Habitat description
Open habitats on dry, nutrient-poor soils typically occurring on glacial outwash. Key indicators of this habitat are a dominant presence of warm-season grasses such as little bluestem and/or heath shrub species like low blueberry, sheep laurel, and teaberry. Trees (typically oak) may occur within dry grassland and heathland, but always at a very low frequency. This disturbance dependent habitat is historically associated with fire occurring on the landscape somewhat regularly. High integrity examples of dry grassland and heathland are now quite rare and represent critical conservation resources for the large and diverse suite of highly specialized and often imperiled plants and animals that dependent upon them.
Characteristic natural communities
Although some occurrences of this habitat may be clearly separated into either dry grassland or heathland based upon a dominance of grass-like plants or heath shrubs, these natural communities often intergrade and occur on a continuum.
Learn more about the natural communities found in dry grassland and heathland:
- Sandplain grassland (S1)
- Sandplain heathland (S1)
- Sandplain grassland inland variant (S2)
- Sandplain heathland inland variant (S2)
Natural communities are given state rarity/imperilment ranks ranging from S1-S5 (S1: rarest/most imperiled).
Characteristic plants and animals
Dry grassland and heathlands support some of the richest suites of specialized and imperiled species in Massachusetts. For example, a few remaining large sandplain grasslands are the primary habitat for state-listed grasshopper sparrows, upland sandpipers, and vesper sparrows. Heathland communities support over two dozen state-listed moths and butterflies. Dry grassland and heathland habitats also support a disproportionally high percentage of the Commonwealth’s bee species. Rare or uncommon plants such as New England liatris and butterfly milkweed also depend upon dry grassland and heathland habitat.
View a complete list of Species of Greatest Conservation Need associated with this habitat.
Associated habitats
This habitat typically occurs within a broader matrix of dry woodlands and barrens, maritime woodlands and shrubland, or coastal beaches and dunes habitats. It can occur in isolation in some settings (e.g., airfields).
Ecological processes
Nutrient-poor, dry soils are a driver for the presence and persistence of this habitat. These harsh conditions favor the establishment of warm-season grasses and heaths, and naturally limit generalist species that would otherwise quickly overwhelm the habitat. Periodic fires or other disturbances are also needed to prevent the accumulation of organic material, soil enrichment, and a shift in vegetation. Natural disturbance processes to maintain the open structure of this habitat may include fire, salt spray, storms, and/or growing season frost.
Threats
Development is a major threat leading to habitat loss and fragmentation. Development can also lead to fire suppression (a form of natural systems modification), and can make it difficult to implement prescribed fire management. Invasive species and off-road vehicles may also be threats (human disturbance). The frequency of natural disturbance is unlikely to be sufficient to maintain high-quality dry grassland and heathland habitat. Therefore, a lack of management (especially prescribed fire) as well as inappropriate management (such as mowing regimes that conflict with the persistence of target species) are major threats. It remains unclear how climate change will affect this habitat that is maintained by dry, harsh conditions.
Conservation actions
- Proactive habitat protection: Protect dry grasslands and heathlands 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 should be considered where applicable.
- Conservation planning: Include key dry grasslands and heathlands 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 dry grasslands and heathlands 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
Due to their importance to Species of Greatest Conservation Need and vulnerability to stressors, dry grasslands and heathlands habitats have been 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, please see: Habitat Management Priorities and Planning.
Restoration of both large and small patches of this habitat is important, as small sites are often embedded within a matrix of associated habitats such as dry oak woodlands and facilitate the persistence and movement of species across the landscape. Established dry grassland and heathland communities require regular disturbance (see ecological processes above). In the absence of adequate natural disturbance processes, active management must now be employed to restore and maintain this important habitat. Prescribed fire, mowing, soil scarification, and invasives control are the primary tools for managing these communities.
Prescribed fire
Whenever possible, prescribed fire should be the primary tool for the management of established sandplain grassland and heathland communities. The frequency of prescribed fire needed to maintain the habitat can vary considerably from site to site, but generally sandplain grassland requires more frequent burning than heathland. Although prescribed fire may be combined with other management techniques if resources are limited, and considerably longer return intervals may be acceptable at some sites, it is often appropriate to burn sandplain grassland habitat approximately every 2-5 years, and heathland habitat every 5-10 years, in the absence of natural disturbance such as salt spray or frost. In most cases, an entire site should not be burned in a single year, but instead at least half of the site (and in some cases more) should be left unburned for at least one growing season to provide refugia for specialized obligate species. Fire is important to maintain structural integrity and remove thatch, and to stimulate germination and increase flowering, fruiting, and seed release for many rare plants.
