Understanding and Predicting Spatio-Temporal Variability of Temperature in Scotland’s Rivers: Implications for Riparian Land Management

Abstract:

Freshwater fish are frequently the focus of river management, and rising water temperature (Tw) has the potential to negatively influence the suitability of habitats for many species, including salmonids. Consequently, an improved understanding of spatial and temporal variability in Tw is required at the river basin, hydrometric region and national scales concurrent with the scales at which management decisions are made. The Scotland River Temperature Monitoring Network (SRTMN) was designed to record Tw variability across the observed environmental range of a suite of landscape characteristics. These characteristics act as proxies for controls known to affect heat and water exchange processes. This national-scale monitoring network provides quality controlled data that enables the scaling up of small-scale process understanding to larger spatial scales. This dataset provided the input to statistical models which were used to investigate controls on summary metrics describing Tw and to predict future change. Following model selection procedures, the most significant and influential variables were found to vary seasonally and in relation to the temperature metric being described, reflecting the time varying importance of landscape controls and their influence on energy exchange processes. The presence of riparian woodland was a significant control on temperature that is also amenable to management control. Future work will focus on applying these models to unmonitored locations and highlighting sensitive areas where riparian management (planting or protecting woodland) could be beneficial to reduce the risks of potentially damaging high temperatures. This large-scale scientific understanding will be important for informing the management of Scottish rivers under a changing climate.