Arthropod and plant abundances, crop yield, field management, and environmental structures

Policies promoting agroecological management aim to counteract the adverse effects of agricultural intensification on biodiversity, and ecosystem health with varying effectiveness. This study evaluates the effects of agroecological management practices and environmental heterogeneity on biodiversity, pest control services, and crop yields in winter wheat, barley, and oilseed rape fields in Switzerland. We assessed plant species diversity, pest and predator populations, and crop yield across 44 agricultural fields managed with either conventional or agroecological practices, including the establishment of wildflower strips (WFS) and reduced pesticide use. Vegetation diversity was higher in agroecological fields compared to conventional fields, but this did not lead to an increase in predator populations. While ground-dwelling beetles are potentially enriched, neither spiders or parasitoids nor pest abundance was higher abundances in agroecological fields. Pest pressure was not affected by predator abundance, while yields were significantly higher in conventional fields, with the differences attributed to farming practices rather than the influence of vegetation diversity or pest presence. The effect of environmental heterogeneity varies across taxa and depends on the landscape feature considered.

Synthesis and applications: Our findings indicate that while agroecological practices can enhance vegetation diversity and support a diverse arthropod community, these benefits do not necessarily lead to improved pest control or increased yields. The variability in responses suggests that the effectiveness of such measures is highly context-dependent. Therefore, tailored strategies that consider specific crop and landscape characteristics are needed to optimize pest management and maintain productivity in sustainable farming systems.

Methods
All data had been collected on a total of 30 agricultural fields, organized in pairs (in close proximity) of one agroecologically and one conventionally managed field belonging to 15 farms in 2022 an 2023. In each year we sampled from 22 fields belonging to 11 farmers. All plots included in the study were in the same lowland Swiss agricultural landscape of Canton Solothurn.

Arthropods (spiders, carabids, staphylinids, paraitoids, cabbage stem flea beetles and cereal leaf beetles) and vascular palnts have been recorded in the field. Additionally, environmental structures within a radius of 500m around each field was analyzed in QGis (QGIS.org, 2023) using swisstopo data (Bundesamt für Landestopografie swisstopo, 2023).

All analyses were performed using the statistical software R (R Core Team, 2024).

Each data file has two sheets, DATA (data) and README (description/ explanation).