Humans as a Keystone Species

There are two assumptions that I do not agree with in the world of biology and conservation. The first is that humans are not a part of nature. The second is that any way humans use the land (natural resources) always does damage to the natural environment. There have been many arguments promoting the idea that humans are a part of nature and investigating the relationships between humans and the natural environment. But even these implies that humans are not a part of nature. What is natural?

Humans are part of nature. We breathe and use natural resources and when we die our bodies become a resource for other forms of life. If we are connected so intimately to the ecosystem, why then are we not a part of the ecosystem?

I say we are, and not only are we a part of the ecosystem, some groups, not all, but some groups, of humans are very important parts of the ecosystem. Take for example certain Mettler's Woods in New Jersey. It is an old growth oak forest considered by some views to be the "climax state" of the ecosystem. When we tried to preserve Mettler's Woods by keeping human disturbance from the area, we found to our surprise that the old growth oaks weren't regenerating. It turns out that the forest oaks required fire to reproduce, and before the preserve was established, much was human-caused. Without human settlements causing the fires, the oak forest probably wouldn't exist.

So what if there are no oak trees? It wouldn't be the end of the world, but it wouldn't be the same ecosystem. If any keystone species were removed from an ecosystem, there would still be life in the area. It would just be a vastly different ecosystem.

Human caused fires were very common once used as a tool to control the ecosystem in North America by American Indian tribes. Tribes would use fire to clear land for farming, or to return nutrients to the soil, and many ecosystems, such as the California chaparral, and the Yellowstone lodgepole pine forests, depend on these fires.

Humans can also act as a top predator in an ecosystem, and play a crucial role that way. In Deerfield, Illinois, white-tailed deer have no natural predator. Without hunting season, the deer population would grow until it caused major damage to the flora in the environment and eventually use up the resource, and crash. Hunting season, or human predatory season, keeps the population in check and healthy, and is crucial to the health of the ecosystem.

The last example I would like to bring up is the ecosystem of the University of California, Berkeley, campus. We don't usually think of a college campus as an ecosystem, but there is life on it that affects each other and is affected by abiotic factors. Species living in the ecosystem include squirrels, crows, dark-eyed juncos, dogwoods, pines, eucalyptus, incense cedar, and of course, humans.

Without humans, this ecosystem wouldn't exist. We all agree to this. We provide the food by dropping crumbs or feeding squirrels, and our activities changed the landscape so that these species (especially the squirrels) could live in this environment. The same thing applies to a garden plot, a farm, a house, or a city.

We are a keystone species unlike any other. We're not just a part of the food web, our social structure and intelligence means that we can analyze ecosystems that we live in and occupy the niche that needs to be occupied to keep the ecosystem healthy. But we mustn't think that we are separate from nature, because that means we can gain by allowing the system to suffer. We can't. We are part of the ecosystem, and we must consciously act for the good of the whole. Only then can we survive.