Efforts over the past decade to save British mammals from extinction have failed to halt population declines in red squirrels, hedgehogs, harvest mice and Scottish wildcats.

Red squirrels (left) could be extinct within 20 years, while the UK hedgehog population has dipped to about 1.5m individuals compared with 30m in the 1950s, according to a report by Oxford University's wildlife conservation unit for the People's Trust for Endangered Species.

Red squirrels are the only squirrel native to the British Isles. They are disappearing from the mainland fast and are being replaced by the introduced American grey squirrel (right). The Isle of Wight
is an important stronghold as the Solent provides a barrier to grey squirrels. However, a grey does find its way to the Island sometimes and there are contingency plans for dealing with greys that arrive on the Isle of Wight. Not only do grey squirrels outcompete reds; they also carry the deadly parapox virus, which is fatal to the reds. It is illegal to bring a grey squirrel into red squirrel territory. The penalty is two years imprisonment or a £5,000 fine. It is also illegal to release a grey anywhere, once it is caught.

The Isle of Wight’s woodland can provide habitat for around 3,500 red squirrels. Numbers fluctuate annually according to the success or failure of the autumn seed crop. They also fluctuate seasonally when young are born. Reds on the Island live mainly in broadleaved woodland - which is unique nowadays as greys dominate this habitat on the mainland. The Island is also free of deer, which nibble young shoots and retard re-growth of under-story trees.

The common dormouse (Muscardinus avellanarius) (left) and mountain hare are also under threat despite efforts to arrest their decline through nationwide biodiversity action plans.

Seven species of mammals whose conservation was given priority status, including some of the most endangered, were still declining last year, says the report – State of Britain's Mammals 2011.

But there was good news with regard to otters (right), bats and water voles, whose populations have
increased. After conservation efforts "akin to rearranging the deckchairs on the Titanic", say the report's authors, there was hope that approaches to conservation were improving.

"Although many of Britain's mammals apparently declined significantly in the past 25 years, some appear to have stabilized or even increased in the last decade," the report states.

"Of the 25 monitored mammal species native to Britain, half are stable (not necessarily in a good state) or increasing."

Otters have benefited from cleaner rivers in Britain, following a ban on chemicals used in sheep
dip in the late 1990s. But hedgehog (left) numbers have fallen due to fragmentation of their habitats, pesticides killing their prey, and hedgerow loss.

Red squirrel populations have dropped more than 50% in 50 years, and, with the discovery in Scotland in 2005 of the first case of squirrel pox virus, which is carried by grey squirrels, "the omens for the red squirrel in the UK" were "bleak", state the report's authors, Dawn Burnham and David MacDonald.

"The last 15 years have seen some successes, particularly recovery of some rare species," they
said. "However, with the ongoing decline of once common species, like hedgehogs, it is widely accepted that targets for the Convention on Biological Diversity, for 2010, were missed.

"In general, progress has been better for species restricted in range that could benefit from targeted, site-based, conservation efforts. There's been less progress on targets for habitats and many widespread species."

Water voles are declining, but brown hare and polecat populations are rising. Greater and lesser horseshoe bat populations have risen 32% and 41% respectively over the past 10 years.


Source:
The Guardian,"British mammals alarm: red squirrel 'could be extinct within next 20 years'", accessed September 26, 2011

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