Habitat description
Coastal beaches and dunes include a suite of dynamic natural communities shaped by the wind and ocean. These communities are generally open, consisting largely of grasses, herbs, and bare sand closest to the ocean, and becoming more shrub-dominated with some trees slightly further inland. These communities, including some interdunal wetlands and swales, occur together in shifting mosaics as barrier beach or dune complexes, moving and changing in response to the daily impacts of wind- and ocean-driven sands. They can be quickly and radically altered by periodic storm events.
Characteristic natural communities
Coastal beaches and dunes can be divided into distinct natural communities. The beach strand community includes the sparsely vegetated area above the mean high tide line characterized by bare sand and wrack and sparse beach grass, complimented by beach pea, seaside goldenrod, and sea rocket. The dune community includes grasses and occasional shrubs on wind-driven hills of sand occurring landward of and often grading into the beach strand community. As distance from the ocean increases, dune vegetation becomes denser, and maritime shrubland and maritime pitch pine communities can establish on the back dunes. The woody plants in these communities are less tolerant of salt and include bayberry, huckleberry, black cherry, sumac, greenbrier and poison ivy. The pitch pine on dune community tends to be more open, with sparse pitch pine, bare sand, beach heather, lichens and sedges. Maritime shrublands may also be found on headlands and bluffs. Finally, coastal interdunal marshes and swales occur in the valleys between dunes are typically small, with variable vegetation including ephemeral pools dominated by grass-like plants, peat wetlands covered in sphagnum moss with thick cranberry, and dense shrub swamps with emergent trees.
Learn more about the natural communities found in coastal beaches and dunes:
- Maritime pitch pine on dunes (S1)
- Coastal interdunal marsh/swale (S2)
- Maritime beach strand community (S3)
- Maritime dune community (S3)
- Maritime shrubland community (S3)
Natural communities are given state rarity/imperilment ranks ranging from S1-S5 (S1: rarest/most imperiled).
Characteristic plants and animals
Coastal beach, and to a somewhat lesser degree, dune habitat, is critically important for a highly specialized suite of often-imperiled species. Piping plovers and least terns breed almost exclusively in these habitats. Other imperiled species, such as the northeastern beach tiger beetle exclusively rely upon the beach strand community. Beaches and dunes support thousands of feeding and migratory seabirds and shorebirds as they rest and forage before and during their journeys of thousands of miles. Many invertebrate specialists depend upon beaches and dunes and the associated intertidal zone, including beetles, amphipods and beach flies. Several Species of Greatest Conservation Need (SGCN) plants such as seabeach amaranth, seabeach needlegrass, and bushy rockrose occur on beaches and dunes. Coastal interdunal marshes/swales support additional highly specialized and often imperiled plants.
View a complete list of Species of Greatest Conservation Need associated with this habitat.
Associated habitats
Coastal beach and dune habitat is often associated with marine, tidal wetland, and maritime forests and shrublands habitats. In MassWildlife's habitat classification, the intertidal zone associated with beaches is included within tidal wetland, and maritime forests and shrublands, and coastal beach and dune habitats often intergrade, such as the transition between maritime shrubland and maritime juniper woodland communities.
Ecological processes
Coastal beach and dune habitat is exposed to some of the most extreme weather conditions in Massachusetts, as well as persistent erosional forces. The beach strand community experiences constant reshaping by tides, wind, blowing sand and ocean spray. During storms, the entire beach and dune system can be reshaped by these forces and including extreme high tides and overwash. Though dynamic, there is also a natural rhythm to these processes: currents and offshore winds build beaches and dunes by depositing sand in the summer; winter storms reverse this process; beach and dune systems slowly migrate in somewhat predictable trajectories based on near-shore currents; and plant communities shift in response.
