Invasive Species: Finding solutions to stop their spread


U.S. Fish and Wildlife Service biologist holds a bighead carp. Photo by R. Hagerty, U.S. Fish and Wildlife Service.

Some are sharp, some are spotted and some are slithery, but all invasive species are bad for public lands. Invasive species are nonnative organisms whose introduction to a particular ecosystem can cause economic or environmental harm, or harm to human, animal or plant health.

Some nonnative species don’t cause harm (They’re not “invasive”), but those that do can cost billions in damage and disrupt an environment’s natural balance.  

National Invasive Species Awareness Week is an international event to raise awareness about invasive species, the threat that they pose, and what can be done to prevent their spread.

No matter where they came from, how they got here or what harm they cause, invasive species are a serious concern for all who protect and preserve America’s public lands and waters. 

Invasive Mussels

Handful of invasive quagga mussels on a white surface.

The quagga mussel is an invasive species that poses a substantial threat to water resources. Photo by S. Pucherelli, Bureau of Reclamation.

Quagga and zebra mussels are invasive species from Eurasia’s Caspian Sea. These tiny mollusks reproduce rapidly and attach to surfaces such as pipes, lake bottoms, docks and break walls, forming a crust of shells. Infestations in dams and water treatment facilities can impact the delivery of water and power. Large colonies in lakes and waterways affect freshwater ecosystems, leading to harmful effects on native and endangered species, including recreational game fish. Mussel infestations may impact recreation in other ways, from sharp shell fragments scattered over beaches to increased requirements and cost for boat inspection and decontamination.

What are we doing to address invasive mussels? 

Since their discovery in the Great Lakes in the 1980s, Interior’s bureaus and partners have worked to prevent, contain and control invasive mussels. Some of the efforts to limit their spread include:  

  • Watercraft inspection and decontamination 
  • Monitoring 
  • Rapid response 
  • Public education 
  • Research on detection and control measures 

Partnership networks are leveraging what has been learned since the initial mussels invasion. For example, the Quagga and Zebra Mussel Action Plan for Western U.S. Waters is a blueprint for actions to protect the uninfested West from mussels and other aquatic invasive species. In the Great Lakes Region, the Invasive Mussel Collaborative connects people, science and management to advance technology for invasive mussel control. 

Get Involved

Invasive mussels primarily spread by hitching rides on boats and other watercraft. Preventing the spread of invasive mussels starts with you! Remember to  clean, drain and dry your watercraft after leaving the water. With your help, we can protect the nation’s waterways and wildlife. 

Rapid ʻŌhiʻa Death

ʻŌhiʻa is a native tree important to Hawaii ecology and culture that is at risk from a tree-killing fungus. Photo by R. Bartlett, U.S. Geological Survey.

ʻŌhiʻa -- the most abundant native tree in Hawai’i -- is both culturally significant and ecologically valuable. Sadly, ʻŌhiʻa are now threatened by two invasive fungal pathogens that cause Rapid ʻŌhiʻa Death (ROD), a serious threat to native forests in the Hawaiian Islands. Unfortunately, the future of the ʻŌhiʻa tree is in doubt. Hundreds of thousands of ʻōhiʻa have already died due to this fast-acting disease.

What are we doing to address Rapid ʻŌhiʻa Death? 

Federal and non-federal partners are undertaking actions in the 2020-2024 Rapid Ōhiʻa Death Strategic Response Plan which describes the needs for emergency response as well as for the long-term health of Hawai‘i’s forests.  Our understanding of the disease and the microscopic fungi that cause it has improved through significant investments in research, remote sensing and field studies. Management measures such as selective cutting of infected trees, sealing wounds on infected trees, fencing to exclude ungulates and biosanitation protocols to minimize the spread of fungal spores all help to address the spread and severity of this devastating disease. 

Get Involved

Whether living in or visiting the Hawaiian Islands, be aware of Rapid ʻŌhiʻa Death and follow biosecurity protocols that are in place (e.g., don’t move ʻōhiʻa, avoid injuring the tree, clean your shoes and gear and wash your vehicle) to reduce the spread of this disease.  Learn more about Rapid ʻŌhiʻa Death so that we can identify and support solutions.   

Invasive Carp: Bighead, Silver, Black and Grass Carp

Silver carp jumping during electrofishing in the Fox River. Photo by R. Hagerty, U.S Fish and Wildlife Service. 

Finding their way into America’s rivers and lakes, invasive carp (bighead, silver, black and grass carp) threaten recreational, commercial and subsistence fisheries worth billions of dollars annually. These aquatic invaders take over habitat and threaten native species, and impact recreational boating and other activities important to the livelihood of many communities.  

What are we doing to address invasive carp?

