Daniella Rabaiotti, Rosie Woodroffe, Tim Coulson

It has been suggested that animals may have evolved co-operative breeding strategies in response to extreme climatic conditions. Climate change, however, may push species beyond their ability to cope with extreme climates, and reduce the group sizes in co-operatively breeding species to a point where populations are no longer viable. Predicting the impact of future climates on these species is challenging as modelling the impact of climate change on their population dynamics requires information on both group and individual level responses to climatic conditions. Using an individual based model incorporating demographic responses to ambient temperature in an endangered species, the African wild dog Lycaon pictus, we show that there is a threshold temperature above which populations of the species are predicted to collapse. For simulated populations with carrying capacities equivalent to the median size of real-world populations (nine packs), this temperature threshold falls close to the best-case climate warming scenario (Representative Concentration Pathway (RCP) 2.6). The threshold is higher (between RCP 4.5 and RCP 6.0) for larger simulated populations (30 packs), but 84% of real-world populations number <30 packs. Simulated populations collapsed because, at high temperatures, juvenile survival was so low that it depressed pack size, with consequent reductions in adult survival, litter size, and the number of dispersers leaving to form new packs. This work highlights the risk that climate change poses to this endangered species, and the importance of social dynamics in determining impacts of climatic variables on social species. Individual based models parameterised on long term data can shed new light on population viability under climate change, and should play a key role in directing conservation interventions that may increase population viability under future climatic conditions.