Managing Your Restored Wetland

This manual for landowners describes where wetland restoration is possible and how it is done. It covers basic wetland concepts, ecological concepts and terms, wetland restoration, and maintenance.
Managing Your Restored Wetland - Articles
Managing Your Restored Wetland

Chapter 1: Introduction

Most people think that wetlands are places where they get their feet wet. This may be true for a marsh, but standing water is often rare in forested wetlands.

The current legal definition says wetlands are “those areas that are inundated or saturated by surface water or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions, including swamps, marshes, bogs, and similar areas” (Section 404 of the Clean Water Act).

What are Wetlands?

Because “wetland” is a collective term encompassing a wide range of wet environments, all wetlands must share three basic characteristics:

  • There must be water present at or near the surface of the ground for a portion of the year.
  • There must be plants adapted to wet conditions.
  • There must be soil types that develop from wet conditions (hydric soils).

Wetland Status and Trends

Prior to the arrival of European settlers, wetlands covered approximately 221 million acres in the lower United States. Today, at least 50 percent of that acreage has been lost, with many of the remaining wetlands badly degraded. Wetlands were once regarded as wastelands, and settlers were encouraged to drain them. As more and more people have became aware of the values of wetlands and the need for their protection, rate of loss has declined in recent years. Still, annual wetland loss continues. Each year over 250,000 acres of wetland habitat are destroyed by urban, industrial, and agricultural development (Dahl and Johnson 1991).

Wetland Functions and Values

Wetlands provide a variety of ecological values and functions that directly and indirectly benefit people. Most residents of rural communities have taken advantage of recreational opportunities afforded by wetlands, such as boating, hunting, and fishing. However, many important functions are far less obvious. For example, a wetland may enhance downstream water quality by filtering chemicals, excess nutrients, and sediments. Wetlands can also act as natural flood control areas through retaining floodwaters and delaying their release downstream. Because of their numerous ecological and sociological functions, every effort should be made to protect existing wetlands and to restore those degraded by human activities.

Wetland Types

Most wetland restoration projects involve the reclamation of agricultural lands. These areas are frequently restored to some form of marsh. However, there are more wetland types than just marshes.Freshwater wetlands are generally categorized into three types:

  • Riverine: those bordering upon rivers and streams.
  • Lacustrine: those found on lakes and reservoirs.
  • Palustrine: those on shallow bodies of water, such as marshes or bogs.

Wetlands are further classified according to the amount of open water and the types of plants present. Open water is found where plants cannot grow above the water, but where the depth is less than about 6 feet. Deep water areas are those where the water is too deep for aquatic plants to typically grow (greater than 6 feet) (Cowardin et al.1979).

Wetland plants are categorized into four general types:

  • Aquatic bed: plants grow under the water and root in the bottom.
  • Emergent: plants grow out of the water and include grasses, sedges, and other nonwoody plants.
  • Scrub-shrub: woody plants grow less than 20 feet tall.
  • Forests: woody plants grow 20 feet tall or more.

While most restoration projects are concerned with emergent wetlands, you may wish to have something different. You’ll learn more about the restoration process as we go along.

Wetland Restoration

Today, many people realize the value of wetlands and are coming together to restore some of the lost wetland acreage. Through programs such as the U.S. Fish and Wildlife Service Partners for Wildlife, landowners are restoring wetlands on previously drained land and enjoying the benefits wetlands provide.

In this manual, we will briefly describe where wetland restoration is possible and how it is done. The majority of the manual will focus on what you, the landowner, can expect from your restored wetland and what you will need to do to maintain and manage your wetland.

Chapter 2: Ecological Concepts and Terms

Wetlands include a wide variety of habitats, from marshes to moist forests. Different groups of wildlife will be attracted to different types of wetlands. For example, a temporary pond, which provides critical spring breeding habitat for spotted salamanders, is not good habitat for beavers. Conversely, a large freshwater marsh created by beaver activity may have excellent habitat for fish populations and birds of prey such as ospreys. By understanding the ecological concepts explained in this chapter, you will know what species to expect in your wetland and how to enhance your wetland for selected species.

Many wetlands are interconnected, forming a mosaic of wetland types. These connected wetlands can form important travel corridors for wildlife. Landowners, however, should not underestimate the importance of isolated wetlands to wildlife. Spring seeps, for example, create snow-free areas during winter (groundwater is too warm to freeze except under the cold-est conditions). These seeps are frequent loafing and feeding sites for such animals as wild turkeys. Knowing the type of wet-land being restored is an important first step in developing realistic goals and expectations for a wetland. Most restored wetlands, for example, are freshwater marshes.

Vegetation Structure and Edge

Wildlife management is based upon well known ecological principles, and their application will allow you to enhance your wetland for wildlife. Two important principles are succession and edge.

  • Succession. This term refers to the progression of plant communities through time, often in some recognizable pattern and order. An old field, for example, if abandoned, may eventually become a forest. The type of forest depends upon a variety of conditions, including climate and range of disturbance. Over time, a freshwater marsh may gradually fill in with dense emergents and shrubs. Different species of wildlife use the different plant communities that develop through time.
  • Edge. This term refers to the boundary between two different habitat types. The interface between a farm field and a forest is a good example of a rather abrupt edge. Wildlife diversity is greater along edges due to the different habitat types. Gradual edges are preferred to more abrupt edges because more intergrading habitat is available.

The concepts of succession and edge are important for a landowner in managing both the wetland and the surrounding upland. Both wetland and the upland buffer change through time if left alone. If this is desired, then you can use “hands-off ” management. If not desirable, then various management activities such as mowing can maintain a certain stage of succession, if that is the desired goal. See the chapter on general management and maintenance for further information.

Wetlands increase the complexity of the landscape and, as a result, help increase the types and numbers of wildlife species present in a region. Many species are dependent upon wetlands for some part of their life cycle. A large proportion of species of special concern (for example, threatened or endangered species) are wetland dependent. Species that are completely dependent upon wetlands are called obligate species and include species such as mallards, green frogs, water snakes, and muskrats. Those species able to use other habitats in addition to wetlands are referred to as facultative wetland species.

Not all wetland types are suitable for all wetland wildlife species. River otters, for example, need large tracts of interconnected wetlands and only incidentally use smaller, isolated wetlands. However, these isolated wetlands may be prime muskrat habitat. You should assess the type of wetland targeted for restoration, and what wetland types are adjacent, and then determine the types of wildlife that will use the area.

Habitat Selection

All animals must have food, water, cover, and space to survive and reproduce. Habitat refers to the general physical and biological properties of a certain area. A high quality habitat for one species may be very poor for another. For example, large trees adjacent to riverine wetlands are important for wood ducks, but their presence likely indicates unsuitable habitat for spotted sandpipers.

Carrying Capacity

Carrying capacity refers to the number of animals of a species that an area can support through time, and varies year to year depending upon such things as availability of food or cover. Carrying capacity is generally highest during spring and summer when food is abundant, and declines during fall and winter when food is scarce. If you are interested in raising carrying capacity, you might wish to consider activities that increase winter food supplies, such as planting certain berry-producing shrubs. Your project manager should have good ideas about species to plant.

  • Density refers to the actual number of animals per unit area of the wetland. It is difficult to measure and, like carrying capacity, varies year to year. The two terms are closely related.
  • Space will ultimately decide how many animals will occupy a site, especially for those that are territorial, such as the red-winged blackbird. Territory size varies widely among species and is not necessarily constant from year to year (depending upon resource availability). As resources become more abundant, territory size generally shrinks. Thus, you can often increase the number of territorial species by increasing the availability of key resources.
  • Predators may be viewed as a problem, although they are a necessary part of any natural system. Increasing desired species may have the additional effect of increasing predators as well. This scenario may be unwelcome if you want to increase numbers of such species as waterfowl. There are several activities that you can do to reduce the effects of predation. For example, be sure to provide deep water around any islands that you have provided for waterfowl nesting. This will make it difficult for most predators to locate the nests.

In any event, you should know that wildlife populations are dynamic and can vary seasonally and year to year for reasons beyond your control.

Life Cycle of a Wetland

Wetlands are not static ecosystems—they change over time. Many wetlands dry up during the summer, only to fill up again with fall and winter rain and snow. These summer low periods are natural and important, for this is the time when many seasonal grasses and herbs germinate on the mudflats. These then provide food for many species of wildlife throughout the summer and fall. Water levels fluctuate throughout the year and from year to year. Long-term water level changes can cause the wetland to change from one type to another. For example, a cattail marsh, if flooded for two to three years, becomes an open system dominated by floating aquatics rather than emergent plants. In time, a drier cycle is likely to occur, and an emergent marsh may form again.

Changes such as these are natural and lead to changes in the wildlife communities associated with the wetland. Different wetland types provide for different wildlife habitats. Active management is needed to maintain a wetland in one stage of ecological succession.

Life Within a Wetland

Although a wide variety of plants and animals can be found in wetlands, a relative few are obliged to live there. Some common wetland plant species, such as red maple, are found from dry to wet habitats, as are animals such as geese and white-tailed deer.

