Hot Dogs: climate change impacts in an endothermic predator

Humans are devastating the world's wildlife, and the impacts of climate change are among the most pervasive. Even the most strictly enforced reserve cannot protect ecosystems from weather patterns that have been profoundly altered by the carbon emissions of human societies. Species unable to cope or adapt will go extinct. Without urgent action, climate change could help drive mass extinction on a scale not seen since the time of the dinosaurs.

Climate change impacts on large carnivores may have particularly far-reaching effects. Predation affects not just prey numbers, but prey behaviour, in ways that can have cascading effects on entire ecosystems.

But, as temperatures rise, the costs of pursuing prey rise too. Large-bodied predators struggle to dissipate the heat they generate by hunting. In hot weather they may hunt less effectively, endangering their own populations, and disrupting their impacts on other species.

Our project will explore how climate change affects predators, and predation, by studying an endangered large carnivore, the African wild dog, across a range of climate settings. In this study system, we can address fundamental questions in ecology while also contributing to the conservation of an endangered species. We have 6 research questions:

1 How does hot weather impact individual wild dogs? We have already shown that wild dogs are more likely to die in hot weather. We shall now test the hypothesis that they eat less on hot days because too few hours are cool enough to hunt. Working at four study sites from the equable equator to the extremes of the Kalahari Desert, we shall fit cutting-edge tracking collars which use GPS, 3D accelerometers, and specialist software to characterise when and where wild dogs hunt and feed, 24hrs a day. We shall implant tiny temperature sensors under the skin of the same animals, to test whether wild dogs overheat on hot days, going hungry rather than hunting.

2 How might these changes in hunting behaviour impact wild dog numbers? We shall use our new insights, plus 75 site-years of data on births and deaths, to simulate wild dog populations using a state-of-the art computer model of wild dog energy budgets. We shall then project how wild dog numbers are likely to change as the climate warms.

3 Could wild dogs change their behaviour to cope with a warming climate? We will use our detailed data to test whether wild dogs respond to hot weather by hunting at night, in shaded habitat, or near water. We shall test whether these behaviours allow wild dogs to secure enough food on hot days and, using our model, whether they may prevent wild dog numbers from falling.

4 Might wild dogs evolve adaptations to hotter weather? Wild dogs have parti-coloured coats of white, brown and black fur; dark fur absorbs the sun's heat, but pale fur reflects it and might thus reduce over-heating. Among our collared wild dogs, we will test whether paler animals are less prone to overheating. We will also use museum specimens to test whether wild dogs are paler in hotter regions of Africa. Again, we will use our model to test whether such adaptation might prevent wild dog numbers from falling.

5 Do wild dogs kill different prey in hot weather? The large body size that leads wild dogs to overheat when running may be an even greater burden for prey that are larger still. We shall test whether wild dogs kill larger prey in hotter weather.

6 Can conservation mitigate climate change impacts? Using our model, we will predict whether routine conservation management (e.g. removing poachers' snares) might be enough to counter the impacts of climate change, or whether climate-change specific management (e.g. moving wild dogs to cooler areas) might be needed to avert extinction.

Answering these questions will show how weather effects on individuals scale up to climate impacts on ecosystems, addressing fundamental questions in ecology and helping to inform global conservation efforts.

Climate change imposes an urgent need for action, to minimise impacts both on human society, and on biodiversity. The need for intervention to minimise species loss is considered a priority by ecologists, conservation practitioners, and policymakers. The broader need to curb climate change impacts is increasingly recognised by politicians and the general public. We thus expect multiple benefits from this project.

Conservation practitioners and policymakers
Our research findings should benefit conservation decision-makers, from governments and NGOs, in the UK and internationally, by improving their understanding of how climate change impacts individuals, populations, and ecosystems, and how to identify management actions likely to mitigate such impacts.
As well as these general benefits for conservation practice, our research should help conservationists in Africa to conserve our study species, the African wild dog. African wildlife authorities are committed to protecting this endangered species, which has been shown to play a role in structuring biodiverse savanna ecosystems.
Our project also offers opportunities for knowledge exchange between UK scientists and conservationists in Kenya, South Africa, and Zimbabwe.

UK Development Goals
The UK government is committed to assisting countries rich in biodiversity but poor in financial resources to meet their objectives under the Convention on Biological Diversity. In the case of climate change threats to biodiversity, it is difficult for the UK to meet this commitment because the actions needed are often unclear, yet UK assistance (channeled via the Darwin Initiative) emphasises action rather than research. Our proposal should thus help provide the scientific underpinning needed to direct the UK government's conservation assistance.
Moreover, African savanna ecosystems support millions of traditional pastoralists, including some of the world's poorest and most marginalised people. With their own livelihoods threatened by climate change, the need for diversification of incomes has never been greater. Wildlife-based tourism provides a crucial source of revenue within African savannas, making a major contribution to the GDPs of countries such as Kenya, Zimbabwe, and South Africa. African wild dogs are a key target for tourists and, by helping to conserve them, our work should help to support an important source of income for developing countries.

Professional development
The project provides extraordinary opportunities for professional development. Being highly inter-disciplinary, the project will open new research directions for all team members, potentially forging new links between the fields of physiology, animal behaviour, ecology, evolutionary biology and conservation biology, and between field research, museum research, and modelling.
The Early Career Researchers fully or partly supported by the project (a PDRA, a UK-based technician, and three African field technicians) will have opportunities to engage, to varying degrees, with all these fields of research. The PDRA will build extensive skills in modelling and statistical analysis. The technicians will all acquire skills likely to equip them to for future PhD research.

General Public
Our project will benefit the general public by raising awareness of the global impact of climate change. Showing that climate change does not only threaten polar bears, but represents an existential threat to an iconic tropical mammal, should increase pressure to curb CO2 emissions, which would benefit society in multiple ways. Our project also offers opportunities to engage with the public in Kenya, South Africa and Zimbabwe, to discuss wildlife conservation and climate change.