Background Information

Invasive Species
Invasive species are those organisms that adapt quickly to a new environment, reproduce, and spread rapidly into new locations, often displacing the organisms that were originally there.

Many invasive species are exotic-not native to our environment-Other invasive species may be native, but may also rapidly reproduce and become nuisances. When a species is introduced into a new location where it does not have any natural enemies, it can quickly take over the area and pose a real threat to the environment by knocking the whole system out of balance. Plants, animals, and pathogens may all become invasive.

Disturbances such as strip-mining, logging, or leveling land at construction sites create opportunities for invasive species to move in. Or, you may have a relatively undisturbed area, introduce a new species into it, and the natural balance may begin to shift.

For centuries, humans have intentionally introduced new plant and animal species to different parts of the world. Some of these have been very beneficial, such as wheat from Egypt, or cattle from Asia. Other introductions have not worked out so well.

Intentional Introduction
The starling was originally brought to North America by a fan of William Shakespeare. He released 60 to 100 birds in New York City's Central Park in the 1890s. His desire was to introduce all the birds ever mentioned in the works of William Shakespeare. It turned out to be a poor tribute-by 1970, millions of theses highly adaptive and prolific birds had reached as far as Alaska. Today, most people view these birds as nuisances because they outcompete native birds for food and nesting sites.

Some introductions have been downright disastrous. Giant Hogweed, a member of the parsley and carrot family, is a tall, majestic plant originally brought to the United States around 1920 as a landscape plant. It "scaped" out of the garden into the wild and is still spreading across northwestern Pennsylvania. It also can cause painful skin rashes when you come in contact with it, and it is now listed on Pennsylvania's noxious weed list.

Multifloral rose is another foreign species run amok. It was originally promoted by the United States Department of Agriculture (USDA) as an excellent plant for erosion control and living fences for livestock and wildlife cover. So, thousands of free cuttings were given out to create hedgerows. Today, millions of dollars are spent trying to eradicate it. It does provide excellent habitat and food sources for many birds and small mammals. However, it is extremely hardy and difficult to get rid of because it can self-seed and quickly take over an area. Birds scatter the seeds widely, then it takes over pasture land, and cows become unwilling to graze in fields conation the thorny plant. It has also been added to the federal and state noxious weed lists.

In the South, kudzu was originally introduced as a forage crop, like hay, for feeding animals. It also traveled beyond its originally intended boundaries and virtually took over huge pieces of the Southern landscape, crowding out all other plants and many animals habitats.

Many more invasive species are brought into the country and transplanted from place to place accidentally. In North America, it is estimated that there are about 50,000 species of exotic plants, animals, and pathogens currently established and that more than 3 million acres of land in the United States are lost to invasive species. Invasive species cost our economy an estimated $138 billion per year.