High temperatures and human pressures interact to influence mortality in an African carnivore.

Daniella Rabaiotti,J Weldon Mcnutt,Jessica Watermeyer,Rosie Woodroffe,Rosemary Groom,Helen M K O'Neill

doi:10.1002/ece3.7601

Abstract

The impacts of high ambient temperatures on mortality in humans and domestic animals are well‐understood. However much less is known about how hot weather affects mortality in wild animals. High ambient temperatures have been associated with African wild dog Lycaon pictus pup mortality, suggesting that high temperatures might also be linked to high adult mortality.We analyzed mortality patterns in African wild dogs radio‐collared in Kenya (0°N), Botswana (20°S), and Zimbabwe (20°S), to examine whether ambient temperature was associated with adult mortality.We found that high ambient temperatures were associated with increased adult wild dog mortality at the Kenya site, and there was some evidence for temperature associations with mortality at the Botswana and Zimbabwe sites.At the Kenya study site, which had the highest human impact, high ambient temperatures were associated with increased risks of wild dogs being killed by people, and by domestic dog diseases. In contrast, temperature was not associated with the risk of snare‐related mortality at the Zimbabwe site, which had the second‐highest human impact. Causes of death varied markedly between sites.Pack size was positively associated with survival at all three sites.These findings suggest that while climate change may not lead to new causes of mortality, rising temperatures may exacerbate existing anthropogenic threats to this endangered species, with implications for conservation. This evidence suggests that temperature‐related mortality, including interactions between temperature and other anthropogenic threats, should be investigated in a greater number of species to understand and mitigate likely impacts of climate change.

Highlights

Weather conditions have well-documented impacts on mortality in both humans and domestic animals
We investigated the relationship between human activity, temperature, and wild dog mortality by (a) examining the mortality rates and causes of wild dogs at three sites of varying human impact and (b) identifying variables that correlate with wild dog mortality at each site
Our findings suggest that human impacts on African wild dog mortality are likely to be pervasive

Summary

| INTRODUCTION

Weather conditions have well-documented impacts on mortality in both humans and domestic animals. African wild dogs' social behavior means that human killings can result in disproportionate impacts at a population level as, if one of the dominant pair dies, the pack will often splinter, meaning that the death of one individual can reduce survival and recruitment rates for the remaining animals (Woodroffe, O'Neill, et al, 2019; Woodroffe, Rabaiotti, et al, 2019). As high ambient temperatures affect the hunting behavior of adult African wild dogs (Rabaiotti & Woodroffe, 2019), and the survival of their pups (Woodroffe et al, 2017), and because high temperatures have been linked to increased mortality in humans and domestic animals, we predicted that high ambient temperatures would be associated with increased adult mortality in African wild dogs We tested this hypothesis by investigating variables associated with adult mortality in African wild dogs at three sites, representing a range of environmental conditions

| METHODS

Findings

| DISCUSSION