One of the ‘ecosystem services’ for agriculture that Geertsema assessed in a project funded by the Dutch Organization for Scientific Research (NWO) is the use of natural enemies to suppress insect plagues. If this ecosystem service is to work in the open air, there must be enough natural enemies (such as ladybirds, hoverflies or parasitic wasps) in arable fields or market gardens to eliminate the harmful pests. That is only possible if these insects are also able to find enough food in the surrounding countryside in the spring, before the crops appear. ‘So the management plan for this ecosystem service extends beyond the farm plot,’ says Geertsema. This also applies to the pollination of crops by bees. The bees use borders with flowers around the plot as a source of food but also natural vegetation in verges and copses.
Other objectives steer the management of the countryside. But if verges are cut for traffic safety reasons, fewer plants will flower to provide food for beneficial insects.
At present, countryside management often does not allow for ecosystem services, says Geertsema. ‘Other objectives steer the management of the countryside. But if verges are cut for traffic safety reasons, fewer plants will flower to provide food for beneficial insects.’
This month Geertsema published about this cooperation in Frontiers in Ecology and the Environment.