Pan trap and plant-flower visitor observation data for: Multi-species crop mixtures increase insect biodiversity in an intercropping experiment

Recent biodiversity declines require action across sectors such as
agriculture. The situation is particularly acute for arthropods, a
species-rich taxon providing important ecosystem services. To counteract
negative consequences of agricultural intensification, creating a less
hostile agricultural “matrix” through growing crop mixtures can reduce
harm for arthropods without yield losses. While grassland biodiversity
experiments showed positive plant biodiversity effects on arthropods,
experiments manipulating crop diversity and agrochemical input use to
study arthropods are lacking. Here, we experimentally manipulated crop
diversity (1–3 species, fallows), crop species (wheat, faba bean, linseed,
oilseed rape) and agrochemical input (high vs. low) and studied responses
of arthropod biodiversity. We tested if arthropod responses were affected
by crop diversity, mixtures and management. Additionally, we measured crop
biomass. Crop biomass increased with crop diversity under high-input
mangement, while under low management intensity, biomass was highest in
two-species mixtures. Increasing crop diversity positively affected
arthropod abundance and diversity, both under low- and high-input
management. Crop mixtures containing faba bean, linseed or oilseed rape
had particularly high arthropod diversity. Mass-flowering crops attracted
more arthropods than legumes or cereals. Integrating intercropping into
agricultural systems could increase flower visits by insects up to 15
million per hectare, thus likely also supporting pollination and
pest-control ecosystem services. Flower-visitor network complexity
increased in mixtures containing linseed and faba bean, and under
low-input management. Intercropping can counteract insect declines in
farmland by creating beneficial matrix habitat without compromising crop
yield.