The U.S. Geological Survey's Ecosystems Mission Area studies invasive plants, animals and pathogens across the United States. With the Department of the Interior (DOI), other agencies, Tribes, industry, agriculture and nonprofits, its scientists build new tools for prevention, prediction, early detection, containment and control.
What makes a species invasive
For a given ecosystem, an invasive species is a nonnative organism whose introduction causes, or is likely to cause, economic or environmental harm, or harm to human, animal or plant health. It can come from another continent, like cheatgrass (Bromus tectorum), or be moved outside its native range within the United States, like the American bullfrog (Lithobates catesbeianus).
- Everywhere: invasive species harm every state, territory and Tribe, from cities to wilderness.
- Spread by people: growing global travel and trade open new pathways.
- Costly: the damage costs governments, industries and citizens billions of dollars a year, and everyone from farmers to every level of government pays for control.
- Wide-ranging harm: lower farm production, pressure on native plants and wildlife, damaged water infrastructure, disease in wildlife and people, threatened fisheries, and less hunting, fishing, boating and swimming.
- Tied to climate change: a changing climate can worsen some invasions, shift ranges, open new pathways and weaken control tools — and invasive species leave ecosystems and communities less resilient to it.
USGS priorities
| Aim | Work |
|---|---|
| Prevention | Keep bighead, black and silver carp out of the Great Lakes and uninvaded waters of the Mississippi River Basin; cut the risk of introductions to the Hawaiian Islands and U.S.-affiliated Pacific Islands through shipping containers and other pathways |
| Detection | Nationwide tracking of freshwater aquatic invasive species; pythons, tegus and other reptiles in southern Florida; zebra and quagga mussels; the INHABIT tool, which predicts where invasive plants will spread |
| Containment and control | Reduce grass carp in the Great Lakes and all four invasive carp in the Mississippi River Basin; control sea lamprey in the Great Lakes and the brown treesnake on Guam; predict and help control cheatgrass, salt cedar, Russian olive, leafy spurge and buffelgrass |
Finding species by their DNA
Environmental DNA (eDNA) reveals a species by the DNA fragments it leaves behind — sloughed from scales, shed from skin cells, or passed in feces. It works in water, on land and even in air.
An eDNA field test in Hawaiʻi, where USGS scientists and partners developed a method to detect Rapid ʻŌhiʻa Death in mature ʻōhiʻa trees. Photo: Carter T. Atkinson, U.S. Geological Survey.
- A portable eDNA kit detects bighead and silver carp and zebra and quagga mussels in under an hour; it is being extended to the Asian fish tapeworm, the spiny water flea and others.
- eDNA detected invasive northern pike in several south-central Alaska lakes after eradication efforts, and tracks the possible spread of Burmese pythons in southern Florida.
- In Hawaiʻi, a field method detects the fungi behind Rapid ʻŌhiʻa Death in mature ʻōhiʻa lehua trees.
- USGS is developing land-based eDNA methods for invasive reptiles, and testing airborne eDNA to find invasive species in shipping containers.
- With other federal partners it is setting eDNA standards and building a toolbox for managers.
Early detection and rapid response
No prevention stops every invader. Early Detection and Rapid Response (EDRR) — coordinated action to find and eradicate a potential invader in one place before it spreads — is an efficient, cost-effective backstop. USGS supplies the science for DOI bureaus and others, and sometimes leads multiagency responses.
It is building the architecture of a national EDRR framework, and a surveillance network that combines traditional sampling and eDNA data to find "hotspots" vulnerable to introductions.
Buffelgrass spreading in the Sonoran Desert. Photo: National Park Service.
On land, USGS and the National Park Service are developing sensors on unmanned aerial systems and high-resolution satellite imagery to find buffelgrass, a nonnative grass spreading fast in the Sonoran Desert of Arizona and California that carries fire quickly and broadly.
The Nonindigenous Aquatic Species database
The USGS Nonindigenous Aquatic Species (NAS) database (nas.er.usgs.gov) is one of the country's best sources of data on nonindigenous aquatic plants and animals. It grew out of the Aquatic Nuisance Species Task Force, created by Congress in 1990. A clearinghouse of confirmed sightings, it offers email alerts, maps, species profiles and risk assessments, and now takes eDNA detections too.
NAS tools predict where invasive lionfish may spread after hurricanes and other floods. Photo: Karen Doody, U.S. Geological Survey.
