British scientists have produced the best evidence yet that our planet is experiencing a mass extinction. Fossil records show five major extinctions and surveys show that current extinction rates are approaching these magnitudes. Scientists have analysed three surveys produced between twenty and forty years ago covering nearly all the UK’s native bird, plant and butterfly populations. The surveys were recently repeated providing the chance to compare changes in species number and abundance of these species. One survey undertaken by Dr Jeremy Thomas at the Centre for Ecology and Hydrology, found that 71% of all butterfly species in Britain have declined in the last 20 years. For the first time it can be clearly stated that this group of insects has suffered as badly as birds or plants which adds strength to the hypothesis that the world is approaching its sixth major extinction event. The surveys in question are said to be the most detailed surveys in the world and for the first time there is good data on butterflies. This is important because insects make up 54% of all known species on our 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.

A second study led 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 and Hydrology and Villanova University in the USA, studied the effects of pollution on the number of plant species on 68 grassland sites throughout Britain. As nitrogen levels increased the number of plant species decreased. Amongst the plants that were particularly sensitive were Erica cinerea, Campanula rotundifolia, Euphrasia nemorosa, Molinia caerulea and Plantago lanceolata. The average levels of nitrogen pollution in Europe may be resulting in an over 20% loss of plant species. 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 but research suggests this limit is too high and that any level of pollution reduces the number of plant species. Some of the changes may be irreversible. "AlphaGalileo" For more information: Sheila Anderson, Head of Communications NERC (Natural Environment Research Council) Tel. 0044 7867 553053 or E-mail: pressoffice@nerc.ac.uk