Britain's changing wildlife
What have the short-haired bumblebee and the red-backed shrike got in common? They are now officially extinct in Britain. Unlike the golden twin-spot moth, a native of North Africa, which quite happily breeds here now. Whether due to global warming, changing farm practices or loss of habitat, Britain's flora and fauna is changing. Stephen Moss charts some of the new arrivals - and those that have sadly departed
by Stephen Moss
Tuesday March 28, 2006, Guardian
People who trap moths are, as a rule, an undemonstrative bunch. But following a vintage year, even they could be forgiven the odd whoop of joy. For 2005 saw an extraordinary invasion of rare and exotic moths - from mainland Europe and beyond - into southern Britain.
The influx was spearheaded by a dull, greyish moth with a wonderfully eccentric name - Clancy's rustic - scores of which turned up on our coasts. These were accompanied by visitors with equally bizarre monikers: beautiful marbled, dewick's plusia and golden twin-spot, to name but three. The highlight, though, was the Tunbridge Wells gem, so called because the original specimen was discovered in the Kentish spa town in the 19th century. Despite its quintessentially English name, this species normally lives in North Africa, yet last year no fewer than seven were recorded here.
So are moth enthusiasts simply becoming more observant, or was the invasion an indicator of some wider phenomenon? Definitely the latter, according to Mark Parsons of the Butterfly Conservation Society. He believes that climate change, leading to shifts in wind-patterns, is responsible for bringing these moths and butterflies from the Mediterranean and North Africa to Britain.
These modest little creatures are not the only new arrivals to our shores. This winter there has been an influx of of cattle egrets, with at least 20 of these attractive herons wandering around southern England. In the past few decades this species has surged north from its Mediterranean home, and now nests as close as Brittany and the Netherlands. The cattle egret may soon become the latest addition to our growing list of British breeding birds.
Marine life is getting into the picture, too. How could we forget the unfortunate northern bottle-nosed whale, which took a wrong turn and ended up in the River Thames, where it expired before a huge crowd of onlookers? This was only the latest in a long line of sea creatures that are turning up in British and Irish waters, including the humpback whale, striped dolphin and leatherback turtle. "Many of the humpback-whale sightings involve mother and calf pairs," says Dylan Walker of Organisation Cetacea (ORCA), "which gives us even more optimism for the future."
But despite this good news, not everything in the British wildlife garden is rosy. Even as we celebrate these new arrivals, we are saying farewell to several native species. The red-backed shrike, known to generations of schoolboy egg-collectors as the "butcher bird" because of its grisly habit of impaling its prey on thorn bushes, finally disappeared as a British breeding species during the 1990s. At about the same time, the short-haired bumblebee was officially declared extinct in Britain. Occasionally, creatures do bounce back: despite apparently becoming extinct in 1990, the greater mouse-eared bat was recently rediscovered in Sussex.
Other rare plants and animals are managing to hang on by the skin of their teeth. Lady's slipper orchid is confined to a single site in Wharfedale in North Yorkshire, with a round-the-clock guard to deter plant thieves. And one of our most attractive butterflies, the marsh fritillary, survives partly as a result of protection by the military. The training area on Salisbury Plain provides just the right level of disturbance (from shells and tank cracks) to allow the butterfly's food plant - devil's-bit scabious - to thrive.
The species with the most tenuous foothold of all is the fingered speedwell, a tiny blue flower confined to the lawns and flowerbeds of a new housing estate in the Norfolk town of Thetford. It is not known what residents think about having one of Britain's rarest plants as a weed in their rose beds.
So why does our flora and fauna continually ebb and flow in this manner? Geography has a lot to do with it. The British Isles stretch across more than 10 degrees of latitude, from the Isles of Scilly in the south to Shetland in the north. As a result we are home to arctic species on the very southern edge of their range, such as ptarmigan, arctic skua and mountain hare; and southern species on the northern edge of their range, such as cirl bunting, southern damselfly and Lulworth skipper. When conditions change, most recently as a result of global warming, we lose existing species and gain new ones.
Our position on the edge of a vast landmass, sandwiched between Eurasia and the Atlantic Ocean, also makes us a global crossroads for migrating birds. These sometimes take a wrong turn, and instead of reaching their intended destination, end up in Britain. If conditions are suitable, they may breed. Several species, including a little egret, have recently colonised Britain as a result of such wanderings.
However, water can also present a formidable barrier to colonisation. Terrestrial species such as mammals, reptiles and amphibians can only cross the Channel with help from humans; while even some birds appear reluctant to fly over the sea, and grind to a halt at Calais. Such is the fate of the zitting cisticola, a tiny warblerlike bird spreading northwards through Europe, and long predicted as a potential colonist. A pair of cisticolas is currently residing on Jersey, but only a few individuals have ever reached mainland Britain, none of which has yet to breed.
But despite these natural arrivals and departures, by far the greatest changes taking place in Britain's fauna and flora are the result of human agency. A recent report by English Nature - "Audit of non-native species in England" - listed no fewer than 2,721 non-native species and hybrids currently found here in the wild. Most of these are flowering plants, but there are also 102 species of bugs and aphids, 101 species of beetle and almost 50 different butterflies and moths.
Only four introduced species, including game birds such as pheasant and red-legged partridge, are considered to bring any economic benefit; while many others, such as the Chinese mitten crab, American mink and Japanese knotweed, are known to have harmful economic and biological consequences.
In recent years, in an attempt to offset these disastrous introductions, we have tried to redress the balance by reintroducing native creatures. The most successful of these schemes, the restoration of red kites to England and Scotland, shows that despite our predisposition to meddle and destroy, we also have the ability to make things better. It may not be too long before kites resume their place over the streets of London, for the first time in more than a century.
Guardian Unlimited © Guardian Newspapers Limited 2006
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