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.