Why keep temperature records?
Climate change is causing increased temperatures in our rivers which can be deadly for fish and other freshwater species.
Water temperature has a huge impact on fauna and flora that live in freshwater ecosystems. That’s why a big part of our nature restoration work is focussed on keeping the river as cool as possible, helping to improve its resilience as the climate continues to change.
Ollie downloading water temperature records
Informing decision-making
To help inform our decisions about priority zones for nature restoration, we take regular temperature logs along the river. It also helps us to create a picture of how the catchment is being impacted by the changing climate.
Exposed, shallow areas are particularly vulnerable to warming, and it is possible for temperatures to rise levels that are detrimental for the cool-water loving species. These may, in turn, become areas that we prioritise for restoration.
With the recent bout of warm, dry weather, some of our team, Guy (Catchment Restoration Lead) & Ollie (Ecologist), wanted to take some temperature logs to see how the river’s temperature had been impacted as a result. The area that Guy and Ollie wanted to test is a five mile long shallow stretch of river that is relatively uniform in depth, at around 5 inches deep. Our latest logs showed a temperature reading of 18 degrees Celsius.
Danger zone
Dangerous temperatures for salmon specifically start around 23 degrees Celsius, as their bodies will begin to shut down and they won’t move or feed. At temperatures beyond 33 degrees Celsius, it is unlikely that they would survive the exposure.
Looking forward to later in the summer, there is a concern that the water temperatures will continue to rise and we could potentially see these dangerous temperature levels. In ten to twenty years time, these temperatures could be the norm, especially throughout the warmer months of the year. This would make the river uninhabitable for salmon and other species.
The solution
Woodlands along rivers (also known as ‘riparian’ woodlands) have numerous positive impacts on the ecosystem, such as adding nutrients, stablising banks, preventing erosion, flood mitigation, creating habitat, and reducing both sedimentation and water temperatures. Many stretches of the River Findhorn and its tributaries have lost their woodlands, meaning they have lost all of the wonderful benefits they bring.
We’ve already planted *** trees along the River Findhorn, and have big plans to continue. Without intervention, the future for our rivers and the species that live within them would be bleak. But thankfully there’s so much we can do to to save them, and the work has already begun!
If you would like to learn more about our nature recovery work, click here.
If you want to support the work of the Findhorn Watershed Initiative and the Findhorn, Nairn and Lossie Rivers Trust, click here.
Invertebrate monitoring to assess river health
Our spring invertebrate sampling training with Wildfish - how we do it, and what it tells us about the river.
Spring invertebrate sampling
Guy Harris, our Catchment Restoration Lead, recently carried out the ‘baseline’ surveys for invertebrates at our key habitat restoration sites. It is referred to as ‘baseline’ data as it is the first invertebrate population information that we’ve collected from the River Findhorn, and it will be used a reference for any changes we observe from hereon in. It help us to identify current conditions and health across the watershed.
Training volunteers
The samples we collected were then used in identification training with a group of volunteers, who will now be able to conduct bi-annual surveys. The information they collect from their local catchments will highlight any increased biodiversity or abundance occurring as a result of restoration activity, or decline from pressures on the system. The surveys will now be conducted twice a year - in spring and autumn* - to monitor population trends and inform our restoration efforts.
* The samples are done around these times as there will always be a difference in the species that are present based on the season.
Volunteer sampling within one of our restoration sites
Repeated monitoring using SmartRivers methodology
SmartRivers is an initiative of the charity WildFish - it is a scheme whereby repeated monitoring of invertebrate populations in rivers across the UK, using the same methodology. We have five SmartRivers sampling sites across the Findhorn Watershed (three in the upper catchment and two in the lower catchment). The repeated sampling provides long term data sets, giving scientists a big picture vision of river health.
Once we performed the invertebrate sampling, we sent our data to WildFish. Their entomologist analysed the data, then sent us a list of the species that are present.
Informing future nature restoration efforts
Moving forward we can compare the data we collect year on year, with our volunteers and in-house, to see whether the health of the river has increased, been maintained or if there are any issues, based on which species are present.
The invertebrate species that are present in the samples will tell us whether our restoration efforts have improved the river ecosystem. They may also tell us if there are any negative processes occurring, such as sediment stress or chemical pollution, which could cause cause reduced population density or the absence of certain species.
By identifying key stressors we hope to be able to address issues quickly and efficiently with the support of landowners. By supporting the base of the food chain, it benefits numerous species and promotes the health of the wider river catchment.
Resilient rivers
All of our sites showed good health throughout the river, including the presence of species that would be absent in areas with pollution or sediment pressures such as mayflies and caddisflies. These were both present at good levels, providing an important food source for wildlife.
Despite positive results, it’s important to understand that the river remains vulnerable. Our restoration efforts aim to improve its resilience from both current and future pressures.
Even rivers with ‘good’ scores have room for improvement. In our case, this may not be the return of missing species, but improving abundance.