Not all groups fared so well. Butterfly diversity continued to fall in all three countries at roughly the same rates as in the past.
Dr Luisa Carvalheiro, lead author on the paper, said: "It is possible that by 1990 the most sensitive species had already gone. However, that's probably not the whole story, as there are still plenty of rare and vulnerable species present in recent records.
"There is a much more encouraging possibility: the conservation work and agri-environment programs paying farmers to encourage biodiversity may be having an effect. We may also be seeing a slowdown of the drivers of decline. The postwar emphasis on getting land into production and on more intensive farming has given way to a more stable situation in which the rate of landscape change has slowed and in which agrichemical excesses are regulated.
Dr Carvalheiro said: "If what we take from the Rio targets is that the investment in conservation gave us no results, then that is a counsel of despair. This study brings a positive message for conservation. But some important groups are undoubtedly still declining, so continued and increased investment in conservation practices is essential for guaranteeing the persistence of a diverse assemblage of species."
Co-author Professor Koos Biesmeijer, who works both at the University of Leeds and Naturalis, said: "This paper builds on a widely-publicised study we published in 2006 that established that the diversity of bees and of wildflowers had declined. Our new work is based on a much bigger dataset and improved analytic methods, and it reveals much more detail about the scale and timing of biodiversity losses.
"However, while we can use biodiversity records to measure changes in the diversity of pollinators, we can't tell
|Contact: Chris Bunting|
University of Leeds