Two, three years ago, a die-off of honey bees was much in the news, with assorted alarms and various proposed explanations.  It became a persistent theme in my favorite (non-ecological) email list, so I got into the act with the following, expanded here.
    About bees: I grew up "country," rural, in the 1930s and early 40s, in Lower Michigan in an era of "general farming" (at least east of the plains).  Orchards, mostly small, were common, as were alfalfa and other clover fields; bee pastures, all of them.  And bees accordingly abundant.  In college I started in agriculture –– and among other things took a course in bee-keeping.  Then switched majors and ended up with two degrees in forestry and a PhD in ecology. 
    In grad school, in the mid-1950s, I took two courses in ecological research methods, one of which included a section on paleoecology.  Even had a little introductory experience with peat cores and pollen sampling.  Which didn't make me an expert on bees, but it gave me a deeper, broader perspective on them than most journalists and bloggers, and my personality traits include Observation and Realist (not Idealist or Cynic). 
    My subsequent science reading has included TIME SCALE by Nigel Calder, which looks at changes in the Earth, its climates, vulcanism –– and life forms, from their beginnings to the time of writing (1983, Viking Press); also AFTER THE ICE AGE: the Return of Life to Glaciated North America, by P.C. Pielou, (1991, University of Chicago Press).  More recently, Calder produced a great, thick, marvelous, highly readable update, MAGIC UNIVERSE: a Grand Tour of Modern Science (2003, Oxford University Press).  Its contents include a number of pieces relevant to the fading and burgeoning of species.  I expect to be reading and re-reading it for years.  Along with Alan Weisman's THE WORLD WITHOUT US (2007, St. Martin's Press), a book I consider inspired, ingenious, and honest; but not necessarily accurate (nor does he claim it is).

    Now, back to the bees.  Neither Calder, Pielou, nor Weisman as I recall, mentions bees at all, but they do deal with climatic and bio-geographic changes big-time, Calder and Weisman broadly throughout Earth history, and Pielou in detail during the ablation of the Great Ice, the drainage of the vast meltwater lakes, and large scale migrations of life of every kind.  Sometimes demonstrating compressed evolution, to fill biological vacuums. 
    I haven't kept up on bees disappearing, but concern seems to have died out (hopefully leaving behind a series of research studies and fuller understanding).  And I did read, a dozen or fifteen years ago, about the imminent destruction of sugar maple throughout its range, by air pollution.  The articles have passed on but the maples are still with us, possibly because of legislation reducing acid rain.
 
    Alarms are rung by idealists.  Some prove more or less correct, or at least point out things worth dealing with.  Others do not.  Some, like Rachel Carson's SILENT SPRING (Houghton Mifflin, 1962), while perhaps overblown, made a valid and powerful case, and served a broad purpose, awakening the public to the risks involved in mucking around with the planetary, and regional and local ecology.  Idealists are a part of the mix; they serve vital purposes, and we needs 'em, we does.  But it is well to read them critically.
    As a Realist dealing with the environment (and with life in general), I try to avoid the negative pole, supposition, an avoidance which produces a sort of learned (rather than innate) skepticism.  (Can you say "suppositional reality?")

    Apis mellifera mellifera makes up by far the bulk of bees in America.  They were introduced here by European colonists, and were new to Native Americans, who are said to have called them "the white man's fly."  Like most life forms, honey bees respond to conditions, natural and man-made.  In the Minnesota border counties (where I spent considerable time in my youth), and very probably North Dakota's border as well, bees do not overwinter successfully.  They will not defecate/urinate in their hives, so in winter they wait for a temperature in the mid-40s.  And if, after 5 weeks or something like that, it doesn't get that warm (we're talking the Minnesota border counties), they'll fly outside anyway; they can't hold it any longer.  And before they can make it back into the hive, they die; perhaps because their body fluids congeal.
    Meanwhile the vast forests and bogs of the Canadian taiga region (the Minnesota border is on the southern fringe of the taiga) do nicely without honey bees.  They have bumble bees and hornets, but not honey bees.  On the other hand, the occasional small farming settlements (shrinking for the past half century due to economic pressures) grow clover hays –– especially alfalfa, as an important cash  crop.  And to cover the need for pollenization, rent bee colonies from "the bee man" (or did then –– the late 1940s) who delivered them in spring and picked them up in autumn.  In fact those severe winters, so hard on the  clovers, make seed from winter-hardy Minnesota alfalfa strains especially valuable.
    On the whole, modern farming may well impact bee populations.  New sanitation laws (mainly I believe in the 1950s) required farmers to have very expensive milk production plants if they wanted to sell milk products.  One result was that most farmers quit the dairy business, switching to cash crops or beef.  And while most farmers quit keeping dairy cows, others borrowed money and went into dairy big-time, more efficiently than ever, and often buy their hay instead of growing it themselves.  Today, in much of the midwest, farming now centers on corn and beans, especially soybeans.  (Beans are legumes, like the clovers.)  I therefore assume (don't actually know) that soybeans are bee pollinated.  If so, they require bees, and I suspect that bees are happy to oblige.
     And if that means modifying farming practices to maintain bees, practices will be modified.  Agricultural scientists are not monsters, nor stupid, nor ignorant, nor, ordinarily, perverse.  Some may have considerably short-term perspectives, but there's a lot of that going around.  Always has been.

   As for people's yards –– in terms of total vegetated area, yards are very minor.  Locally big, but over much of the world they are a minute part of regional landscapes.
   Incidentally, for years I kept a presentable lawn without either spraying for weeds or fertilizing, by using a lawn mower that mulched what it cut.  (I never raked the grass.)  And because of that mulch, plus root-available nitrogen from thunderstorms and the white clover and black melic growing in the lawn, fertility remained good.  Sure I had dandelions (gasp!), but so did most of my spray-happy neighbors.  And the bees — both honey bees and bumble bees –– appreciated the white clover and melic.
    Meanwhile honey is still affordable.  I sweeten my tea with  it regularly.