I could try to explain why this is an issue, but I'm not a biologist or researcher and really wouldn't be the best person for that. But! I am here to tell you that Samantha Jakuboski has written a wonderful article on this very topic over at Scitable.
Meanwhile I am going to google what flowers I can plant now to feed the darling little bees that have stolen my heart. ✿
P.S. If you concur, we should get these.