Insects contribute to ecosystem services by pollinating all kinds of crops. But new research (published yesterday evening in Nature Communications) shows that this is only true for a small group of common species. Rare species barely contribute to pollination. In the international debate on biodiversity conservation the current focus on ecosystem services may have a negative effect on the argument for the protection of rare species.
There is an increasing amount of proof that biodiversity, such as a broad variation in ecosystems, is not only good for nature, but is good for people too. This does not just mean clean water and clean air, but includes factors such as food supply, which is partly dependent on pollination by all kinds of insects. The fact that nature provides these ecosystem services is increasingly recognised as a leading argument for the protection of nature and the promotion of biodiversity. Up until now, however, it was not known to what extent biodiversity is actually required to fulfil nature’s main ecosystem functions. The promotion of biodiversity requires investment so it is relevant to ask the question which investments in nature are needed to fulfil the main functions. People often think that ‘more means better’. Recent research headed by David Kleijn of Alterra and Wageningen University shows surprising conclusions in this respect.In a large international project, David Kleijn together with 57 fellow researchers studied to what extent ecosystem services are a valid argument for the protection and promotion of biodiversity. Their research examined crop pollination by wild bees in farming systems on five continents. These wild pollinators contributed substantially to the production of approximately 20 insect-pollinated crops, which included rapeseed, sunflowers, strawberries, broad beans, apples and pears. The contribution of insects to crop yield – the economic pay-off of pollination – was on average more than 3000 dollars per hectare. This knowledge may encourage producers to take measures to promote bees. “But,” says David Kleijn, “most of these ecosystem services were provided by a small group of common species. Rare species barely contribute to crop pollination.”
It is fairly easy to protect common species by sowing flower strips, for example. This is not true for the protection of rare species. David Kleijn: “Rare species may play a less relevant role economically than common species, but this doesn’t mean that their protection is any less relevant. In nature protection the emphasis must be on species and not just services. This underlines the huge importance of existing instruments such as Natuurnetwerk, Natura 2000 and the Bird and Habitat Directives.”