Threats
- Development: Coastal beaches and dunes are sometimes impacted by development, resulting in habitat loss and fragmentation. Shoreline hardening (natural systems modification) can result in direct habitat loss and may also interfere with natural processes by preventing the natural migration of coastal and maritime habitats. Invasive species may also pose a threat, and development/recreation can lead to increased density of predators such as fox, skunk, and raccoon that prey on rare shorebird nests and chicks. Although Massachusetts is a leader in the protection of ground nesting shorebirds, human disturbance (e.g., trampling, indirect disturbance, oversand vehicles) have the potential to adversely impact these birds and other rare beach strand plants and animals without adequate management.
- Climate change: Coastal beaches and dunes habitats are among the most vulnerable in Massachusetts due to its position on the front-line of sea level rise. At some sites, even daily high tides have already begun to regularly over wash areas that traditionally were influenced only by periodic events. Sea level rise coupled with an increase in the intensity and frequency of storms impacting the entire suite of communities in this complex will cause these communities to erode faster than they can rebuild; associated species may no longer be able to keep pace with the changes.
Conservation actions
- Proactive habitat protection: Protect coastal beaches and dunes 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 and shoreline hardening. Innovative approaches to incentivizing compatible development should be considered where applicable.
- Conservation planning: Include key beaches and dunes in conservation planning efforts at multiple spatial scales. (See BioMap as an example.) Habitat considerations should be carefully considered when engaging in coastal resilience planning tied to sea level rise and climate change.
- Monitoring and research: Monitor the health and trends of SGCN populations, plant communities, and other wildlife.
- Public outreach: Include information about the role of coastal beaches and dunes and associated coastal landscapes in biodiversity conservation, flood mitigation, water filtering, and climate resiliency as part of broader communication strategies.
Restoration & management recommendations
Due to their importance to Species of Greatest Conservation Need and vulnerability to stressors, coastal beaches and dunes habitats have been designated as high priority (tier 2) for restoration and management. The following is an overview of restoration options; get details about specific management practices by clicking on the provided links.
Before undertaking a project, it is important to establish clear goals that are compatible with site conditions. Factors to consider include identifying the resources required for restoration and long-term maintenance, and securing community, stakeholder, and institutional support. For more information, see habitat management priorities and planning.
Ensuring that beach visitors can enjoy the beach without damaging the habitat which is sensitive to erosion and vegetation damage is an important management issue. This may involve managing, and in some cases redirecting access, including foot traffic and oversand vehicles, to protect the rare and sensitive species (access control). The best-known example in Massachusetts is the presence of breeding piping plovers and/or least terns beaches which are also heavily used by people for recreation. In this case, state and federal guidelines dictate the management required to reduce the impacts. Other situations are more subtle: examples include areas of beach strand used for aggregations of migratory shorebirds, sea mammal haul-outs, sensitive plants, and tiger beetle larvae. Working to manage people in relation to these resources is critical: important tools may include installation of symbolic fencing and/or signage, deployment of rangers, restrictions on dogs, and removal of trash (to reduce predators). Although the vegetation may recover on its own after access is controlled, in some cases it may be appropriate to actively restore dunes and other related habitats by planting native species (see native vegetation planting).
Ensuring that the natural beach-building process can continue unabated is also critical to maintaining high integrity coastal beach and dune systems. This primarily involves preventing shoreline hardening. Seawalls, jetties, and groins disrupt the natural flow of nearshore sediment, accelerating erosion at their immediate locations and potentially impacting more distant sites by altering the flow of sediment. Any proposed shoreline erosion control project should be evaluated carefully for both on and off-site impacts.
The coastal interdunal marsh/swale community can be especially suspectable to invasive species colonization. Early detection/rapid response is always the preferred method of keeping invasive species from establishing. For sites that already have established invasive plants, the thoughtful use of herbicide and other controls may be warranted (see invasive plant control). Cutting pioneering woody vegetation can also be an important approach to maintaining otherwise open wetlands, and whenever possible, prescribed fire can be an ideal management tool in the swale, shrubland and pitch pine communities (see prescribed fire).
Examples
- Plum Island
- Crane Beach
- Horseneck Beach
- Cape Cod National Seashore
- Sandy Neck
- South Cape Beach