The vegetation habitat surveying season has come to an end for the team, following the loss of identifying features (e.g. leaves & flowers) across the catchment. Matthew Little (Habitat Audit Officer) and Cody McFarlane (Biologist), have been busy this summer surveying the Leader, Ettrick and Lyne catchments. This has taken them to less visited corners of the catchment and provided some dramatic scenery, covering around 90km of watercourse over the season. We are now underway processing and modelling data to inform riparian tree planting efforts with the aim to shade the channel and lower water temperature in the most sensitive parts of the river. 

Sustained exposure above the critical threshold for salmon (22–28°C) and trout (22–25°C) can eventually lead to mortality over time due to reduced oxygen levels or cumulative stress on the fish. In response to elevated river temperatures, salmonids are known to seek out cooler areas of the river known as cold water refuges. These are vital for fish as the cooler water reduces metabolic stress and allows for the fish to conserve energy which is in turn crucial for fish migrating upstream as they are currently doing during their spawning run. 

Riparian tree planting is key to providing shade, benefitting salmon and other native fish species that are sensitive to rising temperatures. In addition to suitability for planting, we have collected data recording points of erosion, aquatic plants, gravel banks, lamprey habitat, woody debris and bank modifications. This data helps us then create an accurate ‘picture’ of aquatic and riparian habitats, which will then be used to inform management decisions, as well as share with partner organisations to further the cause of conservation and restoration in the Tweed watershed.

Matthew Little

Habitat Officer, Tweed Foundation.