In the 1960's the population of the bald eagle was at dangerously low levels. Numbers of breeding pairs were down to 500 from the 100,000 breeding pairs that existed when our nation was founded. Investigation showed the insecticide DDT, widely used after the World War II, had entered the eagle's food supply and caused eagle eggs to have thin shells and break before hatching. Eliminating the use of DDT allowed the bald eagle to rebound, with their numbers now at greater than 6,400 breeding pairs in the lower 48 states.
The impact of DDT on the bald eagle was an early lesson on the harm pesticides can have on wildlife. Increased care is now taken in the registration and re-registration of pesticides to assure products do not cause unreasonable harm to non-target plants and animals. Of greatest concern is the harm a pesticide might have on endangered and threatened species – plants and animals that are on or near the brink of extinction.
Since the Pilgrim's landing in 1620, over 500 species, subspecies, and varieties of our nation's plants and animals have become extinct. Probably the best known extinct Minnesota species is the passenger pigeon. Lesser known extinct Minnesota species are the eastern elk, blackfin cisco (a Great Lakes fish), and the crescent stripetail stonefly (an aquatic insect of cold water streams).
A plant or animal is extinct when it is no longer found alive on earth. Extinction has serious impacts:
Disruption of the "web of life": Living things interact and depend on each other in complex networks called ecosystems. The loss of one member can disrupt an ecosystem to the point that other members are lost too.
Loss of future medicines and crops: Over a quarter of drug prescriptions written in the United States for human health use chemicals found in plant and animal tissue. Genetic material from wild plants is often used to breed disease and insect resistance into crops. Loss of a plant or an animal means their genetic information can no longer be studied and utilized for human benefit.
Decreased quality of life: Many of us have had the experience of freezing in our tracks to watch an eagle fly overhead or a butterfly settle on a flower. Our lives, and the lives of our children, will be less rich if plant and animal life around us is lost.
Minnesota Department of Agriculture
Collie Graddick, Pesticide Management Unit
U.S. Environmental Protection Agency
Endangered Species Protection Program
Office of Pesticides Programs
U.S. Fish and Wildlife Service
Twin Cities Ecological Services Field Office
Minnesota Department of Natural Resources
Natural Heritage and Nongame Research Program