Whether to use growing-season burns or dormant-season burns is dependent upon time-of-year restrictions for sensitive species as well as the specific objectives of the burn. A reduction in generalist vegetation can be achieved with growing season burns; dormant season burns are useful for reducing thatch and other unwanted fuels. In most cases, it is rare to have the ability to manage a site with prescribed fire alone. Therefore, a comprehensive and adaptive plan that also includes mowing and targeted invasive plant control should be adopted.
Learn more about using prescribed fire for habitat management.
Mowing
Sandplain grassland: Mowing can be an important management tool for reducing woody vegetation. Rotational growing season mowing that leaves a significant portion of the available habitat intact during a given growing season may be necessary to achieve community composition objectives and should be employed in ways that do not cause adverse long-term impacts on populations of target species (i.e., adequate temporal refugia and appropriate return intervals). If a site supports state-listed, a habitat management plan approved under MESA is required. Though mowing is an important tool for maintaining sandplain grassland, mowing alone cannot fully address the threat of accumulating organic material and nutrients that can lead to a shift towards cool season grasses and other generalist vegetation. When prescribed fire is an option, mowing should be viewed as a supplement to prescribed fire. Periodic prescribed fire will always be important for removing thatch that leads to soil enrichment.
Sandplain heathland: Mowing can be an important tool in controlling pioneering woody vegetation (tall shrub and sapling generalists) above low heaths. Growing season mowing can reduce competing woody species, but the potential impact to target heath species should always be considered. Dormant season mowing of undesirable woody vegetation is an effective way of lowering the height of this vegetation, making it available for efficient selective herbicide treatment the following growing season. Where competing vegetation is growing interspersed with desired heath species, mowing decks can be set above the level of the heath layer. As with prescribed fire, maintaining temporary undisturbed refugia to mitigate the disturbance of mowing is important.
Learn more about using mowing for habitat management.
Invasive plant control
The thoughtful and selective use of herbicide can be a critical tool for managing this habitat. Specialty herbicides that do not impact grassy plants can be especially useful in controlling unwanted invasive plants and woody vegetation in dry grasslands. Targeted applications of generalist herbicides can be important for controlling woody vegetation, clonal forbs and invasive species in both dry grassland and heathland. Mowing or cutting woody vegetation prior to herbicide application, and then applying the herbicide to the resprout, will achieve very targeted control of otherwise tall woody vegetation.
Learn more about invasive plant control.
Soil Exposure
Areas of bare mineral soil within these communities are critically important in supporting specialized invertebrates, especially a wide variety of bee species. Scarification can be very beneficial in sandplain grassland communities as both invertebrate habitat and to engage the latent seed bank. Shallow scarification can also be very beneficial in heathland settings, but most heath species are sensitive to deeper scarification, and therefore care should be taken.
Learn more about soil exposure.
Additional project planning considerations
Degraded dry grassland and heathland habitats often require a sequence of restoration activities to achieve high integrity and function. Understanding the feasibility of a restoration project, including consideration of long-term capacity, is essential when deciding whether to take on a project. Fortunately, heathland communities are resilient and typically respond robustly to restoration activities. Sandplain grassland communities are generally more difficult to restore when degraded but also respond quickly and favorably to restoration actions. Some restoration considerations are listed below.
Heathlands that have been degraded by over-topping canopy trees or tall shrubs can be relatively easy to restore by removing enough of the tree canopy to allow light to reach the heath below. In some cases, chemical control may be required to reduce resprouting of tree stumps. Most heaths are clonal and consist of extremely large underground root networks, so even if above-ground heath appears sparse, the root network will often vigorously sprout once canopy trees are removed. Degraded sandplain grasslands can be found in a variety of conditions; the persistence of obligate species (especially little bluestem) is an important factor in determining the feasibility of restoration. In general, woody vegetation can be easier to manage during restoration than cool season grasses and clonal forbs.
Community structure does not need to be “pure” grassland/heathland, and interstitial emergent trees (oak, red cedar, and pitch pine) and aggregations of shrubs (ex. scrub oak and hazelnut) can add important habitat diversity. In general, dry grasslands can function well with sparse emergent trees (savanna-like), and heathlands can function with an even higher rate of retention (up to open woodland). Tree retention should be avoided in the core of grassland bird areas.
Seeding may be necessary or desirable during initial dry grassland restoration. Generally, only little bluestem should be seeded because most other dry grassland obligate species will persist in the seed bank for decades and may already be poised to recolonize a site once the soil is disturbed during restoration activities. In Massachusetts, warm season-grass species other than little bluestem are generally not encouraged for seeding because they can quickly grow too dominant. Any seed brought into a project should always be from a local ecotype and should be clean of unwanted species.
Additional resources
Examples:
- Frances Crane WMA, Falmouth
- Westover Airforce Base, Chicopee
- Southwick WMA, Southwick
- Leyden WMA, Leyden
- Barre Heathland: Ware River Watershed, Barre