Changing climate - Britain offer a warm welcome to new varieties of wildlife
By Paul Kelbie
8th June 2004
Some sub-tropical species are migrating north at a rate of 50 kilometres a year. And many are ending up on our doorsteps.
Almost 30 years after the film Jaws terrorised swimmers across the world, those who comfortably assumed that the UK's chilly waters were as safe as they were grey might have to think again. Experts from the Shark Trust are investigating a number of sightings of great white sharks swimming off the west coast of Scotland.
Sharks are just one of several species thought to be migrating north due to rising sea temperatures around the UK. The warmer waters are having a dramatic effect on the marine population, with sub-tropical species such as seahorses and leatherback turtles being spotted in northern waters.
And the great whites, which can tolerate temperatures of about 6C, are believed to be following their food sources north. Following reports last year of a sighting off Cornwall, Richard Peirce, a director and trustee of the trust, has been gathering evidence from divers convinced they have seen the sharks in Scottish waters. He said: "Scottish waters are well within their temperature tolerance range - some of the waters off the Cape in South Africa are cooler.
"What is likely to be happening is that the sharks are using the North Atlantic drift as a travel corridor. Other animals are moving differently and the great whites are following them. The most credible sightings we have had are usually accompanied by reports of higher than normal catches of pollock - I don't know if that's a reason, but it's worth examining."
Sightings have come from as far north as Ullapool and Skye. During the past two years, Mr Peirce has investigated reports from as far afield as Devon, Cornwall and the Hebrides - usually from experienced fishermen.
In the North Atlantic and North Sea, where cod stocks have been driven to crisis point by climate change, more exotic sub-tropical varieties of fish have been reported. Tuna, red mullet, horse mackerel, pilchards, squid, John Dory, seahorses and leatherback turtles are all increasingly finding their way north.
It is estimated that some sub-tropical species have been migrating north at a rate of 50km a year and the instance of leatherback turtles finding their way to Britain has increased in the last few years with sightings now as far north as Banff in the Moray Firth. The leatherbacks feed on jellyfish and these are also becoming more common around the northern shores of the UK as the water warms up.
But global warming also means higher temperatures on land as well and changes in wildlife across the country. Throughout the UK, different species of moths, butterflies, birds, and insects have been reported establishing new colonies from the south coast of England as they gradually move north across the country.
Nick Collinson of the UK Phenology Network, which has been monitoring the effect of climate change on the environment, said: "We have picked up numerous reports of butterflies and birds which are known to have extended their natural ranges north because of the milder climate."
The global surface temperature for 2002 was the second highest on ever, and 2002 in the UK was the fourth warmest year on record. Experts have already warned that trees are coming into leaf sooner, spring flowers are coming into bloom in November and December, butterflies are appearing earlier and some birds, including the chiffchaff and blackcap, are increasingly over-wintering in the UK.
Andre Farrar of the Royal Society for the Protection of Birds said the overall pattern of different species appeared to show a very compelling one- direction movement north. "Species such as the Cetti's Warbler and Little Egret are new to the UK but how much of it is because of climate change we don't exactly know.
"What we do know is that we have seen some spectacular movements north of moths, dragonflies and butterflies which is consistent with the implications of a warmer climate. We are seeing some species that are moving as their 'climate envelope' moves but some are more able to adapt than others. Eventually some species will find their climate window is going to close rather firmly and they will be lost."
Mark Parsons, head of moth conservation at Butterfly Conservation, said new species of moths were arriving in Britain every year due either to climate change or a combination of warmer temperatures and land management, which is creating the ideal habitats for them.
"Between 1900 and 1909 the number of new species recorded in the UK was three but the number of new species found between 1990 and 1999 was 14."
The Royal Horticultural Society has noticed an increase in garden pests originating from warmer climates, such as the rosemary beetle, the berberis sawfly and the lily beetle. Originally from Southern Europe and the Mediterranean, these are now fully established in Britain as far north as Scotland. It seems that not all visitors can expect a warm welcome.
EXAMPLES OF SOME OF THE NEW SPECIES
Where from: Found throughout Europe.
First appeared in UK: First recorded in the UK in 1961 and is one of the UK's most recent colonists, first breeding here in 1973 in Kent before expanding throughout the South-east in the 1980s. However a series of colder winters in the mid-1980s took its toll on the British population and left only a handful in the South-west.
Preferred habitat: Likes dense, damp cover such as reedbeds, and lives off a diet of insects and larvae.
UK breeding sites: Over the past few years numbers have recovered sufficiently for the birds to be found in Dorset, Devon, Cornwall, Norfolk, Lincolnshire, Warwickshire and south Ceredigion as well as in Kent again.
QUEEN OF SPAIN FRITILLARY
Where it came from: Originally from North Africa, it is now common throughout continental Europe.
Preferred habitat: Dry, open habitats such as limestone pavement, heathland, and dunes.
UK breeding sites: There is now evidence of a permanent colony surviving in eastern England.
Where from: This tiny Mediterranean moth, which has a wingspan of less than 7mm, has been spreading slowly across Europe during the past few years.
First appeared in UK: Finally reached the UK two years ago when larvae was found in Dorset and Cornwall.
UK breeding sites: Experts believe the moth, which was probably swept across the Channel by the wind currents, is now established in the UK and is beginning to make inroads further along the south and south-west coast.
Where from: Western and northern France.
First appeared in UK:
This small white heron with black legs and yellow feet, first arrived in significant numbers in 1989. The species began to breed in the UK in Dorset in 1995 and now populates a number of south-coast sites.
Preferred habitat: Likes lowland shallow waters, especially along coasts and estuaries. They nest communally and feed on fish.
UK breeding sites: Most commonly found along the south coast, and on parts of the east coast as far north as Norfolk.
Where from: Commonly found in the western Indian Ocean, the eastern Atlantic, the Mediterranean, and off New Zealand and Japan.
First appeared in UK: Over recent years there have been more instances of the fish being caught in UK coastal waters.
Preferred habitat: They live at a depth of up to 200m.
UK sites: Southern and western coasts and some sightings in Wales.
First appeared in UK: Spotted in UK waters throughout the summer hunting their main food supply, jellyfish. Preferred habitat: They are warm-blooded, allowing them to migrate from their breeding sites in the Caribbean to colder water feeding grounds. In the UK, they have been sighted as far north as the Moray Firth.
Where it came from: Abundant in southern Europe.
First appeared in UK: Discovered in Weybridge, Surrey in 1994.
Preferred habitat: Attractive 8mm metallic green beetle with purple stripes lays its eggs on the underside of rosemary.
UK breeding sites: Survives happily in the Home Counties, East Anglia and as far north as Yorkshire. May even become a pest.
Where from: Formerly relatively common in the south-east of England, it retreated to mainland Europe.
First appeared in UK: In 1997 it was found in Kent and Essex and has once again become established in the UK.
Preferred habitat: The larvae feed on flowers and seeds of wild and cultivated lettuce.
UK breeding sites: Small area of Kent and Essex, especially around allotments.