Climate induced stress and mortality in vervet monkeys.

Christopher Young,S Peter Henzi,Leslie R Brown,Andre Ganswindt,Richard Mcfarland,Tyler R Bonnell,Stefan Kienzle,Louise Barrett,Marcus J Dostie

doi:10.1098/rsos.191078

Abstract

As the effects of global climate change become more apparent, animal species will become increasingly affected by extreme climate and its effect on the environment. There is a pressing need to understand animal physiological and behavioural responses to climatic stressors. We used the reactive scope model as a framework to investigate the influence of drought conditions on vervet monkey (Chlorocebus pygerythrus) behaviour, physiological stress and survival across 2.5 years in South Africa. Data were collected on climatic, environmental and behavioural variables and physiological stress via faecal glucocorticoid metabolites (fGCMs). There was a meaningful interaction between water availability and resource abundance: when food availability was high but standing water was unavailable, fGCM concentrations were higher compared to when food was abundant and water was available. Vervet monkeys adapted their behaviour during a drought period by spending a greater proportion of time resting at the expense of feeding, moving and social behaviour. As food availability decreased, vervet mortality increased. Peak mortality occurred when food availability was at its lowest and there was no standing water. A survival analysis revealed that higher fGCM concentrations were associated with an increased probability of mortality. Our results suggest that with continued climate change, the increasing prevalence of drought will negatively affect vervet abundance and distribution in our population. Our study contributes to knowledge of the limits and scope of behavioural and physiological plasticity among vervet monkeys in the face of rapid environmental change.

Highlights

Climate change is exposing animals to progressively warmer climates [1,2], but is imposing a higher frequency of extreme weather events, including heat waves, cold snaps, storms, flooding and drought [1,2]
When water was readily available in the home range and food availability was high, faecal glucocorticoid metabolites (fGCMs) concentrations were lower than when food availability was high but there was a complete lack of standing water in the home range
Our results suggest that drought conditions exert a meaningful influence on fGCM concentrations in our vervets

Summary

Introduction

Climate change is exposing animals to progressively warmer climates [1,2], but is imposing a higher frequency of extreme weather events, including heat waves, cold snaps, storms, flooding and drought [1,2]. Such instability and unpredictability in environmental conditions is widely recognized as a major source of stress to animals [3], and extreme conditions have been demonstrated to negatively affect individual fitness and population survival Drought conditions (a water shortage caused by a period of abnormally low rainfall) led to high mortality of aardvarks (Orycteropus afer), most likely due to resource depletion and starvation [5]

Methods

Results

Conclusion