Invasive Species

Working for Biodiversity and Protection from Invasive Species

Everyone is talking about invasive species, but what are they?

Invasive species are plants, animals, and diseases that have been introduced to a particular area from another part of the world or another part of the country. Not all introduced species are invasive, though. Invasive species are rapid growers that produce many seeds and tend to crowd out the native species in an area. These species are capable of thriving in different types of habitats, especially disturbed areas where native plants might have trouble growing.

Invasive species were not necessarily invasive in their homeland. They’re making a new start in your backyard, where they lack natural enemies. “Invasives” are by no means new – they have been entering the U.S. via trade, both intentionally and accidentally, since the first ships arrived on our shores. Some invasive species have also escaped the captivity of aquariums and households. Many have been planted ornamentally or even as natural controls for erosion or other invasive species.

Biodiversity is the main concern associated with invasive species. Native plants have been adapting to Rhode Island’s conditions for thousands of years, but competition from new species can lead to extinction. In fact, 42% of Endangered Species in the U.S. have become endangered due to non-native invasive species (Today’s Forest, Tomorrow’s Legacy, Forest Health Fact Sheet). This can disrupt the long-term natural functions of an ecosystem and lead to economic losses for those depending on the ecosystem’s services.

According to the Southern New England Forests 2017 report by the USDA Forest Service, our most common invasive plants are Asiatic bittersweet, multiflora rose, Japanese barberry, which were each found on more than 25% of forest inventory monitoring plots in the region. Two of the most common invasive insects affecting trees in Rhode Island are the hemlock woolly adelgid, a sap-feeder that predominantly attacks Eastern Hemlocks, and Emerald Ash Borer (EAB), a tiny bright green beetle that threatens all species of ash. See below for more information about individual invasive plant species, or see Forest Health for information about invasive insects and diseases.

See Fact Sheet 5 for tips to protect your land from invasive species. You can also contact the Rhode Island Wild Plant Society for up-to-date information about invasive threats to Rhode Island’s flora and fauna.