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Grasslands and meadows are important habitat for pollinators, grassland birds, and other wildlife. However, a decrease in disturbances that historically perpetuated these ecoystems has resulted in a decline of grasslands and meadows. Careful management can sustain and improve these habitats.
Grasslands and meadows, including savannas (with scattered trees), are ecosystems dominated by herbaceous plants that do not have standing water or fully saturated soil for more than a few days per year. Herbaceous plants are those that lack stems made of wood and in the temperate zone generally die back to the ground in winter, although there are some species with a few evergreen leaves, often arranged in a rosette flat to the ground. There are herbaceous plants in all plant communities in Pennsylvania, but those that are restricted to grasslands, meadows, and other open habitats are obligate heliophytes, that is, they need full sun to prosper and have little or no tolerance for shade.
Most grasslands and meadows in eastern North America are short-lived ecosystems. Without repeated ecological disturbance, woody cover (trees and shrubs) quickly returns. It is now believed that management of the landscape with fire and fallow agriculture by Native Americans maintained extensive grassland ecosystems in this region for thousands of years, and that feeding, wallowing, and trampling by now-extinct megaherbivores and mesoherbivores—mammoths, mastodons, giant ground sloths, horses, tapirs, peccaries, and others—created and maintained a patchwork of meadows and grasslands for millions of years before that, until their demise about 11,000 years ago, within a few thousand years after the first arrival of humans to our region. As a result, many native plant and animal species, including many birds, bees, butterflies, and moths, are dependent on these habitats and are now threatened as they decline. Nearly 40% of Pennsylvania’s native plant species are obligate heliophytes.
Grasslands and meadows share two distinctions with wetlands: they are crucial for biodiversity conservation out of proportion to their small total area and they have declined severely due to human activities. One of the most influential causes of the decline is the rise of mechanized agriculture and artificial fertilizers, which put an end to fallowing—periodically leaving fields uncultivated for one or more years to restore soil organic matter from the growth and decomposition of wild plants. Recognition of grasslands’ and meadows’ importance lags behind that of wetlands but is making steady gains. In Pennsylvania, grasslands and meadows are identified as a high priority for restoration, reclamation, and maintenance by the Pennsylvania Wildlife Action Plan.
Scientists conducting a global study of total areas of habitat converted or destroyed compared with habitat protected in all major ecosystem categories showed a bleak picture for grasslands and meadows worldwide (Hoekstra et al. 2004). For temperate grassland, savanna, and shrubland ecosystems together, the ratio of converted to protected land is ten to one, five times higher than even the beleaguered tropical rainforest. Less than 5% of the land in temperate grassland, savanna, and shrubland has been protected to date while nearly 50% has already been destroyed. Most native grasslands in the eastern United states were converted long ago to agricultural, residential, commercial, and other uses. Since the European colonization of eastern North America over 300 years ago, native grasslands and meadows have steadily diminished in size and species diversity. These ecosystems were once composed of hundreds of native plant species that provided the highest quality food and habitat for native meadow wildlife. The typical grassland or meadow today is an abandoned field invaded by a few introduced invasive species; examples include multiflora rose, autumn-olive, Japanese honeysuckle, Amur honeysuckle, creeping (“Canada”) thistle, common mugwort, mile-a-minute, small carpetgrass, and Japanese stiltgrass. They degrade the habitat for native animal species by failing to provide food for insects and other prey species and crowding out the native plants that have supported native herbivores and the entire food web for millions of years. More information about the problems caused by invasive plants and management is included in Invasive Plants.
Populations of grassland bird species such as bobolink, eastern meadowlark, grasshopper sparrow, savannah sparrow, vesper sparrow, upland sandpiper, and northern bobwhite have declined drastically in recent years due to the loss of habitat and the fragmentation of remaining habitat into pieces that are too small to meet their needs. Most of this loss is from residential and commercial development and from changes in farming practices, such as the lack of fallowing, earlier mowing times and, ironically, the widespread use of conservation tillage (no tilling or minimal tilling), which reduces the availability of bare soil used by some grassland birds.
Declines in populations of Neotropical migrant birds that breed in the forests of eastern North America have received much attention, but grassland and meadow birds in the region are in even greater peril. There is an ongoing effort by scientists and resource managers to better understand what makes ideal habitat for grassland and meadow birds. In the late twentieth century there was wide promotion of native warm-season grasses. Native warm-season grasses are a key part of prime habitat for grassland birds because they are bunchgrasses, in contrast to the sod-forming growth habit of the common introduced species of cool-season grasses planted for hay, pasture, or turf. The bare ground between clumps provides high-quality nesting sites and materials, allows grassland birds to move more easily, and provides better protection from avian predators as they search for food. The open space between clumps also provides space for forbs (wildflowers) to become established.
In spring, ground-nesting birds utilize the cover afforded by graminoids and forbs to brood and rear their young. The higher the diversity and abundance of native plants, the higher the diversity and abundance of insects, which constitute the most important element in the diet of young birds. During the autumn months, native forbs and graminoids produce highly nutritious seeds. These are relished by a variety of songbirds and will attract many migrants that stop over on their long journey south. Throughout the winter, bunchgrasses whose dead stalks remain upright provide food and cover for the resident birds to help them survive the winter months.
