SUSTAINING WILD BEE POPULATIONS FOR POLLINATION SERVICES
2013 Annual Report
1a.Objectives (from AD-416):
The objective of this cooperative research is to determine the diversity of wild bees in the Western U.S. and evaluate factors important to their preservation.
1b.Approach (from AD-416):
Wild bees will be studied in the Western U.S., especially the Great Basin and adjoining regions, sampling in and out of past wildfires on wildflower species targeted for use in restoration seeding projects. All bees will be identified for calculating their abundance and diversity. Geographical information systems will be used to evaluate bee populations as they are distributed in time and space. For bumble bees, historical records and DNA analysis will be used to evaluate whether populations are expanding or contracting in range, and whether any species are under threat of extinction. Their mortality factors, such as diseases and parasites, will also be evaluated.
Wild bees and rangeland fire. The fates of wild bee communities following wildfire are unknown, but critical to anticipating pollination services following large post-fire restoration seedings, such as those across the sage-steppe of the Great Basin. Using a new suite of sampling protocols, bee floral guilds were systematically sampled in pairs far in and outside the boundaries of a sequence of large burns (>50,000 acre), accompanied by characterization of their plant communities. Where rangeland plant communities were in good shape before burning, most plant species and their diverse native bee communities seem little altered by fire. Over several years, the native wildflowers sometimes became abundant. To assist the recovery of native bee communities after a major fire, restoration seed mixes should include some flowering species that bloom the year after fire, plants that are broadly attractive to local native bees. These can sustain bee populations in the year following the fire, a time period when perennial wildflowers will still be establishing and not yet blooming.
Bumble bee diversity. Bumble bee species records were entered into a database from multiple institutions in the western United States and this project resulted in the publication of the Guide to the Bumble Bees of the Western United States, published in 2012. This 144 page document can be accessed at http://www.pollinator.org/PDFs/BumbleBee.GuideWestern.FINAL.pdf.