Tuesday, 15 May 2012

Two Ways to Study the World...but Only One Way to Understand Ecology

When I was a psychology grad student at Victoria University, I took a course called Drugs, Brain and Behaviour. One day we were talking about some particular drug, and I asked “what about side effects?” And our professor said, “This is a psychology class. We’re not interesting in anything that happens below the neck.”

And I thought, “Whoa! So if I take some chemical substance and it makes me feel nauseous or affects my heart or my circulation or my kidney function, that doesn’t affect my brain or my behaviour?”  I thought it was a bizarre way to try and understand how a particular drug might affect an organism.

Yet, this approach in science and medicine, called reductionism, is all too common. It means to hone in on some particular aspect of the subject and become a specialist on that particular item. It means your oncologist might know an awful lot about cancer treatment, but s/he probably has little interest in your back pain or anxiety, how the side effects of your medication impact your daily life, or what dietary and lifestyle changes you could be making to enhance a recovery process. For those things, should you mention them, your oncologist is likely to refer you on to other specialists.

And there’s nothing wrong with people deciding to specialist in particular areas or particular subjects. It is important, however, to realize that without some feel for the overall system within which that subject operates, any understanding gained is likely to be flawed.

Last night I was watching the final episode of the excellent and beautiful 2009 BBC tv documentary Yellowstone, the world’s first national park, on TV One here in New Zealand.   

It was a timely reminder of the interconnectedness of all things in an ecological system. One of the ecological stories explored by the series was the reintroduction of the wolf into Yellowstone and the cascade of unexpected effects this has had on the whole ecosystem. For example, it seems counter-intuitive that the reintroduction of wolves would be of benefit to the park’s beaver population, but it’s true. Here’s why.

Wolves were killed off in the 1930’s in Yellowstone, and as a consequence elk populations thrived with elk free to rove around the park, browsing heavily on the tasty shoots of young willow, cottonwood and alder that grow in the lowlands and alongside streams. These trees are also favoured by beavers for building dams and as food stored (underwater—amazing) for winter. When wolves were re-introduced into the park ten years ago, there was one beaver colony in the park. Today there are ten packs of wolves (around 100 wolves) in the park[i],  nine thriving beaver colonies, and elk numbers have—to the astonishment of naturalists—grown[ii]. Why? Because wolves prey on elk, the elk now spend more time browsing in the protective, deeper forest and less time in the more open wetlands where the willow, cottonwood, and alder grow. Thus, the stream-side trees have thrived, and with the trees, the beavers have thrived, and their dammed ponds are creating new wetlands for the myriad of birds, insects and fish that have taken advantage of the enhanced wetland environment. Elk, meanwhile, have split into smaller herds, and some of these smaller herds migrate out of the park in winter to lower, more pastoral (and wolf-free, if not hunter-free) feeding grounds, easing pressure on park resources. Meanwhile, elk killed by the wolves provide not only food for the wolves, but also for carrion-eaters such as eagles, ravens, magpies, coyotes, and bears who are also thriving. The documentation of how one change in the ecosystem (reintroduction of wolves) can have such far-flung effects is causing “a feeding frenzy of scientific research,” according to Doug Smith, the wildlife biologist in charge of the Yellowstone Wolf Project[iii].

Alas, there is no similar feeding frenzy in New Zealand. I feel like I harp on New Zealand’s aerial 1080 poison story a lot[iv], but this is an ecological issue with a myriad of impacts that cannot be understood or appreciated with a reductionist “let’s drop some poison and kill off the possums and therefore save our forest” approach. Ecology is never that simple. The New Zealand forest has adapted over time to the fauna within it.  According to zoologist Jo Pollard, “1080 is toxic to a broad spectrum of organisms, including native birds...[with] very high mortality rates observed in some species... Its aerial use may have whole ecosystem-level effects, such as on the rate of litter decomposition, the size of nutrient pools, and primary productivity, [as well as on] fungi, microbes, and plants.”[v] Even the targeted “possums may now fulfil an important ecological role in the dispersal of large seeds, due to the decline in large-gaped native birds” (Dungan, et al 2002, as cited in Pollard)   Pollard’s analysis of available research shows impact in many areas of NZ forest ecology following 1080 drops and leads her to conclude that “aerial 1080 has devastating ecological effects.”[vi]  

If we are to understand and appreciate and work with (rather than against) the world we live in, we have to look at the systems within it holistically. When one thing changes in that system, it can affect the whole system. There is a place for the reductionist-specialist of course, but we must be careful not to get so focussed on any one particular aspect of a system that we neglect the surrounding infrastructure that help to keep that system stable.

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