Despite the great benefits of native warm-season grasses, research is showing that they do not fit the needs of all grassland birds. Savannah and grasshopper sparrows prefer warm-season grasses, but bobolink and meadowlark do best in cool-season grasslands. And some birds, e.g., horned larks, are full- or part-time “dirt” birds, using the bare soil created by traditional cultivation (moldboard plowing) and heavy grazing, which mimics the trampling, wallowing, and grazing by megaherbivores that occurred during most of the evolutionary history of Pennsylvania’s native grassland and meadow plant and animal species. There is a growing consensus that a large open landscape (hundreds of acres) with diverse cover types in patches of various sizes, including native warm- and cool-season grasslands and forb-dominated meadows, is best. Agriculture (row crops, pasture, hay fields) without hedgerows can be a compatible economic land use within a mosaic of native grasslands and meadows intended to provide habitat for grassland-interior birds. Structural diversity—created by planting a patchwork of meadow types, each with a mix of species—produces preferred cover for the greatest variety of grassland and meadow wildlife species.
Little is known about the effects of native grassland/meadow decline on other kinds of wildlife in Pennsylvania, including small mammals, snakes, lizards, turtles, insects and other arthropods, and various animals that live in the soil. Surveys of lepidopterans (moths and butterflies) in native-species-dominated grasslands and meadows in Pennsylvania have shown them to support vast numbers of species in just this one group of arthropods. Many moth and butterfly species have developed close relationships with native meadow wildflowers, which they use for the nectar and seeds (adults) and the leaves, stems, and roots (larvae). As our few remaining undisturbed habitats continue to be lost to development, many native plants are becoming increasingly rare. Unless native meadow wildflower and butterfly habitats are restored, we can expect to see further declines in overall butterfly populations and continued losses of imperiled species.
Finally, grasslands and meadows are critical for the conservation of Pennsylvania’s native flora. Nearly 30% of Pennsylvania’s native heliophytes—roughly 250 species—are classified as endangered, threatened, near threatened (“rare”), or extirpated in the state. Those that still exist in the wild in Pennsylvania live mainly in rare remnants of ancient grasslands and meadows, for instance, serpentine barrens, diabase glades, grasslands along the Lake Erie shore, patches of limestone prairie, and ridgetop grasslands. However, some are also found in more ordinary landscapes where repeated disturbance—annual mowing or haying, grazing, frequent burning—has kept forest encroachment at bay but no planting has taken place for many years. Larger examples include utility rights-of-way where herbicides are not used, historical parks where fallow fields are maintained to simulate historical conditions while serving the needs of wildlife, and the vehicle and weapons training corridor at Fort Indiantown Gap in Lebanon and Dauphin Counties.
The broad vegetation categories grassland and meadow refer to areas that are uncultivated, dominated by herbaceous plants, and have soils that are not saturated year-round. A permanently wet herbaceous plant-dominated ecosystem can be a marsh, fen, or bog; see Wetlands. Even though there are no widely accepted criteria for distinguishing grasslands from meadows, it is useful to define them roughly as follows.
Grasslands are dominated by graminoids, with more than 50% cover, and have no trees or less than 5% tree cover. Graminoids are grasses and other grasslike plants lacking colorful (animal-pollinated) flowers—mainly grasses, sedges, and rushes.
Meadows are dominated by forbs or a mixture of forbs and non-flowering plants (ferns, horsetails, clubmosses), with more than 50% cover, and have no trees or less than 5% tree cover. Forbs are flowering herbaceous plants that are not graminoids, commonly called wildflowers.
Savannas are grasslands or meadows dominated by any combination of herbaceous plants with sparse, scattered trees or tall (> 3 feet) shrubs (between 5% and 25% canopy cover).
Prairies are expansive grasslands with no tree or tall shrub cover or less than 5% woody cover.
Any grassland or meadow community may have a significant low-statured (≤ 3 feet) shrub component, as long as herbaceous plant cover is at least 50%.
In practice, there is not a sharp dividing line between grassland and meadow. In many places there are patches of both types present and in some, grasses and forbs each cover about the same total area. Where stewardship goals include maximizing native species and habitat diversity, patchiness in species composition is crucial. Some plant species, especially native tall warm-season grasses (Indian-grass, big bluestem, switchgrass, and eastern gamagrass), can overwhelm their shorter neighbors and gradually eliminate them by shading and root competition. Planting native warm-season grass seed in patches interspersed with planted patches of cool-season grasses and forbs is a powerful way to enhance and prolong the native diversity of grassland/meadow species and habitats.
Even though open habitats in Pennsylvania are dependent on recurring tree-killing disturbances to persist, some grasslands and meadows resist encroachment by trees (described as persistent) and others facilitate transformation to forest (described as successional).
Successional grasslands and meadows are the most common of those two categories in Pennsylvania. They are short-lived communities dominated by early successional plants, often mixed with seedlings of forest trees, that follow severe disturbance or farmland abandonment. Soils are generally moist (not wet or dry) and average to rich in nutrient content. A large fraction of the plants in many present-day successional grasslands are introduced invasive species.
Succession is the non-seasonal, directional, and continuous pattern of colonization, changing relative abundance and dominance, and extinction on a site by populations of plants, animals, fungi, and other organisms, usually set in motion by disturbance. Early successional plants tend to be shade-intolerant; have many small seeds that travel long distances, dispersed by wind, birds, or bats; and have a low root-to-shoot biomass ratio, short mature height, low stem structural strength, fast growth rate, and short life span. Early successional plants tend to facilitate their own replacement by late successional species, e.g., by enriching the soil, protecting tender tree seedlings from heat and moisture loss, and lacking the ability to grow tall enough to shade their late successional neighbors.
