The common pigeon is perhaps the best illustration of the problem. I suppose that everyone would agree that they are a nuisance. At the same time they have been with us for so long that we have come to expect their presence. The reality is that the pigeon is not a native species in North America. It is native to the Mediterranean. A cliff dwelling bird in its natural habitat, it has adapted to living on widow sills and ledges in large and small towns alike. They are a documented vector of disease, and cost us a many millions of dollars in building and park maintenance each year.
Other animal species are noted : The European Wild Boar, which has proliferated in the Appalachian region. (I have seen places in the Great Smoky Mountains National Park which appear as if a small bulldozer had been working in the area).
In the plant world the examples are much more numerous.
Almost anyone who lives in the South has seen roadsides covered with Kudzu, a Korean species originally imported to North America for use in soil conservation. This vine grows quickly and overtops native trees, smothering out all other plant life. Presently in covers several thousand acres of one of our State Forests, Natchez Trace.
Another pernicious example is the Nodding Thistle, which can be seen in abundance along Tennessee highways. It has a purple top and thorns. The thorns cause problems for livestock when the plants find their way into straw and hay bales which are use as animal feed.
Certain more familiar plant species are equally problematical. The Honeysuckle Bush, Honeysuckle Vine, Mimosa Tree, Privet Hedge and Euonymus Vine are the main offenders in Urban neighborhoods and forests. Each of these plant types are prolific producers of seed. Which seed is, in turn, spread by birds over large areas. Left unchecked they quickly spread and become a dominant species on the landscape.
At Radnor Lake State Park and Warner Park (City of Nashville) extraordinary measures are being taken to eradicate these species, so that native species can thrive. It will take many years to rid the parks of these pests. Additionally, the effort will be futile unless the community as a whole curtails the use of these species in household landscapes.
For more information on this topic check out the website of the Tennessee Exotic Pest Council, http://www.webriver.com/tn-eppc.
1. Be sure your own property is free from plant pests
2. Talk to your neighbors and neighborhood associations
3. Write the mayor and tell him that you want pigeons and non-native plants species to be closely controlled and removed if at all possible.
4. Volunteer to assist the City and State Parks Divisions in their efforts to eradicate non-native pests from the Parks and other public land
5. Try to incorporate Tennessee native plant species in your household landscape.