Alpine ibex usually descend from the safe mountainous highlands of Europe during the day, feeding on grass at lower altitudes. But researchers tracking the animals have noticed that they are increasingly reluctant to make this vertical migration during the day.
These bighorn goats (capra ibex) now spend more time resting at dawn than foraging at night – a huge risk as wolves lurk in these areas under the cover of darkness.
Nocturnal activity is a problem for this species – it's a big problem," Stefano Grignolio, a behavioral ecologist at the University of Ferrara, told Benji Jones of VOX.
The open foraging grounds of wild goats provide less cover for them to escape from the wolves.
For this reason, Francesca Brivio, an ecologist at the University of Ferrara, and her colleagues hope to find higher nocturnal activity in wolf-free Alpine regions such as Switzerland. But that's not the case.
We found higher activity in areas where there were wolves," Brivio told The Guardian's Olivia Lee.
Instead, 47 wild goats tracked by researchers between 2006 and 2019 increased their nocturnal activity after days of high maximum temperatures. Thus, despite the increased risk of encountering predators, warm-blooded mammals seem to prioritize seeking refuge from the heat.
Alpine goats were once common throughout Europe, but as guns became more popular among hunters, Alpine goats dwindled to just 100 by the 1800s. As a result of the hunting ban and conservation efforts of 1854, the species** now numbers in the tens of thousands.
However, the persistent low genetic diversity in these wild goat populations makes them vulnerable to multiple threats, including problematic mutations that increase susceptibility to disease. Now, we're adding even more pressure by changing the climate in their home.
Ibex cope with warmer temperatures by becoming more nocturnal," the researchers concluded, noting that this may not have good results.
The steep, rocky habitat of mountain goats can be more complex and more laborious to navigate in the dark with an eye acclimatized to daylight, which may reduce their foraging ability and increase their chances of becoming food on their own by shifting their most vulnerable activities closer to predator exposure.
Behavioral adaptation is the fastest way for animals to respond to rapid environmental changes. In fact, human interference, from hiking and gardening to mining and hunting, is driving many mammals, including wild boars and coyotes, to become more nocturnal. We can now add climate change to this list.
Our disturbances not only make it impossible for our wildlife to inhabit certain places, but also at certain times of the day.
Whether across space or time, such changes are cutting off millions of years of interaction between species, further disintegrating the once-functioning ecosystems we depend on.
The study was published in the Proceedings of the Royal Society.