Brussels, 19 Mar 2004
A new wildlife study in the UK has provided evidence that many bird, butterfly and plant species are in sharp decline, which it says could signal the arrival of a new phase of global mass extinction.
The study, published in the journal Science, analysed six surveys of UK butterfly, bird and plant species produced over the last 40 years. Worryingly, they found that the majority of butterfly species, a total of 71 per cent, has been in decline over the last 20 years.
The study also showed that 54 per cent of bird species have fallen in number over the last two decades, as well as 28 per cent of native plant species during the last 40 years. 'There are simply no data sets that approach this detail and scale in the world,' said Dr Jeremy Thomas of the Natural Environment Research Council (NERC), co-author of the study.
Researchers believe that one of the major factors behind the decline in animal species is habitat loss due to changes in land use by humans, including ploughing up heathlands and clearing woodland. Pollution can then degrade the remaining habitats, and climate change could also be a contributing factor
While previous studies have already confirmed the decline in numbers among many bird species, the decline in butterfly numbers is significant. While birds comprise only 0.6 per cent of the world's total described species, insects account for 54 per cent.
'The argument among some naysayers is that biologists exaggerate the threat because insects are nowhere near as vulnerable to extinction as plants, birds and mammals. The results show this isn't true,' the NERC's chief executive, Professor John Lawton, told the BBC.
The study's authors warn that if this trend is reflected throughout the world, it strengthens the view held by some researchers that the world is heading for its sixth mass extinction. Dr Thomas describes drawing such a conclusion on the basis of their study 'a huge jump', but adds: 'it is the only firm evidence we've got at the moment.'
The last global mass extinction occurred 65 million years ago. Believed to have been caused by a large meteor striking the Earth, it resulted in the extinction of the dinosaurs.