Ecology at Acadia National Park
Learn more about the ecology of Acadia National Park.
Acadia National Park is located in the transition zone between two ecosystems: northern boreal forest and eastern deciduous forest. Northern boreal forests, found primarily north of Acadia in Canada, are dominated by conifers. Eastern deciduous forests, which dominate the American east coast, are characterized by broad-leaf trees which shed their leaves in autumn and tend to be located in places which have four distinct seasons each year. This makes for an interesting ecological mix throughout the park and enables the presence of species common both in northern and southern regions.
Acadia National Park contains both coniferous trees (which generally don’t lose their leaves/needles in the autumn) and deciduous trees (which generally shed their leaves). Spruce-fir forests are most common throughout Acadia, but oak, maple, beech, and other New England hardwoods are plentiful in the area as well. Isolated communities of trees from farther north or south can also be found here. Pitch pine and scrub oak woodlands reach their northeastern range limit within Acadia, and jack pine reaches its southern limit.
Thousands of feet in the air, plants on Acadia’s mountain peaks are well-adapted to the cold. Spruce and pitch pine thrive in the low mountain temperatures, while subalpine plants blossom amongst cracks in the granite and on the leeward side of rocks. Gnarled, stunted trees tend to be the only ones found on open ridges on mountain peaks, which bear the brunt of the harsh Maine weather.
Far below its mountain peaks, Acadia is also home to a very different type of habitat: wetlands. Wetlands, which comprise over 20% of the park, provide a rich ecosystem for numerous plant and animal species. Each wetland in Acadia is home to at least one rare species of plant, and more than half of the species classified as “rare” within Maine are indigenous to wetlands. These plants provide critical food and shelter for species which live in the park year-round, as well as those which pass through Acadia during migration. Acadia is home to both mineral soil and organic soil wetlands, allowing a diverse range of plants and animals to grow in these critical, delicate, areas. Closer to the coast, intertidal and subtidal zones characterize Acadia’s shoreline. Tidal pools, left behind as the ocean recedes with each low tide, are populated by sea cucumbers, rockweed, sea stars, dog whelks, mussels, and more.
Loons are large, deep-diving water birds with a unique call, and are some of Acadia’s most iconic residents. They build their nests along the edges of small ponds, often close to areas where humans enjoy swimming, kayaking, and walking their dogs. Acadia is also home to amphibians and reptiles, including snapping turtles and painted turtles.
Non-native species pose a direct threat to native species, who must compete with invasive species for food, water, sunlight, and other critical resources. Nearly one third of the park’s flora is non-native, and the National Parks Service currently categorizes the spread of 12 non-native species throughout the park as being of “high management concern.” To combat the encroachment of non-native species, officials in Acadia employ an integrated pest management strategy which relies upon an understanding of the invasive species’ biology and prioritizes the use of the least toxic treatments possible.
Fire is also an important factor in Acadia’s natural history. A large fire in 1947 burned most of the eastern side of Mount Desert Island is the most recent extensive fire Post-fire aspen-birch communities are still abundant. The spruce-fir forests, the dominant closed-canopy forest type on the island, include a large earlier-successional birch and red maple within the area that burned, along with the maturing spruce and fir. Vegetation on the western half of the island, which escaped the 1947 fire, reflects more clearly the underlying characteristics rather than the effects of recent fire.
Scientists supported by the USGS Northeast Climate Adaptation Science Center study a wide range of topics in the northeastern United States, including how climate may impact wildlife health, water quality and quantity, and ecosystems. Additionally, the USGS has been working with the National Park Service and other agencies to provide comprehensive maps of vegetation in several national parks, including Acadia.