Interior experts provide key leadership, research and tactical assistance across the Great Lakes, Upper Mississippi River and Ohio River basins. By developing the “Management and Control Plan for Bighead, Black, Grass, and Silver Carps in the United States,” we can use it as a national blueprint on the management of invasive carp. We’ve been developing critical new technologies to combat the threat posed by all invasive carp life stages (eggs, larvae, juveniles and adults) and working with natural resource managers to improve early detection and rapid response activities.

Get Involved

Everyone can play a role in preventing the spread of invasive carp. Ways you can help: 

  • Learn to identify juvenile invasive carp  
  • Only use wild-caught bait fish in waters where they came from 
  • Don’t move live fish from one location to another 
  • Drain lake or river water from live wells and bilges before moving your watercraft 

Finally, become an ambassador for your watershed and help others learn how to help!   

Invasive Rodents

Invasive house mice cause injury to nesting birds like this injured Laysan albatross at Midway Atoll National Wildlife Refuge. Photo by U.S. Fish and Wildlife Service.

Invasive rodents on islands cause serious impacts to both native biodiversity and infrastructure. These harmful rodents, such as mice and rats, prey upon and compete with native wildlife, reducing native biodiversity and sometimes leading to the extinction of a species. Rodents damage buildings by chewing through wood and insulation and gnawing on wiring which can trigger fires. Islands represent some of the greatest concentration of biodiversity, with island species often being evolutionarily distinctive. Unfortunately, these species are often highly vulnerable to novel disturbances, particularly invasive rodents.

What are we doing to address invasive rodents on islands?

Interior works with a variety of partners on invasive rodent prevention and eradication. The main goal is to prevent rodents from reaching new islands. Where already found, invasive rodents are eliminated to limit their impact on native species and infrastructure. Helicopter dispersed rodenticide is used to completely eradicate rodents from islands. Successful rat eradications can lead to amazing native restoration stories. For example, a rat eradication at Desecho National Wildlife Refuge in the Caribbean enabled seabirds, the island’s endemic lizards, three endemic arachnids, and the federally threatened higo chumbo cactus to thrive once again.  

Get Involved

Whether you’re traveling or supporting island conservation, here are a few ways to help:  

  • Prevent invasive rodents from reaching new islands (i.e., using rat guards on boat mooring lines) 
  • Spread the word on how devastating rodents can be for native species on islands 
  • Learn more about rat eradication and island restoration

Invasive Plants 

Tall purple flowered weeds in front of mountain backdrop

Spotted knapweed is an invasive plant that forms dense stands, decreasing native vegetation and degrading forage quality for wildlife. Efforts are underway to limit impacts and prevent the spread of knapweed and other invasive plants. Photo by Bureau of Land Management.

Today, noxious weeds and other invasive plant species infest more than 80 million acres of Interior-managed public lands, and they continue to spread. This presents multiple impacts to threatened ecosystems. For example, downy brome (cheatgrass), infests 50 million acres and provides fuel to wildfires that burn across increasingly larger areas. And in a devastating one-two punch, cheatgrass can quickly re-establish itself on burned lands, outcompeting native grasses and increasing the extent of infestation. 

What are we doing to address invasive plants in the West?

Interior is responsible for preventing and controlling invasive plants on the lands that we manage. We prioritize invasive species projects to protect the most critical resources — such as stream corridors or greater sage-grouse habitat. We work with numerous partners to support effective all-lands inventory, treatments and monitoring. Within Interior, the Invasive Species and Wildland Fire Management programs are also working together to address the dual threats of invasives and wildfires to our communities, natural landscapes and cultural resources.  

Get Involved 

Prevention is key, so identifying invasive plant species is crucial. Helping with early detection, rapid response and public awareness is also important. Report invasive plant infestations to your local Interior bureau field offices. 

Preventing the Next Invasive Species 

The invasion curve depicts that as time goes on, invasive species are more costly to manage. Graphic by S. Sparhawk, National Park Service.

Once an invasive species becomes established, it is rarely possible to eradicate. The best way to avoid the harm that invasive species can cause is to prevent them from entering the country.  

We use several ways to predict species at risk of becoming invasive and then preventing them from being imported if possible. By monitoring and inspecting wildlife imported into the United States at designated wildlife ports we can intercept problematic species. 

Get Involved

You can be involved in prevention in various ways. Please keep your pets secure and do not release them—under any circumstances. Animals like exotic fish and reptiles can wreak havoc on native wildlife and habitat when they escape or are released. If you must surrender a pet because you can no longer care for it, do so responsibly. Other excellent sources for how to prevent the spread of invasive species include: 

Volunteer shows a kōlea lau nui plant freed from the invasive plant, Himalayan ginger. Photo by National Park Service.

The Power of Partnerships

Invasive species may be widespread and vastly different, but luckily so are the methods and teams protecting public lands. The Department of the Interior is forging strong partnerships with others to collectively address the threat of invasive species. Our 2021-2025 Invasive Species Strategic Plan charts a path forward. We can’t do it alone. Together, success is possible!