May 22, 2013
Improving Bee Biodiversity
Brett Smith for redOrbit.com - Your Universe Online
With beekeepers around the world still reporting a high rate of colony collapse, a new study from the University of Leeds comes as an encouraging sign for those worried about the level of bee biodiversity.
In collaboration with Naturalis Biodiversity Centre in the Netherlands, the Leeds researchers found a dramatic drop in the amount of biodiversity in many species throughout Britain, Belgium and the Netherlands between the 1950s and 1980s. However, biodiversity losses among bees, hoverflies and wild plants slowed throughout the 1990s, according to the researchers´ report published in the journal Ecology Letters.
"Most observers have been saying that the 1992 Rio Earth Summit targets to slow biodiversity loss by 2010 failed, but what we are seeing is a significant slowing or reversal of the declines for wild plants and their insect pollinators,” said co-author Bill Kunin, an ecologist at the University of Leeds.
"These species are important to us," he added. “About a third of our food production, including most of our fruit and vegetables, depends on animal pollination and we know that most crop pollination is done by wild pollinators. Biodiversity is important to ensuring we don't lose that service. Relying on a few species could be risky in a changing environment.”
Using data collected from various academic, civic, and private conservation groups, the research team created a series of graphs and models depicting biodiversity of various species across four 20-year periods.
The team discovered a 30 percent drop in local bumblebee diversity across all three countries in the study from the 1950s to the 1980s. However, the reduction slowed to about 10 percent in Britain by 2010. In Belgium and the Netherlands, bumblebee biodiversity remained constant.
Other wild bees fared even better, with an 8 percent drop in diversity in the Netherlands and the UK showing significant increases during the past 20 years.
The study also showed recent improvement for hoverfly diversity, switching from a stable situation in the 1980s to 20 percent increases in recent decades. Meanwhile, UK wildflower diversity also significantly increased in the past 20 years.
Unfortunately, butterfly biodiversity showed a steady decline throughout all time periods included in the study.
"It is possible that by 1990 the most sensitive species had already gone,” said lead author Luisa Carvalheiro, a biologist at Leeds. “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,” she added. “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.”
“This study brings a positive message for conservation,” Carvalheiro said. “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."