Effects of abundance, diversity, and health of native pollinators in urban forest fragments

Date
2015
Journal Title
Journal ISSN
Volume Title
Publisher
University of Delaware
Abstract
Bees are essential for crop pollination services; however, the ecosystem services they provide by pollinating native plants are crucial for maintaining biodiversity in natural systems. This study analyzed bee community changes within, on the edge, and outside of forest fragments. Phenological variation over two seasons and modeling to predict bee abundance associated with forest characteristics was performed. Finally the genetic diversity of two species of Bombus was analyzed. Bowl traps and aerial sweep netting in and near forest patches were used to sample bee communities in northern Delaware between March and August, 2013 and 2014. Bee phenology stayed consistent between field seasons, but fewer bees were collected in 2014 compared to 2013. Abundance modeling (R: unmarked) predicted that bee abundance was negatively impacted primarily by agriculture surrounding the forest patch. Analyses using microsatellites revealed that B. impatiens lacked overt population genetic structure while B. bimaculatus showed two genetically distinct populations. Pesticide analysis revealed 17 pesticides observed on adult bees from seven urban and suburban forest patches. Further studies investigating natural bee fluctuations in response to multiple field seasons, floral diversity, and chronic pesticide exposure are crucial in order to assess native pollinator health.
Description
Keywords
Citation