Species’ need to escape excess heat outweighing drive to avoid predators, finds study
Alpine ibexes (Capra ibex) are a mountain goat species in the European Alps. Photo: iStock
Warmer temperatures caused by climate change are changing the lifestyles of mountain goats in the European Alps, according to research. Alpine ibexes (Capra ibex), a mountain goat species, are forced to change their diurnal habits to nocturnal to avoid hot days. This lifestyle shift is making them vulnerable to predators such as wolves, hindering their movement and may lead to eventual population decline.
The researchers from the University of Sassari and University of Ferrara in Italy studied 47 ibexes over a span of 14 years. The study, titled Seeking temporal refugia to heat stress: increasing nocturnal activity despite predation risk was published in Royal Society Journal. The goats were tracked between 2006 and 2019 using motion sensors and global positioning system trackers.
The ibexes’ nocturnal activities increased during warmer days and brighter nights due to moon illuminance, the researchers noted. “Migration to favourable areas can be hindered by the widespread presence of humans or the landscape structure. In such cases, animals may maintain their current distribution range and optimal thermal niche by modifying their ecological niche in the temporal dimension, i.e. their daily activity rhythms,” they wrote.
The animals do this to achieve energy balance and efficient heat dissipation due to the cooler evening hours.
Males and females were active during nocturnal hours, but with females less active when accompanied by a kid. However, ibex activity was considerably higher in areas having the presence of nocturnal predators, the paper said.
“Nevertheless, we found a consistent increase in the nocturnal activity of females in response to high diurnal temperatures, even when accompanied by kids and in the presence of predators,” it said.
The shift in behavioural pattern is the primary evidence stating that animals are avoiding heat stress and adopting nocturnal activity and, in the process, increasing predation risks, it noted.
Apart from climate change, other pressures such as human activities, urban development, agriculture, hunting and others are also driving global increase in nocturnal activity of mammal species.
However, a mismatch between animal adaptations and environmental conditions may occur due to a shift to a nocturnal lifestyle, which may impact the animals in the long run. The change in activity time may disrupt inter-related aspects such as competition and parasitism.
“This shift towards nocturnality may facilitate animal adaptations to anthropogenic global change; on the other hand, it may bring negative consequences at individual, population and community levels. When active at night, diurnally adapted mammals may suffer from reduced foraging efficiency, weakened antipredator behaviours, restricted movement capacity, and ultimately reduced reproduction and survival rates,” it noted.
Such changes may further hinder humans’ ability to detect animals for population estimates, affecting conservation planning, it noted.
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