Energy management in a demanding landscape: assessing long-term temporal and individual variation in energy management strategies among free ranging hill sheep.

Grazing by domestic hill sheep is the primary tool for sustainable management of upland areas of the UK. However, surprisingly little is known about the behaviour and energetics of sheep in these harsh upland landscapes. This project will investigate the links between behaviour and energetics in free ranging hill sheep using a combination of in-field behavioural observations and biotelemetry. Hill sheep experience a variety of energetic challenges during their annual cycle, wintering in enclosed pastures, but roaming on exposed moorland in summer. To be productive, sheep must manage constantly changing energy inputs and outputs effectively. Ecologists have long debated how different taxa manage energy and whether universal rules apply across or within taxa. However, the extent to which individuals within a species can alter their energy management strategies to suit different conditions (e.g. changing seasons and life-history stages) remains largely unknown and untested.
Hill sheep present an interesting opportunity to examine individual level patterns in energy management, as they exist in a challenging and relatively nutrient poor habitat, yet they are artificially selected to maximise production. This study will employ heart-rate monitors to provide measures of daily minimum and mean heart-rate for individual sheep over extended periods. These metrics provide proxies for maintenance and total daily energy expenditure respectively, and the relationship between these can give insights into individuals’ energy management strategies. The research will involve extensive fieldwork in the Upper Teesdale National Nature Reserve. This established research site benefits from detailed environmental and habitat data from ongoing studies on micrometeorology, microtopography and microhabitat. Individual sheep behaviour will be monitored using in situ visual observation, supplemented by video recordings and mapping, allowing the student to integrate behavioural and energetics data with environmental data within a GIS. The study will aim to instrument c. 30 ewes per year, and monitor the same individuals over multiple years, providing insights into inter-annual variation in energy management and behaviour in relation to changing annual conditions (weather, sheep age and experience). This study will provide valuable information on how intrinsic and extrinsic factors interact to modulate individual energy management strategies and behaviour, allowing consideration of practical management techniques that can be used to influence the spatial distribution and feeding choices of sheep.
The student will gain extensive interdisciplinary training in fieldwork logistics, behavioural observation, deployment of telemetry devices, and analytical skills for behavioural and telemetry data. The student will also benefit from communication, and networking as part of a collaboration combining two universities and Natural England. Potential candidates should be able to demonstrate the ability to conduct prolonged fieldwork in potentially harsh conditions, while remaining dedicated and enthusiastic. Ability to work independently and as part of a team is essential. In addition, candidates will require strong analytical skills, including experience of modern ecological and statistical modelling techniques. Experience with R and analysis of telemetry data is advantageous, but not essential. A UK driving licence (or equivalent) is essential. Further details of the project and candidate requirements can be obtained from Dr. Twiss.