Predation-mediated ecosystem services and disservices in agricultural landscapes.

Abstract

Ecological intensification may reduce environmental externalities of agriculture by harnessing biodiversity to benefit regulating ecosystem services. However, to propose management options for the production of such services, there is a need to understand the spatiotemporal dynamics of net effects between ecosystem services and disservices provided by wild organisms across taxonomic groups in relation to habitat and landscape management. We studied the contribution of predatory vertebrates and invertebrates (including both carnivores and seed herbivores) to regulating ecosystem services and disservices in 16 cereal fields in response to a local habitat contrast and a landscape complexity gradient. From May to November 2016, we provided weed (predation reflects an ecosystem service) and crop (predation reflects a disservice) seeds, as well as pest (predation reflects an ecosystem service) and beneficial (predation reflects a disservice) invertebrate prey to predators. Seed predation was dominated by vertebrates, while vertebrates and invertebrates contributed equally to predation of animal prey. Before harvest, predation steadily increased from very low levels in May to high levels in July independent of the resource type. After harvest, ecosystem services declined more rapidly than disservices. The presence of adjacent seminatural grasslands promoted crop seed predation, but reduced pest prey predation. Predation on beneficial prey decreased with increasing proportions of seminatural grassland in the landscape. Predatory vertebrates and invertebrates provide important ecosystem services due to the consumption of pests. However, beneficial invertebrates and crop seeds were often consumed to a similar or even higher extent than harmful invertebrates or weed seeds. Our results therefore raise concerns that management options aimed at enhancing service providers may simultaneously increase levels of disservices. By considering positive and negative effects simultaneously, this study addresses an important knowledge gap and highlights the importance of interactions between local management, landscape composition, and service and disservice provision across taxa and over time. Considering trade-offs between ecosystem services and disservices when evaluating the net effects of biodiversity conservation measures on ecosystem service provision is crucial. Future agri-environment schemes that offer payments for seminatural habitats may need to provide higher compensation for farmers in cases where net effects are likely to be negative.