African wild dogs are adapting to rising temperatures using an index that no longer accurately predicts the best breeding conditions.
Wild animals react and adapt to climate change in various ways. Some adaptations are more obvious. Flowering plants, for example, bloom more early each year in parts of the northern hemisphere, as climate change makes spring appear earlier and earlier on the calendar.
Other adaptations are more discreet, as we discovered in the case of the African wild dog, or “lycaon”.
The wild dog is a large carnivore threatened with extinction whose world population counts less than 700 packs (less than 7 individuals) distributed over the African continent in isolated subpopulations. They usually raise their young during the cooler months of the year. However, our new study shows that they adapt to warmer temperatures by giving birth later each year, as they follow the decrease in the cool period.
By tracking the fate of 60 packs of wild dogs in Botswana's Okavango Delta – the species' largest remaining subpopulation – we learned that the average whelping date is now more than three weeks later than 'thirty years ago. This lag corresponds almost perfectly to an increase in average daily temperature of 1,6°C over the same period.
At first glance, our conclusion that wild dogs are keeping pace with warming suggests that there is no cause for alarm. Puppies born during the cooler months are more likely to survive. So isn't this an effective strategy to deal with a changing climate? Unfortunately no.
With the coolest time of the year also getting shorter, the net effect of tracking these temperature changes is that wild dogs are now inadvertently raising their young in warmer temperatures.
It's a problem because we have already shown that higher temperatures after birth affect the survival rate of pups in Kenya, and our new study shows the same in Botswana.
During the three months of the year, when the vulnerable cubs remain in the safety of the den, the pack must Browse de long distances between his hunting grounds and the den. It is possible that the travel costs associated with these daily deliveries of meat explain why fewer young tend to survive the hottest times of the year. It is also possible that warmer temperatures will affect the hunting success of dogs. Finally, high temperatures are also linked to a drop in the rate of adult survival. This may be due to factors such as the energy cost of hunting at high temperatures.
The increase in mortality is a great threat for a species like the wild dog, whose survival depends on its numbers. Indeed, pack size is inextricably linked to their survival and success. Fewer surviving pups means fewer future helpers to find food, which leads to fewer pups the following year, which in turn leads to fewer helpers – that's the situation.
Moving forward is not an option
Unfortunately, it is not possible to move to more suitable environments. Wild dogs are reputed to have a vast territory, with individual packs occupying home ranges of several hundred to over a thousand square kilometers. Confined to only 7% of their historic range, they don't have much room, and people are understandably reluctant to share extra space with predators that threaten their livestock.
Indeed, people take revenge for livestock losses by poisoning and killing wild dogs, and exposure to disease of domestic dogs contributes to their decline.
Why is this important?
The wild dogs are caught in a kind of trap. They adapt to rising temperatures using an index that, thanks to climate change, no longer accurately predicts the best breeding conditions.
While it is certainly not the only species to exhibit climate-related behavioral change, the wild dog is, to our knowledge, the only large carnivorous mammal for which such a change has been documented. Since monitoring large carnivore populations over several decades is difficult and expensive, such long-term data do not exist or have not been assessed for most large carnivores.
However, each time we research the impact of temperature on wild dogs, we discover something new and unexpected. The effects of climate on the behavior, populations and life cycle of large carnivores may well be more widespread than previously thought. As large carnivores play an important role in shaping ecosystems, these impacts have much wider implications.
take in account the increase forecast As temperatures continue across their range, the effects of climate change on this already endangered species – and others like it – are of serious concern.
Neil R Jordan, Senior Reader, UNSW Sydney; Briana Abrahms, Assistant Professor of Biology, University of Washington; Daniella Rabaiotti, Postdoctoral Researcher, Zoological Society of London; Kasim Rafik, Postdoctoral Researcher in Wildlife Ecology and Conservation, University of Washington, and Rosie Woodroffe, Professor, Zoological Society of London
This article is republished from The Conversation under Creative Commons license. Read theoriginal article.