Persistent grasslands and meadows are rare in Pennsylvania. They are long-lived communities dominated by generally stress-tolerant herbaceous and low shrub species, some of which have a few of the characteristics of late successional plants, including having seeds that are dispersed short distances by gravity, ground-dwelling mammals, or ants; a high root-to-shoot biomass ratio; a slow growth rate; and a long life span. Persistence of these communities depends on chronic stress of natural origin that delays or prevents invasion by trees and other forest species (e.g., shallow soil, sandy soil, frequent flooding, nutrient deprivation, unusual soil chemistry, salt spray, frost pockets) or disturbances of human origin that don’t penetrate the soil, especially frequent fire or annual hay harvest. In some cases, through positive feedbacks the dominant plants may create or maintain stresses that potential competitors are sensitive to. Many persistent grasslands and meadows in Pennsylvania have existed at or near their present locations for so long that they have accumulated clusters of plant species that live nowhere else nearby, even though they may have mainly short-distance seed dispersal; in some places they include rare, threatened, or endangered species.
The key to knowing if a grassland or meadow is successional and of limited value for conservation and wildlife habitat in its present condition, or if it is persistent and of high value—a “special place”—is its plant species composition. The tables above give examples of indicator species that can be used to judge where the existing condition of a grassland or meadow lies along that spectrum. The lists of characteristic species in the tables are not exhaustive, but they can be used as a rough guide. The services of a knowledgeable botanist may be helpful. A grassland or meadow dominated by species in the “successional” list is in need of reclamation, intensive restoration, or conversion to shrubland or forest if it is to become valuable for conservation and wildlife habitat. A grassland or meadow that includes multiple species in the “persistent” list is already valuable and needs maintenance or minor restoration to sustain or improve its value.
Below are examples of characteristic species in successional grasslands and meadows in Pennsylvania:
INTRODUCED WARM-SEASON GRASSES
NATIVE WARM-SEASON GRASSES
INTRODUCED COOL-SEASON GRASSES
NATIVE COOL-SEASON GRASSES AND OTHER GRAMINOIDS
INTRODUCED VINES
INTRODUCED FORBS
NATIVE FORBS
NATIVE FERNS
Below are examples of characteristic species in persistent, high-quality grasslands and meadows in Pennsylvania:
NATIVE WARM-SEASON GRASSES AND OTHER GRAMINOIDS
NATIVE COOL-SEASON GRASSES AND OTHER GRAMINOIDS
NATIVE FORBS
NATIVE FERNS
Most grasslands and meadows in eastern North America are short-lived ecosystems. Without repeated ecological disturbance, woody cover (trees and shrubs) quickly returns. It is now believed that agriculture and burning by Native Americans, coupled with the more recent agriculture of European settlers, maintained extensive herbaceous openings in this region for thousands of years, and that feeding, wallowing, and trampling by now-extinct megaherbivores—mammoths, mastodons, giant ground sloths, horses, tapirs, peccaries, and others—created and maintained a patchwork of meadows and grasslands for millions of years before that, until their demise soon after the arrival of humans to our region between 15,000 and 11,000 years ago. As a result, numerous native plant and animal species, many birds, bees, butterflies, and moths in particular, are completely dependent upon these habitats and are now threatened as they decline. Nearly 40% of Pennsylvania’s native plant species are obligate heliophytes. They require grasslands, meadows, or other open habitats such as rock outcrops to thrive.
Key features of healthy grasslands and meadows include:
High diversity of native herbaceous heliophyte species, including forbs, warm-season graminoids, cool-season graminoids, tall plants, short plants, annuals, biennials, perennials
Grasslands and meadows can be quite complex and multidimensional with regard to ecosystem function, and gleaning critical hydrologic, habitat, and diversity information can be equally complex. A baseline assessment and regular follow-up monitoring is essential to assessing a grassland/meadow’s health, identify problems and threats, and track trends due to management activity and external stressors. These assessments are used to determine management goals and actions adaptively over time. Inventory and monitoring are important, but they can be resource-intensive. Under each of the following assessment categories, three levels of inventories are suggested—good, better, and best—to accommodate how much time, funds, and expertise are available.
The types of plant communities found in an area can tell us a lot about a site. Plant community surveys provide information about plant species presence, the structure and composition of the plant community, soil chemistry, bedrock geology, and wildlife habitat quality, including patch diversity. The Pennsylvania Natural Heritage Program provides a dichotomous key to wetland communities in Pennsylvania to help land stewards determine what type of plant community is found on a site (see Related Items of Note).
Another tool developed by the Pennsylvania Natural Heritage Program to help restoration practitioners in their efforts to establish native plant communities identifies species most likely to thrive at a site. The user draws the land area on a map and natural communities with similar characteristics are shown in the results, along with a list of suggested species to plant based on common species found in similar natural communities (see Related Items of Note).
If the type is a wet meadow type (marked by the presence of wetland hydrology, wetland vegetation, wetland soils), follow guidance for inventory and stewardship of wetlands (see Wetlands).
Good—Determine the size of the grassland or meadow within the site. Determine whether the dominant species in the grassland or meadow are uniformly distributed within the site or if there is significant patch diversity.
Better (in addition to Good)—Identify the dominant species across the site. Determine whether the dominant species in the grassland or meadow are uniformly distributed within the site and roughly map the extent of each.
Best (in addition to Good and Better)—Determine the specific community types that make up the grassland or meadow according to the Pennsylvania Terrestrial and Palustrine Community Classification (see Related Items of Note). Map the boundaries and describe each plant community within the site.
