The effects of surrounding habitat on plant, pollinator, and plant-pollinator interaction richness and abundance

Montane meadows comprise less than 5% of the landscape of the western Cascades of Oregon, but they provide habitat for diverse species of plants and pollinators. This study quantified plant-pollinator interactions over the summer of 2011, based on six observations of ten permanent subplots in fifteen meadows, stratified by size and isolation.  The study examined: (1) relationships between richness and abundance of flowers, pollinators, and interactions; (2) abundance and diversity of flowers, pollinators, and interactions and their relationship to meadow size and the amount of meadow area within 3 km; and (3) abundance of several bee guilds based on meadow size and surrounding meadow area. The study showed that: (1) richness of pollinators increased two times faster than richness of flowers with increased abundance; (2) density of flowers and interactions was positively correlated with meadow size, and diversity of pollinators and interactions was correlated with the amount of surrounding meadow at multiple spatial scales; and (3) Apis mellifera abundance was positively associated with high amounts of meadow within 1500 m, whereas Bombus spp. were limited in the most extensive meadow complex.  The amount of surrounding meadow area, rather than meadow size, was related to plant-pollinator community richness at multiple spatial scales, emphasizing the variability of pollinator dispersal capacity and landscape scale habitat requirements of pollinator species.