Ecological Management of Problem Vegetation (aka. "Invasive Weeds")
In 1491, North America contained a wide diversity of ecosystems and human cultures. Today, the landscape is more homogeneous. Most of the prairie is gone, replaced by large areas of monocultures of corn, wheat, and soybeans. The eastern forests have largely been replaced by concrete jungles, which have spread across the rest of the continent as well. Whole cultures have disappeared. Whole species are going extinct at an alarming rate.
Other changes have occurred as well. The replacement of diverse ecosystems with monocultures and concrete has been accompanied by disturbances that create new habitats. As people have moved around, they have carried with them —sometimes unwittingly, sometimes purposely —plants and animals from their former homes. When the habitat suits the new species, they move in.
When these new inhabitants interfere with what we want to do, we call them “pests” or “weeds.” There has been a lot of attention recently to weeds that seem to be especially difficult to manage, particularly those that have become established in “natural” or managed ecosystems.
Are these species “invasive?" Or are they opportunists taking advantage of disturbed ecosystems? When, if ever, should we mount campaigns to eradicate these species in their adopted homes? David Pimentel, PhD argues that alien weeds pose serious problems for agricultural and natural ecosystems. Virginia Daley and Fritzi Cohen argue that humans have always been assisting the spread of plants wherever they moved, and that the current hype over “invasive plants” is an excuse to mount chemical warfare campaigns. Either way, toxic chemicals are not the answer—in fact, they pose greater threats than the problems they are meant to solve.
There are many other approaches to managing problem vegetation that have proved to be successful. As can be seen in the following descriptions of other approaches, successful land management needs to consider the whole system.