Habitat description
Coastal plain pondshores occur along the perimeter of acidic, nutrient-poor, groundwater-fed ponds with fluctuating water levels driven by precipitation and evapotranspiration patterns. Although most coastal plain ponds do not have permanent inlets or outlets, some larger ponds may have stream outflows, in conjunction with water level fluctuations influenced by groundwater. Coastal plain ponds were formed in glacial outwash plains or glacial lake beds dominated by sand and gravel deposits. Coastal plain pondshores are concentrated in Cape Cod and southeastern MA as well as at a few inland sites in the Connecticut River watershed. Coastal plain pondshores typically occur in clusters tied to a single groundwater source or aquifer. Natural water level fluctuations set the stage for a rich assemblage of distinct, rare plant and invertebrate communities found on coastal plain pondshores.
Characteristic natural communities
Coastal plain pondshores are quite variable in their physical characteristics including basin size, shoreline slope, depth, and substrate, including sand, gravel, cobble, and organic bottoms. This in turn results in variation in shoreline plant and invertebrate communities. Pondshore and aquatic communities may vary in size and composition from year to year depending on seasonal and annual water level changes. Learn more:
Characteristic plants and animals
Plant communities of the gently sloping shoreline follow a typical zonation from dry to flooded. The upper shoreline is often characterized by tree oaks and pitch pine, bordered by a narrow shrub zone of highbush blueberry, sweet pepperbush, maleberry, and greenbrier. In low water years, a pronounced zone of herbaceous vegetation emerges, and may include grasses, sedges, and wildflowers of state and regional significance such as Torrey’s beak-sedge, thread-leaved sundew, New England boneset, and Plymouth gentian. In high water years, only a few plants such as bayonet rush and floating leaved aquatic plants, like white or yellow waterlily, are visible. Larger coastal plain ponds with fish populations (i.e., waterbodies typically with surface outflows) can harbor relatively rich freshwater mussel communities including species of conservation concern such as the tidewater mucket, eastern pondmussel, triangle floater, and alewife floater. Coastal plain pondshores also harbor rich dragonfly and damselfly communities, including several species that are restricted to this habitat.
View a complete list of Species of Greatest Conservation Need associated with this habitat.
Associated habitats
CPPs are most often found within dry woodlands and barrens, but may also occur within oak forests and woodlands, maritime forests, and in association with other habitats such as shrub swamps. CPPs are most often associated with shallow or deep isolated ponds.
Ecological processes
Fluctuation in water levels, seasonally and across years, driven by precipitation and groundwater flux, is a major driver of plant zonation and maintenance of the rare plant community. Many of these plants do not compete well and are adapted to irregular disturbance regimes (long but variable periods of inundation and occasional fire). Many coastal plain pondshores occur within the pine barrens landscape and have a history of fire that can help to reduce woody vegetation and shading on and adjacent to the pondshore. The careful reintroduction of prescribed fire in this setting is warranted in some cases.
Threats
Development along coastal plain pondshores and within the watershed is a major threat. This can include direct alteration of the pondshore (e.g. armoring), as well as indirect effects of development on water quality (pollution), and water quantity (natural system modification). Nutrient inputs and other pollutants from development and agriculture (e.g., cranberry bogs) such as herbicides and pesticides can impact water quality and result in harmful algal blooms. Water withdrawals, from groundwater wells or surface water withdrawals for irrigation, can alter the natural pattern of water level fluctuations that sustain the coastal plain pondshore natural community.
Human disturbance, including excessive pedestrian activity, off-road vehicles, and in some cases horses, can damage the sensitive pondshore plant community. Invasive species like grey willow and common reed pose a significant threat; Asian clams can also alter these natural systems.
Climate change will impact coastal plain pondshores. Increases in summer droughts, winter precipitation, and sea level rise associated with climate change will influence water level regimes. Ponds will respond differently to climate change based on their water clarity, depth, surface area, and volume. Sea level rise will also increase the risk of saltwater infiltration into low-lying coastal plain pondshores.
Conservation actions
- Proactive habitat protection: Protect coastal plain pondshores in conjunction with other associated 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 and managing water withdrawals and water quality should be considered where applicable.
