- Department of Ecology, Swedish University of Agricultural Sciences
Cropping practices alter the occurrence and abundance of species, and their interactions, in agricultural fields. Such alterations can impede the delivery of ecosystem functions by disrupting processes that would otherwise nourish and protect the crops. I examine how single and combined diversification practices of lowering tillage intensity or including perennial leys in crop rotations with or without amendment of organic fertiliser affect predatory ground beetles, herbivores, and soil fauna within and across crop growing seasons. I examined the effects of changes in coupled above- and belowground communities on predator-prey interactions, focusing on consequences for biological pest regulation. Molecular gut content analysis of what predators had eaten demonstrated that species rich predator communities strengthen pest regulation through predators’ trophic redundancy. Increased tillage intensity decreased the abundance of soil mesofauna, resulting in resource discontinuity for predators relying on soil fauna as alternative prey early in the crop growing season. I discovered that communities of above- and belowground arthropods are inextricably linked in time, and that arthropods benefit from habitat continuity and increased structural complexity of arable habitats. However, the recovery and recolonisation after disturbance was only marginally linked to predator overwintering within arable fields. Although results vary across diversification practices and temporal scales examined in this thesis, I identified habitat and resource continuity across the growing season as a key property of diversified management that bolsters predatory and soil arthropods. Variable effects found across taxa emphasise the need to focus on species ecology, and to put effort into identifying ecological linkages across species. By this approach, we can understand the impact of management on ecosystem functions derived from these communities.
beneficial arthropods; temporal dynamics; diversified management; tillage; organic fertiliser; perennial ley
Acta Universitatis Agriculturae Sueciae
2023, number: 2023:87
ISBN: 978-91-8046-226-6, eISBN: 978-91-8046-227-3
Publisher: Swedish University of Agricultural Sciences