When invasive species come to town, they wreak environmental and economic havoc, and native plants and animals get muscled out. It has gotten so bad in Washington state that the U.S. Fish and Wildlife Service now offers a controversial proposal to shoot around 450,000 invasive barred owls to save native spotted owls. Another invasive species, Zebra mussels, arrived in the Great Lakes via transoceanic ships nearly 40 years ago, then hitched rides on the hulls of recreational boats from lake to lake. They’ve spread to 32 states, clogging power plant water intakes, incapacitating native mussels and destroying algae that native species rely on. Invasive species are expensive to eradicate: It now costs over $423 billion annually, according to the United Nations. Many species appear in multiple states; today’s map shows just two of the many invasive species found in each state.
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