Warming seas drive shoreline species north
ALOK JHA
|
Climate change is having a big impact on British shorelines
|
CLIMATE CHANGE has forced seashore creatures around Britain to relocate, with warming seas pushing many species of barnacles, snails and limpets north in search of cooler areas of coast, according to a new study.
"Climate change is having a big impact on British shorelines," said Nova Mieszkowska of the Marine Biology Association, who led the four-year MarClim project to track the distribution of 57 species at more than 400 sites around the U.K.
New data
By comparing their new data with 1950s records from the same areas, researchers found that some marine species adapted to cold-water were migrating away from warming seas, and were moving faster than their terrestrial counterparts.
They include toothed and flat top shells, acorn barnacles, China limpets and small periwinkles. Some cold-water species, such as the tortoiseshell limpet, have almost disappeared from Britain's shores.
Global temperature
Increased global temperatures have also confused birds this winter. Robins, thrushes and ducks that would normally fly south from Scandinavia have only been turning up in Britain in December - long after snow usually drives them south.
According to ornithologists, Berwick's swans, which usually arrive in Britain in October from Siberia, seemed to have stopped for longer than usual in countries such as Estonia or the Netherlands because of plentiful food there.
The average temperature of the Earth increased by 0.7C in the 20th century. Globally, nine out of the 10 warmest years on record were between1990 and 2000, and 2006 looks likely to be the warmest in Britain since records began.
Sea surface temperatures around Britain have increased in line with global warming, in some places by more than the global average: the western English Channel has seen a 1C rise since 1990, bigger than any changes since records began.
Similar changes
There have been similar changes in the eastern Channel. "Global predictions are that species ranges will move pole-wards as the climate warms, regardless of them being terrestrial or marine," said Dr. Mieszkowska.
According to modelling done by the U.K. climate impacts programme at Oxford University, sea surface temperatures will continue to rise as climate change takes hold. Around some parts of Britain, the temperatures are predicted to rise by up to 3C over the next century. Some species are thriving in the warmer seas.
Range extension
"Warm water species are able to extend their ranges now into areas where the climate was too cold in the past, whereas a lot of our native species that have cold water species distribution are struggling as waters are warming up."
Top shells, a type of warm water snail, have extended their ranges in Britain by up to 85 km since the end of the 1980s.
"We have data from the 1970s and 80s and, for a 10-year period, the range didn't move at all. Then, suddenly, in 16 years they've really extended their range."
The warmer seas have also brought invasive species with them. A type of Japanese seaweed called Sargassum muticum was brought to Britain in the1940s in the ballast water of ships, and in the last 20 years it has expanded its range rapidly.
"Biodiversity is going to be changed, possibly irreversibly, within a reasonably short time because it's only going to get warmer and warmer quicker and quicker according to the scenarios," said Dr. Mieszkowska.
The MarClim researchers will continue their new work in a project called IndiRock. This will monitor entire ecosystems on the shoreline, rather than individual species.
Warning effects
Dr. Mieszkowska said, that changes to shoreline species act as a warning for the effects of climate change on biodiversity.
"A lot of them are food for the fish. If something happens to them first, you can guarantee there will probably be a severe knock-on effect higher up the food chain .
© Guardian Newspapers Limited 2006
Printer friendly
page
Send this article to Friends by
E-Mail
Sci Tech
