Invasive Species
Invasive species cause harm when they establish themselves at the expense of native plants and animals.
Overview
Invasive species are plants, animals or other organisms that have been introduced to a new ecosystem, where they risk harm to the environment, economy and human health. In the Chesapeake Bay watershed, species like blue catfish and Chesapeake channa have disrupted food webs, fisheries and the Bay’s overall resilience to environmental threats. Understanding how invasive species arrive, spread and are managed is an important step toward protecting biodiversity across the region.
Watch: Bay 101: Blue Catfish
How do invasive species impact the Bay?
Invasive species cause harm when they establish themselves at the expense of native plants and animals. This can occur when an invasive species’ new environment lacks the predators, disease or other natural controls that might otherwise keep them in check. By outcompeting native species for food or habitat, invasive species can destabilize food webs, disrupt fisheries, reduce biodiversity and make ecosystems less resilient to pollution, climate change and other environmental threats.
After habitat loss, invasive species are one of the top threats to native plants and animals. According to the Center for Invasive Species and Ecosystem Health, invasive species have put more than 40% of the nation’s threatened or endangered species at risk of further decline.
What are some invasive species in the Chesapeake region?
The Chesapeake region is home to more than 200 known or possible invasive species, including plants, insects, fish and birds. These species can be found in a range of habitats, from rivers, wetlands and forests to agricultural and developed landscapes.
Spotted lanternfly
The spotted lanternfly is a planthopper native to Asia. Introduced to Pennsylvania in 2014 on a commercial shipment of stone, it has since been detected in all seven watershed jurisdictions. Because spotted lanternflies can damage and even kill some plants, they pose a threat to timber, orchard and viticulture industries. States have encouraged residents to destroy the insects and their egg masses to help control their spread.
Phragmites
Phragmites is a tall perennial grass found in wetlands and on shorelines throughout the Bay watershed. Native to Europe, the invasive strain arrived in North America in the 19th century in the dry ballast of European ships. Phragmites forms large, dense stands that can crowd out the native plants that would otherwise serve as habitat for endangered or threatened bird species. The plant often requires a combination of herbicides, mowing or flooding to control.
Chesapeake channa
Also known as northern snakehead, Chesapeake channa is a freshwater fish native to China. It was first detected in Maryland in 2002, likely after live fish were released into a pond, and has since become established in Maryland, Virginia and Washington, D.C. An aggressive predator, Chesapeake channa can outcompete native fish species for food. Many states prohibit the possession or transport of live snakehead, and encourage anglers who catch them to kill them.
Find more examples in our Field Guide
How are invasive species managed?
Once an invasive species is established, it can be impossible to completely eradicate. Instead, natural resource managers must focus on monitoring, removal, and education and outreach. Studying the diet, health and reproduction of invasive species, for example, can teach us about their impact on the environment. Marketing invasive species to chefs and consumers can create demand for these species as food, and easing harvesting regulations can encourage individuals to help with their removal. Regulations can also limit the spread of known invasives, and require natural resource agencies to assess risk before non-native species are introduced.
How can you help?
To prevent the spread of invasive species, consider planting native flowers, shrubs and trees in your garden, or volunteering at a local park during invasive plant removal events. You can also protect waters from aquatic hitchhikers by cleaning your boat hull before moving it to another body of water and by keeping bait or aquarium species out of storm drains and waterways.