and organic material, effectively grading sediment transport, promoting deposition and reducing local erosion.

Erosion is a natural process in rivers systems and in places is influenced by anthropomorphic modifications. Map 5 shows the areas with identified geomorphological risk (erosion areas shown, SEPA geomorphological data from Flood Risk map version 1.3). From experiences in Tayside and work carried out by the River Restoration Centre, we seen that in some instances beaver activity can result in changes to the bank of a river, e.g. when burrows collapse and this can occur in areas already subject to erosional processes. Map 5 indicates existing erosion features around Tomich and Cannich and around Kilmorack. Overall the extent of areas depicting erosion processes are very limited. Erosion is classed as moderate in all cases and appears to be balanced by deposition.

Burrowing activity on rivers with soft banks (Rivers Glass and Beauly) has the potential to release sand and silt into the water. As beavers generally prefer slack areas it is anticipated that fine sediment release may be confined to these areas and will have minimal impact on salmon spawning substrate in the main stem of the river.

The options for mitigating existing excessive erosion and burrowing impacts involve making space for the river to evolve and by having riparian buffer zones or naturalised habitat. Approaches to river bank protection advocated by SEPA* and NatureScot are based on natural flood management principles and the use of natural materials such as riparian planting and naturalised vegetation to improve resilience or green bank works to stabilise banks. Hard engineering approaches will rarely be appropriate, but may be required to protect specific built infrastructure where a risk is posed by burrowing.

The presence of embankments and the risk of beaver burrows contributing to bank failure poses a specific risk and there have been examples of breaches in Tayside in spate conditions where there are existing river erosion pressures. The options for mitigating impacts in such cases are again focused on making space for the river and potentially moving embankments back from the river, ideally more than 20m, where most beaver activity is focused. There are existing agri-environment measures that support the restoration and protection of riverbanks, but such works can be costly.

Map 6 illustrates there is 6.3km of embankment within 25m of Potential Core Beaver Woodland. The most significant stretch of embankment is to the south east of Kirkhill on the Newton burn. This is surrounded by woodland and has dam capacity on some of the adjacent channels. This section of embankment is adjacent to, and presumably serves to protect, land with a Land Capability for Agriculture class of 3.1 and 3.2. However, there is a good margin of woodland and existing ponds, which may negate the need to burrow should beavers colonise this area. There are also sections of embankment on the river Glass above and below Cannich adjacent to land that has a Land Capability for Agriculture class of 4.1 to 5.1.

Beaver licensing has been applied in instances where there are specific risks to embankments protecting high value agricultural crops. The licensing approach takes account of the seriousness of impact/ damage to the individual land manager. Hence there is the potential need for some licensed intervention in the catchment in relation to burrowing impacts, but these are anticipated to be relatively few instances/ geographically localised.

3.2 Population and human health

Effects on flooding

The River Beauly catchment has 10.5 ha of built up area that is adjacent to Potential Core Beaver Woodland. This is primarily in the Cannich and Tomich areas. The coastal catchment has 3.2 ha of built up area that is adjacent to Potential Core Beaver Woodland. This is primarily around the Beauly area.

Interactive Flood Risk Management Maps are hosted on the SEPA website. The maps show areas that may flood given the type of flooding (river, surface water, coastal) and the likelihood. i.e. an area with a ‘High’ likelihood is liable to more regular flooding (1 in 10) as compared with an area depicted as ‘Low’ which may only experience flooding in extreme events (1 in 1000 years). Map 7 shows flood extent and likelihood mapping for the whole catchment.

Beauly is designated as a potentially vulnerable area due to the risk of flooding from the River Beauly. The SEPA flood risk management plan (2021) states - Beauly is at risk from surface water, river and coastal flooding. However there is also risk of river and coastal flooding. There are approximately 170 people and 90 homes and businesses currently at risk from flooding. This is likely to increase to 250 people and 130 homes and businesses by the 2080s due to climate change.  The existing flood risks can be further explored in the SEPA visualisation tool.

