National Invasive Species Awareness Week is February 24-28, 2025. Invasive species can take over an ecosystem, outcompeting native species and reducing biodiversity. Lancaster Conservancy’s stewardship team and volunteers are constantly battling invasive species on our nature preserves, but we have seen some signs for hope as native trees and wildflowers reemerge where invasive plants have been removed.
Here are some not-so-fun facts about invasive species (and some fun ones, too)…
Invasive garlic mustard covers the forest floor along this trail (Photo by Keith Williams)
1. Not all non-native species are necessarily invasive. Non-native species can sometimes become naturalized into a new ecosystem without dominating it, instead coexisting with the species that are already there. Non-native species become invasive when they start outcompeting native ones, often leading to a reduction in biodiversity.
2. Invasive shrubs like multiflora rose are some of the first plants to turn green in the spring. Because they get their leaves earlier than native species, they can block sunlight from reaching other species trying to grow on the forest floor, such as native spring ephemeral wildflowers. (Source: Penn State)
3. Garlic mustard, an invasive herbaceous plant, kills off other plants around it by releasing chemicals from its roots that alter the network of fungi that help native plants spread their nutrients between one another. Garlic mustard also emerges earlier in the spring than other species, like spring ephemeral wildflowers. It has been a particular threat at the Conservancy’s Shenks Ferry Wildflower Preserve. (Source: The Nature Conservancy)
A close-up of a branch of invasive multiflora rose (Photo by Avery Van Etten)
4. Invasive species reduce biodiversity by outcompeting native species and taking over ecosystems, which makes those ecosystems less resilient. Biodiverse ecosystems are better able to withstand and adapt to stressors like disease, drought, or climate change. Biodiverse ecosystems are also better able to provide services humans rely on like fresh water, pollination, and soil fertility and stability. (Sources: NRDC & Conservation International)
5. Native species depend on one another. Native birds, insects, mammals, and amphibians are specifically adapted to native plants for food and shelter. And many native plants rely on animals to pollinate them and help spread their seeds. When invasive species outcompete native ones, it can have a domino effect that ripples through an entire ecosystem.
6. Those pretty ornamental plants you have in your garden might actually be bad for the local environment. Species like the common daylily, English ivy, and burning bush are all examples of non-native ornamentals that easily escape cultivation and threaten native habitats. The good news is you can plant native species on your property and in your community to help support native wildlife!
Volunteers from Congregation Shaarai Shomayim pull garlic mustard at Shenks Ferry Wildflower Preserve (Photo by Rachel Haynes)
7. Last year, Lancaster Conservancy volunteers removed 6,000 gallons of garlic mustard and 1,100 cubic yards of invasive shrubs from our nature preserves! Where we remove invasive species from our preserves, we have seen native ones like Dutchman’s breeches, yellow trout lily, black locust, and pawpaw reemerge.
You can volunteer with Lancaster Conservancy to help fight invasive species on our nature preserves! Learn more at lancasterconservancy.org/volunteer. Also, learn how you can support native wildlife on your property and in your community at lancasterconservancy.org/habitat!
