What is an invasive species and why are they a problem?
An invasive species is an introduced, nonnative organism (disease, parasite, plant, or animal) that begins to spread or expand its range from the site of its original introduction and that has the potential to cause harm to the environment, the economy, or to human health.
A few well-known examples include the unintentional introduction of the West Nile virus, chestnut blight, the South American fire ant, zebra mussels, Burmese pythons, and sea lamprey. These are in addition to the intentional introductions of salt cedar (Tamarisk), kudzu vine, house sparrows, starlings, and nutria.
More than 6,500 of these harmful, non-native species cause more than 100 billion dollars in damage each year to the U.S. economy. Costly effects include crop decimation, clogging of water facilities and waterways, wildlife and human disease transmission, threats to fisheries, increased fire vulnerability, and adverse effects for ranchers and farmers.
Learn more: USGS Invasive Species Program
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Invasive species research within the U.S. Geological Survey’s Ecosystems Mission Area focuses on invasive organisms throughout the United States. U.S. Geological Survey scientists work with partners in the Department of the Interior, other Federal, State and Territorial agencies, Tribes, industry, and agriculture to provide the information needed...
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USGS science and technology help managers battle invading Asian carp
The U.S. Geological Survey (USGS) conducts Asian carp research focused on early detection, risk assessment, and development of control tools and strategies. The goals are to prevent the establishment of invasive Asian carp in the Great Lakes and to reduce their impacts in the Ohio River and Mississippi River Basins and elsewhere. Managers can use...
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Identify potential lock treatment options to prevent movement of aquatic invasive species through the Chicago Area Waterways System (CAWS)
Introduction The Illinois River is a primary tributary of the Mississippi River, connecting with the Mississippi at Grafton, Illinois. The headwaters of the river are at the confluence of the Des Plaines and Kankakee Rivers in eastern Grundy County, Illinois. Approximately 273 miles long, it runs through the heart of Illinois and is the connection...
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Invasive Species Science Branch: research and management tools for controlling invasive species
Invasive, nonnative species of plants, animals, and disease organisms adversely affect the ecosystems they enter. Like “biological wildfires,” they can quickly spread and affect nearly all terrestrial and aquatic ecosystems. Invasive species have become one of the greatest environmental challenges of the 21st century in economic,...
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Movements of wild pigs in Louisiana and Mississippi, 2011-13
The prolific breeding capability, behavioral adaptation, and adverse environmental impacts of invasive wild pigs (Sus scrofa) have increased efforts towards managing their populations and understanding their movements. Currently, little is known about wild pig populations and movements in Louisiana and Mississippi. From 2011 to 2013, the U.S....
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Invasive lionfish use a diversity of habitats in Florida
Two species of lionfish (Pterois volitans and Pterois miles) are the first marine fishes known to invade and establish self-sustaining populations along the eastern seaboard of the United States. First documented off the coast of Florida in 1985, lionfish are now found along the Atlantic coast of the United States as well as in the Caribbean Sea...
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Using genetic research to inform imperiled and invasive species management
The long-term viability of species and populations is related to their potential to migrate, reproduce, and adapt to environmental changes. In the southeast United States, U.S. Geological Survey (USGS) scientists are providing resource managers with genetic information to improve the long-term survival and sustainability of the Nation's aquatic...
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Satellite tracking and geospatial analysis of feral swine and their habitat use in Louisiana and Mississippi
Feral swine (Sus scrofa) is an invasive species that was first introduced to the continental United States in the 1500s by European explorers. Also known as feral hogs or feral pigs, the animals typically weigh about 200 pounds (up to 400 pounds), have characteristic tusks up to 3 inches long, are territorial, and live in groups, except for the...
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Invasive crayfish in the Pacific Northwest
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Applying remote sensing to invasive species science—A tamarisk example
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How Hurricanes Michael, Florence May Have Spread Nonnative Species
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A population of exotic invasive Cuban treefrogs has been discovered in New Orleans, more than 430 miles (700 kilometers) from the nearest known population in Florida, making this the first known breeding population in the mainland United States outside that state, reports a new study by the U.S. Geological Survey.
Scroll down to hear and download calls of Cuban treefrogs and two native treefrogs.
USGS Tracks How Hurricane Floodwaters Spread Non-Native Freshwater Plants and Animals
Hurricanes Harvey, Irma, Maria, and Nate may have spread non-native freshwater plants and animals into new water bodies, where some of them can disrupt living communities or change the landscape.
Wildfire and Invasive Species Drives Increasing Size and Cost of Public Land Restoration Efforts
An examination of long-term data for lands managed by the Bureau of Land Management finds that land treatments in the southwestern United States are increasingly large, expensive and related to fire and invasive species control.
Invasive Pest May Not Be Only Cause of Recent Louisiana Marsh Die-off
A non-native insect infestation may not be the only factor involved in the ongoing die-back of a marsh grass in the Mississippi River’s “bird foot delta,” the ecologically and economically important part of coastal Louisiana where the river meets the Gulf of Mexico.
A Breakthrough in Controlling Invasive Fish
On a windy July morning on Lake Superior’s Whitefish Bay, fisherman Ralph Wilcox of the Sault Ste. Marie Tribe of Chippewa Indians and his son, Dan, netted 300 pounds of wriggling whitefish. The mild-flavored salmon relative is served in restaurants, in smoked fish spreads, and as gefilte fish at Passover. However, two of the fish in the Michigan fishermen’s nets were badly wounded.
Around 600 Non-Native Mountain Goats Now Roam the Olympic Mountains
Population has Increased 8 Percent a Year Since 2004
USGS Study Reveals Interactive Effects of Climate Change, Invasive Species on Native Fish
A new USGS study shows non-native Brown Trout can place a burden on native Brook Trout under the increased water temperatures climate change can cause.
Controlling Those Suckers Known as Sea Lamprey
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In Hot Water: Climate Change is Affecting North American Fish
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Continued Decline of the Northern Spotted Owl Associated with the Invasive Barred Owl, Habitat Loss, and Climate Variation
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Invasive Northern Snakehead Carries Bacteria as Bad as its Bite
The invasive northern snakehead fish found in the mid-Atlantic area is now cause for more concern, potentially bringing diseases into the region that may spread to native fish and wildlife, according to a team of U.S. Geological Survey scientists.
Invasive Annual Grass Fills the Space Between Shrubs, Mojave
An unburned low elevation community in the central Mojave where the interspaces between shrubs have been filled in with a continuous layer of Mediterranean split grass Schismus barbatus. If a fire started here it would spread much more rapidly and be far more extensive than in a low elevation community where the interspaces are rocky or bare.
Invasive Burmese Python
Invasive Burmese python in the Greater Everglades Photograph credit: Brian Smith, USGS
Axis deer bounds through a grassy field
Snakehead Fish
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Sample of invasive northern pike in south central Alaska
USGS scientist Adam Sepulveda sits with a sample of invasive northern pike in south central Alaska.
An invasive American bullfrog with tracking device.
An invasive American bullfrog with tracking device.
Invasive New Zealand mud snails as seen under a microscope.
Invasive New Zealand mud snails as seen under a microscope.
Sea Lamprey, an Invasive Fish
Invasive sea lamprey prey on commercially important fish species such as lake trout, living off of the blood and body fluids of adult fish. It is one of many fish species that USGS scientists study from the USGS Research Vessel Muskie. These lamprey belong to the Great Lakes Fisheries Commission.
The R/V Muskie was temporarily moored in Buffalo, N.Y., August 8 and 9
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Invasive tamarisk on the Colorado River.
This image is of invasive tamarisk (salt cedar) growing on the banks of the Colorado River.