Agricultural landscape structure affects arthropod diversity and arthropod-derived ecosystem services

• Field width and distance-from-forest affected arthropod abundance and diversity.
• Pest regulation increased with field width and landscape simplification.
• Effects of arthropod diversity and abundance on pest regulation were inconsistent.
• Distance-from-forest affected both pest regulation and soybean yield.
• Soybean yield was unrelated to pest regulation or changes in arthropods.

Knowledge of how landscape structure impacts the diversity and abundance of beneficial and harmful arthropods, pest regulation, and ultimately crop yield has the potential to significantly improve management of agricultural landscapes. We examined how landscape structure in southern Québec affected soybean herbivores, predators of aphids, pest regulation including aphid and herbivory regulation, and crop production. Local-scale field characteristics and landscape structure at distances less than 2 km around each field were the most important predictors for these variables. Increasing field width consistently decreased arthropod diversity and abundance for both predators of aphids and soybean herbivores, but the effects of these changes on pest regulation were inconsistent. Increased field width resulted in less damage to soybean plants from herbivores; but in contrast, aphid numbers were greatest in more complex landscapes where fields were generally narrower. Distance-from-forest within fields and no-till planting methods also decreased pest regulation. Despite these results, soybean yield was not strongly related to pest regulation and instead varied most with distance-from-forest. Thus, patterns of arthropod diversity and abundance may not necessarily coincide with those of pest regulation or crop yield.