River Otter Beaver Trial site visit, Devon

Last week RRC held their Annual General Meeting (AGM) at the Devon Clinton Estates, between East Budleigh and Yettington. This coincided with the second RRC Members Site Visit of the year, to the River Otter Beaver Trial in Devon. Following the RRC AGM in the morning, the RRC team, along with our extended Board of Directors and a small group of RRC Members, ventured to a couple of sites on the search for local beaver activity.

Sam Bridgewater (Clinton Devon Estates) led the group to the first visit at Budleigh Salterton, right at the mouth of the River Otter, at the estuary with the English Channel, along the Jurassic Coast. Here, there are huge threats of sea level rise, and potential coastal erosion, leading to opportunities for managed retreat. There are 30 hectares of saltmarsh and mudflat, and a developed floodplain with a road running through it. There is an embankment to protect low lying land behind the floodplain, with a small culvert running through it. This low lying fossilised floodplain is approx. 1.5 lower than the immediate floodplain, and drains via a culvert running under the car park. During high tide or heavy rainfall/flow, these drainage passages can become inundated, weakening the embankment locally, and reducing the efficacy of this drainage.

The plan is to create a large tunnel through the embankment and rebuild the footpath, creating the opportunity for 55 more hectares of saltmarsh and mudflat. This would mean the Budleigh Salterton Cricket Club would have to be relocated – a comment the group found rather amusing due to the hilly nature of the local landscape; and also rather fitting considering England were currently batting for a place in the Final of the Cricket World Cup! This development would mean massive landscape enhancement in this area. The group engaged in discussion with Sam, and seemed to come to an overall consensus that this would be a good idea for enhancement in the area.

A 45minute drive took us to the second site of the afternoon on the River Tale near Clyst William. Here, Mark Elliott (Devon Wildlife Trust) gave us a short background to the beaver populations in Devon, mentioning that they were first discovered living in the wild in 2013. Beaver kits were born on the river near Ottery St Mary, and the community rallied to keep them, and have them monitored. This shows a great opportunity for community engagement within river restoration and conservation.

Mark then mentioned they were granted a 5 year trial licence (2015-2020) to monitor the beavers, as long as they were found and tested to make sure they were healthy and not a threat to UK wildlife. The licence allows Devon Wildlife Trust to introduce different species of beavers for genetic diversity. The beavers were first introduced at this site in 2016, and there are now 2 adult pairs and 5 younger beavers along the River Otter. There are a couple of PhD projects at the University of Exeter which are working in collaboration to monitor the activity and habitats, and Devon Wildlife Trust are mapping the locations of dams in the catchment. The site and stability of the dam structure are checked approximately fortnightly by the landowners and Devon Wildlife Trust.

We met the landowners who have been cooperating with the Wildlife Trust, and helping monitor the beaver activity, before Mark lead the group around a small meadow where beavers have been introduced. This is not a large watercourse, however we saw ponds, large woody debris, trees which had been chewed by beavers, a beaver lodge and a large leaky woody dam (approx. 1.25m) which has been engineered by beavers, and stood for 9 months. In this time the dam has collapsed and been rebuilt. The dam is so strong, rather than the dam collapsing, the bank collapsed and opened up potential for new hydrological processes and functions. It has been observed that when they build their woody dams in higher energy streams, they start building at the banks and narrow the channel into a V shape before blocking off the middle of the channel last.

Beavers prefer deep water, and are attracted to the sound of running water, as they perceive this as an opportunity to dam and create and area of deeper water. Mark mentioned that if they aren’t forced to, or don’t need to build dams, then they won’t. This site is considered ideal for beavers when you want them to remain where you introduced them, in order to monitor them. These beavers have helped with scrub vegetation management, as they use local wood, branches and vegetation for their habitats.

Visiting this site was great, to actually see the structures these natural engineers can produce, and how they impact hydrological processes.

Thanks to Sam and Mark, and the landowners for allowing us to have a look at the work on their land. We hope everyone who came along to the visit enjoyed seeing the sites, and will keep up to date on the progression of these animals as nature’s engineers.

More information on the Lower Otter Restoration Project

RiverWiki case study



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