TABLE OF CONTENTS People Spread Invasive Species 4 Kudzu Is the Vine that Ate the South 6 Burmese Pythons Are Predators of Predators 8 Introducing Killer Bees Was a Serious Error 10 Invasive Asian Carp Are Eating Machines 12 Zebra Mussels Thrive in Polluted Waters 14 Black Rats Carried the Black Death 16 The European Rabbit Invaded Australia 18 The Cane Toad Is Toxic to Predators 20 Asian Tiger Mosquitos Arrived in Tires 22 Northern Snakehead Fish Can Live on Land Too 24 The Cost of Invasive Species Is High 26 Fact Sheet 28 Glossary 30 For More Information 31 Index 32 About the Author 32
1 PEOPLE SPREAD INVASIVE SPECIES Invasive species are a worldwide problem A plant animal or microorganism species that thrives in an area outside its normal territory is called invasive It does not belong there Invasive species can cause great harm They compete with other species for food shelter and other natural resources Most have been introduced by humans Historically humans have introduced invasive species while traveling or invasive species while traveling or exploring Sometimes they brought species with them on purpose Early colonists to North America carried plants seeds and animals from Europe Such species include cows and horses Other plants animals insects and microorganisms hid in crates They were accidentally introduced to North America Asian tiger mosquitos were introduced to the United States by accident 4
A sign warns boaters to watch for invasive zebra mussels Today humans continue to introduce invasive species both on purpose and by accident Some such as the kudzu vine were introduced to provide food for animals and humans Others such as the Burmese python were brought into their new habitats as pets When they escape or are released they cause problems for other species Humans try to manage invasive species They may physically remove them Or they may use chemicals or other species to kill the invasive species 4,300 Invasive species currently in the United States Early colonists brought many invasive species to their new homes Invasive species alter habitats by competing with native plants and animals Invasive species can be pets that have escaped or been released into the wild THE EARLIEST INVADERS Humans were the first species to spread outside of their original territory Humans first emerged from Africa 50,000 to 70,000 years ago Gradually they spread across the globe Early humans brought invasive species with them They brought possums and dogs to Indonesia They introduced dingoes to Australia 5
