Extinction

18 March 2004

Two teams of British scientists have produced the best evidence yet that our planet is experiencing a mass extinction.

Two separate papers, published in Science 19 March and funded largely by the Natural Environment Research Council (NERC) highlight the serious concerns that have been growing among the world's scientists for over ten years.

John Lawton, chief executive of NERC and co-author of one of the papers said, "Fossil records show five major extinctions. Current extinction rates are approaching these magnitudes. The difference is that this extinction is caused by one species - us."

Both teams based their findings on surveys carried out on species diversity in plants and animals in Britain.

The first team, led by Dr Jeremy Thomas from the Centre for Ecology & Hydrology Dorset, looked at the drop in the numbers of bird, butterfly and plant species over a 40-year period here in Britain.

They analysed three surveys produced between twenty and forty years ago covering nearly all the UK's native bird, plant and butterfly populations. Thousands of volunteers collected the data by scrutinising 10km squares of countryside on the Ordnance Survey national.

The surveys were recently repeated providing the chance to compare changes in species number and abundance of birds, plants and butterflies in Britain.

Jeremy said, "In the last ten years there has been an enormous interest in global extinction rates but it has always been difficult to quantify. These are the most detailed surveys in the world, and, for the first time, we have good data on one group of insects - butterflies. The reason this is important is because insects make up 54% of all known species on this planet."

"Past assumptions about extinction were based on just a small number of species studied; mainly birds. But birds make up only 0·6% of all species on Earth."

He went on to say, "The results are appalling. In Britain 71% of all butterfly species have declined in the last 20 years. For the first time we can say, that in the UK, one group of insects has suffered as badly as birds or plants - this adds enormous strength to hypothesis that that the world is approaching its sixth major extinction event."

The second paper, led by Carly Stevens of the Open University, points the finger at mankind as the cause for this loss of biodiversity.

Carly and colleagues at the Centre for Ecology & Hydrology Monkswood, and Villanova University in the USA, studied the effects of pollution on the number of plant species on 68 grassland sites throughout Britain. In particular they looked at nitrogen pollution from industry, traffic, and agricultural emissions such as fertilisers and animal waste.

They discovered that as nitrogen levels increased the number of plant species decreased.

Carly, 25, an Open University and NERC-funded PhD student, said, "I studied the same type of grassland in different sites. Plants that were particularly sensitive were heather, harebell, eyebright, purple moor grass, mountain fern moss and ribwort plantain.

"The average levels of nitrogen pollution in the UK and Europe may be resulting in over 20% loss of species richness. This is a very strong argument for the need to reduce pollution."

EU legislation has set a maximum level for nitrogen emissions of 25kg per hectare per year. Below this, legislators say, nitrogen levels do not cause noticeable damage to the grasslands. Carly's research suggests this limit is too high and that any level of pollution reduces the number of plant species, thus affecting biodiversity.

Co-author Nancy Dise said, "The data suggests that it has taken around 40 years of high nitrogen deposition to get to this state, so it may take some time for species to return. And some of the changes may be irreversible."

Further information

Dr Jeremy Thomas
Centre for Ecology & Hydrology
Tel: 01305 213502
Mob: 07884 306634

Carly Stevens
Tel: 07791 101233

NERC Press Office
Natural Environment Research Council
Polaris House, North Star Avenue
Swindon, SN2 1EU
Tel: 01793 411561
Mob: 07917 557215

Notes

1. The UK Natural Environment Research Council funds and carries out impartial scientific research in the sciences of the environment. NERC trains the next generation of independent environmental scientists.

2. You can access the Science papers at the journal's website from 21:00 GMT on Thursday 18 March.

Biographies

Dr Jeremy Thomas, lead author, is a senior research scientist and Director at the Centre for Hydrology & Ecology (CEH) Dorset, one of NERC's wholly-owned research centres. He was among the first to apply a scientific approach to global insect conservation and is author of six books, over 100 scientific papers and about 100 conservation reports. With John Heath and Ernie Pollard, he initiated the scientific monitoring of UK butterfly distributions and abundance, and co-authored the first UK Atlas of Butterflies in Britain & Ireland (1984).

Dr Mark Telfer was a biometrician and database expert at the Biological Records Centre at CEH Monks Wood. He played a major role in collating the data for the Millennium Atlas of Butterflies of Britain & Ireland (2001) and the New Atlas of the British & Irish Flora (2002). He is now employed by the Royal Society for the Protection of Birds (RSPB).

David Roy is an entomologist and database expert at the Biological Records Centre. He is responsible for leading the UK's Butterfly Monitoring Scheme.

Dr Chris Preston is the Biological Records Centre's chief botanist. He played a major role organising the second survey of UK plants and in interpreting the results. He is first author of the New Atlas of the British & Irish Flora (2002).

Dr Jeremy Greenwood is Director of the British Trust for Ornithology (BTO), whose scientists organised the two definitive surveys of UK breeding birds and compiled both of the UK bird atlases.

Dr Jim Asher is a chemist, amateur entomologist and database expert, who played a lead role with the Butterfly Conservation Society and CEH in organising the second survey of UK butterflies. He co-authored the Millennium Atlas of Butterflies of Britain & Ireland (2001).

Dr Richard Fox is a data base expert at the Butterfly Conservation Society. He co-ordinated data management for the Millennium Atlas of Butterflies of Britain & Europe (2001), of which he is a co-author.

Ralph Clarke is the senior biometrician and statistician at CEH Dorset.

Professor John H Lawton FRS is chief executive of the Natural Environment Research Council. A leading international ecologist and author of about 300 scientific papers. He has been Director of NERC's Centre for Population Ecology at Imperial College, Chairman of the Royal Society for the Protection of Birds (RSPB) and council member of the British Trust for Ornithology (BTO).

Carly Stevens, lead author of the second study, is a PhD student working jointly between the Departments of Earth Sciences and of Biological Sciences at the Open University and CEH Monks Wood. She is due to finish her PhD, looking at the effects of nitrogen deposition on UK grasslands, this autumn. Tel: 07791 101233.

Extinction

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