- Conservation planning: Include coastal plain pondshores 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. Monitoring the effectiveness of habitat restoration efforts is a high priority for this habitat to inform adaptive and cost-effective management. Conduct targeted research to improve habitat and population management.
- Public outreach: Include information about the role of coastal plain pondshores and associated landscapes such as the Southeast Pine Barrens in biodiversity conservation, climate resiliency, and water resource protection as part of broader communication strategies.
Restoration & management recommendations
Coastal plain pondshores are designated as very high priority (tier 1) 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.
- Water quantity and quality restoration: Coastal plain pondshore management requires maintaining and restoring natural hydrology and variable water level regimes. Restoration efforts should focus on strategical removal of impoundments and ditches, avoiding excessive long-term drawdown or flooding, and preventing activities that harden pond substrates or alter wetland habitats. Trails and roads should be rerouted around wetlands and their buffer zones to minimize impact. Long-term monitoring of water level fluctuations is essential to evaluate the effects of climate change, while balancing human water demands with ecological needs is critical to sustaining these ecosystems amid droughts, storms, and sea-level rise. Hydrologists and restoration ecologists play a key role in understanding site-specific conditions, like determining how the ground and surface water moves through the wetland ecosystem and watershed, as well as implementing appropriate water restoration techniques. Maintaining water quality is equally vital, which includes restoring nearshore vegetation buffers, reducing stormwater runoff, and limiting inputs from fertilizers, septic systems, pesticides, salt, and animal waste like Canada geese and horses. Collaboration with pondshore neighbors and local authorities to develop best management practices can further reduce stormwater impacts and eutrophication, ensuring the long-term health of these habitats.
- Invasive plant control: The primary species of concern are common reed and grey willow. However, there are many other invasive species that can adversely affect coastal plain pondshores. In some cases, it may be desirable to control native shrubs and trees that are encroaching onto or shading the pondshore, noting that the presence of these shrubs may be an indication of altered hydrology. The careful application of herbicide is usually the most effective way to treat nearly all invasive species occurrences, though it should be expected that it will take several years of treatment to completely eradicate any established invasive occurrences due to persistent seedbanks and the clonal nature of certain species. Prior to completing any such work, regulatory approvals from the local conservation commission and the Natural Heritage and Endangered Species Program (NHESP) are likely to be required. It should also be noted that the continued presence of invasive species may be an indicator of an underlying stressor such as altered hydrology or unnatural chemical inputs, and therefore addressing both the invasive species and the underlying stressors is critical to restoring the long-term viability of a site.
- Access control: Control access, relocate trails, and refrain from pond shore disturbances such as raking vegetation and using illegal off-road vehicles which increase potential pathways for invasive plants, destroy vegetation, and compact soil substrates.
- Prescribed fire: Reintroduce prescribed fire within appropriate coastal plain pondshores and adjacent terrestrial buffers associated with barren restoration and management efforts. Prescribed fire may be employed to improve habitat conditions for fire dependent pondshore herbaceous plants, to remove thatch and debris associated with invasive species control efforts, improve nesting habitat for wildlife, and to control woody understory vegetation encroaching on pondshores.
Additional resources
Examples of coastal plain pondshores in Massachusetts: Myles Standish State Forest, Nickerson State Park, and Hyannis Ponds Wildlife Management Area.
New York coastal plain pondshores website
Cape Cod Commission: Freshwater Pond Restoration Projects website
Sorrie, B. A. 1994. Coastal Plain Ponds in New England. Biological Conservation 68:225 – 233.
Smith, S. M., and K. C. Medeiros. 2019. Recent groundwater and lake-stage trends in Cape Cod National Seashore: relationships with sea level rise, precipitation, and air temperature. Journal of Water and Climate Change 10.4:953 – 967.
Perales, K. M., C. L. Hein, N. R. Lottig, M. J. Vander Zanden. 2020. Lake water level response to drought in a lake-rich region explained by lake and landscape characteristics. Canadian Journal of Fisheries and Aquatic Science 77:1836-1845.