Plants

Plants are categorized based upon their ability to tolerate standing water. Obligate species must have permanent water to survive. Facultative wet species can live in standing water, but do better with moist soils. Facultative species fare best in moist to somewhat dry soils.

Most of us are familiar with the larger plants, such as the submergents, emergents, shrubs, and trees. Submergent plants live under water, but are rooted in the bottom. They grow to depths of 3 to 4 feet in clear water. Excess sediment can cut off light for these species and lead to their decline. Other plants, such as the pond lilies, float on the surface while rooting in the bottom. Both submergents and floating-leaved aquatic plants need permanent water to survive, thus depths of about 6 feet are needed within the wetland.

In shallower water, we find emergent species. These plants can live in water about 2 feet deep, but usually require mudflats for seed germination. Many species such as the sedges and the rushes provide good wildlife cover and habitat. Other species can provide food (such as arrow arum), and still others are sometimes considered pest species (e.g., cattail and common reed). In wetlands with fluctuating water levels, emergent species are most common.

In any particular wetland, plant species vary tremendously depending upon climate, water levels, landscape position, and other variables. Floodplain wetlands, under water in spring, are dry during summer. This condition leads to quite different plant communities than are seen in a northern bog, whose constant water levels and acidic waters are tolerated by only a few species.

Fewer woody plants (shrubs and trees) are specifically adapted to wetlands. Most are facultative wetland species. Examples of typical obligate woody species include the buttonbush (shrub) and the overcup oak (tree). See the accompanying heading,
“selected wetland plants and their indicator status,” for other examples of plants and their relationships to water.

Selected Wetland Plants and Their Wetland Indicator Status

The following listing is a selection of plants adapted to wetlands. Plants are grouped under headings indicating their ability to tolerate standing water. Appendix A describes these and other common wetland plants, and their benefits for wildlife.

Obligate

  • Arrow arum (Peltandra virginica)
  • Beaked spikerush (Eleocharis rostellata)
  • Blue flag (Iris versicolor)
  • Cattail (Typha spp.)
  • Buttonbush (Cephalanthus occidentalis)
  • Hardstem bulrush (Scirpus acutus)
  • Manna grass (Glyceria striata)
  • Overcup oak (Quercus lyrata)
  • Rice cutgrass (Leersia oryzoides)
  • Skunk cabbage (Symplocarpus foetidus)
  • Tussock sedge (Carex stricta)
  • Water tupelo (Nyssa aquatica)

Arrow arum (Peltandra virginica)

Facultative Wet

  • Black ash (Fraxinus nigra)
  • Cinnamon fern (Osmunda cinnamomea)
  • Green ash (Fraxinus pennsylvanica)
  • Joe-pye weed (Eupatoriadelphus fistulosus)
  • Pennsylvania smartweed (Polygonum pensylvanicum)
  • Pin oak (Quercus palustris)
  • Pussy willow (Salix discolor)
  • Redtop (Agrostis alba)
  • Silky dogwood (Cornus amomum)
  • Wild mint (Mentha arvensis)

Joe-pye weed (Eupatoriadelphus fistulosus)

Facultative

  • Arrowwood (Viburnum dentatum)
  • Hophornbeam (Carpinus caroliniana)
  • Catalpa (Catalpa speciosa)
  • Cottonwood (Populus deltoides)
  • Greenbriar (Smilax rotundifolia)
  • Poison ivy (Toxicodendron radicans)
  • Red maple (Acer rubrum)
  • Slippery elm (Ulmus rubra)
  • American yew (Taxus canadensis)

Source: Brooks and Tiner 1989

Invertebrates

Although we know much about the larger animals that use wetlands (birds and mammals, for example), we do not know as much about the smaller creatures, including the invertebrates. Invertebrates are those animals without a backbone. The type of invertebrate found often depends upon the quality of the water. Indeed, some invertebrates are used in the legal definition of clean water in a few states. Oxygen content, in particular, is very important. Wetlands are shallow environments by nature, and often have lower levels of available oxygen. This occurs because shallow waters tend to be warmer and warmer water holds less oxygen. Also, wetlands are not fast flowing waters. Fast waters hold more oxygen. Thus, in wetlands, fewer entirely aquatic invertebrates will be present than you might see in a mountain stream (such as water boatmen). However, many semi-aquatic invertebrates are widely distributed throughout wetlands. These include beetles, water fleas, crayfish, dragonflies, snails, clams, and mussels.

From an ecological point of view, invertebrates form an important food resource for nearly all other animals that use wetlands. For example, ducklings rely almost exclusively upon invertebrates as their source of protein during their first few months of life. Some wetlands are specifically managed for invertebrates as a food source for shore-birds. Invertebrates are predators themselves, as well as parasites, and competitors for food and space. Many species aid in the decomposition of plant and animal matter, vital processes in wetlands. Some live in the narrow oxygenated zone of the substrate (e.g., earthworms), while others are primarily found in substrates with little or no oxygen (e.g., some fly larvae).

Crayfish (Cambarus sp.)

Amphibians and Reptiles

By their very nature, amphibians require water during their breeding period. Their jelly-like eggs must be kept wet during development. In addition, many amphibians, such as frogs, need water all year. Not all amphibians need standing water year round for their survival. Many salamanders do quite well with very moist conditions. Wetlands with a variety of depths and water levels provide critical habitat for amphibians. Wetlands with a deep water component also provide a place where some amphibians can overwinter in the mud.

Reptiles as a group are less dependent upon water, but some species are adapted for aquatic life. The water snake and painted turtle, for example, lay their eggs on dry land but spend their lives in water.

In some areas, amphibians and reptiles are dependent upon a very special type of wetland called a vernal pond (or temporary pond). These small pools (sometimes only a few feet across) provide critical breeding habitat during spring. After a few weeks, the ponds dry completely and it takes an expert eye to find them during late summer. Some species of amphibians come back to the same pool for years on end. If these areas are lost, those amphibians will not be able to breed.

Painted Turtle (Chrysemys picta marginata)

Fish

Different fish live in wetlands than in nearby rivers and streams. To a large degree, this is due to the shallow nature of wetlands. Shallow waters are warmer and hold less oxygen, thus somewhat limiting fish species. A wetland must also have permanent deep water somewhere for fish survival. Common fish species include many of the minnows, sunfish, and bass, as well as nuisance fish like carp. Some fish, such as sunfish and catfish, make extensive use of wetland shallows as nesting areas during the spring. Bass, on the other hand, use submerged aquatics to lay their eggs upon. A common misunderstanding among landowners is that cold water species, such as trout, will live in their wetland. Trout may survive for a time, but cannot withstand the warmer waters during summer. Depending upon the type of wetland you have, fish can be an important component of insect pest control. In warmer waters, mosquitofish control mosquito larvae. Most small fish will feed upon any invertebrate small enough to eat.

Birds

Wetlands provide valuable habitat for more than 100 species of birds in the eastern United States. Some birds are obligate wetland species that require wetlands for their survival. Others are facultative species which may use wetlands, but do not require them for their survival. Waterfowl are the group of birds most people associate with wetlands. Waterfowl include the ducks, geese, and swans. Dabbling ducks use shallow areas of restored wetlands, where they can tip up and feed off the bottom. Divers need deeper water in which to dive and feed. Geese are grazers and will feed on pastures and croplands near restored wetlands. Swans are surface feeders, but also will feed on underwater vegetation.

Shorebirds include species such as the plovers, rails, and sandpipers. These birds feed on exposed mudflats, including those which occur as a result of summer drawdown. Wading birds include the herons, egrets, and bitterns. They feed on invertebrates, fish, and amphibians, which they find in the shallows. Water deeper than about 18 inches will not be used much by wading birds.

Many species of songbirds are associated with wetlands, including the red-winged blackbird, the marsh wren, and the common yellowthroat. These species require emergent vegetation or shrubs in which to nest. Swallows are common summer residents because they feed upon the abundant insects around wetlands.

Some species of gamebirds are affiliated with wetlands. The American woodcock is most commonly found in wooded or shrubby wetland habitats which are moist but not flooded. These areas provide abundant earthworms, a primary food source for the American woodcock. It may take some time for a restored wetland to reach this successional stage. Ruffed Grouse and the wild turkey use alder thickets and wet meadows as areas to search for food and cover for their young. Spring seeps are important wintering areas for turkey, because they feed in the open areas not covered with snow. Pheasants also forage for insects in wet meadows. Of these habitat types, the wet meadow is the easiest to restore; shrub thickets and woodlands can take many years to mature.

Mammals

The five medium-sized mammals commonly associated with wetlands in the northeastern United States are the beaver, muskrat, mink, otter, and raccoon. Only the raccoon is not an obligate aquatic species. All five are valuable furbearers and are thus extensively trapped. Beavers and muskrats may be the most frequently seen mammals in wetlands (see the special sections on muskrat and beaver), although bats are a frequent sight on a summer evening. The mink is a common wetland animal, but is secretive and rarely seen. Although the otter frequents rivers and streams, large marshes can provide excellent otter habitat. The raccoon is another common wetland visitor, but less frequently observed due to its more nocturnal nature. Raccoon tracks might be the most common sign of wildlife around a wetland.

