Habitat description
Maritime forests and shrublands are influenced by wind, salt spray, and nutrient-poor soils, and occur in a shifting mosaic of natural communities (woodlands and shrublands, with cliff communities including areas of grassland). Maritime forests tend to occur slightly further inland. Occurrences closer to the shoreline are more open, especially on cliffs, and trees tend to be short because of salt spray and strong winds.
Characteristic natural communities
Maritime forests and shrublands can be divided into distinct natural communities. Tree cover varies from closed canopy in some maritime forests to completely open on many cliffs. Trees are typically short compared to inland forests and woodlands and sometimes resemble shrub thickets. Oak, cherry, beech, red cedar, pitch pine, and holly species are prevalent. 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. Areas with red cedar (juniper) as a major component may contain shrubs such as bayberry and sumac, with dune-grass, little bluestem, and beach heathers in the herb layer. Cliffs are usually sparsely vegetated, and where vegetation is supported, vines and invasive and/or weedy plants are usually most abundant.
Learn more about the natural communities found in maritime forests and shrublands:
- Maritime juniper woodland/shrubland (S1)
- Maritime erosional cliff community (S2)
- Maritime forest/woodland (S2)
- Maritime rock cliff community (S2)
Natural communities are given state rarity/imperilment ranks ranging from S1-S5 (S1: rarest/most imperiled).
Characteristic plants and animals
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 state-threatened 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 include eastern towhee, gray catbird, black-and-white warbler, and common yellowthroat. White-tailed deer and gray squirrels are often abundant. Chain dot geometer, a state-listed rare moth, often inhabits maritime shrublands. Maritime habitats are important migratory stopover areas for songbirds, raptors, and monarch butterflies.
View a complete list of Species of Greatest Conservation Need associated with this habitat.
Associated habitats
Maritime forests and shrublands often occur in association with coastal beaches and dunes and dry grasslands and heathlands habitats. For example, coastal 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. Inland maritime habitat may grade into coastal oak forests and woodlands or dry woodlands and barrens.
Ecological processes
The maritime environment is defined by a harsh growing environment influenced by salt spray, wind, erosion and nutrient-poor, sandy soils. Blowing sand and high winds limit vegetation height and alter 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 and associated habitat fragmentation in coastal regions experiencing significant development expansion.
Natural systems modification also impact this habitat. Shoreline hardening can result in direct habitat loss and may also interfere with natural processes by preventing the natural migration of coastal and maritime habitats. Fire exclusion is also a threat at some sites. Without occasional fire, dense vegetation growth may block salt spray that helps maintain maritime habitat, and fire-adapted plants such as oaks, warm-season grasses, and heaths fail to thrive. Over-browsing of seedlings and saplings by white-tailed deer is a threat to regeneration of canopy trees and desirable forbs.
Because maritime systems are so frequently subjected to disturbance, they are easily invaded by numerous non-native invasive species such as honeysuckles, Asiatic bittersweet, multiflora rose, mugwort, common reed, and non-native cool-season grasses. At some sites, fire exclusion is an additional threat.
Human disturbance (e.g., improperly sited walking trails and off-road vehicles) can damage sensitive vegetation and cause increased erosion, especially on cliffs.
Climate change is expected to cause sea level rise, and increased storm intensity and frequency 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.
Conservation actions
- Proactive habitat protection: Protect maritime forests and shrublands in conjunction with other coastal habitats to maintain healthy and resilient landscapes for people and biodiversity conservation. Prioritize sites supporting state-listed animals and plants and other SGCN, as well as other protection priorities identified in BioMap and other conservation planning tools (e.g., municipal open space plans).
- Habitat restoration and management: See recommendations below.
- Law and policy: Regulate and limit the impacts of development, pollutants, and shoreline hardening. Innovative approaches to incentivizing compatible development should be considered where applicable.
- Conservation planning: Include key maritime forests and shrublands in conservation planning efforts at multiple spatial scales. (See BioMap as an example.)
- Monitoring and research: Monitor the health and trends of SGCN populations, plant communities, and other wildlife. Monitor the effectiveness of habitat restoration efforts and conduct targeted research to improve habitat and population management.
- Public outreach: Include information about the role of maritime forest and shrublands and associated coastal landscapes in biodiversity conservation, flood mitigation, water filtering, and climate resiliency as part of broader communication strategies.
Restoration & management recommendations
Restoration and management activities can vary from simple actions to prevent degradation to full-scale restoration of natural communities and ecological processes. Before implementing a project, planning should be undertaken to identify clear goals and actions that are compatible with site conditions and designed to address threats. The following is an overview of restoration options; get details about specific management practices by clicking on the provided links.
Access control: Foot traffic, bicycles, and ORVs can increase the rate of erosion and land loss at erosional cliffs. Controlling access (e.g., signage, trail siting, and fencing) can reduce erosion. Bank shoreline hardening should be avoided whenever possible because it interferes with natural beach and shoreline migration and sediment transport processes. Maritime forests and shrublands, and associated coastal habitats 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 ORVs and heavy foot traffic. It can take many years for soils and biotic soil crusts to recover after being damaged.
Invasive plant control: Maritime habitat is 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. Mechanical and chemical treatments may be effective in controlling invasive plants.
Prescribed fire: Prescribed fire can be used to restore and maintain maritime native plant communities. In maritime forests and woodlands that have experienced long periods of fire exclusion, the initial interval between fires may be closer to reduce hazardous fuels and restore vegetation and eventually spread to longer fire return intervals (>15 - 20 years). For more information about prescribed fire, see oak forests and woodlands7 . Prescribed fire can also play an important role in managing more open juniper woodlands/shrublands. Fire promotes warm season grasses, pitch pine, and numerous other characteristic species. Fire also reduces vegetation density allowing red cedar seedlings to establish. When 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 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. Mowing and mulching can also be an important 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.
Native vegetation planting: In areas where erosion has become a major problem, revegetation may be necessary. Local ecotype seeds that are free of weeds should always be used.