News releases | Research | Science
June 27, 2022
African wild dog pups.Bobby-Jo Vial
As climate change alters environments across the globe, scientists have discovered that in response, many species are shifting the timing of major life events, such as reproduction. With an earlier spring thaw, for example, some flowers bloom sooner. But scientists don’t know whether making these significant changes in life history will ultimately help a species survive or lead to bigger problems.
A study published the week of June 27 in the Proceedings of the National Academy of Sciences shows for the first time that a species of large carnivore has made a major change to its life history in response to a changing climate — and may be worse off for it.
African wild dog pups.Bobby-Jo Vial
A team led by researchers at the University of Washington, in collaboration with Botswana Predator Conservation, a local NGO, analyzed field observations and demographic data from 1989 to 2020 for populations of the African wild dog — Lycaon pictus. They discovered that, over a 30-year period, the animals shifted their average birthing dates later by 22 days, an adaptation that allowed them to match the birth of new litters with the coolest temperatures in early winter. But as a result of this significant shift, fewer pups survived their most vulnerable period because temperatures during their critical post-birth “denning period” increased over the same time period, threatening the population of this already endangered species.
This study shows that African wild dogs, which are distantly related to wolves and raise young cooperatively in packs, may be caught in a “phenological trap,” according to lead author Briana Abrahms, a UW assistant professor of biology and researcher with the Center for Ecosystem Sentinels. In a phenological trap, a species changes the timing of a major life event in response to an environmental cue — but, that shift proves maladaptive due to unprecedented environmental conditions like climate change.
“It is an unfortunate ‘out of the frying pan, into the fire’ situation,” said Abrahms. “African wild dogs shifted birthing dates later in order to keep pace with optimal cool temperatures, but this led to hotter temperatures during the denning period once those pups were born, which ultimately lowered survival.”
An African wild dog mother and pup.Bobby-Jo Vial
The study demonstrates that species on high “trophic levels” in ecosystems — like large predators — can be just as sensitive to climate change as other species, something that scientists were uncertain about. Other research has shown that long-term warming can trigger phenological shifts, or shifts in the timing of major life events, in “primary producer” species like plants and “primary consumers” that feed on plants, including many birds and insects. But, until now, scientists had never documented a climate-driven phenological shift in a large mammalian carnivore. Abrahms and her colleagues show that large predators can indeed exhibit strong responses to long-term climate change, even though predators are “farther removed” up the food chain.
For this study, the team analyzed more than three decades of data that they and collaborators collected on 60 packs of African wild dogs that live across a more than 1,000 square-mile region of northern Botswana. This species breeds annually each winter. After birth, pups spend about 3 months with their mother at the den before beginning to travel and hunt with the pack.
An African wild dog mother and pups.Krystyna Golabek
Abrahms and her colleagues analyzed the dates that African wild dog mothers gave birth to their litters each year, which is how they determined that adults gradually delayed breeding by about one week per decade over the 30-year study period.
“Although most animal species are advancing their life history events earlier in the year with climate change, this fi …