It has been obvious for many years now that bees are in trouble. We've covered the issue quite extensively, including the recent controversy surrounding neonicotinoids-based pesticides (4 chemicals in that family were banned last year in the EU). But one thing that has made it hard to pinpoint the cause, or causes, of bees problems is that there were few truly large-scale studies of bee populations.
That's where EPILOBEE comes in, a harmonized epidemiological surveillance programme that is taking place in 17 European countries. This means that the continent-wide data is collected using compatible methodologies and can thus be aggregated together and compared to try to get a better idea of what ails our pollinator friends.
The study determined that 10% was an "acceptable threshold for bee colony mortality", so countries that are above that - especially those that are significantly above that level - are definitely red flags that should be investigated:
Winter colony mortality rates ranged from 3.5 % to 33.6 % with a south-north geographical pattern. In Greece, Hungary, Italy, Lithuania, Slovakia and Spain over winter colony losses were below 10%. In Germany, France, Latvia Poland and Portugal mortality rates were between 10 and 15%. In Belgium, Denmark, Estonia, Finland, Sweden and the United Kingdom winter mortality rates were above 20%. Overall rates of seasonal colony mortality (during beekeeping season) were lower than winter mortality and ranged from 0.3% to 13.6% (source)
Above is a map showing winter mortality rates for bee colonies located in 17 EU countries during the 2012-2013 winter.
Below is the same map, but for mortality rate during the spring-summer 2013:
Here's the shocking part, though: Authors of the study wanted pesticide impacts to be included in EPILOBEE, but that was overruled by the governments of the countries in the study at a the commission level. That's such a missed opportunity to learn more...