We think of diversity in human terms. People are from diverse cultures and traditions, and we are all culturally enriched by the blending of these backgrounds. The melting pot theory is premised on the proposition that people should cherish individualism, while they also grow from the rich multi-cultural experience associated with our large cities.

Diversity can be most enriching when it is people that we are talking about. But, in the case of plants and animal species, tremendous harm can result from reckless transplantation of alien species.

We are seeing the problem, and its negative consequences, with increasing frequency both here in the United States and though out the world. Largely, it is the jet age that is to blame. When we didn't step foot out of our village, alien species had few opportunities to invade our borders. But now that we all go everywhere, these species follow in empty shoes, bald tires, suit cases, cargo boxes, and every other imaginable trans-global crevice.

The most celebrated invaders are the zebra mussel, the brown tree snake, nutria, and kudzu. These invaders have gotten a lot of press, but they are just the tip of the alien iceberg. Bio invasion is occurring virtually everywhere, every day.

Kudzu is now called the green menace in the south. But, originally it was imported by southern farmers to curtail soil erosion. Over the last 70 years, or so, the plant's creeping vines have taken over hefty portions of the southern landscape. And the plant kills native species when it takes over.

According to the U.S. Geological Survey, another pervasive problem is the nutria rodent, which invaded the Chesapeake Bay Area, as well as many other areas. Nutria are small rodents which effectively destroy ecologically important swamp lands.

Of course, the rodents did not purchase boarding passes and fly here by themselves. Farmers originally imported the rodents for their furs. Now nobody wants the furs, and these animals are wreaking havoc all over the place. Scientists have referred to them as a cancer on the Chesapeake.

According to United States Fish and Wildlife Service, 42 percent of the species on our endangered and threatened species lists are being threatened as a result of alien species. President Clinton assembled a Task Force to address this issue and 20 federal agencies have been given a role in this fight.

The Nature Conservancy and the Worldwatch Institute, as well as other ecology groups, are joined by federal and state agencies, in their efforts to define the extent of the non-alien species problem and identify a cure. And this is apparently a very stubborn issue.

The problem is that this kind of "pollution" has the ability to, in effect, think. When non-native species invade, the can multiply and they can adapt. Contrasted with traditional forms of pollution, such as oil spills, which in certain cases can dissipate naturally, non-native invaders repopulate and become better at fitting in. And when they settle in, it is often at the cost of killing native species.

While the term bio-invasion sounds like something out of a James Bond movie, it is a proper term for defining this problem. According to the federal government, there are thousands of alien species invaders in the United States, and new ones are always being introduced. In Florida, the federal government estimates that 25% of the species are non-native.

Traditionally, natural boundaries such as mountains and lakes once isolated species so as to prevent cross-overs. But, human intervention, such as the creation of roads, bridges, railroad tracks, etc., has changed all of that. It now turns out that climbing every mountain has created a negative impact.

The cures they speak of are very high tech, involving large scale sprayings and areal surveillance. And success rates are not generally impressive.

Now that physical boundaries are less significant, alien species invasions will inevitably continue. Just as the plants must do, we will all have to adapt to these changes to our landscape.

The information provided in this column is written by Stuart Lieberman,a practicing environmental attorney, and is for general information purposes only. It is not legal advice and should not be used in place of legal advice.

Stuart Lieberman, Esq., and IRED.Com, Inc., will not accept any responsibilty for any reliance on the information in this column or any damages whatsoever resulting from reading this column.