PARENT SESSION
Contributed Oral Session 54: Urban Plant Communities
Tuesday, August 9, 8:00 AM - 11:30 AM, Meeting Room 524 C, Level 5, Palais des congrès de Montréal
Pollination in an urbanizing environment: effects of habitat fragmentation on wild bee assemblages.
Hinners, Sarah *,1, Kearns, Carol1, Wessman, Carol1, 1 University of Colorado, Boulder, CO, USA
ABSTRACT- Pollination is a vital ecosystem function in most terrestrial ecosystems. Because it relies on mutualistic relationships among organisms, pollination function may be subject to disruption in the face of disturbance or habitat loss. Currently, one of the major potential threats to pollination systems is habitat fragmentation: theory predicts that smaller fragments will support fewer pollinators, and that surviving populations will face higher risks of local extinction within fragments. Therefore, plants that rely on animal pollinators for successful reproduction also face an increased extinction risk. Urban development, especially medium- and low-density suburban sprawl is a particularly effective creator of fragmented landscapes as it results in small pockets of original habitat surrounded by residential, commercial, and industrial land use. The research reported here is part of a multi-year study in the greater Denver area, Colorado, aimed at determining the effects of suburban development on the wild bee assemblages primarily responsible for pollination in Colorado shortgrass prairie. We are characterizing the wild bee assemblages in 12 prairie fragments surrounded by residential land use and comparing these with assemblages found in 3 large unfragmented prairie sites. Fragments range from 2 to 60 hectares in size. Early analyses show that richness at the genus level is predicted by fragment size in small- to medium-sized fragments. However, larger fragments appear to behave more like open prairie, where assemblage diversity is related to local habitat characteristics. Abundance is highly spatially variable, but appears to be slightly higher on unfragmented prairie. As analyses on these data continue, we will build a comprehensive picture of the status of pollinator assemblages and pollination in an urbanizing ecosystem.
Key words: fragmentation, pollination, urban, pollinator assemblage