|from Science Daily|
Science Daily reports that localized changes in climate is a major factor.
"Bee numbers may have declined at our research site, but we suspect that a climate-driven mismatch between the times when flowers open and when bees emerge from hibernation is a more important factor," says James Thomson, a scientist with U of T's Department of Ecology and Evolutionary Biology."
"Early in the year, when bumble bee queens are still hibernating, the fruiting rates are especially low," he says. "This is sobering because it suggests that pollination is vulnerable even in a relatively pristine environment that is free of pesticides and human disturbance but still subject to climate change."This has potential to occur an any climate where there are changes progressive changes in temperature patterns. With increased warming, temperature increases also start to occur earlier in the year. This can affect not only the availability of seasonal pollinators, but also the animals which depend on the plants for nutrition.
Obviously, these changes have occurred throughout the life of the planet. This is just one factor in extinctions as well as the adaptations that new species make with time. Much as we would like to keep the planet, or at least our neighborhood, just as it "always was", time marches on. We just need to be sure that we aren't causing it to march too fast.