Maritime

A suite of coastal cliff, woodland, and forest communities influenced by wind, salt spray, poor soils and fire. Oak, red cedar and heath species are prevalent.

Habitat description

Maritime habitats are directly influenced by wind, salt spray, nutrient-poor soils, and occur in a shifting mosaic of communities (woodlands and shrublands, with cliff communities including areas of grassland). Trees tend to be short because of salt spray and strong winds, and vegetation is often sparse, especially on cliffs.

Associated habitat types

Closer to coastal waters, habitats in the Coastal Beach and Dune Complex typically occur adjacent to Maritime habitats. Inland of Maritime habitats and beyond the influence of salt spray, coastal Oak Forests and Woodlands, Barrens, or Sandplain Grasslands and Heathlands often occur because of the prevalence of sandy soils near the coast.

Characteristic communities and species

More information on the specific natural communities (Swain 2020) within this habitat type is available from the following fact sheets:

Maritime Erosional Cliff Community S2
Maritime Forest / Woodland S2
Maritime Juniper Woodland / Shrubland S1
Maritime Rock Cliff Community S2

Tree cover varies from closed canopy in some maritime forests to completely open on many cliffs. Trees occurring in the Maritime habitat are typically shorter (<10m) relative to inland forests and woodlands, and sometimes resemble shrub thickets. Oak, cherry, beech, red cedar, pitch pine, and holly species are prevalent. The understory composition varies depending on soil conditions and exposure to salt spray and wind. Cliffs are usually sparsely vegetated, and where vegetation is supported, vines and invasive and/or weedy plants are usually most abundant. Relatively protected maritime woodlands and forests in acidic soils often have an oak overstory and a mixed understory of bayberry, inkberry, sumac, shadbush, greenbrier, and sweet pepperbush. Low, damp areas may contain viburnums, highbush blueberry, and swamp azalea. Areas with red cedar as a major component may contain various shrubs such as bayberry and sumac, with dunegrass, little bluestem, and beach heathers in the herbaceous layer. Maritime grasslands found on several Elizabeth Islands and Cape Cod are part of the Coastal Beach and Dune Complex. These grasslands are generally dominated by warm season grasses, especially switchgrass, with scattered shrubs and small trees, such as oaks, cherry, bayberry, heathers, and other heaths.

Erosional cliffs are important nesting habitat for Bank Swallows, and Peregrine Falcons perch on and hunt from sea cliffs during fall migration. Erosional cliffs with a clay component may provide habitat for the threatened species Claybank Tiger Beetle. Many of the species that use maritime forests, woodlands, and shrublands are species typical of oak woodlands and early successional habitats. Examples are Eastern Towhee, Gray Catbird, Black-and-White Warbler, and Common Yellowthroat. White-tailed deer and gray squirrels are often abundant. Chain Dot Geometer, a moth species of concern, often inhabits maritime shrublands. Maritime habitats are important migratory stopover areas for songbirds, raptors, and monarch butterflies.

Ecological processes

The influences of salt spray, wind, and erosion occurring in a harsh growing environment of nutrient-poor and sandy soils define the maritime environment. Salt blown over dunes by high winds limits the height of vegetation, and alters its form. The interaction of salt exposure and fire is an important disturbance that can shape some communities. Fire clears understory vegetation allowing salt spray to penetrate deeper inland. Salt spray, in turn, desiccates vegetation making it more flammable. Fire also promotes suitable growing conditions for herbaceous plants including rare plants such as Crested Fringed Orchid and encourages regeneration of shrubs and trees. The dynamic coastline can cause changes to maritime habitats by increasing or decreasing exposure to marine influences. Waves and storms occasionally cause portions of Maritime cliffs to slough into the sea or onto the beach below.

Threats

Maritime habitats are threatened by development, fragmentation, shoreline hardening, unmanaged recreation, invasive species, fire exclusion, and climate change. Outright loss and fragmentation of habitat is a major pressure as coastal regions continue to undergo development. Improperly sited walking trails and off-highway vehicle (OHV) use can damage sensitive vegetation and cause increased erosion, especially on cliffs. Bank stabilization, beach nourishment, and shoreline hardening interfere with natural coastal processes preventing the natural migration of coastal and maritime habitats. Because maritime systems are so frequently subjected to disturbance, they are easily invaded by numerous non-native invasive plants such as honeysuckles, Asiatic bittersweet, multiflora rose, mugwort, common reed, and non-native cool-season grasses. Over-browsing of seedlings and saplings by White-tailed Deer is a threat to regeneration of canopy trees and desirable forbs. At some sites, fire exclusion is an additional threat. Without regular fire occurrences, dense vegetation often grows near the coastal areas, blocking much of the salt spray that can help maintain the typical maritime vegetation, and fire adapted plants such as oaks, warm-season grasses, and heaths fail to thrive.

Climate change is expected to cause sea levels to rise, and storm intensity and frequency to increase, which could stress Maritime habitats. These habitats are often positioned between the shore and developed areas. As sea levels rise, they need room to migrate inland, but developed areas may prevent that from happening. Additionally, the hardening of shorelines in response to rising sea levels is major threat indirectly caused by climate change.

