Habitat description
A suite of highly dynamic natural communities shaped by the constant influence of the wind and the ocean. When these communities occur together, they form shifting mosaics, either as barrier beaches or dune complexes. The location, extent, and even the persistence of these communities within any given complex will slowly-but-steadily shift due to the daily impacts of wind-driven sands, but periodically they will also be quickly and often radically altered by storm events.
Associated habitat types
As a suite of communities, the Coastal Beach and Dune Complex habitat is often represented by barrier beach systems, and therefore will interact directly with the Tidal Wetland, and the Maritime habitat groups.
Characteristic communities and species
In the MassWildlife Habitat classification, the following natural communities are considered part of the Coastal Beach and Dune Complex. Note that other “maritime” natural communities are included in the Maritime Habitat group.
- Maritime Beach Strand Community (S3): A very harsh community of sparse grasses and other non-woody plants on beach sand occurring above the mean high tide mark. Salt influence from spray and over wash, along with dry, hot and unstable conditions result in a sparse environment dominated by bare sand with aggregations of beach grass (Ammophila), complimented by plants such as beach pea, seaside goldenrod and sea rocket.
- Maritime Dune Community (S3): A very harsh community of sparse grasses, other non-woody plants, and occasional shrubs on wind-driven hills of sand occurring behind - and often grading into - Maritime Beach Strand communities. A gradient can develop in larger dune complexes where the ocean-facing dune ridge will be sparse, but each subsequent ridge moving away from the ocean will be increasingly vegetated due to its relative protection from wind and over wash. It is often in these more protected back dunes where complementary communities such as Maritime Shrubland and Maritime Pitch Pine communities will establish.
- Maritime Shrubland Community (S3): Maritime Shrubland communities can occur in a variety of coastal settings (ex. dunes, headlands, bluffs) where poor soils, salt-spray and constant exposure to wind shape both their structure and composition. The woody species associated with this community do not tolerate salt over wash, though historically, fire was an important disturbance agent. Low, dense woody vegetation is dominant, and is typically comprised of bayberry, huckleberry, black cherry, sumac, greenbrier and poison ivy. Grasses, forbs and low heaths are generally sparse, but may temporarily become dense in patches of recent disturbance. The scale of this community can be highly variable: ranging from relatively small and ephemeral on barrier beach dune complexes, to sprawling across hundreds of acres on the offshore islands.
- Coastal Interdunal Marsh/Swale (S2): Wetlands that occur in the valleys within dune complexes. Most of these community occurrences are relatively small, with their hydrology dependent upon groundwater and/or precipitation. This is a fairly diverse community type, ranging from ephemeral pools dominated by grass-like plants, to peat wetlands covered in sphagnum moss with thick cranberry, to dense shrub swamps with emergent trees. The presence of a wetland in the basin of a dune complex is the defining characteristic.
- Maritime Pitch Pine on Dunes (S1): Open woodlands dominated by pitch pine occurring in sheltered valleys of dune complexes beyond the reach of most salt-spray influences. Occurrences in more dynamic settings have a ground cover of wind-blown sand, beach heather and lichens; occurrences in more stable settings will develop a ground cover of low, dense sedges.
Coastal Beach, and to a somewhat lesser degree, Dune habitats, are critically important habitats for a highly specialized suite of often imperiled species. Piping plovers and least terns are signature species of these communities, and their populations breed almost exclusively in these habitats. Other imperiled species, such as the northeastern beach tiger beetle also rely upon the beach strand community as their exclusive habitat. In migration, the strand and dune communities support thousands of feeding and roosting shorebirds as they rest on their journeys of thousands of miles. Coastal Interdunal Marsh/Swale communities support their own suite of highly specialize and often imperiled plants, and Maritime Pitch Pine Woodlands often support breeding populations of whip-poor-wills.