Beaver

Other than humans, no animal more modifies its own environment than the beaver. They cut trees, create openings, build dams, and create canals. As the stream backs up behind a dam, water overflows the banks and creates a beaver pond. Through time, any trees are eventually killed. The typical sequence of succession in a beaver pond then leads to a gradual filling in behind the dam as sediments carried by the stream are dropped as the water slows. This allows for emergent vegetation to invade and eventually the area becomes a wet meadow. Because beaver like open water, they have usually left by this stage and the dam inevitably breaks due to lack of repair. The area begins the long process of drying out and, over many years, a forest might once again dominate.

Beaver feed upon the inner bark of woody plants. This is part of the reason they ultimately leave a site. They have eaten all the trees they can safely reach. During summer, beaver also feed upon some aquatic plants such as water lily or burreed. Beaver dams and lodges themselves make good wildlife habitat, especially as resting and basking areas for reptiles, such as turtles and snakes. Trees killed by the flood become excellent den trees for many birds and mammals. Wood ducks are common in beaver ponds. In the grassy clearing adjacent to the pond (caused by the removal of trees) species such as the cottontail rabbit, the ruffed grouse, and the wild turkey find excellent feeding and brood habitat.

Not everyone wants to find beaver on their property. See the section on troubleshooting for help on handling problems with beaver.

Muskrat

Muskrats are also builders, but they do not modify the local environment as does the beaver. Muskrat build lodges in the shallow waters of marshes, or they burrow into banks along marshes, lakes, and streams if suitable soils are available. Muskrat breed prolifically, often producing as many as three litters per year, each with up to six young. This often leads to muskrat overpopulation problems. Under certain conditions, musk-rat have been known to completely remove the vegetation in a marsh. See the trouble-shooting section for information on muskrat problems.

Other Mammals

A number of smaller mammals make extensive use of wetlands. The water shrew is found in rivers and streams, and might be found in deeper wetlands. The star-nosed mole is semi-aquatic and is found in water and burrowing in moist soils after food. Many other shrews, voles, and mice use wetlands. Bats are commonly found flying over wetlands at dusk in their search for flying insects. Larger mammals, such as the black bear and the white-tailed deer, use forested wetlands as cover during winter. Coniferous wetlands provide better conditions for shelter and warmer temperatures than are provided by the surrounding deciduous forest.

Box for Summer Maternity Bat Colony

Chapter 3: Wetland Restoration

Wetland restoration is the process of returning a functioning wetland to an area that was previously wetland habitat. Restoration of a wetland is not the same as creating a wetland where one never existed. Consequently, the success of a restoration project depends in large part on selecting a suitable area for the project.

Where Wetland Restoration Is Possible

Appropriate areas are not always easy to recognize due to current land use. A wetland drained in the past may today be a farmed field, and the only sign that it was once a wetland may be standing water during the spring. If you are unsure about the history of your land and whether you have a site suitable for restoration, contact your local Natural Resource Conservation Service (NRCS) or the U.S. Fish and Wildlife Service (FWS) office. They will have maps which show whether hydric soils (necessary for wetland restoration) are present and whether the area was previously ditched or drained. Sometimes they have maps showing the specific locations of the tiles and ditches used to drain the wetland.

Frequently, the best chance for success is to restore a shallow marsh community with some open water. Emergent plants, such as grasses and sedges, can be established in a few years (versus shrubs and trees, which take much longer). You should be aware that full plant diversity may take several years to develop. Keep in mind that stable water levels or floods can maintain these emergent species indefinitely, with no progression towards shrub or forested communities.

How to Restore a Wetland

Restoring a wetland may be as simple as removing a dam or some drainage tile that was denying water to the site. Once the proper water flow has been re-established, some degraded wetlands return quickly with no other help. In other instances, considerable work must be done to effect a change. In these instances, the typical sequence of events is as follows:

  • Contact a government natural resource agency (such as your county conservation district) or a private project manager and discuss your objectives.
  • Survey the site.
  • Design the wetland according to your needs.
  • Obtain the necessary permits.
  • Begin to move the earth.
  • Prepare the soil and substrate for water and plants.
  • Allow wetland plants to become established over time.
  • Monitor the site and conduct routine maintenance.

Landowner Objectives

If you wish to have a restored wetland, you also might have some interest in providing wild-life habitat. Discuss with the project manager the kinds of species you wish to see. Your input can help the manager design the overall wetland to meet your desires. Typically, most restored wetlands are shallow, averaging no more than 18 inches in depth. Depending upon the size, shape, and adjacent landscape, these wetlands may attract a variety of wildlife. See the section on management concepts to learn more about how wetland design can influence wildlife. Most restored wetlands are not deep enough to support fish populations. However, if you are interested in providing habitat for fish, discuss this with your project manager. You should also be aware of how your restoration project fits into the surrounding watershed. The contributing drainage basin will do much to determine the type of wetland restoration possible.

Permits

Make sure you know which permits (if any) need to be obtained before beginning construction. With larger areas (more than 5 acres, for example), an earth disturbance permit and an erosion and sedimentation (E&S) control permit will probably be necessary. If you are going to be involved with an existing wetland in any way, you also might need a permit from the U.S. Army Corps of Engineers. Determine who will be responsible for getting these permits. In many instances, the Natural Resources Conservation Service (NRCS) or the Fish and Wildlife Service (FWS) can take care of these permits for you.

Site Survey

Property boundaries, access points, construction staging areas, topography of the planned wetland areas, and critical habitats or structures which are off limits must be surveyed and staked. From this information, a base map will be prepared. The project manager should coordinate this phase.

Construction

If your wetland is being restored as part of the U.S. Fish and Wildlife Service (FWS) Partners for Wildlife Program, the FWS will often have contractors working with them, and you will not need to locate one. In other cases, your project manager may need to select a contractor. Contractors who may wish to bid on the project will need some very specific information, such as the amount of site preparation required. Thus, you will need to know such things as whether bridges or roads will be installed, if existing vegetation will be removed, how much soil will be extracted, and where it will be placed. You will also have to specify special construction work such as dams or other water control structures. The project manager should handle this phase. Develop good communication links among the project manager, the construction crew, and yourself. This will help to make sure that everyone knows the goals and that any on-site changes proceed smoothly.

Soil and Substrate Preparation

Most restoration projects do not involve a lot of soil disturbance, unless a goal is to increase topographic diversity. In some cases, however, more construction might be necessary. Before construction proceeds, make sure proper erosion and sedimentation controls are in place (sediment fences are commonly used). During construction, any topsoil or hydric soil that is to be reused should be stockpiled and properly marked (all topsoil should be replaced). Initial construction may involve large machinery, such as a grader. Fine grading should be done with smaller equipment to avoid excessive soil compaction (most restoration projects do not require fine grading). At this stage, the topsoil or hydric soils are replaced to 6 to 18 inches. The project consultant can provide for some basic soil tests to determine whether a slow release fertilizer is appropriate as well.

Establishment of Plants

Most restored wetlands do not require planting, as long as the topsoil is preserved during construction and then properly replaced. Seeds of wetland plants which have lain dormant for years while the land was drained may become active once water is restored to the area. Landowners are often surprised at the variety of wetland plants which become established within the first growing season. The longer the interval between draining and restoration, however, the less successful these “seed banks” are, and planting may become necessary. Natural invasion of native plants is preferred, but you should not wait too long to decide whether or not to plant. Invasive and aggressive species, such as cattail, can quickly overrun a site, and this is not desirable. Planting of nursery stock may be needed to supplement wetland plants growing from seed banks or colonizing from off-site. Timing is critical for plant survival. The proper season for seed germination may be quite different from that for tree seedling survival. Nursery stock may have to be ordered several months to a year prior to planting. Plants and seeds should be appropriate for your region (southern plants, for example, may not fare well in northern climates). Check with your project manager for details. If you are working with the FWS’ Partners for Wildlife Program, seedlings might be provided for you.

The selection of plants should reflect the expected water conditions of the site. Many grasses, sedges, and rushes require moderate fluctuations in water level, but submergent or floating species (such as pond lilies) need more stable and deeper waters. Few woody species can tolerate continuous flooding, so they are usually placed in the transitional zone between the wetland and adjacent uplands. A detailed map, showing topographic levels and associated plants, should be prepared by the project manager. FWS biologists can provide specific advice for your site. Landowners looking for more information on suitable plants should see the reference sections of this publication and study the guide by Thunhorst (1993).

Many landowners are planting the upland areas adjacent to the wetland with warm season grasses, such as big bluestem, Indian grass, and switch grass. They are called warm season grasses because they grow primarily during the heat of the summer. These grasses are popular because they provide excellent habitat for many upland game birds and grassland species. When mixed with wildflowers, they provide an attractive border around the wetland.

Maintenance and Monitoring

Even the best projects rarely perform perfectly, so you should be prepared for repairs and maintenance to the site. Unpredictable weather, high water levels, wildlife damage, and vandalism can destroy or delay the progress of the wetland. Monitoring your wetland’s progress will help you determine if your goals are being met. For any wetland monitoring program to make sense, you must have some idea of the conditions of the wetland after restoration. See the section later in this chapter for more information on monitoring.