SEPA manage flood risk in the area with flood warning areas and cover a range of properties (Flo). SEPA anticipate that there will be an increase in risk to properties in the catchment from climate change as well as offering solutions such as runoff reduction and floodplain storage, noting that the sediment in the entire Loch Ness system is varied and approximately in balance.

There is good evidence that beaver dams further up a catchment can attenuate peak flows and thereby reduce flooding (as reviewed in the CREW report). Where flooding risks are principally from peak flows due to rain and snowmelt there is the potential for beavers to complement man-made flood mitigation schemes.

Using the Beaver Dam Capacity Model outputs (Map 3) the river Beauly is ranked 12^th ranked nationally in terms of the extent of watercourse with a beaver dam capacity from ‘occasional’ to ‘pervasive’ and thereby with a high potential for water retention/flood attenuation. The Beauly coastal catchment has less potential for beaver damming with a shorter length of water course, but still has some potential for damming in the burns running into the Beauly Firth between Bunchrew and Kirkhill. We do not currently have the tools to quantify the potential effects of damming at a sub-catchment/ catchment level, but note that for beavers to have a role in helping to attenuate peak flows and these benefits to be realised, beaver dams would need to be allowed to remain and for more wetlands to be created, even of a temporary nature.

Human health

A detailed review of the potential effects of beavers on human health was included in the 2017 SEA report (section 4.12.2) and in the SEA Addendum. In summary there is no evidence to suggest that beavers would present a significant additional human health risk. Where translocations are approved, disease screening of translocated animals is a condition of a release licence and additional public health surveillance is recommended.

Both catchments have lochs and rivers that are used recreationally. There are human health risks associated from these activities, but there is no evidence to suggest that beavers would present a significant additional risk.

Beaver burrowing has the potential to impact on paths used by a variety of recreational users. The catchment has some significant core paths and informal access. There are examples of paths, cycle paths and fisheries access that have been locally impacted by beavers in Tayside through tree felling, collapse of burrows and localised flooding. Such impacts could incur additional costs, however, there are established mitigation techniques to address these impacts.

3.3 Cultural heritage

We have identified some of the key cultural features within catchments where there is predicted potential for overlap with Potential Core Beaver Woodland, indicating that at some point, beavers may occur close to these features with the potential for beaver activity to impact on these features (Table 3, Figure 5 a and b). Established mitigation measures can be adapted to suit heritage sites, however, some specialist mitigation, pro-active mitigation or monitoring may be appropriate.

Table 3. Scheduled Ancient Monuments that intersect with Potential Core Beaver Woodland in the River Beauly catchments.

Scheduled Ancient Monuments in the Beauly catchments
South Clunes lime kiln 500m S of Muir of Clunes
Kiltarlity Old Parish Church
Auchvaich, chambered cairn 650m W of
Phoineas Hill, enclosure 900m ESE of Phoineas House
Tom-a'-Caisteal, castle 400m S of Kirkton
Caledonian Canal, Clachnaharry Sea Lock to Muirtown Quay
Badger Fall, still 150m SSE of, Glen Affric
Battle of Glenshel

 

The inventory of Gardens and Designed Landscapes highlights 90ha that potentially perhaps with Potential Core Beaver Woodland, largely around Beaufort castle.

Mapping indicates there are 90 ancient trees within 10m of Potential Core Beaver Woodland. The majority of these are in the upper catchment arounds Lochs Affric and Beinn á Mheadhoin, with outliers in Guisachan forest, Loch Affric, one near Tighchuig on the river Glass and one in Moniack Burn.

Ancient trees within 10m of Potential Core Beaver Woodland

 

b) Lower catchment

3.4 Material assets

Fisheries

These catchments are served by the Beauly District Fishery Board (BDFB) and the Ness and Beauly Fisheries Trust (NBFT) with both groups aims aligned to the improvement of native fish stocks in the catchments. The BDFB is the statutory body responsible for the protection and enhancement of salmon and sea trout fisheries in the district. It takes its remit from the Salmon and Freshwater Fisheries (Consolidation) (Scotland) Act 2003. The NBFT is an environmental charity established in 2006 to secure the preservation, protection, development and improvement of both the Rivers Beauly and Ness and the native fish stocks within their catchments.

Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) are the two main species fished in the catchment and provide the local economy with business. The presence of migratory fish species has led to the addition of fish passes to the hydro dams in the form of lifts.

The potential impacts on fish are described in section 3.1.2 with recommendations for monitoring and mitigation, in the form of dam modification or removal under licence where necessary. Arrangements would need to be put in place to facilitate this surveillance and management and hence there could be additional time and costs considerations for fisheries managers.  

Forestry

The forest use is varied across the catchment but a large proportion of conifer or mixed mainly conifer, plantations exist around the likely beaver habitats. Hence beavers may occupy areas of amenity and commercial woodland. There is a mixture of public, private and community ownership. See MAP 8 for the National Forest Inventory of woodland extent and type. Foraging impacts are likely to focus on preferred broadleaves species and will likely be constrained to within 20m and occasionally 50m of freshwater. Beaver dams can affect drainage over a wider area where the topography is flat. Mapping indicates that much of the catchment is steep (Map 9) other than the Strath itself, with the majority of forestry plantations located on the slopes. Hence impacts through waterlogging are likely to be very localised.

Experience elsewhere has found there to be very few impacts on forestry plantations, forest roads and timber crops. In the longer-term it will be possible to adapt woodland design, particularly riparian woodland and around wetlands to beaver presence for example by influencing species choice or scheme layouts in some cases. Such changes could bring wider biodiversity benefits and reduce potential beaver conflicts.

Agriculture

Map 10 illustrates the Land Capability for Agriculture class of land adjacent to areas of Potential Core Beaver Woodland in the Beauly catchments. From experiences elsewhere LCA classes 1-31 Prime Agricultural Land and LCA 3.2 tend to be those most impacted by beaver activity due to the topography and reliance on field drains. They are also the land classes where impacts are likely to be the most economically significant. However, all LCA classes are shown, with arable and mixed agriculture largely in the lower and coastal catchment.

There is 16 ha of LCA 1-3.1 and 78 ha of LCA 3.2 in the Beauly catchment and 21 ha of LCA 1-3.1 and 50 ha of LCA 3.2 in the Beauly coastal catchment. This compares with 587 ha of LCA 1-3.1 and 861 ha of LCA 3.2 ha in Tayside. Hence the extent of potential conflict is much less than in Tayside. On Tayside impacts have been linked to damming of drainage ditches leading to flooding of crops and pastures and burrowing in embankments posing a risk to arable crops and collapsed burrows posing a risk to farm machinery.

Where beaver impacts can be tolerated there will likely be a range of environmental benefits. Mitigation such as leaving margins and buffers for beavers will help to reduce conflicts. In some cases licensed intervention may be merited. This includes dam modification, the installation of flow devices or beaver removal. However, we expect the need for licensed intervention to be relatively small scale and at least initially to focus on interventions towards the lower end of the beaver management hierachy, i.e. dam modification or removal, rather than beaver removal.

There is a crofting presence in the catchments with larger farms towards the coast. Crofting is a locally and nationally important historical right and while the food provided does not meet national demands, the practice can still meet the licensing purpose under “the prevention of serious damage to agriculture”. Hence, protected species licencing could be used to protect crofting interests where the licensing tests are met.

3.5 Infrastructure

There are 30km of trunk and minor roads that overlap with the Potential Core Beaver Woodland. There is a small portion of the Beauly to Inverness railway that overlaps with Potential Core Beaver Woodland, approximately 2.1km. Hence the scale of potential conflict is small, but there is the potential need for mitigation or licenced intervention.

There is potential for beavers to move through the Caledonian Canals, but locks such as those on Muirtown basin are likely to form barriers to dispersal. It is likely that the route via the River Ness would offer more opportunities for the spread of the population into the Ness catchment.  There are no canals or feeder reservoirs within the Beauly or Beauly Coastal catchment.

