Multiregional evaluation of pollinator response to climate change in critical habitats service-wide.

Rodman, Ann

"PIs propose to evaluate bee communities in a high elevation grassy bald community (Purchase Knob) and a dry, lowland site (western edge of the park; the VUL site), both of which may be at risk from climate change. With similar inventories being conducted in 74 other park sites at other at-risk habitats, the broad scale of this project will also allow comparisons of bee communities across habitats and parks. Native bees provide a critical ecosystem service, pollination, yet we know little about their abundances and distributions across NPS lands, and even less about the possible effects of climate change on bee populations and the subsequent ramifications for native plant communities. High elevation, coastal, and arid areas are particularly vulnerable to climate change and these areas are often hot spots for bee and plant endemism. In 2011, bees were collected during nine 2-day sampling periods (5/7-8 (PKnob), 5/10-11(VUL), 5/30-31 (both), 7/9-10 (VUL), 7/13-14 (PKnob), 9/18-19 (VUL), and 10/17-18 (VUL)). Two additional autumn collections and one April collection was made in 2012. The 576 specimens of 76 species in 18 genera have been pinned and labeled. Three species were new park records. The contrasts between the two sites are great. Total numbers of bees are clearly lower in the dry area than Purchase Knob. One can see a strong field signal at Purchase Knob in the numbers of Andrena nasonii (a classic lawn species) and field species such as Augochlorella aurata, Hylaeus affinis (favors flat umbelliferous species), and Lasioglossum ceanothi. The large number of Andrena species found at Purchase Knob is also matched by a large number of their nest parasites, Nomada. The Ceratina species are an interesting contrast. The low elevation site has a good number of C. strenua, a southern species, while the upper elevations have good numbers of the other 2 common species, C. calcarata and C. dupla. All told these are two areas with very different bee faunas. The O. cornifrons are unfortunately not surprising to see. This is an invasive species that is commonly distributed both purposely and as stow-aways by the Orchard Bee crowd. They are of the same subgenus and size as the native O. lignaria (the blue orchard bee) and in the Mid-Atlantic area they can be one of the dominant bees in woodland environments in the spring, though interestingly, the most common Osmia is now in the Mid-Atlantic is often O. taurus another invasive from the same genus. It is spreading and should be expected in forested areas throughout the East. The consequences of these 2 species arrivals for native Osmia is unknown."