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