Whole-earth mentor: a conversation with Eugene P. Odum

Natural History, Oct, 1998 by J. Thomas Chaffin

Over the past few years, the so-called nonequilibrium ecologists have charged that your brand of ecology overstates the role of balances and order in nature. Looking at forests, for instance, they see a continually shifting crazy quilt of patch forests, rather than orderly succession.

If you believe that's the way things work, then there's no order, and why bother about conservation? You can't possibly take that viewpoint and then try to do anything about our problems.

The nonequilibrium ecologists argue that the instances of stability--the natural balances--are the exception.

For at least a billion years, we've had a rough balance between oxygen and [CO.sub.2]. What do you call that? The so-called nonequilibrium ecologist never looks at the big things--the environment to him is a backdrop. There is no steady state, but there sure as hell are a lot of balances.

We say that the control of organisms is at a set point. From the organism on down, everything is tightly controlled. When you're growing and when you get to be an adolescent, you stop growing automatically because of genes and hormones. And whether you like it or not, you go from youth to maturity. That's called homeostasis, a well-known physiological term. It means that your body functions are highly controlled and maintained. Cancer and obesity happen when things get out of control.

But above the organism, and for society, there's no set-point control. So if society goes from youth to maturity, it's only because the balance of nature is pulsating. We have a Greek word for this--homeorhesis, which means "same flow." The balance of nature is like a river; it rises and falls. Nature pulses. That's why it's a little hard to be sure whether global warming is a permanent change or a pulse. El Nino, of course, pulses.

You have written that as an ecosystem moves toward maturity, it gains species diversity and stability increases. But it's been argued that a monoculture, such as a spartina salt marsh or tundra, has very little diversity but is actually more stable than, say, a tropical rainforest with many species.

Salt marshes have just one big plant because very few higher plants can tolerate the salt. But the [salt marsh] system is extraordinarily diverse in microorganisms and algae. You need to measure their activity, rather than count their numbers, in microbial ecology, and this is a field most traditional ecologists don't know about. The marsh is not stabilized by diversity but by pulsing tides. Organisms are adapted to pulsing, and if you stop the pulses, the marsh will become something else. The cornfields of the Midwest are also pulse-stabilized systems, maintained for years and years, not by species diversity but by machines and people.

In the tundra, there's also a tremendous variety in kinds of organisms. It is pulse stabilized by huge weather changes. Organisms only have a short period in which to grow, so only certain lichens, grasses, sedges, and the hardiest land plants are adapted to that kind of life.