Good—Based on the site and the types of habitat patches, determine what kinds of wildlife the grassland or meadow may support using the Conservation Opportunities Area Tool (see Related Items of Note).
Better (in addition to Good)—Collect and review any information available on the grassland/meadow of interest. Consider not only natural communities but also specific species that are present in the grassland/meadow. Consult local and state agencies, review community science sites such as iNaturalist and eBird, review PNHP’s website, including any nearby Natural Heritage Areas (NHAs) in the county natural heritage inventories (see Related Items of Note), and talk to local experts.
Best (in addition to Good and Better)—Perform field inventories to determine what species and habitats are present and ground-truth or enhance any information that has already been collected. Tailor the inventory to the taxa or habitats that are likely to be most valuable or rare or widespread in the grassland/meadow. These may become the central focus of any monitoring or management that will take place in the future.
Assessing the condition and viability of an ecosystem provides the baseline data to develop a stewardship, restoration, and management framework for a natural area. A model framework for ecological assessments (often called ecological integrity assessments, or EIA) has been developed by NatureServe to guide development of site assessment methods that are used to assess and monitor the ecological condition and viability of a site (see Related Items of Note). Originally created for wetlands, the concepts may be used for grasslands or meadows as well. Grassland conservation and management share several characteristics with wetlands: they are crucial for biodiversity conservation out of proportion to their small total area and they have declined severely in the last hundred years.
Good—Review aerial photos and walk the landscape looking for signs of disturbance, encroachment, invasive species coverage, and general landscape condition. Consider any data available on use by wildlife and presence of specific habitats or species. According to the NatureServe EIA, this type of assessment is often referred to as a “Level 1” or landscape-level assessment. In Pennsylvania, landscape-level assessments may be conducted using a tool called the Pennsylvania Landscape Condition Model (LCM), which is a protocol that can be applied in geographic information system (GIS) software (see Related Items of Note).
Better (in addition to Good)—Based on the information from above, further investigate through field visits possible impacts including hydrological alterations (dams, channels, drainage tiles, etc.), presence of invasive species, particularly if dense and widespread, and any obvious disturbance (timbering, mowing, structures, etc.). This step is referred to, by NatureServe, as a “Level 2” assessment and requires a basic understanding of ecological processes and knowledge of local flora and fauna. A trained botanist or ecologist is not necessarily required. For the Level 2 assessment, as described by NatureServe, the grassland or meadow is evaluated for a set of ecological stressors, such invasive species, presence of garbage, or nutrification, and a level of severity (usually 1-3) is assigned to each stressor present. This “stressor checklist” results in a condition score for each anthropogenic (human-caused) stressor. Note any changes over time and further investigate with field observation and consultation with experts.
Best (in addition to Good and Better)—A formal site visit should be conducted by a trained botanist or ecologist to determine the plant composition of the site and ecological variables that contribute to the site’s condition and viability. Plant species are extremely important in assessing the ecological quality of a site and are important indicators of condition that can be monitored over time to see if site quality is maintained or is declining. For this level of assessment, called “Level 3” by NatureServe, a full species list and quantified community composition, often assessed using fixed plots or other methods, is determined by a trained botanist or ecologist. A wetland delineation is often helpful and multiple assessments are required to determine change over time. If a wetland is present, see Wetlands section. Basic steps also include review of historical aerial photos and comparison to present images to determine the change in condition and extent.
Most grasslands and meadows in eastern North America are short-lived ecosystems. Without repeated disturbance, woody cover (trees, shrubs, and lianas) quickly returns. It is now believed that agriculture and burning by Native Americans, coupled with the more recent agriculture of European settlers, maintained extensive grassland ecosystems in this region for thousands of years, and that feeding, wallowing, and trampling by now-extinct megaherbivores—mammoths, mastodons, giant ground sloths—and mesoherbivores—elk, horses, tapirs, peccaries, giant beaver, and others—created and maintained a patchwork of meadows and grasslands for millions of years before that, until their demise about 11,000 years ago, soon after the arrival of humans to our region. As a result, many native plant and animal species, including birds, bees, butterflies, and moths, are dependent on these habitats and are now threatened as they decline. Nearly 40% of Pennsylvania’s native plant species are obligate heliophytes.
Short-term goals can be more directed toward specific problems or needs. Short-term goals include: control or elimination of selected invasive species, control or elimination of selected shrub and tree species, adding interpretive signage, erecting nesting boxes, and various other stewardship practices.
Establishing long-term goals can help give context to the many management issues that may arise. Long-term goals may include: establishing and maintaining a buffer around the grassland, keeping populations of selected species healthy, maintaining and conserving important habitat connections in the landscape, and restoration to a previous or preferred state.
Broadly, the management of grasslands and meadows can fit into three categories: maintenance, restoration, and conversion/creation. The type of management undertaken will dictate many of the goals that are decided upon for the grassland or meadow in question. It is important to understand how to structure the thinking and consequent management based upon the overall condition and context for the grassland or meadow. Assessment of existing condition is part of the baseline inventory process.
Even though open habitats in Pennsylvania are dependent on recurring tree-killing disturbances to persist, some grasslands and meadows resist encroachment by trees (described as persistent) and others facilitate that transformation (described as successional). Resistance is in part due to plant species composition and in part due to soil characteristics, some of which are in turn produced or influenced by the plants themselves.
