Local and landscape effects on bee communities of Hungarian winter cereal fields
Abstract:• Pollination is a key ecosystem service. Although bees are the most important pollinators, they are endangered by intensive agricultural practices. The present study investigated the effects of farmland management and environmental factors at local and landscape scales on bees in Central Hungary.
• Bees were sampled in winter cereal fields that varied in the amount of applied fertilizer and insecticide use. Measurements included total, small and large bee species richness and abundance; stability of total species richness and abundance (coefficient of variation, CV); the nitrogen content of fertilizers; the number of insecticide applications; within-field location; species richness and abundance of insect-pollinated plants; and the percentage of semi-natural areas in a 500-m radius circle around the fields under study.
• Increasing the amount of fertilizer decreased total and small bee abundance and increased the CV of total bee abundance. Insecticide use had a significant negative effect on total and small bee species richness and on large bee abundance. The percentage of semi-natural habitats in a 500-m radius did not influence bee species richness and abundance.
• The results obtained confirms that the intensification of farmland management poses a threat to bee diversity, and thus may reduce pollination services. Recently-introduced agri-environment schemes are one potential approach for managing agricultural land use: reduced amounts of fertilizer and a cessation of insecticide application might lead to high bee species richness and abundance and ensure the pollination of wild plants and flowering crops.