Ecological processes
Coastal beach and dune habitat is exposed to some of the most extreme weather conditions in Massachusetts, as well as to some of the state’s most persistent erosional forces. The beach strand community, occurring at the leading edge of this suite, experiences the most constant of these forces with the daily change of tides, the constant pressure of wind and blowing sand, the harshness of unshaded sun, and the influence of salt spray. With storms, these agents will impact the entire suite of communities by introducing pulses of over wash, salt-spray, high winds and shifting sand across the entire complex. And though dynamic, there is also a natural rhythm to these processes: currents and offshore winds will build beaches and dunes with deposited sand in the summer, while washing much of these deposits away with winter storms; complexes will slowly migrate in somewhat predictable trajectories based on near-shore currents; and plant communities will shift in relationship to these factors.
Threats
Sea level rise, public recreation, off-road vehicles, invasive species, increased predators (for associated shorebirds), impacts to natural sand deposition.
- Climate Change: The Coastal Beach and Dune Complex is one of the most vulnerable community suites in Massachusetts due to its position at the front-line of sea level rise. The beach strand community and its associated species are especially vulnerable, as even daily high tides have already begun to threaten over wash to areas that traditionally only saw periodic events. Couple sea level rise with an increase in the intensity and frequency of coastal storms that impact the entire suite of communities in this complex, and the foundations of these communities will begin to erode faster than they can rebuild, and their associated species may no longer be able to keep pace with the changes to these systems.
Restoration & management recommendations
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, please see: Habitat Management Priorities and Planning.
The primary management issues facing this habitat are related to public use and access, which include addressing the erosion of sensitive dune communities by managing and in some cases redirecting access, protecting the rare and sensitive species that occupy these communities from direct and indirect public impacts, and ensuring that natural process continue unabated by not armoring or groining shorelines, either onsite or off.
The direct impacts of public access fall into two major categories: erosion and the direct disturbance of obligate species. Erosion can be especially acute on upper beach strand and dune communities, where foot or off-road vehicle traffic will quickly lead to the disruption of sensitive vegetation, resulting in the rapid breakdown and ultimate loss of the plant community. This can be avoided by directing foot traffic away from sensitive areas and restricting off-road vehicle use. Degraded areas can be restored by establishing plugs of native obligate plant species in the degraded areas.
Taking measures to reduce the disturbance of obligate species is a critical consideration in the management of these resources. The first step in addressing this situation will always be to understand what species are using the site, where these species occur in any given year, and at what season will public management be necessary. The most well-known example of this situation in Massachusetts is the presence of breeding piping plovers and/or least terns on a strand community, and under this scenario, state and federal guidelines will dictate the minimum amount of public management required. Other situations are more subtle, and examples include areas of strand communities being used for aggregations of resting migratory shorebirds, sea mammals hauling up upon stand communities, or an upper strand community supporting sensitive plant communities and tiger beetle larval areas. Working to manage the presence of people in relation to these resources is critical, and such solutions as symbolic fencing, the deployment of rangers, the restriction of dogs, and the required removal of trash (to reduce the presence of predators) are all important tools under the appropriate situation.
Ensuring that the natural beach building process continues unabated is also critical in maintaining a high integrity Coastal Beach and Dune complex. This primarily involves avoiding anything that disrupts the natural flow of nearshore sediment, such as the armoring of beaches, or the establishment of jetties and groins. These structures may not only accelerate erosion at their immediate site, but they can also impact distant sites by altering or cutting off the flow of sediment to them. Any proposed shoreline erosion control project needs to be evaluated carefully for both on and off-site impacts.
Aside from managing public impacts in the strand and primary dune communities, some habitat management concerns are present in the supporting communities in this complex. Most notable, the Coastal Interdunal Marsh/Swale community can be especially susceptible to invasive species colonization and a shift toward aggressive generalist plant species. Early detection/rapid response is always the preferred method of keeping invasive species from establishing, but for sites that already have established issues, the thoughtful use of herbicide is an important tool. 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.
Examples
- Plum Island
- Crane Beach
- Horseneck Beach
- Cape Cod National Seashore
- Sandy Neck
- South Cape Beach
Additional resources
- Coming soon