Researchers with the New Hampshire Agricultural Experiment Station at the University of New Hampshire have found three of the state's most important bumble bee species have experienced drastic declines and range constriction over the last 150 years, with a fourth bee also in significant decline. The research was published in Biological Conservation. Scientists found drastic decline in Bombus affinis, Bombus fervidus, and Bombus terricola, as well as significant decline in Bombus vagans, with data suggesting it has been ecologically replaced by Bombus impatiens over time. The study adds critical floral associations and demographic data for New England bumble bees and those undergoing national decline, to better inform management decisions and conservation efforts going into the future. The value of pollination to agriculture is estimated at more than $200 billion a year worldwide, with abundance of and diversity of pollinators declining in many agricultural landscapes across the United States.