Dear Science,
I’m trying to figure out the worth of climax community. It’s very important for me to see if it has any validity. I had hoped to establish a moral system on the basis of opposing pioneer communities and climax communities.
Charles Mudede
The climax community hypothesis is indeed an appealing idea: For any given place, there is a collection of plants and animals ideally suited to it, interconnected in a balance that can sustain itself indefinitely. Over time, if the climax community hypothesis is true, one would expect a given region’s organisms to slowly reach this idealized mix—with the less ideally adapted organisms succeeded by those better suited to the environment. It’s like thinking of the development of a place as we think of the development of an organism—an orderly progression from a starting nucleus to a complete, complex, and carefully balanced living thing. In essence, entire places are thought of as gigantic superorganisms—the forest is a living thing, with individual living things and species in the forest analogous to organs. Described by the ecologist Frederic Clements early in the 20th century, the hypothesis has been built upon by subsequent ecologists.
One could apply similar thinking to human environments. Instead of a forest, one could think of a city, a neighborhood, or a block as a sort of superorganism, with people as the organs that make the community flow. In a similar way, one would imagine a community slowly gravitating toward an ever more ideal mix of people—each balanced in what they need from and can provide to the whole.
If we are to approach this as scientists, an appealing idea is not enough. We must go looking for evidence that the idea does, or does not, describe well what happens in the real world. On this measure, the climax community idea falls short. In the same location—over brief periods of time—we can observe entirely different ecosystems arising. Unlike organisms, communities don’t really demonstrate clear boundaries from one to the next. Rather, there are often gentle gradients—a blurring of boundaries, resulting in a more interesting set of overlapping combinations of living things that don’t seem to follow sharp edges.
Finally, the climax community idea—at least in the minds of some ecologists—doesn’t account well enough for random events: disasters, the slow change in the nature of a given place due to the drift of tectonic plates, changes in the atmosphere, solar activity, and a multitude of other factors that change the underlying nature of a place. Things happen to change a place well before the living things in it can reach their idealized place.
The short of it: Don’t fall too deeply in love with a lovely idea. Empirically, things are usually more complex and more interesting.
Communally yours,
Science
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Interesting article. At first glance I thought the climax community was another “sex positive” orgy warehouse. I guess I will have to read more on the subject.
Jonathan you are wonderful.
You’re presenting a very different version of the climax community than the one I’m familiar with. As far as I’m aware, the climax community is nothing more (or less) than the community that will stick around in a given area if nothing changes (no natural disasters and the like). In this view, a climax community is neither good nor bad (none of this “ideal” and “superorganism” stuff); it’s just the one that isn’t going to change on its own.
Example: a forest in the Northwest burns down. You now have dirt, ashes, and various other debris. Then grass starts to grow. Then shrubs. Then little trees. Then big trees. As this happens, the trees start shading out the grass and shrubs, killing them. Fast growing trees are overtaken by slow growing trees. Eventually you have lots and lots of big, slow growing trees but no grass and shrubs. The grassland isn’t a climax community will go away on it’s own (to be replaced by trees). Unless something happens (natural disaster, etc,) the forest won’t go away ; it’s a climax community. The forest isn’t more ideal than the grassland, it’s just more permanent.
Lorran@3 What you’re referring to is a mature or old-growth community. While that is sometimes referred to as a “climax community” by non-scientists today, it doesn’t actually fit the definition of climax theory.
It is worth bringing up the red queen hypothesis of evolutionary biology. There is a great pop sci book names “The Red Queen” that is written at a level anyone can understand to explain it.
Basically, it points out that evolution is not a always moving “forward” and must be thought of as much more cyclical. There is competition between differences species so you would assume the arms race leads to better and better genes for things such as running faster or jumping higher. The theory explains why we actually see many evolution constantly coming around in a circle, whereas what was advantageous yesterday might not be advantageous tomorrow.
I think the climax community idea is far too idealistic that there is a “best” community. That idea not only does not work in practice but the very theory of a best community does not pan out.
I am not an advocate of climax hypothesis, but in the study of biomimicry we look for long term sustainable communities like prairie to replace monoculture annual type crops. By discovering self sustaining (i.e. little to no pesticides, fertilizers) communities that are capable of nitrogen fixation and productive edible crops perennially the concept of “climax communities” are important.
@3, thanks for the clarity. really, that made the matter plain to me. and neatly removed my moralism from the picture. Your response, and Golob’s, put me on solid ground.
charles, you’re a religious man without a religion, something i understand
I’m glad @3 helped clear things up for you, Charles, but s/he is wrong.@4 is right. For more information about how plant community succession actually works, I would recommend reading Henry A. Gleason’s classic 1926 article (available to anyone with internet access, has been cited over 1200 times): The individualistic concept of the plant association. Bulletin of the Torrey Botanical Club 53: 7-26. Or better yet, go interview Jerry Franklin at UW, for the love of God. He’s one of the top researchers on forest succession and processes and he lives in your own city.
Jonathan’s great and all, but this is a much too difficult and intricate topic to be adequately dealt with in a few paragraphs.
Jonathan, you need to need to steer clear of ecology questions. They obviously aren’t your strong point.