Wetland Design

A restored wetland may not reach full functional capability for many years. Emergent wetlands, such as marshes, develop faster than forested wetlands, for obvious reasons. Thus, you should be prepared to wait for some time before assessing success, especially when the project is a forested site.

Examining the following characteristics will help you reach your objectives. Assess this list both before and after construction to see how well you reached your goals. All 10 are important factors in the success of your wetland management plan. See Brooks, et al. (1993) for more details.

Water

The most important characteristic of your wetland is the amount of water present and the time of year it is there. This factor determines the type of wetland and which wild-life frequent the area. The simplest way to restore a wetland is to remove the factor which is denying the area needed water. Water control structures can be installed to more accurately control water levels. Many designs are available, and they range from the very simple (a spillway with flashboards) to the complex (pumps).

Size

Generally, the greater the area of wetland present, the more diverse the wildlife community. A larger size also means potential for more plant types. Larger populations of territorial wildlife are supported with bigger wetlands. A reasonably diverse wildlife community can be expected in wetlands ranging in size from 0.5 acre to 5 acres.

Shape

Shape becomes quite important, beyond a certain minimum size. Irregular shapes tend to promote structural diversity in the basin and the surrounding plant communities. A round basin or straight stream channel contains the minimum amount of shoreline habitat. More habitat types are supported in coves, peninsulas, islands, and varied shorelines. Irregular shapes, combined with variable bank slopes and water depths, promote wildlife diversity. Consider shape before construction because it becomes very difficult to change afterwards.

Slope

The amount of bank slope surrounding a wetland largely determines area wetness and thus, which plants are present. Gentle slopes (1:10) are preferred because a large amount of land is then exposed during low water. This often results in extensive mudflats, a condition which encourages growth of many species of emergent plants such as grasses and rushes. In any event, the effect is to produce valuable wildlife habitat. Dense emergent vegetation is preferred by some birds (for instance, the American bittern) as nesting areas. Open mudflats are preferred by shorebirds, such as plovers, for feeding. Low slopes also encourage amphibians and reptiles to use the wetland for breeding and foraging. Steep slopes prevent these groups from easy travel to and from the site. However, steep slopes are preferred denning areas for muskrats.

A sensible approach is to plan for a variety of slopes with a higher percentage of gentle than steep slopes. This promotes diverse plant and animal communities.

Depth

The depth of the wetland controls the plant types present and helps determine the extent of water level fluctuation. Shallow depths (less than 18 inches) favor emergent plants, such as sedges. In these areas, water temperatures are warmer and the bottom is more often exposed during low water. Wading birds (herons), dabbling ducks, raccoons, and frogs benefit from shallow regions. Submergent and floating plants need water depth between 18 and 48 inches. Here, fish lay eggs and muskrats build houses. At depths greater than 48 inches, open water typically results. At depths of 6 feet or more, permanent water is assured. In these deeper areas, fish overwinter, and reptiles and amphibians successfully hibernate in the bottom mud. Therefore, a variety of water depths is preferred. This is accomplished through an irregular bottom; one that is rough and undulating, not flat.

Plant Life Form

Wildlife breeding areas, feeding sites, and resting habitats more often depend upon the form of the vegetation found than the actual plant species. Keep in mind that some wild-life species require several different plant life forms during their life history, and your wetland may not provide all of these. However, a wide variety of plant life forms often are encouraged simply by having irregular shapes and variable depths in the wetland.

Dominant Plants

A wetland’s character is defined by the dominant plants present. These plants are con-trolled by the amount of water present and the available substrate. You can select specific food and cover plants to favor certain wildlife species. If you rely upon volunteer colonization, then the dominant plants become similar to those found in wetlands which are nearby. Take some time to visit those wetlands to see what yours might become with time. Permanent water levels are generally not good for wetlands. Most wetland plants will not germinate underwater. They require some form of drawdown for successful germination. You can exert considerable control over the type and extent of plants you get by manipulating water levels.

Interspersion

The degree of mixing among various plant types and open water is what often makes one wetland more visually appealing than another. A wetland with vegetation of different heights, interspersed with open water, is likely to be more aesthetically pleasing and ecologically diverse than one with only open water or one plant type. How much interspersion you should have will depend upon your goals for wildlife. For example, muskrat prefer about 20 percent open water to 80 percent vegetation. Waterfowl, however, like the mix at 50:50. If you wish to encourage both groups, then perhaps a mix of 33 per-cent open water to 67 percent vegetation is appropriate. Fish need more open water than shrub nesting birds require. A combination of water depth, bank slope, bottom substrate, and water level fluctuation determines interspersion within a wetland.

Surrounding Landscape

What happens in your wetland is determined, to a large extent, by what goes on outside the wetland. Wetlands do not exist in isolation. They can connect to other wetlands, or fringe upon a large lake. The type and condition of the surrounding upland area is of great concern. The majority of restored wetlands are surrounded by agricultural fields. Activities such as farming can introduce excess fertilizers into the wetland. These nutrients can promote excess plant growth, and a typical algal bloom may result.

Managing the surrounding uplands can often affect the wetland and its inhabitants more significantly than tinkering with the wetland itself. A 100- to 300-foot buffer zone of native vegetation around the wetland helps to protect the site from pollutants and is a visual and noise barrier.

Choosing where to restore a wetland is also important. A wetland located near a variety of other natural habitats is more valuable to wildlife than one which is isolated or subject to degradation from surrounding land uses.

Water Quality

The quality of water in a wetland has considerable impact upon its general character. The science and management of water quality is complex and beyond the scope of this book. However, any management plan should consider the potential impact of water quality. The value of a well designed wetland is greatly reduced if water quality is poor. A few aspects of water quality are listed below:

  • pH. Wetland plants typically have a limited tolerance to sudden changes in pH. The careful addition of lime can raise pH, if necessary. Transplanted plants should come from nearby waters of similar pH.
  • Fertility. The surrounding landscape can introduce excess amounts of nitrogen and phosphorus into the wetland, promoting excessive plant growth and eventually lower oxygen levels in the water.
  • Turbidity. Submergent plants need clear water to receive sunlight, and are hurt by excess turbidity in the water. A buffer zone around the wetland can reduce incoming sediments and lower turbidity.
  • Temperature. More oxygen is available in cool water than in warm water. If fish survival is a goal, shade and deep pools help attain the goal.
  • Pollutants and Toxins. A buffer zone does a lot towards preventing these contaminants and sediments from entering the wetland. In areas where a stream is polluted, the best alternative may be to avoid restoration in that area.

Having reviewed these 10 characteristics, do you need to modify the wetland construction plan? Do you need to correct a maintenance problem? Do you wish to enhance some aspect of the site, perhaps to benefit some wildlife group? Careful consideration of the issues listed above goes a long way towards preventing and resolving problems.

Wetland Monitoring

At the conclusion of the restoration, you should make a map of the conditions at that time (an “as-built” map). Even a rough sketch provides an important documentation of baseline conditions. A map allows you to refer back to initial conditions and document changes.

As-built condition field map • CT – T1 • July 1987

Most landowners take considerable pride in their restored wetland and enjoy documenting its development. A monitoring program during the early years following restoration allows you to identify and correct any problems which arise. Such a program also allows you to see if your objectives are being met in the manner you wish. After 3 or 5 years, you can probably adjust monitoring efforts to once every 5 years or so. If wildlife observation is one of your goals, you will likely be on the site on a frequent enough basis to
observe any changes. (Download Sample Wildlife Observation Data Sheet. ) A list of suggested monitoring activities is given below.

  • Permanent photographic stations. A series of photographs from the same point at different times will document the stages in your wetland’s development. They also show seasonal changes, such as water level rise and fall. (See inside front cover.)
  • Water levels. Monitoring the hydrology of a site is easily done by measuring water depth against a staff gauge (a stake with increments to measure depth), or by measuring depth to groundwater in a shallow well made from PVC pipe. In either case, a hydrograph can be developed to show fluctuations in depth through time. Stable water levels result in different plant and animal communities than fluctuating water levels.
  • Soil characteristics. Some soil qualities are helpful indicators of wetland status. Areas under water for a part of the year develop hydric properties, such as color changes. A soil scientist can help you learn how to identify hydric soil traits.
  • Plant species. A plant species list is helpful when you identify wetland species. The U.S. Fish and Wildlife Service has developed an indicator status for many species of plants. This list displays the degree of “wetness” associated with the plant. Additional (though time intensive) studies could include an assessment of plant cover or the success of planted species through time. Check with your project consultant for other ways to assess your wetland.
    • Wildlife. Wildlife habitat is often a primary concern in restored wetlands. Direct counting of animals is costly and time consuming. As an alternative, you can keep a running list of what species you see, where you see them, and when (download Sample Wildlife Observation Data Sheet ). Long-term observations yield a useful index to wildlife use.

Chapter 4: General Management and Maintenance

At this stage, you should have gone through the 10-step list given earlier so that your project manager knows precisely what your objectives are for your wetland. Management options differ dramatically for different objectives.