Restoration & management recommendations

Management and restoration activities can vary from simple actions to prevent degradation to full-scale restoration of natural communities and ecological processes. The actions for any individual site will be dependent on planning which includes clear goals that are compatible with site conditions and are designed to address threats. Because Maritime habitats lie between the tidal and coastal environments, management activities can range from protecting dunes and shorelines to more typical forest and woodland silvicultural practices.

• Access Control: Erosional cliffs are highly susceptible to excessive erosion. Foot traffic, bicycles, and OHVs can dramatically increase the rate of erosion, causing land loss on the top of the cliff. Blocking access can help stabilize the rate at which erosion occurs. People may attempt to limit erosion through bank stabilization measures which should generally be avoided because it interferes with the natural erosional process. Maritime forests, shrublands, and grasslands are highly sensitive to disturbance; even improperly managed foot traffic can damage the plant communities. The thin layer of organic material atop sand is easily broken by OHVs and heavy foot traffic. It can take many years for soils and biotic soil crusts to recover after being damaged.
• Tidal Restoration: Because Maritime habitats are so closely connected to the tidal habitats, impediments to coastal processes can damage Maritime habitats. Reducing the hardening of the shoreline and enabling natural beach and dune migration will allow for the Maritime habitats to move and adapt to changes in the dynamic coastal environment.
• Invasive Plant Control: Maritime habitats are often highly invaded by non-native plants. Asiatic bittersweet and other vines can overtake native shrubs and trees, smothering them and acting as a sail to cause them to be blown over during storms. Invasive shrubs such as bush honeysuckles, multiflora rose, glossy buckthorn, and Japanese barberry can dominate the understory to the exclusion of native species. Wetland areas are often invaded by non-native phragmites, which can form dense monocultures. Mechanical and chemical treatments may be effective in controlling invasive plants.
• Prescribed Fire: In many Maritime natural communities, prescribed fire can, and should be used to promote native plant communities. Prescribed fire helps maintain open structure, allowing light and salt spray to penetrate woodlands, helps maintain typical groundcover and prevents establishment by generalist trees species. In oak woodlands and forests, fire should be applied every 3-8 years usually in the spring or fall. More information about fire implementation in oak habitats is discussed in the Oak Forests and Woodlands factsheet. Maritime grasslands should ideally be burned every 1-3 years, although less frequent burns can still have significant benefits. Spring burns can be used to help promote warm season grass and growing season burns can be used to reduce the vigor of shrubs. Prescribed fire can also play an important role in managing Maritime Juniper Woodlands and Shrublands. Fire promotes warm season grasses, pitch pine, and numerous other characteristic species. Fire also reduces vegetation density allowing red cedar seedlings to establish. Whenever possible, fire should be allowed to carry through transitional zones into the dune systems and inland into adjacent habitats including wetlands.
• Mowing and Mulching: In areas where fire suppression and invasion by non-native and generalist plants have allowed vegetation to grow too dense, mechanical treatments such as tree removal, mowing, and/or mulching may be helpful to reestablish desirable structure. Following a major disturbance such as a storm or field abandonment, the edges of Maritime habitats often grow up in a dense thicket draped in vines. Mowing and mulching can be used to clear dense vegetation from around desirable trees, which can improve light penetration and allow salt spray to carry more deeply into the habitat. Opening the woodland edge can help promote desirable maritime species and improve the ecotone between the marine and coastal environments. It can also be a helpful tool to prepare a site for prescribed fire.
• Wildlife Control: Managing White-tailed Deer populations is important in areas where desirable herbaceous plants and trees are over browsed.
• Revegetation: In areas where erosion has become a major problem, revegetation may be necessary. In extremely sandy settings, planting dunegrass plugs may be an appropriate strategy for stabilization and revegetation. Maritime grasslands that are dominated by cool-season grasses may need to be seeded as part of the restoration effort. Local ecotype seeds that are free of weeds should always be used.

Examples

• Cape Cod National Seashore in Orleans, MA – Managed by the US National Park Service, Cape Cod National Seashore is a mosaic of coastal and maritime habitats.

• Crowe’s Pasture in Dennis, MA – Maritime grassland and oak woodlands owned by the Town of Dennis.

• Cuttyhunk Island in Gosnold, MA – A collection of maritime forests, woodlands, and grasslands, portions of the island were recently put under conservation restriction.

• Aquinnah Cliffs in Aquinnah, MA – A collection of conservation properties make up the Aquinnah Cliffs. The Aquinnah Wampanoag Cultural Center is located atop the cliffs.

• Allen’s Pond in Dartmouth, MA – This MassAudubon preserve contains trails that meander through a variety of beach, coastal, and maritime habitats.

• Halibut Point State Park in Rockport, MA – This state park contains rock cliffs and various maritime and coastal habitat types.

• Parker River National Wildlife Refuge in Newburyport, MA – This NWR contains maritime forest, woodland, and grassland with boardwalks through multiple habitats.

• Nasketucket Bay State Reservation in Mattapoisett, MA – This state reservation contains a maritime forest with an American holly component, as well as a salt marsh and a rocky shore.