Using physiological markers to identify environmental challenges in African herbivores.

Abstract

Species live in a matrix of opportunities, challenges, and trade-offs. For successful reproduction and survival, animals need to gain sufficient resources whilst minimizing risk. When confronted with a threat, individuals respond through behavioural and physiological changes. To understand the associated responses, functional indicators provide insight into biological processes. Glucocorticoid (GC) and thyroid (T3) hormones act as biomarkers which work in tandem to regulate metabolism. Studies which use multiple biomarkers are limited. Here we show how three endangered African herbivores respond to environmental stressors using two hormone biomarkers. T3 and GC showed to work in tandem to regulate energy output. Environmental factors including elevation, NDVI, rainfall, and habitat type were all significant predictors of GC and T3. Yet the relationships varied between species, populations, and spatial scales. The study reinforces the idea that GC response potential is context-dependent. No consistent trends were seen with hormonal response across individual sites. The inclusion of other biomarkers are necessary to mechanistically break-down responses. From this, we can begin to understand animals' perceptions of ecological trade-offs. Conservation management protocols and decisions can be more informed, and therefore improved.

Date of Award	1 Aug 2023
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Catherine Walton (Supervisor) & Susanne Shultz (Supervisor)