Septic tanks are commonplace in these catchments and locally there may be implications from raised water levels from beaver presence. Dam removal under licence is likely to apply in such cases.

4. Summary of key report findings

Table 5 provides a summary of the most likely and significant effects that may arise in the River Beauly and Beauly Coastal catchments from the translocation of beavers, noting that beavers already have a presence in the catchment.

These catchments are highly suitable for beavers in terms of habitat availability and suitability. The overall benefits to biodiversity from beaver activity are well established in the literature, as is the potential for beaver activity to contribute to a wide range of ecosystem services including water supply and purification, the moderation of flood and drought events, nutrient cycling and river restoration. Hence although it is not yet possible to quantify the likely economic scale of benefits, we can assess there is the potential for beavers to significantly contribute in these catchments to the nature and climate challenges currently faced.

The catchments are also considered to present low risks in terms of the likelihood and scale of negative impacts that may arise from beaver release. If negative impacts do occur, there are existing mechanisms available through the Beaver Management Framework to deal with them. It is understood the main effects of concern from the community perspective are impacts on farming/crofting and fisheries. The likely scale of impacts on agriculture is assessed to be small and localised, though undoubtedly will be of importance to the farmers and crofters who may be affected. Whilst there are licensing and mitigation approaches that are expected to be able to deal with these scenarios, there may be an additional time consideration that will be seen as an unwanted addition. The presence of existing bank erosion is noted in the catchment, but is limited in extent. Hence beavers’ interaction with existing erosion processes is likely to be small-scale. Again there are mitigation approaches that may help with the existing pressures and reducing beaver impacts.

The only designated freshwater species interest in the catchments is freshwater pearl mussel, a species dependent on salmonids for their life-cycle. The watercourses in the catchment are nonetheless important for fish and fisheries. Whilst we are continuing to learn more about beaver-fish interactions, it is recommended that surveillance for dams is carried out in areas that that are important for spawning and are likely to be dammed. Surveillance should be carried out in advance of key migration periods to ensure dams are not presenting a barrier to fish passage. Agreed criteria for dam modification or removal are expected to be developed via a sub-group of the Scottish Beaver Advisory Group.

Beaver releases into suitable new catchments are expected to deliver greater benefits and fewer conflicts that have been experienced in Tayside; which can be attributed to the combination of topography and land use. However, for these benefits to be realised there needs to be space for beavers to dam, build canals and create wetlands, rather than their activity being subject to high levels of intervention. The adaption and accommodation required to live alongside beavers and realise the benefits at a societal level is an area of ongoing discussion, including how to support those bearing these land-use change costs.

Beavers could also act as a catalyst for riparian woodland creation and management, for the better management of other herbivore impacts, and provide a range of socio-economic and socio-cultural benefits including ecotourism provision.

The HRA has highlighted the potential for beaver translocation to adversely affect the site integrity of three features of the Strathglass Complex SAC in the absence of mitigation (Table 4). In each case, the requirements of mitigation and management are outlined. For the Clear water lakes or lochs with poor to moderate nutrient levels and the Caledonian forest, the monitoring and mitigation relates to the features themselves, whereas for otter the mitigations relate to potential impacts of dams on migratory fish as prey for otter. Hence to ensure there is no adverse effect on otters, it is considered necessary to ensure appropriate monitoring and mitigation measures are in place to facilitate fish passage, as is recommended more widely to minimise effects on fish and fisheries. Surveillance for dams is also recommended close to fresh water pearl mussel beds.

Table 4. Table of interest for European sites conservation objectives.

