Tuesday, December 14, 2010

Waldsterben all over again?

Michelle tipped me off to yet another "all the bees are dying" article.

The new wrinkle in the story is a leaked EPA memo that suggests that Bayer CropScience's seed treatment, chlothianidin, was registered without sufficient proof that it didn't hurt bees. Aside from the fact that this registration was completed in 2004 and (according to the same article) this whole bee business started in the mid-1990s, I'm skeptical that any new pesticide is causing all this. We were SO much more indiscriminate and profligate with our agricultural sprays and industrial dumping in past decades (and with much more dangerous chemicals) than we are now - it seems a funny time for a problem to pop up. I haven't paid a lot of attention to the CCD story, but the persistent failure to identify a cause makes me wonder if the cause really is as simple as an anthropogenic chemical or exotic pathogen.

Back in acid-rain days, Waldsterben ("forest death") was defined as "the widespread and substantial decline in growth and change in behavior of many softwood and hardwood forest ecosystems in central Europe." News reports documented the widespread death of specific tree species in temperate Northern hemisphere woodlands. Both the related fields of forest biology and the general public were swept up in the fear that the world's forests were atrophying (due to some atmospheric pollutant), which would soon leave us in a dusty, tree-barren landscape.
"These works further suggested that unknown causal stress factors were involved, but stated that atmospheric deposition was known to be involved. They listed six basic hypotheses, including acidification-aluminum toxicity, ozone effects, magnesium deficiency, general disturbance of physiological function, excess nutrients, and air transport of growth-altering organic substances, all put forward as explanations for particular portions of the syndrome. It was proposed that many forest ecosystems would likely be destroyed."
The thing is - it never happened:
There was no systemic decline in northern forests.

Individual trees suffered from a series of epidemics of natural diseases and exotic pests while individual forest plots suffered from local acts of god. Many of these "declines" were simply normal cyclical ecological processes that went unrecognized by scientists - both due to our very short history of paying attention to this type of thing and to groupthink. Scientists and the public were quick to take it for granted that a decline of trees was occurring and that strong evidence incriminated anthropogenic pollution. Some walked through acres of apparently health forest only to ascribe Waldsterben to a patch of disrupted growth. Others over-scrutinized "symptoms" that they would not previously have looked for or noticed.

I think landscape-scale ecological studies are particularly prone to this type of uncertainty - forests are big, slow and normally no one pays any attention to them - meaning when a problem pops up, there's not a lot of literature describing what the historical status-quo was. Meanwhile, once the meme is out there, people can see it everywhere. Thorough studies are expensive, difficult, time-consuming and rare while any grad student with some compelling data can toss out a paper that inadvertently contributes to a false sense of a tidal wave of evidence. Sometimes (like with climate change), the continuing ferver of research confirms the initial suspicions, other times (like Waldsterben), it all seems a little naive in hindsight.

I don't know anything about entomology and I haven't been paying much attention to the Colony Collapse Disorder story, but I'm hoping this is another instance of a short-sighted species over-reacting to an unusual, but normal, event.


John M. Skelly, & John L. Innes (1994). Waldsterben in the Forests of Central Europe and Eastern North America: Fantasy or Reality? Plant Disease, 78 (11), 1021-1032

7 comments:

  1. I tend to think it's a bee disease issue. Something that the media fails to describe about CCD is that it is a disease of farmed bees. That is, domesticated bees that are being kept in human-built beehives. These bees are highly inbred (susceptible to disease, anyone?). CCD has not been described in wild bee populations.

    This does not diminish the importance of CCD, domestic bees are *very* important for quite a number of agricultural crops. But it also points to a likely culprit that is almost certainly not an environmental pollutant. While the published evidence is not yet rock-solid, everything published so far points towards microbial pathogens.

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  2. The current scientific explanation of CCD is, some viruses got on their cell phones and called up some fungi and was like "Yo! I'm inside a bee! Why don't you come join me?"

    And that is the cause of CCD.

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  3. Ah, very interesting Bbq, thanks.

    @ Mr - great description!

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  4. Thanks Matt, it's good to hear a different take on the matter.

    LOL at mister ants! :)

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  5. Ha! Mr. ILoveTheAnts, I was about to write the same thing about the virus and fungi combination causing CCD, but I like your description of it much better than anything I could have written!

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  6. Contrary to what's sometimes been said, CCD is specifically a US problem, and there have been large-scale die-offs there before. Whatever it is, it seems to be multifactorial. I haven't paid a lot of attention though, as I've got other problems keeping my own bees going. The specific pathogens they're talking about are not confined to the US, so why does the problem, whatever it is, only occur there? I suspect myself that it's something to do with their industrial-scale beekeeping. If you put a whole lot of hives together in one place, that creates perfect conditions for disease to spread.

    Feral hives are scarce now due to varroa, and tend to be well spaced out. As you can probably imagine, funds for bee research are very limited, and nothing's really being done on them.

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  7. Not so fast BBQ and Ilovetheants, there is research that suggests that the royal jelly and bee bread are negatively affected by fungicides - especially the new class of strobilurins. According to the research, this class of fungicide (as well as a few more) kills the fungi that are responsible for the fermentation of the bee bread and royal jelly. These materials are needed for the development of the queen and new brood.

    Think about it, if the queen isn't able to lay as many eggs due to reduction of food source, and if the laid eggs yield bees that aren't as healthy and don't live as long due to viruses, fungi, and parasites, it wouldn't take long for a hive to collapse, hence CCD.

    Granted this is new research and the results aren't all in, but I think they may be onto something.

    I wrote about this subject this past March, here is the link: http://www.thealmonddoctor.com/2010/03/fungicides-and-bee-health.html

    Currently, beekeepers and farmers out here are developing stewardship practices to help reduce the amount of fungicides making its way into the hive.

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