The simplest management option is to do nothing. Benign neglect is a positive option if your objectives are to let natural processes rule your restored wetland. This implies a basic understanding of wetland succession and, therefore, some knowledge of what your wetland will look like at various points in the future. The classic example of wetland succession shows a marsh eventually becoming an old field and then a forest. While this does happen, this scenario is only one of many possible pathways that might occur. Examining the wetlands in the surrounding watershed will help you visualize what a restored site might look like without any management from you and help you determine the types of management practices needed.

Managing the Surrounding Landscape

Wetlands do not exist in isolation. Much of what goes on around a wetland directly impacts the function of that wetland. Thus, the landowner can influence the wetland through activities on the adjacent lands.

Buffers

A buffer between the adjacent land and the wetland is an important management tool in many respects. It filters nutrients, sediments, and toxins. It is a visual and noise buffer for the wildlife of the wetland. Simply leaving an area unmowed can result in a grassy area which will buffer the wetland from many types of runoff. With periodic mowing (every 2 to 4 years), these grassy areas can be maintained. If not maintained, in time (or through plantings), these areas can become shrubby and thus also serve as a visual barrier. Finally, a band of trees can be maintained, perhaps some 50 to 100 feet in width. Shrub and tree buffers are more difficult to establish because they are slower to develop. Depending on the type of buffer, the buffer can serve as valuable breeding habitat for wildlife. For example, many dabbling ducks nest in grassy areas near wet-lands. If you retain a forest and have snags, you might be able to attract wood ducks.

Mowing

Buffers do require some management, especially grassy areas. In order to keep grasses from giving way to shrubs, the site must be mowed every three years or so. Waiting until late summer or fall will allow nesting birds to leave before you mow. Sites covered with shrubs can be made grassy if you treat the area with a brushhog. You should find that local grasses quickly emerge from the soil. If not, you can seed with a local grass mix.

Burning

Although prescribed burning is a recognized and valuable wildlife habitat management technique, we do not recommend that you attempt this alone. Burns do not always go where expected and can prove hazardous to property and life. Rely upon your project manager to advise you on the appropriateness of burning. Burning is an important management tool for warm season grasses, but mowing often accomplishes the same goal, and is much safer.

Plantings

A large variety of herbaceous, shrubby, and tree species furnish food and cover for wildlife (see Appendix A). We recommend that you do not plant exotic or non-native species as these will either not do as well as local species, or may become pest species. Warm season grasses, such as switch grass, are valuable food and cover for wildlife. Important shrubs include alder, buttonbush, and elderberry. Useful trees include pin oak, beech, and sweetgum. Ask your project manager for more information on correct species and where they can be planted.

Fencing

For wetlands in agricultural areas, you might need perimeter fences to keep cattle or other livestock from entering the wetland. Cattle in particular do considerable damage to the plants and cause a lot of mud to enter the water, thus increasing turbidity. Options can include single-strand or double-strand, high-tensile electric fence. Woven wire is more likely to trap debris and is less favored as an option. Fencing is placed as far from the wetland as the landowner can afford. Fences less than 10 feet from a wetland are not of much benefit to wildlife, although they can help improve water quality. In areas where streams and wetlands coincide, you can make controlled crossings for livestock; you can place railroad ties or rocks in the stream to discourage erosion. See Davis et al. (1991) for further information.

Managing Wetland Water Levels

As we have already mentioned, the type of wetland you have depends entirely upon the level and constancy of the supply of water. The easiest way to control water levels is through a small dam with flashboards situated at the outlet of the wetland. Adding flashboards allows you to retain more water. This is important if you are trying to maintain a wetland comprised primarily of submergent or floating-leaved plants. Many emergent species need mudflats for germination, thereby necessitating the removal of some boards. This is called “drawdown.” More expensive dams are available with more complex water level controls, including pumps and overflow tubes. In addition to being more costly to build, they cost more to maintain. Dams should be inspected regularly for muskrat damage (burrows) and areas of slumping (if the dam is an earthen one). If you find excess sedimentation behind the dam, removing some flashboards during higher flow will scour away some of that excess. Finally, you must keep the structure free of debris in order for it to work properly.

Chapter 5: Managing for Wildlife

A variety of management techniques provide for the needs of many different wildlife species. However, there can be times when managing for more than one group may not be possible because the groups may be incompatible. For example, managing for amphibians and fish together is difficult, because fish tend to feed upon amphibian eggs. With knowledge of the habitat needs of different groups of wildlife, you should be able to develop a management plan suitable for the wildlife species you want to attract, whether you are interested in hunting, fishing, or just observing wildlife on your property.

General Habitat Management

How you manage your wetland will depend upon what sort of wildlife you wish to see. Wildlife need some place for shelter and protection from the elements and predators. You can enhance this aspect of wildlife habitat by constructing such things as brush piles or by planting dense shrubs. In areas which are drier, evergreens are useful because they furnish excellent winter cover. Fish like to have submerged trees and shrubs as both shade and cover. The following paragraphs discuss general management for wildlife of all types. For specific information on groups of species (such as waterfowl) see Appendices D and E.

Habitat Management for Invertebrates

If you build it, they will come. In truth, a successful wetland restoration project is quickly colonized by many forms of invertebrates. The water regime and the plants determine what you get. Different invertebrate communities are found in wetlands with different water quality. Invertebrates can be encouraged by maintaining oxygen levels in the water and by having a good amount of organic debris in the substrate. The best management, therefore, might consist of keeping excess nutrients from entering the wetland, thus leading to lower oxygen levels. Maintaining a buffer zone around the wetland is an effective method for preserving the quality of the water. Actively drawing down (lowering) water levels will increase the availability of invertebrates for shore-birds, an important habitat management activity during migration periods.

Habitat Management for Amphibians and Reptiles

The single most important management activity for amphibians and reptiles occurs during the design phase. The slopes of the wetland must be about 1:10 or they will be too steep for easy access by the animals. Shallower slopes are preferred. Salamanders make good use of logs and brush left around the perimeter of the wetland, so you should not be too hasty in cleaning up debris. A leaf-litter mat also encourages amphibian use. Frogs make good use of shallows for feeding provided there is available cover nearby. Thus, a dense stand of emergents or submergents should prove helpful. Having fish in the wetland creates some problems because the fish will feed upon amphibians and their eggs. There must be shallow areas where fish cannot reach if the two groups are to co-exist. Reptiles like to bask in the sun to raise their body temperature. Leaving some trees and logs in the water with parts sticking out will provide excellent basking areas (download Wetland Wildlife Species and Selected Management Activities ). Nearby deep water will serve as an escape route. Keeping good water quality is also important. Bog turtles, spotted turtles, and pickerel frogs all require emergent plants with clear, unpolluted water. You can encourage reproduction by several species of reptiles and amphibians if you have an area of sandy soil with a warm, southern exposure. Turtles and snakes will lay their eggs in these areas and burrowing toads will also be attracted.

Habitat Management for Fish

It is common for landowners to want to use part of their restored wetland for fishing. Of course, this means that deep areas must be provided for during the design phase. Fish will have to be stocked into the wetland, and providing for a self-perpetuating fish community can be tricky. You will need forage fish (like sunfish) and predators (such as bass). Your project manager can help, or you can discuss the problem with a fisheries biologist. As with all wildlife, fish need food, cover, and breeding areas. If you have a good invertebrate community, you have a food source on hand. Cover can be provided by planting shrubs along the edge, creating shady spots. You can also place structures underwater. Several tires strung together or sunken brushpiles are good cover for fish. Breeding areas are found within the plant types that you have. Remember, different species of fish require different habitats. Again, good water quality is essential. Clear water allows submerged aquatics to survive and these plants then provide good cover and breeding areas for fish.

Habitat Management for Birds

Birds are a popular reason for wildlife management of wetlands. Many specific techniques are used to attract specific groups of birds.

Water Depths

Having a variety of water depths within a wetland provides for different plants and invertebrates, and thus for different birds. Most birds frequent the shallow areas; only a few, such as the waterfowl, venture out into deeper waters. Naturally fluctuating water levels on gentle slopes expose large areas of mudflats; these sites are frequented by shorebirds searching for food. The emergent plants in this area become feeding sites for waterfowl, bitterns, and rails, and also serve as nest sites for some songbirds. Deeper waters allow for submergent plants; these plants are used by ducks, swans, and grebes for food.

Plant Diversity

The more types of plants present, the more species of wildlife will use the wetland. In general, a mix of open water, mudflats, and areas covered with emergents and shrubs will attract a good mix of wildlife.

Select Beneficial Plants

Different plants provide different foods for a variety of birds throughout the year. See Appendix A for a list of common food plants and their value to birds.

Riparian Habitats

These are areas which directly abut a water body. They may not actually be considered wetlands. But they are vital for many wildlife species. In addition to cleaning the water (as buffers), aiding in bank stabilization, and reducing erosion, they provide wildlife habitat and travel corridors.