Maintenance is an ongoing, permanent necessity for nearly all grasslands and meadows in Pennsylvania, whether they are persistent historical remnants or the result of restoration or reclamation. Heliophyte species are distinguished from others by their usually high tolerance for disturbance and low tolerance for the shade beneath a forest canopy. Virtually all grassland and meadow occurrences in the state are the result of disturbance. Given the prevailing soils and current climate of Pennsylvania, a prolonged lack of tree-killing disturbance eventually leads to forest cover. Maintenance of native grasslands and meadows consists of mimicking key aspects of the disturbances that maintained such plant communities in the past, either for the roughly 13,000 years of human occupation before European settlement or during the many interglacial periods when the climate was similar to today’s, totaling several hundred thousand years over the past two million years of ice ages and continuously for millions of years before that. This can be accomplished either by annual mowing, intermittent livestock grazing, prescribed fire, selective removal of undesired species, or two or more of these methods in combination.
Good—Maintain the herbaceous plant-dominated ecosystem by mowing. The frequency and timing of mowing has a dramatic effect on the composition of a meadow and its wildlife residents. When and how often to mow will depend upon your conservation priorities and the environmental conditions of the grassland or meadow. In general, it is best to mow when wildlife is less vulnerable to disturbance, that is, during the non-growing season. A late winter or early spring mowing (prior to March 15th) is best. Mowing at this time conserves winter cover for wildlife and avoids disturbing nesting and feeding wildlife (birds, small mammals, butterflies) in spring and summer. If wet soil conditions prohibit mowing in late winter/early spring a fall mowing (after the first hard frost) when the area is dry or a winter mowing when the ground is frozen are other preferred options. Sometimes a second mowing is needed to control undesirable plants during the growing season; a mid-July to early August mowing will help control woody and invasive plants, encourage warm-season grasses, and provide sufficient time to establish winter cover. The only case where this would not be appropriate is in larger (> 50 acres) grasslands and meadows (or smaller meadows in a larger open landscape), which can support interior grassland and meadow birds. These birds can nest into mid-August. In this situation it is best to mow only one-third to one-half of the grassland or meadow each year to minimize disturbance of ground-nesting birds.
It is best to mow meadows when the ground is dry or frozen. They should be cut at a height of 8-12 inches. It is beneficial to grassland/meadow insects and other arthropods, and therefore to the entire food web, to leave 20-foot-wide strips unmown each year totaling 10% of the total area and rotating the location of the strips every year to avoid any area being unmown two years in a row. Some pollinators and other beneficial insects and spiders overwinter in or on standing dead grasses and other vegetation.
To emphasize that a meadow is intentional and managed, it is often beneficial to maintain a frequently mowed turf swath around the public edges and consider incorporating a trail network. Well-maintained trails encourage people to get into the meadow and discover its beauty up close. However, care should be taken to minimize the extent of trails to prevent undue disturbance of wildlife. This is especially true in meadows that support grassland-interior birds where trails can fragment the habitat and provide easy access for predators. Dog-walking during nesting season, even on a leash, is incompatible with grassland-interior bird nesting and fledging success.
Meadows must also be monitored for intrusion by introduced invasive plants. Invasives in meadows can be eliminated by spot mowing, spot-spraying, or wick application of an appropriate herbicide (see Invasive Plants), or manual or mechanical pulling. Haying (removing mowed biomass) can benefit native plants and discourage introduced invasives by reducing soil fertility over time. In some parts of Pennsylvania, there is a market for hay consisting of a diverse mixture of species, which is used in mushroom farming and production of compost for horticultural use.
Best (in addition to Good)—Another tool for managing meadows is prescribed fire. Native Americans used fire to manage the landscape for thousands of years, which selected fire-adapted species to dominate native grasslands and meadows. Periodic spring fires (with at least 3-5 years between burns in a given area), rotating among sections of the meadow landscape to maintain a refugium from which insects can re-colonize the treated area, will effectively discourage invasion by woody plants. For meadows less than 50 acres only 10%-20% should be burned in any year; for larger meadows one-third to one-half can be treated. Prescribed fire should be applied only by qualified teams of well-trained personnel and in accordance with federal, state, and local laws (see Prescribed Fire).
Where tall warm-season grasses become overdominant, crowding out most other kinds of plants, sites may require post-planting maintenance to reduce the grass cover and make room for forbs. Prescribed fire and tillage have been used to reduce grass cover, as has selective herbiciding. Though still uncommon in the East as an ecosystem management tool, grazing at low density (less than 0.5 “animal units”—1,000 pounds of grazer—per acre) should be considered as an alternative, especially in meadows. Grazing is widely used in Europe as a tool for the conservation management of native grasslands, meadows, and shrublands.
Another option that has been used successfully is to clear large circular patches in warm-season grass expanses using herbicide, then planting them with forb-only Pennsylvania-native seed mixes. Circles are used because they have the smallest edge-to-area ratio and thus should be slowest to be recolonized by overdominant grasses from their edges. This should be done only in grasslands that were created by planting, never in a long-persisting grassland or meadow that acquired its native-dominated flora by natural means over many years, especially not one with remnant (not planted) stands of endangered, threatened, or rare species. Such communities are irreplaceable repositories of locally indigenous genetic diversity.
The Society for Ecological Restoration International (SERI) defines ecological restoration as “an intentional activity that initiates or accelerates the recovery of an ecosystem with respect to its health, integrity and sustainability.” As we use the term in this handbook, it applies only to remnants of long-persisting historical grasslands and meadows that have been degraded as the direct or indirect result of human activities. Such remnants are exceedingly rare in Pennsylvania, but they do exist. (See link to the SER International Primer on Ecological Restoration, under Related Items of Note.)
