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We all know global warming has a huge number of devastating effects on the planet – from the melting of the polar ice caps to increased desertification and the extinction of certain animal species. However, a new study led by Professor Robin Dunbar from the University of Oxford has revealed that increasing global temperatures could lead to a population explosion for goats. The study, published in Oikos, states that global warming causes two major changes that have a crucial impact on goats – increased daylight hours and, of course, warmer temperatures.
According to Dunbar and his research team, feral goat populations which live further north will benefit as problems that previously hampered the populations—low temperatures, sparse food supplies and short days—will soon disappear.
The team looked at one specific population on the Isle of Rum, off the northwest coast of Scotland, where the goats barely have enough winter daylight hours to eat. As the days get shorter and the temperature gets colder, the goats need more food to maintain their body temperature, but in these conditions the quality of vegetation is poor, so a goat needs even more eating time to get enough energy to survive. “As temperatures have started to climb by bits of a degree over the last half century we’ve been seeing the numbers of goats on the Isle of Rum increasing,” says Professor Robin Dunbar.
“The further north they go, the more the goats are trapped by a combination of the costs of thermoregulation and declining vegetation quality, both of which require them to spend more time feeding. But winter day lengths get shorter as you go further north. There comes a point where those two opposing forces crash together and they run out of time. That’s the point north of which goats can’t live,” explains Dunbar.
“[However,] as the climate warms, goats will be able to live further north. It’s about one degree latitude further north for every one degree warmer in mean annual temperature. Although here in the UK this may be offset by changes in the Gulf stream and other climate factors,” he added.
Whereas the cold previously led to low fertility and high kid mortality, the warm weather would have the opposite effect and with increased food supplies, goat populations in the northern regions would begin to grow. However there is a problematic side-effect, especially in the Galapagos where several islands have become overrun by goats who devastate the local vegetation.
However Dunbar is eager to point out the goats’ benefits. “In some respect, goats have got a bad reputation. They’re often not themselves the cause of habitat degradation, it’s just that they’re very good survivors. When well managed, they can be good landscape managers,” he concludes.