Invasive Plants

Acadia's IPMT removing glossy buckthorn near Great Meadow.

NPS Photo

Acadia National Park protects the biodiversity of unique ecosystems, including coastline, forests, mountain summits, and wetlands, that support over a thousand different species of plants. However, nearly a third of the park’s plant species are non-native, and some are considered invasive because they cause harm to the environment, economy, or human, animal, or plant health.

Acadia’s Invasive Plant Management Team (IPMT) has developed management goals for 29 non-native invasive plant species that threaten the park’s natural and cultural resources. Beginning in 1988 with efforts to remove purple loosestrife (Lythrum salicaria) from Acadia’s wetlands, park managers maintain low levels of invasion compared to other areas of the northeast. Yet, with climate change and increasing pressures from more invasive species, Acadia’s resilient ecosystems remain vulnerable. The IPMT’s high-priority target species now include shrubs like glossy buckthorn (Rhamnus frangula), Japanese barberry (Berberis thunbergii), and Morrow’s honeysuckle (Lonicera morrowii); vines like Asiatic bittersweet (Celastrus orbiculatus); and herbaceous plants like Japanese knotweed (Fallopia japonica).

In addition to removal efforts, NPS collaborates with partners, Friends of Acadia, and Schoodic Institute, to research best methods for invasive plant removal and restoration.

Target Invasive Plant Species

Glossy buckthorn (Frangula alnus)

Amur maple (Acer ginnala)

Asiatic bittersweet (Celastrus orbiculatus)

Autumn olive (Elaeagnus umbellata)

Barberry (Japanese & Common) (Berberis thunbergii, B. vulgaris)

Bull thistle (Cirsium vulgare)

Burning bush (Euonymus spp.)

Bush honeysuckle species (Lonicera spp.)

Canada thistle (Cirsium arvense)

European bittercress (Cardamine impatiens)

Foxglove (Digitalis purpurea)

Garlic mustard (Alliaria petiolata)

Giant hogweed (Heracleum mantegazzianum)

Japanese honeysuckle (Lonicera japonica)

Japanese knotweed (Fallopia japonica)

Multiflora rose (Rosa multiflora)

Norway maple (Acer platanoides)

Privet (Ligustrum spp.)

Purple loosestrife (Lythrum salicaria)

Spotted knapweed (Centaurea stoebe)

Yellow iris (Iris pseudacorus)

 

Purple loosestrife's bright magenta flowers seen along Marshall Brook in Acadia National Park.

NPS/FOA photo by Will Greene

How Invasive Species Spread

This landscape has been shaped by people over thousands of years, long before the establishment of the national park. Acadia National Park lies within the homeland of four tribes—the Maliseet, Micmac, Passamaquoddy and Penobscot—known collectively as the Wabanaki, and Native American peoples have inhabited this region for at least 12,000 years. Non-native species arrived with settlers who farmed, kept livestock, harvested timber, and built homes and gardens in the 19th and 20th centuries. This intensive land use rapidly altered conditions for native species and introduced non-native species that succeed after human disturbances. Many of the invasive species now managed by the IPMT were intentionally brought to the area as horticultural species, but others were unintentional introductions.

The IPMT is also on the lookout for new arrivals that may pose a threat to park ecosystems. Climate change, urban development, and outdoor recreation all have the potential to bring new invasive species to Acadia, and natural resource managers must act quickly to adapt to these challenges. Still, the most effective way to manage invasive species is to prevent their arrival in the first place.

 

Stay on trails to avoid spreading invasive plant material and forest pests like hemlock woolly adelgid.

NPS Photo

What You Can Do

Acadia welcomes millions of visitors each year, bringing vehicles, watercraft, firewood, pets, and outdoor equipment into close contact with natural resources. Taking a few simple actions to reduce the spread of invasive species will help protect public lands and communities for future generations:

• Clean your gear: Use boot brush stations to remove dirt and debris that could contain plant material from footwear. Clean your clothing, bags, and other equipment when traveling to outdoor areas.
• Leave No Trace: While there are many good reasons to follow LNT principles, staying on marked trails and keeping pets on a leash also helps prevent the accidental spread of invasive plants and pests. Reducing contact with vegetation makes it harder for invasive species to reach sensitive areas where people don’t usually go.
• Always buy firewood locally: It is prohibited to bring out-of-state firewood into Maine, but even moving firewood within the state can transport invasive forest pests to new areas. There are many places to buy firewood in nearby communities, so buy it where you burn it.
• Clean vehicles and watercraft: Learn how to inspect and remove vegetation from boating and fishing equipment to reduce the spread of aquatic invasive species.
• Learn more: If you’re a park neighbor, learn what you can do as a landowner to reduce invasive plant presence on your property. Learn to identify invasive species and report sightings in Acadia.

 

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