Unmanned aerial vehicle (UAV) technology for monitoring thermal microhabitats in natural and regulated rivers

The preservation of freshwater biodiversity and ecosystem services is an internationally recognised priority. Conservation strategies are complicated by the need to balance human and ecological water needs: specifically, we are reliant on maintaining and increasing the outputs of hydropower as part of national decarbonisation strategies while not compromising river ecosystem integrity. There is a strong need for monitoring tools to understand the changing ecological impacts of dams in the context of human water needs and the ecological uncertainty relating to climate change.
Dams, climate change, and alterations to riparian cover all have major effects on river thermal regimes. While temporal and large-scale thermal consequences of dams are well known, prior technological limitations have prevented an understanding of finer-scale thermal processes downstream of dams, and have prohibited extensive or repeat sampling of spatial temperature variation. Thus the drivers and distributions of suitable local thermal microclimates in regulated and natural rivers are poorly characterised, and the ability of these rivers to sustain or protect economically and ecologically relevant species over a range of climatic conditions has not been adequately assessed.
We propose to develop a technologically-led monitoring tool for freshwater temperatures, which will, in the course of the project, generate novel data about the drivers and ecological consequences of microclimates in regulated and unregulated freshwater systems. Specifically, the student will co-develop a novel river temperature monitoring system comprising new- generation thermal sensors mounted to UAVs (drones), which holds the promise of providing unprecedented detail in the spatial distribution of freshwater thermal regimes. Unlike traditional infrared sensors, new-generation thermal sensors yielddirectly measured values of water surface temperature. When mounted on a UAV flown at relatively low altitude, they can produce high resolution digital maps (1 pixel ~ 1 cm) of water temperature. Spatially extensive (km-scale) low level flights provide data that can be used to investigate spatial patterns (e.g. distribution of thermal refugia) and, after repeat flights, temporal variation.
Aim: The student will exploit novel technologies to provide unprecedentedly detailed assessments of thermal properties of shaded, regulated, and natural upland rivers, and to characterise the ecological role of fine-scale thermal heterogeneity in these ecosystems.
To achieve this aim, the student will:
1) Calibrate and validate thermal data from new-generation, UAV-mounted sensors, and develop appropriate statistical relations to predict temperatures at the river bed from airborne sensor data.
2) Assess spatial and temporal thermal microhabitat variability in natural upland rivers, and explore how this is influenced by climate and modified by dam release regimes and riparian shading.
3) Improve understanding of the biotic implications of between- and within-reach thermal variability, in the context of benthic invertebrate communities and known thermal tolerances of salmonid fish.
The University of Aberdeen (UofA) will lead the project, in collaboration with the University of Nottingham, Scottish and Southern Energy (SSE; one of the UK's largest provider of renewable energy), Buglife, the Tay District Salmon Fisheries Board, and Bristow UAV Ltd. Outputs will inform UK upland river management strategies, with the aim of effectively balancing needs for hydropower and ecosystem services against the backdrop of climate change. The study will have broad and transferable impact via the development of a cutting-edge method for efficient, cost-effective, and high-resolution monitoring of freshwater thermal regimes and ecosystem consequences, and the training of a technologically-innovative ecologist who can work effectively across academia, applied conservation, and industry.