Columbia subject headings:
Biological invasions--United States.
Endangered species--United States.
Nature conservation--United States.
Nonindigenous pests--Control--United States.
Nonindigenous pests--United States.
Pest introduction--Government policy--United States.
Pest introduction--United States.
Harvard subject headings:
Competition (Biology)
Endangered species--United States
Nature conservation--United States.
Species--United States.
Princeton subject headings:
Animal introduction--Government policy--United States.
Plant introduction--Government policy--United States.