Research examples
Invasive carp
Dense populations of bighead, black, grass and silver carp harm the nation's waterways. USGS research on deterrents, removal and spawning areas helps managers keep bighead, black and silver carp out of the Great Lakes, reduce grass carp there, and prevent or reduce invasions in six subbasins of the Mississippi River Basin. It is field-testing acoustic deterrents, bubble screens, baits and genetic methods, and has developed:
- the pesticide Carbon Dioxide Carp;
- the Modified Unified Method for mass removal of silver and bighead carp;
- the Fluvial Egg Drift Simulator (FluEgg), which predicts where carp spawn and where their eggs and larvae end up;
- SpawnCast, which helps field crews plan sampling and removal.
Photo: U.S. Geological Survey.
Grass carp threaten the nearshore and wetland plants native fish need. Photo: Patrick Kocovsky, U.S. Geological Survey.
Burmese pythons
Invasive snakes that can exceed 18 feet and 150 pounds. USGS and partners documented that they have devastated mammal communities in Everglades National Park, and they are known to have eaten wood storks and Key Largo woodrats, both threatened or endangered. USGS research is measuring their birth rates and movements for managers in southern Florida.
Photo: U.S. Geological Survey.
Invasive mosquitoes
In the Hawaiian Islands, a warming climate has let the nonnative southern house mosquito reach high-elevation forests, bringing deadly avian malaria to what had been the last disease-free habitat of highly endangered native birds. USGS studies mosquito populations to support using naturally occurring Wolbachia bacteria as mosquito "birth control" across whole landscapes.
A mosquito near the eye of an ʻapapane, one of the Hawaiian forest birds it threatens. Photo: Jack Jeffrey, U.S. Fish and Wildlife Service.
Cheatgrass
Cheatgrass keeps spreading into western sagebrush. It colonizes burned ground before native plants can, adding fuel and intensifying the cycle of fire and invasion. USGS is testing ways to restore native vegetation after fire and maps cheatgrass cover to help managers plan fire operations.
Invasive grasses burning in an Idaho wildfire. Photo: National Interagency Fire Center.
Brown treesnakes
Accidentally brought to Guam in the late 1940s, the brown treesnake has caused the global or island-wide extinction of 9 of 13 native forest birds, and it often short-circuits power lines. USGS developed traps and barriers and leads the regional rapid response team that answers sightings in new places across the Pacific Islands.
A brown treesnake on Guam, where significant quarantine efforts keep it from spreading. Photo: Bjorn Lardner, U.S. Geological Survey.
European green crab
Established on both coasts, it has recently spread into Tribal waters of the Pacific Northwest, threatening Tribal fisheries for native Dungeness crab. USGS is developing eDNA methods to track it and studying its early life history for control.
A voracious predator of clams and oysters. Photo: Patrick DeHaan, U.S. Fish and Wildlife Service.
Zebra and quagga mussels
Dreissenid mussels clog infrastructure, hamper recreation and severely alter aquatic ecosystems as they spread across North America; they also smother native unionid mussels. USGS researches genetic detection, molluscicides and carbon dioxide injected under mats laid over them, and is improving early detection in the Northern Rocky Mountains and Columbia River Basin.
Photo: John Byrnes, U.S. Geological Survey.
Black and white tegus
Large omnivorous lizards from South America, likely escaped or released pets, now established in at least four Florida counties. They specialize in eggs, including American alligators', and USGS found conditions may suit them across the southern third of the continental United States.
Photo: U.S. Geological Survey.
Salt cedar (tamarisk)
Salt cedar, or tamarisk, has replaced native vegetation along western rivers, affecting plant communities, water loss, erosion, wildlife and recreation. USGS is studying how well biological control reduces it.
Its many flowers, and so many seeds, help salt cedar dominate riparian habitat. Photo: Pamela Nagler, U.S. Geological Survey.
Sea lamprey
The parasitic sea lamprey invaded the Great Lakes in the mid-20th century, feeding on native fish and devastating fisheries. With the Great Lakes Fishery Commission, the U.S. Fish and Wildlife Service and others, USGS developed a trap and electrical-guidance array that removes 75 percent of sea lamprey from a stream, and registered with the U.S. Environmental Protection Agency the first vertebrate pheromone, which can raise trap catch by 35 percent.
Photo: Andrea L. Miehls, U.S. Geological Survey.
Sources
Based on Heimowitz PJ, Kocovsky PM and English JJ, Invasive Species Research—Science for Prevention, Detection, Containment, and Control, USGS Fact Sheet 2024–3001, U.S. Geological Survey; a work of the United States government in the public domain. The photographs come from the fact sheet's PDF, each credited to a federal photographer or agency; two credited otherwise are not reproduced. The sheet also calls FluEgg the "Fluvial Drift Simulator".
Licence: CC0 1.0 (public domain) · Adapted from pubs.usgs.gov
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