Hedging our bets: Bees and biodiversity on California's Central Coast

Agroecosystems dominate the U.S. landscape, and conversion of natural land to crop fields is often cited as a leading threat to biodiversity. Agricultural practices designed to enhance biodiversity and support biological control of pests, such as incorporating native flora in on-farm hedgerows, may also provide farms with ecological services such as pollination. Native insect pollinators, including bees, are widely considered to be indicators of ecosystem health as a result of their co-evolved relationships with the plants they pollinate and recent failures of European Honeybee colonies have led to greater interest in restoring native bee pollination services.

This study explored whether native plant hedgerows can enhance native and/or non-native pollinator presence in and around agricultural fields. Bees were sampled at six organically managed farms in Central California, four of which had hedgerows and two that did not. On hedgerow sites, bees were collected at varying distances out from the hedgerows. Native bee abundance and richness were markedly greater on hedgerow sites, but no effect was found for non-native honeybees. Additionally, native bee presence and species richness were higher in samples collected within the hedgerow than in those collected at further distances from these native plantings. Native hedgerows may thus be a valuable tool in supporting pollinators.