Nest Sites

The value of a wetland is enhanced if nest sites are available. Different species of birds will use different vegetation types within the wetland and in the areas adjacent. Dense stands of emergent plants are used by red-winged blackbirds and marsh wrens. Dead trees are used by wood ducks and prothonotary warblers. Adjacent upland areas are frequently used as waterfowl nesting areas. Some species will readily utilize artificial structures, such as nest boxes or floating platforms. Most of us are familiar with providing nesting cover for birds through the making of bird boxes. The wood duck box is probably one of the most common nest boxes placed within a wetland, and is one of the reasons responsible for the recent resurgence in wood duck populations. You can increase nesting success by adding a predator guard to the box. Floating nest structures are useful for Canada geese. These must be some distance from shore and surrounded by relatively deep water in order to prevent predators, such as the raccoon, from eating the eggs. As with any animal group, each species has its own habitat requirements. If you like shrub-nesting birds, such as the common yellowthroat, then you will want dense thickets of shrubs throughout the wetland. If you want a mix of birds, then a mix of plant communities is your best choice. Many waterfowl nest in areas adjacent to wet-lands, thus it is important to limit disturbances such as mowing during the breeding season.

Wood Duck Nest Box

Habitat Management for Mammals

There are a variety of activities that you can undertake to manage for mammals. In general, planting food, such as berry producing shrubs, and cover will do much to increase mammal and bird use of your wetland. A knowledge of the habitat requirements for any species will determine what actions you might employ. One of the more recent trends is to provide roosting boxes for bats. These animals are colonial and many will crowd together in a bat box. Once you have a colony on your wetland, you will be the beneficiary of free insect control (see above for a diagram on building a bat box). As with other animal groups, keeping a buffer around the wetland increases mammal use of the wetland.

Beaver and Muskrat

You might find that you are trying to get beavers off of your property rather than the reverse. Beavers can cause considerable damage through their dam-building activities. However, through proper water elevation management (e.g., using drainage control tubes), beaver ponds can be some of the most productive wetlands around. Muskrat are a problem when they overpopulate an area and destroy the vegetation. See the chapter on troubleshooting for additional information.

Intake device for Clemson beaver pond leveler (close-up).

Chapter 6: Troubleshooting

Not every restoration project proceeds as planned. One thing you can count on is the unexpected. Certain problems, however, are common and we have discussed them in this chapter.

Purple Loosestrife

Purple loosestrife is an exotic, aggressive, and invasive plant found increasingly in wetlands throughout the northern United States. Although beautiful in flower, the species can quickly outcompete many native wetland plants. It provides little in the way of food and cover for wildlife. It is extremely difficult to eradicate. Possible methods include pulling the plant by hand, by cutting and burning the plant, or by applying herbicide to the plant. However, because of a strong rootstock, these methods sometimes are ineffective. If you can find the plant before it becomes established and set seed, then some herbicides might be effective in controlling purple loosestrife. Flooding for several years will kill purple loosestrife, but the seeds may remain viable in the soil for a long time, ready to germinate during the next drawdown (Payne 1992). In northern areas, drawdown prior to May 15 reduces germination of purple loosestrife and encourages species better adapted to cooler temperatures (Payne 1992). Newer methods focus upon biological control by using weevils and beetles. See Malecki et al.(1993) for more information on biological control.

Purple Loosestrife (Lythrum Salicaria)

Reed Canary Grass, Cattail, and Phragmites

Each of these three species is an aggressive invader of moist soils and will form solid stands if left unchecked. Reed canary grass and cattail are native, but phragmites (also known as the common reed) was probably imported from Europe with the early European colonizers. All three germinate best on moist soils, and will eventually die off if flooded continuously to a depth of about 3 feet. Maintaining high water levels in spring will discourage germination. Cutting, burning, and herbicide applications all work to some degree, but you risk damage to other wetland plants in the process. Cattail and phragmites are hard to pull by hand because they have extensive and large rhizomes. You might also control cattail with a fall drawdown, cutting the stems in early winter, and then reflooding the area. This stresses the plants and eventually kills them. Perhaps the best long-term management involves continuous flooding and then continuing with careful water level management.

Reed Canary Grass (Phalaris arundinacea)

Common Reed (Phragmites communis)

Duckweed and Algal Blooms

Duckweed is a tiny flowering plant and thus differs from algae. Both are floating plants and respond quickly to excess nutrients in the water. With too much nitrogen and phosphorus present, both “bloom” and eventually cover the surface of the water. When they die, their decomposing mass can use all the available oxygen in the water, leading to the death of most of the aquatic animals living there, such as fish. You can physically scoop both duckweed and algae from the water surface, but this is a temporary solution. Herbicides are a last-resort option associated with environmental problems (Payne 1992). The best long-term management involves having a buffer around the wetland, perhaps 50 to 100 feet wide. This prevents many of the nutrients from reaching the wetland in the first place.

Muskrats

Muskrats are a native rodent commonly found in wetlands throughout the United States. They live in bank dens or construct houses in open water, much as do beaver. Muskrats can overpopulate an area and “eat-out” the vegetation. If the plant is cattail, then you have a natural control agent! If not, then the muskrat is a pest. Also, they burrow into dikes and dams, possibly causing leakage. Six-inch layers of sand, gravel, or riprap will discourage burrowing, as will fencing the dike with wire mesh. Dike thickness and slope can be increased as a deterrent to the animals. Control involves trapping and removal of the animals, or fencing the dikes with wire mesh.

Cattail (Typha spp.)

Beaver

Despite the benefits of wetland habitat creation, beaver are increasingly becoming a nuisance species because of their dam-building abilities. As beavers block small streams and creeks, the water backs up behind the dam and low-lying areas are flooded. Any structures or timber in that area will be flood damaged. Loss of timber or crops can be significant. Beavers may plug culverts or water control structures, thus flooding roads and property. Beaver also kill small trees for food in the region near the dam. Plantings and ornamentals can thus suffer considerable harm. Control for the beaver involves trapping the animals or placing some sort of drain tube in the dam itself to keep water levels low (Bookhout 1994). The FWS has drawings and designs for beaver dam water control structures (see p. 27). Destroying the dam does little good if the beavers remain in the area because they simply rebuild. In any event, beaver ponds are often highly productive wetlands.

Geese

Canada geese historically have wintered in the southern United States after breeding in northern Canada. More recently, Canada geese have been stopping in areas short of their historic wintering areas. Reasons include increasing resident populations (often from releases) and increasing amounts of open, grassy areas, such as golf courses. Geese are grazers and like to feed in these areas. Congregations of geese are noisy, damage turf grass, and leave a large mess behind. If you mow the grass around your wetland, grazing geese can become a problem. Geese like to watch for predators as they graze. One of the best ways to discourage geese is to plant dense patches of shrubs that make it difficult for geese to see over long distances. They generally avoid these areas. In addition, planting tall grasses, such as switch grass, and leaving them unmowed, or planting a dense buffer of shrubs along the water’s edge may discourage geese from taking up permanent residence on your property. Discouraging geese through habitat management is much easier than trying to actively control them. For example, avoid making islands in your wetland which could be used by nesting geese. Control involves trapping and transporting problem geese to other states (most states will no longer accept transplanted geese), noisemakers to scare them away, and hunting (Bookhout 1994). Geese are migratory waterfowl, and as such are under federal protection. You should talk to your state wildlife agency or the Fish and Wildlife Service if you wish to discourage geese from using your wetland.

Carp

Carp are non-native fish that thrive in most shallow and warm water areas. They cause damage through their feeding activity, which involves rooting through the substrate and stirring up large amounts of sediment. This activity clouds the water and leads to the deposition of silt over plants and the bottom, which can then interfere with other species’ abilities to breed and feed. The only sure control for carp is to drain the site enough that the fish can be removed by hand. With most wetlands that is not a problem, because this procedure mimics normal drawdown. You can also apply Rotenone (a chemical) to kill carp, but this is a nonselective method that will kill other, more desirable fish. You will likely need to obtain a permit to apply Rotenone.

References

Bookhout, T.A. 1994. Research and management techniques for wildlife and habitats. The Wildlife Society, Bethesda, MD. 740 pp.

Brooks, R.P., D.A. Devlin, J. Hassinger, G.A. Hoover, and M. Brittingham. 1993. Wetlands and wildlife. Penn State, College of Agricultural Sciences, School of Forest Resources, University Park, PA. 55 pp.

Brooks, R.P., and R.W. Tiner, Jr. 1989. Vascular plant communities in wetlands of Pennsylvania. pp. 114-123, in S. K. Majumdar, R.P. Brooks, F.J. Brenner, and R.W. Tiner, Jr., eds. Wetlands ecology and conservation: Emphasis in Pennsylvania. Pennsylvania Academy of Science, Easton, PA. 395 pp.

Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deepwater habitats of the United States. Fish and Wildlife Service, FWS/OBS-79/31. U.S. Department of Interior, Washington, D.C. 103 pp.

Dahl, T.E., and C.E. Johnson. 1991. Wetlands status and trends in the conterminous United States, mid–1970s to mid–1980s. U.S. Department of Interior, Fish and Wildlife Service, Washington, D.C. 28 pp.

Davis, L., M. Brittingham, L. Garber, and D. Rourke. 1991. Streambank fencing. Extension Circular 397, Penn State, College of Agricultural Sciences, University Park, PA. 12 pp.

Hammer, D.A. 1992. Creating freshwater wetlands. Lewis Publ., Boca Raton, FL. 298 pp.

