Towards ecological intensification : the relative importance of wild pollinators as an agricultural input in seed production

The importance of wild pollinators compared to conventional agricultural management is undervalued, suggests the PhD thesis of Thijs Fijen of Wageningen University. A study in commercial leek seed production fields shows that wild pollinators contribute as much to crop yield as plant quality. Honeybees, placed next to flowering leek fields specifically for pollination, do not contribute much to crop yield. Experimental work confirmed these findings: a 50% reduction in pollination leads to much larger reductions in seed yield than similar reductions in fertilizer applications or irrigation. Surprisingly, a 50% reduction in fertilisation resulted in equally high, or higher crop yields. These results may explain the international trend that crop yields of insect-pollinated crops increase less fast as those of wind-pollinated crops. The research of Fijen furthermore shows that both crop pollination and pollinator biodiversity in agricultural landscapes can be promoted by better protection of semi-natural habitats such as flower-rich road sides and nature areas.