Measuring behaviour, energy expenditure and parasite transmission in the face of climate change

: Comparisons with a domestic and wild caprid

Abstract

Animal movement, behaviour and the transmission of parasites are closely linked to the environment in which animals are found. Mountain ecosystems are expected to be affected by climate change at a faster rate, and with implications for species such as the ungulate Alpine ibex (Capra ibex). These species are adapted to extreme conditions, thus understanding how they cope with their environment is important to estimate the effect of climatic changes. Biologging tools enable remarkable insights into the behaviour and movement of elusive species. However, the ease with which these data can be collected is in stark contrast to the difficulties in analysing and interpreting such large data sets. This thesis addressed: 1) the application of biologging tools using a domestic counterpart, African pygmy goats (Capra aegagrus hircus), specifically refining methods used to estimate behaviour and energy expenditure, and 2) measuring the behaviour, physiology and parasites of a mountain ungulate, Alpine ibex, in the face of climate change.

I demonstrate that to accurately measure body acceleration when using collar-attached devices, the collar must be of an appropriate size and weight to reduce acceleration measured due to extraneous collar movement. Using these methods, I then demonstrate the use of tri-axial acceleration and magnetometry to classify the behaviours of domestic and captive Caprids. I refined random forest methods to enable analysis of data, predicting the slope of terrain for locomotion behaviours and demonstrating how individual split data better represents the ability of models to predict the behaviour of unobserved individuals. Model accuracy was high when using the same individuals to train and validate the model, but lower when predicting on individuals not used to train the models. Pygmy goat data was used to predict Alpine ibex behaviours with a similar accuracy.

Using biologging tools, the interaction between the environment, energy expenditure and behaviours was then investigated. Using open-flow respirometry I measured the relationships between oxygen consumption and ambient temperature, and oxygen consumption and body acceleration when walking at different speeds and terrain slopes. These estimates were then applied, with the above behavioural classification methods, to estimate the daily behaviour and energy expenditure of pygmy goats in two enclosures. Activity levels were higher in a flat enclosure in warmer temperatures, but energy expenditure was higher in the enclosure that was sloped and measured at lower temperatures. These calculations show the importance of accounting for extrinsic factors and can be applied to free-ranging ungulates.

To predict the parasite transmission of gastrointestinal nematodes in Alpine ibex, I adapted the Gloworm-FL model framework to account for seasonal elevational host movement. I demonstrated that host movement is more important than the elevational change in environmental conditions (temperature and precipitation), and that domestic sheep contribute significantly to parasites in this system. Alpine ibex are predicted to be exposed to the highest infection pressure in the Autumn, a critical time to gain body condition prior to winter and using projected climate scenarios suggested that although infection pressure is likely to increase, this may be moderated by Alpine ibex as they select areas with cooler temperatures.

In response to climate change, Alpine ibex are likely to shift their range, within the constraints of their elevations, and alter their behaviour and movement to cope with warmer temperatures. I hypothesise that this, coupled with an increase in parasite transmission, will affect their over-winter survival and thus their population growth. Using the above methods and calculations of energy expenditure, the behaviour and energy expenditure of Alpine ungulates can be measured which will help us understand how these species will respond and cope with climatic changes. Overall, this work shows how to best apply biologging tools, and the interaction between the environment, behaviour and energy expenditure in the context of climatic changes.

Thesis embargoed until 31 December 2022.

Date of Award	Dec 2021
Original language	English
Awarding Institution	Queen's University Belfast
Sponsors	Northern Ireland Department for the Economy
Supervisor	Michael Scantlebury (Supervisor), Nikki Marks (Supervisor) & Philip Stephens (Supervisor)