How does coal mine reclamation influence bumble bee colony success and pollen use?

Bumble bees are highly efficient pollinators of both crops and wildflowers, and are of conservation interest given recent reports of declines in species richness and abundance in temperate regions.  Anthropogenic disturbances such as coal mining cause extensive changes to the landscape in the Appalachian region, and alter the amount and quality of bee habitat. Reclamation of former mine sites creates long-standing grasslands that may mature to old field communities, and thereby increase the amount of suitable bee habitat and the stability of floral resources at the landscape level.  The object of this study is to determine: (1) which flower species are critical to bees in mine-impacted areas, (2) in what proportion bees rely on resources from reclamations versus adjacent habitats, and (3) if reclamations increase in value to pollinators over time.  I will analyze pollen from returning foragers and nest contents of sentinel colonies on a chronosequence of 12 reclaimed surface mines (aged 2-25+ years). I expect site age to be positively related to floral diversity, and thus pollen diversity utilized by bees.  If older sites offer more diverse resources, I also expect bumble bee colonies to have higher overall productivity (measured in worker, male, and queen production) and greater reliance on reclamation relative to adjacent habitats as sites mature.  Herein, I also consider the effect of landscape context on bee foraging and productivity. Tracking which wildflowers bees rely on in mine-impacted landscapes will allow us to make recommendations on land management practices that encourage pollinators.