Investigating the Role of Local Floristic Diversity in Provisioning Wild Bees in Pennsylvania Apple Orchards
Open Access
- Author:
- Kammerer, Melanie Anne
- Graduate Program:
- Ecology
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- November 19, 2013
- Committee Members:
- David A Mortensen, Thesis Advisor/Co-Advisor
- Keywords:
- pollinators
wild bees
floristic diversity
ecosystem services
apple production - Abstract:
- Wild pollinators supply essential, historically undervalued pollination services to crops and natural plant communities, with great potential to insure agricultural production against the loss of managed pollinators. Local plant communities provision wild bees with crucial floral and nesting resources, but the distribution of floristic diversity in North American agricultural landscapes and effects on pollinators are poorly understood. Therefore, I documented floristic diversity in orchard, forest, and forest edge habitats in an apple (Malus domestica Borkh.) production region in south-central Pennsylvania, USA. I tested the correlation between plant diversity and orchard pollinator communities in two field seasons. I showed that local non-crop habitats, specifically forest edges, contain a majority of the floristic diversity in this agricultural landscape. Plant diversity in forest and forest edge habitats is correlated with bee richness, abundance, and community composition in apple orchards. Within an orchard, I found a significant spatial pattern in wild bee abundance as a factor of proximity to the adjacent forest edge. Wild bee abundance substantially decreased with increasing distance from the forest edge. I used a spatially explicit model to explore how resource provisioning from local habitats underlie this trend, and showed that it is likely resulting from the lack of nesting sites in the orchard compared with the forest. Even in heterogeneous landscapes, the proximity to and quality of resources in local semi-natural habitats is correlated with wild bee communities in agricultural fields. Management and conservation of non-crop areas to promote pollinators is crucial for maintaining and enhancing pollination services in agricultural landscapes.