Tim O'Mahony and Ben Bravery, Kexue Communications
Coverage of climate change in the media normally focuses on the effect it will have on humans. Examples include rising sea levels displacing Bangladeshis, worsening droughts in Africa contributing to food shortages, increased precipitation causing flooding and deaths in southern China, and coral bleaching affecting tourism on Australia’s Great Barrier Reef.
What we often don’t hear about in the mainstream media is how animals will cope with such a major problem which we, as a species, have caused. We have already begun to adapt our lifestyles in the face of climate change, but most animals are unable to make drastic changes easily.
An international initiative called the ‘Biological Consequences of Global Change’ has brought together scientists from four continents to discuss and research the effects of climate change on animals. A selection of the group’s findings have recently been presented in a special edition of the journal Integrative Zoology.
Animal habitats are complex, and vary in temperature, rainfall, vegetation, access to prey, and presence of predators. Animals are often perfectly adapted to their habitats, yet climate change has already changed many environmental parameters.
Global increases in temperature have led to a mass migration of animals towards the north and south poles. One of the papers published in the journal cites a recent study of the distribution of 1700 species, which found they had moved an average of 6.1 km in the direction of the poles over the past decade.
Changes to climate over such a relatively short period have led to unexpected alterations in the sizes of some animal populations. The likelihood of heavy rain events has risen as a result of climate change, and scientists have found that high rainfall events lead to population outbreaks of Yangtze voles, a rodent found in south-eastern China. The voles normally live on lake beaches, but are forced to move into neighbouring rice fields as a result of the rapid increase in population. This affects other animals in the area and local farmers.
Changes to the Earth’s climate over the past one hundred years have led to many tropical fish moving back towards the Mediterranean Sea. It is believed that these fish may have lived there millions of years ago and have returned to their ancestral home as a result of warmer oceans, and the Suez Canal allowing them to move from Asia to Europe without having to swim around Africa.
Interestingly the rise in water temperatures in the Mediterranean Sea has had a positive effect on the diversity of tropical fish species in the area, although the effect on fish suited to colder temperatures may lead to an overall decrease in fish numbers.
Many reptile and amphibian offspring are acutely sensitive to temperature changes. One of the studies published in the special edition found that the spotted skink of Tasmania, Australia gives birth at an earlier date as temperatures increase, although there is no reduction in the quality of its offspring. This may give the offspring a better chance of survival during their first year, as they are born when the weather is warmer. A potential issue is that offspring are normally born when their prey, insects, are swarming, and earlier birthdates could disrupt this timing.
Although this research focuses on the effects of global warming on animals, the end results are still being felt by humans. Of particular concern are changes to insect dispersion, especially pests. Climate warming means insects can disperse earlier in the season, and are more likely to survive over winter. Increases in temperature can also speed up insect development, resulting in larger swarms of pests.
The importance of this international effort, spearheaded by the International Society of Zoological Sciences and Chinese Academy of Sciences, is highlighted by its three year duration. Special journal editions reporting on the group’s progress will be published again in 2011 and 2012.
Tim O'Mahony and Ben Bravery are science communicators with Kexue Communications, based in Beijing. They both have a science degree and a communication degree and now work with Chinese researchers to disseminate Sino science to the English-speaking world.
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