Some management strategies, such as prescribed fire, are useful for both maintenance (see above) and restoration. In any case, at some point during restoration, or even from the start in portions of a site that are near desired conditions, both restoration and maintenance need to be practiced at the same time in different patches.
Good—Following determination of plant community type and verification that the site is a remnant persistent grassland or meadow based on the presence of multiple indicator species (see Table 2), identify activities to eliminate environmental stressors, such as removal of woody plants and introduced invasive species.
Prioritize among the woody and introduced invasive plants present on the site for spot-treatment to stop and reverse the growth of the fastest-spreading species. This category includes common mugwort (Artemisia vulgaris), creeping (“Canada”) thistle (Cirsium arvense), Russian-olive (Elaeagnus angustifolia), autumn-olive (Elaeagnus umbellata), glossy buckthorn (Frangula alnus), introduced honeysuckles (Lonicera japonica, L. maackii, L. morrowii, L. tatarica); Chinese silvergrass (Miscanthus sinensis), common reed (Phragmites australis), kudzu (Pueraria montana), Callery (“Bradford”) pear (Pyrus calleryana), Japanese knotweed (Reynoutria japonica), giant knotweed (Reynoutria sachalinensis), European buckthorn (Rhamnus cathartica), black locust (Robinia pseudoacacia), multiflora rose (Rosa multiflora), and black swallow-wort (Vincetoxicum nigrum). Do not use spray application of herbicide near any endangered, threatened, or rare plant species.
Plant only using plants reared from seed gathered on-site or from nearby, similar sites. Avoid commercial seed mixes, even of native species, and any other seed not from established indigenous populations within a short distance (a few miles) of the planted area; the sole exception is the nonnative annual ryegrass (Lolium multiflorum), which does not persist and can be a quick soil conservation measure while slower-growing native plants, seeded at the same time, become established. Restoration planting should take place only in areas that are vacant of native desired species due to the removal of invasives, woody plants, or encroaching forest.
Better (in addition to Good)—Set goals for cover, species composition, re-establishment of any rare plants or animals, and general function for the grassland or meadow, based on those characteristics of at least one, and preferably more, intact reference sites—the least degraded, most ecologically intact nearby natural areas of the same community type—as interpreted by an experienced, qualified restoration ecologist. Establish a monitoring plan and protocol to monitor changes in performance indicators. Conduct the baseline assessment.
Employing a qualified, experienced burn crew to implement prescribed fire is mainly a tool for maintenance (see above); however, in some situations fire can also be useful for restoration. Where undesired shrubs, tree seedlings, and tree saplings have encroached but are still relatively small or sparse, burning once or in successive years can reduce woody cover and encourage native herbaceous plants to fill in. Prescribed fire is unlikely to restore grasslands or meadows where encroaching trees are one inch in stem diameter or larger, which must be cut down, uprooted, or killed by basal bark herbicide application (see Conversion, below).
Note that some native grassland types in Pennsylvania are savannas, with scattered, often somewhat dwarfed trees of fire-tolerant species, mainly blackjack oak (Quercus marilandica), post oak (Q. stellata), and pitch pine (Pinus rigida); sometimes other somewhat fire-tolerant species such as scarlet oak (Q. coccinea), shingle oak (Q. imbricaria), chestnut oak (Q. montana), black oak (Q. velutina), and sassafras (Sassafras albidum); and usually some fire-sensitive trees that have nonetheless survived past fires or seeded in later, notably eastern redcedar (Juniperus virginiana) and Virginia pine (P. virginiana). The goal of fire in these communities is not to prevent tree establishment and persistence entirely, but rather to maintain sparse tree cover of fire-tolerant savanna species and keep other trees from encroaching and eventually replacing the grassland.
Best (in addition to Good and Better)—Based on the judgment of a restoration ecologist expert or team of experts, develop an adaptive management plan with selected indicators of desired conditions (e.g., estimated population numbers for the rarest plant and bird species; cover of functional groups such as native graminoids, native forbs, introduced invasive plants; total unfragmented acreage; etc.), target ranges (e.g., poor, fair, good, excellent) for each performance indicator, and a prioritized schedule of management actions (e.g., prescribed fire, mowing, or grazing; planting; control of invasives).
Monitor changes in performance indicators starting with two-year intervals and progressing to longer intervals as desired conditions are approached. Adjust management actions after each monitoring round as the needs are highlighted by trends in performance indicators. Monitoring, data analysis, and adaptation of management actions for a site that supports endangered, threatened, or rare species generally require the services of an experienced, qualified restoration ecologist.
Reclamation involves similar activities to restoration but occurs on land that may or may not have originally supported native-species-dominated grasslands or meadows historically and is now, or is about to become, a “blank slate,” such as a residential, office complex, or campus lawn; a floodwater detention basin, an abandoned farm field, pasture, or golf course; an area overgrown with introduced invasive species; a strip mine; or an abandoned industrial or commercial site. “The main objectives of reclamation include the stabilization of the terrain, assurance of public safety, aesthetic improvement, and usually a return of the land to what, within the regional context, is considered to be a useful purpose” (Society for Ecological Restoration International Science and Policy Working Group 2004; see Related Items of Note). The best management practices for restoration and reclamation are similar, but there are important differences. Restoration often involves the recovery to long-term viability of endangered, threatened, or rare plant populations already present on a site, whereas reclamation projects should avoid using seed of these species unless they are part of a scientifically sound, carefully planned recovery program using translocation, either reintroduction or augmentation . Both restoration and reclamation aim to maximize ecosystem services, including habitat for wildlife, especially species of greatest conservation need (SGCN).
