March 18, 2004. Copyright 2004. Graphic News. All rights reserved.

Census of British species loss suggests Òsixth extinctionÓ

LONDON, March 18, Graphic News: Plant, bird and butterfly species are all dwindling in Britain, say two new reports that present firm evidence to back the theory that the world is experiencing a sixth major extinction.

The studies, published in the March 19 issue of the journal Science, present a comprehensive census of UK wildlife. Their results show that environmental factors have led to a decline in species diversity, which reflects a global mass extinction event on a par with the five others in history.

Jeremy Thomas, from the Natural Environment Research Council (NERC) Centre for Ecology and Hydrology in Dorchester, analysed six large surveys -- with more than 15 million records -- of native plant, butterfly and bird species over the last 40 years. By recording the number of species observed in 10-km square areas throughout the UK, his team found that a third of all species had vanished from their habitats of 20-40 years ago.

Butterflies fared particularly badly in his study, disproving old theories that flying insects are more resilient. Two of BritainÕs 58 native wild breeding butterfly species became extinct during the census. The large blue was last seen in Devon in 1979, and the large tortoiseshell has been assumed extinct since the 1980s.

ThomasÕ team found that 54 percent of native bird species and the majority of butterfly species -- 71 percent -- had suffered a population decline to some degree over the past 20 years.

Of BritainÕs 1,254 vascular plant species -- those that use stems and shoots to transport water, nutrients and photosynthetic products -- six species have become extinct over the past 70 years, and a further six are critically endangered. ÒWe found that 28 percent of native plant species have declined in Britain over the past 40 yearsÓ, said Thomas.

The second report, by Carly Stevens of the NERC, pinpointed nitrogen pollution as the most likely reason for the decline of grassland species in Britain -- excess nitrogen permits some species to crowd out others. It found that Agrostis-Festuca (acidic) grasslands with an average amount of nitrogen deposition in the UK have already lost more than 20 percent of their species diversity.

The decline in species not only makes for a less beautiful landscape but also harms our fragile ecosystem. Scientists say the extinction rates indicated by these two reports present a strong case for new policies to redress the damage already done by man.
/ENDS

Sources: Science, English Nature