Malecki, R.A., B. Blossey, S.D. Hight, D. Schroeder, L.T. Kok, and J.R. Coulson. 1993. Biological control of purple loosestrife. BioScience 3 (10):680-686.

Payne, N.F. 1992. Techniques for wildlife habitat management of wetlands. McGraw-Hill, Inc., New York, NY. 549 pp.

Payne, N.F., and F. Copes (eds.). 1988. Wildlife and fisheries habitat improvement handbook. USDA, Forest Service, Wildlife and Fisheries, Washington, D.C.

Thunhorst, G.W. 1993. Wetland planting guide for the northeastern United States. Environmental Concern, Inc., St. Michaels, MD. 160 pp.

Wetland Journal, published by Ed Garbisch’s nonprofit corporation, Environmental Concern, Inc., is a professionally prepared journal and newsletter which covers current research, restoration topics, and education. Address: P.O. Box P, 210 West Chew Ave., St. Michaels, MD. 21663

Appendix A: Native Trees, Shrubs and Vines with Wildlife Value

Trees

Plant name common (Latin)FormWildlife useWildlife value, main season of use1Soils, notesWetland indicator status2
Green Ash, Red Ash (Fraxinus pennsylvanica)Deciduous tree 30-80 feetCover, seedsE, FallMoist to wet soils, streambank stabilizerFACW
White Ash (Fraxinus americana)Deciduous tree 40-100 feetSeedsE, FallDry to moist soilsFACU
Big-toothed Aspen (Populus grandidentata)Deciduous tree 30-40 feetCatkins, preferred by grouseF, WinterBarren, burned-over, or cleared soils, early successional speciesFACU-
Quaking Aspen, Trembling Aspen (Populus tremuloides)Deciduous tree 30-40 feetCatkins, preferred by grouseE, WinterBarren, burned-over, or cleared soils, early successional speciesFACU
American Beech (Fagus grandifolia)Deciduous tree 60-80 feetNuts, buds, catkinsE, FallRich, well drained loam soilsFACU
Black Gum, Sour Gum, Tupelo (Nyssa sylvatica)Deciduous tree 30-60 feetFruit, seedsE, FallMoist soilsFAC
Pin Cherry, Fire Cherry (Prunus pensylvanica)Deciduous tree 30-40 feetFruit, budsE, SummerDry, often burned-over soil, pioneer speciesFACU-
Wild Black Cherry (Prunus serotina)Deciduous tree 60-80 feetFruit, twigs, barkE, SummerMoist, upland soilsFACU
American Crabapple, Sweet Crab (Malus coronaria)Deciduous tree 15-30 feetFruitF, WinterDry, open soilsNo indicator
Devil’s-walking-stick, Hercules’-club (Aralia spinosa)Deciduous tree 10-30 feetFruit, seeds provides winter foodF, FallMoist soils, often near riversFAC
Hackberry, Sugarberry (Celtis occidentalis)Deciduous tree 30-60 feetFruit, used in winterE, WinterDry to moist soilsFACU
Eastern Hemlock (Tsuga canadensis)Deciduous tree 60-100 feetNest sites, seeds, coverE, WinterMoist, acidic soilsFACU
Hickory (Carya spp.)Deciduous tree 60-80 feetNutsE, FallDry to moist soilsFAC to FACU-
American Holly (Ilex opaca)Evergreen tree 10-40 feetFruit, coverE, FallAcidic soilsFACU+
Hop-hornbeam (Ostrya virginiana)Deciduous tree 20-40 feetSeeds, catkins, buds, mid-story food producerF, SummerDry, often calcareous soilsFACU-
Hornbeam, Blue-beech (Carpinus caroliniana)Deciduous tree 20-30 feetSeeds, catkins, budsF, FallRich, moist soilsFAC
American Larch, Tamarack (Larix laricina)Conifer, tree 20-40 feetNest tree, seedsE, WinterAcidic, boggy soilsFACW
Red Maple (Acer rubrum)Deciduous tree 40-70 feetSeeds, browse, nest sitesG. SummerMoist to wet soilsFAC
Silver Maple (Acer saccarinum)Deciduous tree 60-80 feetSeeds, nest sitesF, SummerMoist to wet soilsFACW
Oak (Quercus spp.)Deciduous tree 50-100 feetAcornsE, FallWell-drained to moist to wet soilsFACW+ to UPL
Persimmon (Diospyros virginiana)Deciduous tree 30 feetFruit, coverG, FallWell-drained soilsFAC-
Eastern White Pine (Pinus strobus)Conifer tree 80-110 feetSeeds, coverE, WinterDry to moist soilsFACU
Sassafras (Sassafras albidum)Deciduous tree 40-80 feetBrowse, fruitF, FallDisturbed soilsFACU-
Shadbush, Serviceberry, Juneberry (Amelanchier arborea)Deciduous tree 15-20 feetFruit, coverE, SummerDry, upland soilsFAC-
Sweet Gum (Liquidambar styraciflua)Deciduous tree 50-70 feetSeeds, nest sitesF, FallTolerates acid or clay soilsFAC
Sycamore (Platanus occidentalis)Deciduous tree 60-100 feetCoverF, Summer (cover)Moist to wet, streambanks, floodplainsFACW-
Tuliptree, Yellow Poplar (Liriodendron tulipifera)Deciduous tree 70-120 feetSeeds, nest sitesF, FallMoist, well drainedFACU

1Wildlife Value Key: E is excellent value; G is good value; F is fair value. From Henderson (1987) or Martin, et al. (1951).

2Wetland Indicator Status: OBL is obligate wetland (occurs with estimated 99% probability in wetlands); FACW is facultative wetland (estimated 67% - 99% probability of occurrence in wetlands); FAC is facultative (equally likely to occur in wetlands and nonwetlands; 34% - 66% probability); FACU is facultative upland (67% - 99% probability in non-wetlands, 1% - 34% in wetlands); and UPL is obligate upland (>99% nonwetlands in this region, may occur in wetlands in other regions). From Sabine (1992) or Rhoads and Klein (1993).

Positive or negative signs indicate a frequency toward higher (+) or lower (-) frequency of occurrence within each category.

Shrubs

Plant name common (Latin)FormWildlife useWildlife value, main season of use1Soils, notesWetland indicator status2
Smooth Alder (Alnus serrulata)Deciduous 6-12 feetBuds, catkins, seeds, important cover for woodcock, grouseG, Fall (food), Summer (cover)Wet soilsOBL
Speckled Alder (Alnus incana)Deciduous shrub 6-12 feetBuds, catkins, seeds, important cover for woodcock, grouseG, Fall (food), Summer (cover)Wet soilsFACW+
Southern Arrowwood (Viburnum dentatum)Deciduous shrub to 10 feetFruit, cover, browse, nest sitesG, FallMoist to wet soilsFAC
Blackberry, Raspberry (Rubus spp.)Deciduous shrub 5-10 feetFruit, coverE, SummerDisturbed soilsFACW+ to UPL
Black-haw (Viburnum prunifolium)Deciduous shrub to 25 feetFruit, cover, browse, nest sitesG, FallDry to moist soilsFACU
Blueberry (Vaccinium spp.)Deciduous shrub 1-3 feetFruitE, SummerWell-drained, acidic sitesOBL to FACU-
Buttonbush (Cephalanthus occidentalis)Deciduous shrub 6-9 feetSeeds, nectar, used by ducks and butterflies

G, Summer (nectar), Fall (seeds)