Some management strategies, such as prescribed fire, are useful for both maintenance (see above) and reclamation. In any case, at some point during reclamation both reclamation and maintenance need to be practiced at the same time in different patches. The “best” management strategies for reclamation are the same as those for restoration (see above).
Good—Identify a target grassland/meadow community type (or types) to be reclaimed on the site. Identify activities to reduce environmental stressors, such as removal of woody plants and introduced invasive species. Turf grasses can be eliminated either by physically removing the sod (digging small areas or plowing and disking larger sites) or treating the area with an herbicide and seeding with a no-till drill. Determine the type of disturbance (mowing, livestock grazing, fire) and recurrence interval to maintain the open grassland or meadow community. Arrange for the future availability of what is needed to carry out needed management actions (expertise, labor, equipment, operator, livestock, qualified burn crew, qualified herbicide applicator, etc.).
Control introduced invasive species and plant native species in their place as soon as possible to inhibit recolonization by invasives. Use species mixes that will ensure high native species and functional group diversity. Plant native forbs and native cool-season grasses in patches separate from native warm-season grasses to prevent overdominance. Tailor seed species mixes to soil conditions in different patches, which may be wet, mesic, or dry, and to your goals for the site (e.g., habitat for desired wildlife species, habitat for pollinators’ entire life cycles, showy wildflower displays, erosion control).
Spring (before the beginning of June) and late summer or early fall are the preferred times to plant meadows. If a rapid conversion to native grasses is not an option for lack of funding or equipment, the landowner can encourage a gradual change from introduced to native grass dominance through the timing of management. Certain bird species, particularly bobolinks and meadowlarks, can thrive in large open areas dominated by introduced turf grasses created simply by reducing the mowing frequency of turf, pasture, or hay field to once per year.
Use seed mixes of species native to Pennsylvania, descended from seeds collected from wild plants growing within the same plant hardiness zone as the site or the next zone south (see linked USDA Plant Hardiness Zone Map under Related Items of Note), and within roughly 200 miles east or west of Pennsylvania’s borders, 50 miles north, and 250 miles south. Southern genotypes are predicted to do better with continued rising maximum and minimum temperatures. Reputable conservation seed purveyors should be able to provide at least an approximate location where the ancestral seed was originally collected.
One of the challenges of meadow establishment and management is a tendency for the planted native grass species to become overdominant. This is particularly true of the warm-season “tallgrasses,” notably big bluestem, Indian-grass, and switchgrass. It is best to mass forb plantings and separate them spatially from the tallgrass plantings. This type of patchiness is common in nature and should be imitated to the extent possible in new meadow establishment. Grasses should be planted in rates not exceeding 1-2 pounds per acre to achieve high species diversity. Fertilizer application should be strictly avoided; increasing soil nutrient availability would boost nonnative invasives’ competitive advantage over most native species.
During the first growing season meadows should be mowed whenever they are approximately 18-24 inches tall to a height of 8 inches. This will prevent cover crops, which are not intended to carry into subsequent years, from seeding and will encourage root establishment for the desired native plant species. It will also prevent incursion of woody plants. After the meadows are established (approximately two years), mowing should be done annually when there is least danger to wildlife and when the ground is dry or frozen, generally in March. In meadows that are typically wet in the spring, mowing should be done in the fall after the first hard frost. The meadows should be mowed to a height of 10-12 inches.
Initial failure of meadow and grassland plantings, especially of warm-season grasses, is not uncommon. Weather and other factors are beyond the control of even an experienced practitioner. Such setbacks are temporary and should not be a cause to give up on efforts to establish native meadow vegetation. Often, where initial plantings do not produce the desired result, a follow-up attempt a year later is successful. Additionally, it can take three years for native meadow plants to flourish, meaning that it may take multiple growing seasons to establish a meadow with good diversity and limited invasive plants.
Better (in addition to Good)—Consider the feasibility of employing a qualified, experienced burn crew to implement prescribed fire. With the help of a professional ecologist, determine the range of fire recurrence intervals needed to maintain the open grassland or meadow community.
Best (in addition to Good and Better)—Same as given under Restoration Management Strategies, above.
Conversion to native grassland and meadow ecosystems from forest, woodland, or shrubland is achieved by eliminating existing plants that can aggressively compete for nutrients, water, and light, namely forest trees, shrubs, and introduced invasive species. Conversion of grasslands and meadows is similar to reclamation except that the starting point is removing tree or shrub cover. The goal of converting forest, woodland, or shrubland to grassland or meadow is to improve an existing open community by targeting small tree or shrub stands that fragment otherwise high-quality grasslands/meadows, or those in the process of becoming high quality through restoration or reclamation. Tree- or shrub-dominated “peninsulas” jutting into an opening from adjacent forest, “island” stands in the middle of an opening, and fencerows greatly reduce the value of grasslands and meadows for forest-interior birds and other wildlife. Converting is not a net gain for biodiversity conservation if the target stand is a healthy forest, neither fragmented nor fragmenting, and dominated by native tree species; good targets for conversion are forest, woodland, or shrubland stands that cover only a small area and whose removal will not significantly reduce the quality of adjacent healthy, unfragmented forest.
After the initial tree removal, management strategies for conversion are the same as for reclamation in combination with those for maintenance (see two sections above). The “best” management strategies for conversion are the same as those for restoration (see above).
