Bee diversity and abundance in perennial irrigated crops and adjacent habitats in central Washington state

Abstract Pollinators are critical to ecosystem health and agricultural productivity. Endemic bee diversity and abundance among different crops has not been extensively studied, especially among perennial crops in Washington state. The goals of this study were to characterize bee genera diversity in south central Washington state, determine the abundance and diversity of bees among crop types, and determine if farming practices influence abundance and diversity by comparing bee diversity in managed agricultural sites to adjacent unmanaged, natural sites. This study investigated bee genera diversity and abundance in blueberry fields produced under organic certification programs, conventionally produced Concord juice and wine grape vineyards, conventionally produced spearmint and peppermint fields, and conventionally produced hopyards. The majority of bees found in the study were ground-nesting. Mint fields had the highest pollinator abundance and richness. In general, there was a greater abundance, diversity, and richness of bees found in unmanaged compared with managed sites. This indicates that areas of high agricultural intensity have relatively low bee genera abundance and diversity.