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.
3. Progress Report
The geographic and ecological extent of the decline of Bombus occidentalis was evaluated. To obtain historic data on the distribution of bumble bees, 28 insect collections at universities and public institutions were utilized to build a relational database using the data from bumble bee specimen labels from more than 40,000 specimens. To obtain current distributions, the largest standardized survey of bumble bees ever conducted in North America was completed this year. Several species distribution models were created using geographical mapping software. Two manuscripts of the research were completed and submitted to peer reviewed journals, and the results were also presented as a poster at two national conferences. In addition, the fate of solitary bee communities after a wild fire was evaluated across the northern Great Basin. Sampling methods were developed and refined, and were found to be efficient and effective for evaluating bee guilds. Bees were sampled in pairs of in- and out-of large burn sites. The salinity attributes, plant communities (species richness), and spatial scales (densities of dominant bee-flowers and woody vegetation) were characterized for each site. To date, 17 burned/intact site pairs (including the 1999 City of Rocks fire site) have been sampled. Most of the focus was on species of Balsamorhiza and their bees. Nearly all of the bee identifications have been completed. Statistical analyses was begun to compare the burn vs. no burn areas, as well as to map the ecological data geographically. Preliminary results show that bee and forb density was slightly, but not significantly, higher in burned habitats, probably explained by the burning of competing shrubs. Forb diversity was similar before and after the burn, suggesting that fire did not alter the forb community. Ground nesting bees dominated the post-fire community (as predicted), just as they do in intact habitats. Surprisingly, however, it appears that the above-ground nesting bees survived just fine, contrary to our prediction. For example, the stem-nesting bees Ceratina and Hoplitus were more common in burned sites. Finally, the nesting biology of two of the three dominant bee genera (Eucera and Andrena) is well established as ground-nesters, however the genus Osmia includes both ground and cavity nesting species. ADODR monitoring is performed via e-mail, phone calls, on-site discussions/meetings.