Good—Remove all woody stems manually or by cutting (chainsaw, whole-tree forest harvester, field mower). If the larger stumps cannot be removed they should be flush-cut or ground down even with the surrounding soil surface and treated with a systemic herbicide to prevent resprouting (see discussion of appropriate use of herbicides). If left in place, even the shortest tree stumps severely limit the options for grassland/meadow creation and maintenance.
In addition, follow the steps given under Reclamation Management Strategies (Good), above.
Better (in addition to Good)— Same as given under Reclamation Management Strategies, above.
Best (in addition to Good and Better)—Same as given under Restoration Management Strategies, above.
Numerous climate models analyzing varying emissions rates predict that Pennsylvania will face warmer daily high and low temperatures and increasing length, frequency, and severity of both droughts and pluvials (extended periods of very wet weather). The impacts of ongoing climate change on grasslands and meadows are unknown. Ecological principles give us mixed expectations.
Because Pennsylvania’s grassland and meadow ecosystems are “islands” in a “sea” of forest, farmland, and urban/suburban/small town development, the distances between them and the inhospitality of the intervening landscape severely limit immigration of new genotypes and new species. Even if genotypes and species exist elsewhere that are better adapted to the coming climate stresses, unlike in episodes of climate warming in the deep past, natural migration of grassland/ecosystem species from afar is not going to be able to contribute to maintaining ecosystem resilience. Small, isolated populations often are depleted in genetic diversity, and so are unlikely to evolve tolerance to new conditions without infusion of genes from other populations. In some cases, assisted migration using greenhouse propagation and out-planting may be the only way to ensure that key plant populations, particularly of rare species, can continue.
At the same time, native grasslands and meadows are rich in species with broad tolerances of stressful conditions, a trait ecologists term the “stress resistance syndrome.” It has long been observed that plants with a high tolerance for one kind of stress (e.g., water or nutrient limitation, the presence of toxins or pollutants, excesses of required nutrients, soil compaction, frequent fire) are often highly tolerant of several. It stands to reason that such communities should do better than many others in the face of climate change. Under this theory, as climate changes, the relative abundances of the species in grassland/meadow communities will change, depending on species’ relative tolerances of what is to come, but the full community may sustain its resilience.
Management strategies are given above under maintenance, restoration, reclamation, and conversion. Climate resilience should be built into all of those strategies. Here are some additional pointers.
Good—Increase resilience of grassland and meadows by reducing other stressors such as deer, pests, and invasive plants to support healthier plants that can better withstand climate change impacts.
For reclamation and conversion activities, plant a diverse mix of native plant species. Having a diverse mix of plants will increase the likelihood that at least some species will survive shifts in habitat zones and pests and diseases that may move into the area and continue to provide food sources for native wildlife species.
Better (in addition to Good)—Improve connectivity between nearby grassland/meadow areas by converting the intervening forest or other community.
Monitor for changes in populations of key species to assess if they are stable, increasing, or decreasing as the climate changes. Monitor changes in maximum and minimum daily temperature, hydrology, and precipitation. Monitor for changes in phenology that result in mismatches between interdependent species (e.g., plant flowering times and pollinator emergence times), which may be addressed by seeking expert assistance in choosing substitute native plant species to extend resource availability. Monitor for changes in phenology that affect specific management actions (e.g., earlier nest construction or fledging times of ground-nesting birds driving changes in times of hay mowing).
Best (in addition to Good and Better)—Consider introducing new genotypes of key species that are already present or of new grassland/meadow species, in either case from seed collected in indigenous stands up to 250 miles to the south.
Focus on resilient species. Often called “climate winners,” these species may tolerate warmer and wetter conditions predicted in future climate models. Resilient species may better tolerate catastrophic flooding, for example, and lessen the impact of these events (see Related Items of Note).
If a link is broken, try searching on the keyword string preceding the link.
Climate Change Response Framework: Climate Change Projections for Individual Tree Species in Pennsylvania (forestadaptation.org/learn/resource-finder/climate-change-projections-individual-tree-species-pennsylvania, as of 2024)
Society for Ecological Restoration International Science and Policy Working Group. 2004. The SER International Primer on Ecological Restoration. Society for Ecological Restoration International, Tucson, Arizona. 13 pages. (cdn.ymaws.com/www.ser.org/resource/resmgr/custompages/publications/SER_Primer/ser_primer.pdf, as of 2024)
U.S. Department of Agriculture: 2023 USDA Plant Hardiness Zone Map (planthardiness.ars.usda.gov, as of 2024)
NatureServe: Ecological Integrity Assessment (natureserve.org/products/ecological-integrity-assessment, as of 2024).
Tracey, C. et al. 2018. A Landscape Condition Model (LCM) for Pennsylvania. NatureServe (researchgate.net/publication/324569897_A_Landscape_Condition_Model_LCM_for_Pennsylvania, as of 2024).
Pennsylvania Natural Heritage Program: County Natural Heritage Inventories (naturalheritage.state.pa.us/inventories.aspx, as of 2024).
Pennsylvania Wildlife Action Plan: Conservation Opportunities Area Tool (wildlifeactionmap.pa.gov, as of 2024).
Pennsylvania Natural Heritage Program: Palustrine Community Descriptions (naturalheritage.state.pa.us/Wetlands.aspx, as of 2024)
Pennsylvania Natural Heritage Program: Pennsylvania Community Prediction Tool for Site Restoration (naturalheritage.state.pa.us/RestorationTool.aspx, as of 2024)
Pennsylvania Natural Heritage Program: Terrestrial Community Descriptions (naturalheritage.state.pa.us/Uplands.aspx, as of 2024)