The following is a July 2024 programme update for Save the Spring, a partnership between the River Dee and Atlantic Salmon Trust, supported by the University of Stirling and University of Highlands & Islands, Inverness.
Girnock Burn groundwork begins
Led by the River Dee team, this July saw action along the Girnock Burn with the first large woody structures being installed in this important location.
While the River Muick has been prioritised for the Save the Spring pilot year as mentioned in previous updates, earlier this year we reported that the other tributaries we want to prioritise early in the programme are the Clunie, Feardar, Gairn and Girnock. We are pleased to report that the River Dee team this July began in earnest with the habitat restoration element of work on the Girnock.
With a monitoring programme running since 1966, and currently under the management of the Scottish Government’s Marine Directorate, the Girnock Burn has seen Scotland’s longest running study of salmon population dynamics. Together with the Baddoch Burn, these sites include pairs of fish traps which monitor both juvenile and returning adult salmon numbers, with annual electrofishing programmes providing additional information on juvenile abundance. Through this work, we know that the Girnock has seen a dramatic decline in returning wild Atlantic salmon over recent decades.
Where at one time several hundred adult fish returned to the burn to spawn, that number fell to just two adult females recorded in 2023. The River Dee team is therefore progressing restoration work on the burn with urgency, in the hope that the few returning adult fish which remain can be preserved and numbers can begin to increase.
Historical maps show that the area along the burn had significant natural woodland cover in the 18th Century and, as part of long-term plans to build climate resilience and biodiversity along the burn in order to provide an environment where wild salmon and other wildlife can once again flourish, the restoration of this native woodland is a key aim.
Prior to replanting taking place in the near future, aided by the creation of fenced enclosures to prevent deer grazing and allow for natural regeneration, the team aims to give natural processes a head start via the installation of 61 large woody structures (LWS) – action which has now been delivered with the support of the landowner. Similar work has already been conducted at scale in other parts of the catchment, including on the Clunie, Muick and upper mainstem of the River Dee itself.
Installing dead trees into the stream channel mimics what would happen once mature woodland is re-established and natural tree-fall occurs, contributing to in-stream habitat diversity by altering its hydrology (the way water flows). These LWS begin to have an effect on flows immediately, though the full benefits will be seen over a longer period of time as they properly bed-in. The result will be a diversified channel, more resilient and adaptive to impacts from climate change and with a variety of habitat types to benefit wild Atlantic salmon at different life stages.
The process of installing LWS is a detailed one, ensuring that their location and positioning will bring the greatest benefit to the watercourse. Thorough assessments and plans for the Girnock work were undertaken with cbec eco engineering UK Ltd.
This July, 61 large woody structures have been strategically installed in the Girnock Burn to kick-start natural processes ahead of large-scale native woodland restoration.
Conducting this work on remote and difficult terrain has been a huge combined effort, none of which would have been possible without the support of the landowner and hands-on assistance from estate staff. We are incredibly grateful for their enthusiasm and knowledge of the land which enabled this work to go smoothly and successfully.
Although we’ve been busy in the Girnock this month, planning for additional future habitat work has not slowed. The River Dee team has been moving ahead with pre-works planning for other areas of the catchment, including on the Geldie, Cattie, Culter and upper Dee floodplain.
We have also progressed our work with the wild fish repopulation element of the programme, including discussions with the University of Stirling Institute of Aquaculture around fish husbandry and future capacity. Our team has also been developing monitoring plans, including for genetic analysis, with UHI Inverness, in order to measure the success of the wild fish repopulation work in the future.
While the strategic focus of the programme is on the combined approach of habitat restoration in the upper catchment with wild fish repopulation, we have also been developing plans for work in the marine transition zone. This work will aim to take a detailed look at the pressures affecting both downstream and upstream migration of wild Atlantic salmon in this area and develop management strategies to ensure as many juveniles on their way out to sea, and adults on their way back upriver to spawn, can successfully complete their migration.
In our next monthly update we intend to revisit the wild fish repopulation element of the programme and bring you up to date with the smolt-to-adult supplementation (S2A) work.
Our July 2024 Update can also be read and downloaded as a PDF
This project is supported by the Scottish Government’s Nature Restoration Fund, managed by NatureScot.
