Going Hungry

It’s a given that climate change could wipe out many species. “But what will actually cause these extinctions?” researchers ask in a new review article. It turns out that dwindling food supplies may be one of the strongest factors — not just an inability to handle the heat.

Global warming could drive plants and animals extinct in many ways. The most obvious is that species simply can’t tolerate hotter weather. But the effects could also be more subtle: for example, some animals might escape the heat by hiding in cooler areas, reducing their time spent foraging for food. Changes in rain, snow, or fire patterns could also put stress on wildlife. A species’ prey could go extinct, or its predators could thrive.

The authors examined 136 studies in which scientists reported that species had dwindled or vanished from part of their habitat due to climate change. In seven studies, the researchers also suggested a specific reason for a species’ disappearance. “Surprisingly, none of the seven studies shows a straightforward relationship between local extinction and limited tolerances to high temperature,” the authors write in Proceedings of the Royal Society B. Instead, several species had suffered from altered interactions with other species, which often cut their food supply.

Heat intolerance could become a bigger factor as the planet keeps warming. Still, the results raise “the disturbing possibility” that many species could go extinct for other reasons in the meantime, the authors write.Roberta Kwok | 17 October 2012

Source: Cahill, A.E. et al. 2012. How does climate change cause extinction? Proceedings of the Royal Society B doi: 10.1098/rspb.2012.1890.

Image © olegkalina | iStockPhoto.com