Worldwide decline of bees not reducing crop yields just yet

Washington, Nov 12 : An international study has determined that the well-documented worldwide decline in the number of bees and other pollinators is not, at this stage, limiting global crop yields.

"The research team scored crops on how much they depend on pollinators for maximum production," said Co-author, CSIRO Entomology's Dr Saul Cunningham.

"Depending on the crop, this dependence ranges from zero to 100 per cent. For example, cereal crops like wheat don't need to be pollinated but at the other end of the scale, unpollinated almond trees produce no nuts," she added.

The team found that between 1961 and 2006, the yields of most crops have consistently grown at about 1.5 per cent a year because of improvements in agriculture.

There was also no difference in yield growth between crops that require pollinators and those that do not.

"While this is a positive finding, the interaction between yields and pollination is a hugely complex issue which needs to be teased-out further," Dr Cunningham said. he researchers were surprised to discover that there has been a global increase in the growing of pollinator-dependent crops, particularly in the developing world.

"The fact that, while pollinators are declining in various parts of the world, global agricultural systems are becoming more dependent on pollinators, could create serious problems in the future," Dr Cunningham said.

When the group looked at pollinated crops in more detail, they found that pollinator shortages might be beginning to affect crops that rely heavily on pollination because their yield growth was lower than for crops that were less dependent.

According to Dr Cunningham, they now want to examine how declining pollinator supply might be increasing the costs of production.

Increased yields are usually the result of increasing farm inputs such as fertilizer, labour and water.

For some crops, this increasingly intensive management may have, for now, overcome any losses in pollinator service, but it also increases production costs.

ANI