European site	Qualifying feature	Mitigation Needed
Strathglass complex SAC	Clear-water lakes or lochs with poor to moderate nutrient levels	A programme of site checks to support Site Condition Monitoring.   This would identify any impacts before they had an adverse effect on site  integrity.  Mitigation is likely to include the use of flow control devices to manage dams, the removal of dams, or if necessary beavers.
Strathglass complex SAC	Caledonian forest	Monitoring should be carried out using the Woodland Herbivore Impact Assessment (WHIA) methodology and incorporating monitoring of beaver signs.  This should be done through annual site checks and the results used to inform deer/livestock management to ensure appropriate levels of herbivore impacts are maintained where beavers are present.  Where herbivore impacts are higher than ‘low’ further action is required - it is recognised they are not currently “low” in much of the SAC.  For beavers, licenced intervention could be considered where there is serious risk of damage to a conservation interest, but proactive mitigation in the form of selective tree protection is more likely, but is unlikely to be appropriate on a large scale. Hence the focus would be on ensuring the impact of other herbivores are sufficiently low to allow beaver presence.
Strathglass complex SAC	Otter	Ensure any beaver dams do not impact on the passage of fish and so provide sufficient prey for otters.

 

We have also recommended that monitoring and where appropriate mitigation of important stands of aspen and sensitive lichen sites be considered. Annex 1 highlights the features on SSSIs for which beaver interactions are proposed to be monitored largely through the programme of Site Condition Monitoring.

Monitoring of herbivore impacts on existing native woodland and woodland creation schemes outwith designated sites, is likely to be required to ensure, their condition and successful establishment. Such assessments should routinely be being carried out on Scottish Forestry Grant Schemes and Management Plans supported by Forestry Grants. Where herbivore impacts are not at a level compatible with regeneration or coppice regrowth, it will be necessary to review the herbivore management plan or consider further measures to reduce other herbivore impacts.

The impacts on infrastructure, material assets and cultural assets are likely to be those where established licensing or site-specific mitigation approaches could be applied.

Whilst the evidence points to their being low additional risks to human health, any animals released will be subject to disease screening protocols and there are recommendations for additional public health monitoring to provide public assurances.

Table 5. Summary of likelihood and significance of beaver effects within the River Beauly and Beauly coastal catchments (SAC interests are reflected in Table 4 above).

SEA category	Receptor or interest potentially affected	Effect	Likelihood of impacts	Significance in absence of mitigation	Specific mitigation/ actions proposed should a licence for release be issued
Biodiversity	Other interests comprehensively reviewed in Beavers in Scotland Report and 2017 SEA – not repeated here for brevity	+	High	NA	Largely positive
Biodiversity	Riparian woodland	+/-	High	High	Management of herbivore impacts at a level that can support beaver presence. Exploration of using beavers as a means of further promoting the restoration of riparian woodlands.
Biodiversity	Lichens	+/-	Low	Low	Risk assessment and implementation of monitoring and proactive protection of specific trees where appropriate.
Biodiversity	Salmon and freshwater pearl mussel and otter.	+/-	Medium	High	Risk assessment and implementation of dam surveillance programme to ensure timely intervention to ensure unimpeded fish passage. Aligned with monitoring, there is a need for research to determine the pass-ability of beaver dams by adult salmon (upstream) and smolts (downstream), into the wider effects (positive and negative) of beaver on salmonid/fish populations, and into the effectiveness of flow devices incorporating fish passage.
Water quality, resource and ecological status.		+	High	NA	Benefits will be tempered where dam removal is required.
Population and human health		Neutral	Low	High	Disease screening protocol and additional public health surveillance.
Cultural heritage		Neutral/-	Low	Medium	Site specific mitigation
Material assets	Forestry	+/-	Low	Low	Exploration of impacts on forestry grants and herbivore management requirements and opportunities for beavers to promote riparian woodland restoration.
Material assets	Fisheries	+/-	Medium	High	As for salmon
Material assets	Agriculture	+/-	Low	Low	Existing measures through the Beaver Management Framework to mitigate or consider the use of licensing approaches. Opportunity to work with farming interests to deliver environmental benefits that are supported by rural support mechanisms.
Infrastructure	Railways	Neutral/-	Low	Low	Limited in this catchment. Existing measures through the Beaver Management Framework to mitigate or consider the use of licensing approaches.
Infrastructure	Roads	Neutral/-	Low	Low	Existing measures through the Beaver Management Framework to mitigate or consider the use of licensing approaches.

ANNEX

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River Beauly Catchment Habitats Regulations Assessment of the potential effects on Natura sites in the catchment

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