Wildlife moving faster as the heat piles on

By Martin Leggett - 18 Aug 2011 18:1:0 GMT
Wildlife moving faster as the heat piles on

It seems that the natural world has gotten the message about climate change, even if certain sections of humanity seem to have successfully turned a blind eye to it. A paper out in Science today has found that animals and plants are responding quickly to a warming planet - moving at three times the speed many scientists had previously predicted. But the picture for the 2000 species looked at is more mixed, when looking at the individual-level.

Some are making decided haste away from the heat, others are stick-in-the-muds, whilst a few are even going against the flow. The varied reaction of each species to the rising temperatures appears to boil down to temperature sensitivity - as well as to the level of threat from other sources, such as habitat loss. The paper put together its conclusions by looking at every single  previous study of how plants and animals are changing their distributions.

Moving polewards

That added up to four decades of coverage, for groups as diverse as mammals, and reptiles, birds and spiders, insects and plants. Co-author Jane Hill, from the the UK-based team behind the meta-study, explained the approach: 'We have taken the published literature and analyzed it to detect what the overall pattern of change is, something that is not possible from an individual study. It's a summary of the state of world knowledge about how the ranges of species are responding to climate change.'

In the main, as the planet warms, species had been expected to move with the changing climate. Most need to live within certain temperature ranges, or in climate-adapted ecosystems, which are shifting as a whole.

That is resulting in most animals and plants moving away from the tropics, and closer to the poles. For mountain-dwelling species, the path to cooler pastures is to climb upwards. The worry is that such a strategy ultimately fails, when the mountain runs out.

Can the stragglers keep up?

This new paper not only demonstrates an unexpected speed of travel amongst plants and animals; it also showed that those parts of the planet warming the most had the fastest migration. 'This research shows that it is global warming that is causing species to move towards the poles and to higher elevations,' said first author Dr I-Ching Chen. 'We have for the first time shown that the amount by which the distributions of species have changed is correlated with the amount the climate has changed in that region.'

The distances being covered averaged 10 miles towards the poles, and 35 feet up the mountain, for every decade. Some species, such as Britain's comma butterfly have moved much faster - it expanded its range by 140 miles in just 20 years, as it fluttered into Scotland.

'These changes are equivalent to animals and plants shifting away from the Equator at around 20 cm per hour, for every hour of the day, for every day of the year. This has been going on for the last 40 years and is set to continue for at least the rest of this century,' said project leader Chris Thomas, Professor of Conservation Biology at the University of York.

Not all species are going to be able to keep up, though, suggests Professor Thomas. 'Realization of how fast species are moving because of climate change indicates that many species may indeed be heading rapidly towards extinction, where climatic conditions are deteriorating. On the other hand, other species are moving to new areas where the climate has become suitable; so there will be some winners as well as many losers.'

Top Image Credit: © strelok