Soils near streambanks or near swampsOBL
Chokeberry (Aronia spp.)Deciduous shrub 2-8 feetCover, fruit persists in winterF, FallMoist to wet to boggy soilsFACW to FAC
Chokecherry (Prunus virginiana)Deciduous shrub 6-20 feetFruit, coverE, SummerWell-drained to moist soilsFACU
Highbush Cranberry (Viburnum trilobum)Deciduous shrub 10 feetFruit, cover, browse, nest sites emergency winter foodE, WinterAcidic soilsFACW
Flowering Dogwood (Cornus florida)Deciduous shrub 10-30 feetFruit, coverE, FallMoist soilsFACU-
Red-osier Dogwood (Cornus sericea)Deciduous shrub 4-8 feetFruit, coverE, FallMoist soils often near streambanks, stabilizes streambanksFACW+
Silky Dogwood (Cornus amomum)Deciduous shrub 4-10 feetFruit, coverE, FallMoist to wet soilsFACW
Swamp, Gray Dogwood (Cornus racemosa)Deciduous shrub 10 feetFruit, coverE, FallMoist soilsFAC
American Elder (Sambucus canadensis)Deciduous shrub 3-12 feetFruit, cover, nest sitesE, SummerMoist soilsFACW-
American Filbert, Hazelnut (Corylus americana)Deciduous shrub to 10 feetNuts, catkins, browseE, FallWell-drained to moist soils, good forest edge plantsFACU-
Hardhack, Steeplebush (Spiraea tomentosa)Deciduous shrub to 10 feetCover for rabbits, woodcockF, SummerSwampy soils, moist conditionsFACW
Hawthorne (Crataegus spp.)Deciduous shrub 15-30 feetFruit cover, nest sitesE, WinterWell-drained to moist, to wet soilsFAC to FACU
Black Huckleberry (Gaylussacia baccata)Deciduous shrub to 3 feetCover, fruit, browseG, SummerDry to moist, acidic soilsFACU
Inkberry (Ilex glabra)Evergreen shrub to 10 feetFruit, coverG, FallBogs, swamps, wet woods, believed extirpatedFACW-
Mountain Laurel (Kalmia latifolia)Evergreen shrub 5-10 feetValuable winter cover, nectar used by hummingbirds, browseF, Summer (nectar), Winter (cover)Dry to moist, acidic soilsFACU
Meadowsweet (Spiraea latifolia)Deciduous shrub to 8 feetBrowse, cover for rabbits, woodcockF, SummerMoist to boggy soilsFAC+
Red Mulberry (Morus rubra)Deciduous shrub to 30 feetFruitE, SummerMoist soilsUPL
Rhododendron spp.Evergreen shrub 5-12 feetCover, nectar, used by hummingbirdsG, Winter (cover), Summer (Nectar)Acid soilOBL to FAC
Spicebush (Lindera benzoin)Deciduous shrub 12-25 feetFruit, coverF, FallRich soilsFACW-
Sumac (Rhus spp.)Deciduous shrub 10-30 feetFruit, emergency winter foodE, WinterDry soilsNo indicator
Maple-leaved Viburnum (Viburnum acerifolium)Deciduous shrub to 6 feetFruit, browse, cover, nest sitesE, FallDry to moist soilsUPL
Winterberry (Ilex verticillata)Deciduous shrub to 15 feetFruit, coverE, FallWet to swampy soilsFACW+
Witch Hazel (Hamamelis virginiana)Deciduous shrub to 10 feetNest sites, seedsF, Summer (nests)Moist soilsFAC-

1Wildlife Value Key: E is excellent value; G is good value; F is fair value. From Henderson (1987) or Martin, et al. (1951).

2Wetland Indicator Status: OBL is obligate wetland (occurs with estimated 99% probability in wetlands); FACW is facultative wetland (estimated 67% - 99% probability of occurrence in wetlands); FAC is facultative (equally likely to occur in wetlands and nonwetlands; 34% - 66% probability); FACU is facultative upland (67% - 99% probability in non-wetlands, 1% - 34% in wetlands); and UPL is obligate upland (>99% nonwetlands in this region, may occur in wetlands in other regions). From Sabine (1992) or Rhoads and Klein (1993).

Positive or negative signs indicate a frequency toward higher (+) or lower (-) frequency of occurrence within each category.

Vines

Plant name common (Latin)FormWildlife useWildlife value, main season of use1Soils, notesWetland indicator status2
Bittersweet (Celastrus scandens)Woody vineFruit, buds, leaves, cover, nest sites, important in winterE, WinterMoist to boggy soilsFACU-
Grape (Vitis spp.)Woody vineFruit cover, nest sitesE, SummerWell-drained to moist soilsFACW to FACU-
Common Greenbriar, Catbriar (Smilax rotundifolia)Woody vineFruit, seeds, browse, coverE, WinterWell-drained to moist soilsFAC
Poison Ivy (Toxicodendron radicans)Woody vineFruitE, Fall, WinterDry to moist soilsFAC
Virginia Creeper (Parthenocissus quinquefolia)Woody vineFruitE, FallWell-drained to moist soilsFACU

1Wildlife Value Key: E is excellent value; G is good value; F is fair value. From Henderson (1987) or Martin, et al. (1951).

2Wetland Indicator Status: OBL is obligate wetland (occurs with estimated 99% probability in wetlands); FACW is facultative wetland (estimated 67% - 99% probability of occurrence in wetlands); FAC is facultative (equally likely to occur in wetlands and nonwetlands; 34% - 66% probability); FACU is facultative upland (67% - 99% probability in non-wetlands, 1% - 34% in wetlands); and UPL is obligate upland (>99% nonwetlands in this region, may occur in wetlands in other regions). From Sabine (1992) or Rhoads and Klein (1993).

Positive or negative signs indicate a frequency toward higher (+) or lower (-) frequency of occurrence within each category.

Herbaceous

Plant name common (Latin)FormWildlife useWildlife value, main season of use1Soils, notesWetland indicator status2
Arrow Arum, Duck Corn (Peltandra virginica)Herbaceous perennialSeeds eaten by wood ducks, railsG, Summer, FallWet to inundated soilsOBL
Arrowhead, Duck Potato (Sagittaria latifolia)Herbaceous perennialSeeds, tuber, plants eaten by variety of wildlifeE, Summer, FallWet to inundates soilsOBL
Cattail (Typha spp.)Herbaceous perennialSeeds and tubers eaten by waterfowl, muskratG, Summer, FallMoist to wet soilsOBL
Common Three-square (Scirpus americanus)Herbaceous perennialSeeds and rhizomes eaten by a variety of birdsE, Summer, FallMoist to wet soilsFACW+
Soft-stem Bulrush (Scirpus validus)Herbaceous perennialSeeds and rhizomes eaten by a variety of birdsE, Summer, FallMoist to wet soilsOBL
Pondweed (Potamogeton spp.)Herbaceous perennial (aquatic)Seeds, stems, and rootstock eaten by waterfowlE, Summer, FallSubmerged systemsOBL
Rice Cutgrass (Leersia oryzoides)Herbaceous perennialSeed eaten by waterfowl and songbirdsG, Summer, FallMoist to wet soilsOBL
Sedges (Carex spp.)Herbaceous perennialSeeds and cover for a variety of birdsE, Summer, FallMoist to wet soilsFAC-OBL
Smartweed (Polygonum pensylvanicum)Herbaceous annualCover and food for variety of birds and mammalsE, SummerMoist to wet soilsFAC
Spatterdock (Nuphar luteum)Herbaceous perennialFood for ducks, beaver, muskrat, deerG, SummerSubmerged systemsOBL

1Wildlife Value Key: E is excellent value; G is good value; F is fair value. From Henderson (1987) or Martin, et al. (1951).

2Wetland Indicator Status: OBL is obligate wetland (occurs with estimated 99% probability in wetlands); FACW is facultative wetland (estimated 67% - 99% probability of occurrence in wetlands); FAC is facultative (equally likely to occur in wetlands and nonwetlands; 34% - 66% probability); FACU is facultative upland (67% - 99% probability in non-wetlands, 1% - 34% in wetlands); and UPL is obligate upland (>99% nonwetlands in this region, may occur in wetlands in other regions). From Sabine (1992) or Rhoads and Klein (1993).

Positive or negative signs indicate a frequency toward higher (+) or lower (-) frequency of occurrence within each category.

Miscellaneous

Plant name common (Latin)FormWildlife useWildlife value, main season of use1Soils, notesWetland indicator status2
Partridgeberry (Mitchella repens)Herbaceous perennialFruit, leaves, important to grouseF, WinterMoist, acidic soilsFACU
Teaberry, Wintergreen (Gaultheria procumbens)Evergreen sub-shrubFruit, leaves, persists year-roundF, WinterDry to moist, acidic soilsFACU

1Wildlife Value Key: E is excellent value; G is good value; F is fair value. From Henderson (1987) or Martin, et al. (1951).

2Wetland Indicator Status: OBL is obligate wetland (occurs with estimated 99% probability in wetlands); FACW is facultative wetland (estimated 67% - 99% probability of occurrence in wetlands); FAC is facultative (equally likely to occur in wetlands and nonwetlands; 34% - 66% probability); FACU is facultative upland (67% - 99% probability in non-wetlands, 1% - 34% in wetlands); and UPL is obligate upland (>99% nonwetlands in this region, may occur in wetlands in other regions). From Sabine (1992) or Rhoads and Klein (1993).

Positive or negative signs indicate a frequency toward higher (+) or lower (-) frequency of occurrence within each category.

References

Gill, John D. and William M. Healy. 1974. Shrubs and Vines for Northeastern Wildlife. USDA Forest Service, General Technical Report NE-9.

Gleason, Henry A. and Arthur Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. Second Edition. The New York Botanical Garden, New York.

Henderson, Carrol L. 1987. Landscaping for Wildlife. Minnesota Department of Natural Resources, MI.

Martin, Alexander C., Herbert S. Zim, and Arnold L. Nelson. 1951. American Wildlife and Plants: A Guide to Wildlife Food Habits. Dover Publications, Inc., New York.

Rhoads, Ann F. and William M. Klein Jr. 1993. The Vascular Flora of Pennsylvania: Annotated Checklist and Atlas. American Philosophical Society, Philadelphia.

Sabine, B.J. (ed.). 1992. National List of Plant Species that Occur in Wetlands: Region 1-Northeast. Resource Management Group, Inc. Grand Haven, MI.

Thunhorst, G.A. 1993. Wetland Planting Guide for the Northeastern United States. Environmental Concern, Inc., St. Michaels, MD. 179 pp.

Before old field excavation.

Excavation and dike construction for a restored wetland.

Restored wetland after construction.

Authors

Avian ecology Effects of shale gas development on forests and birds forest songbirds Human impacts on bird population Wildlife habitat management on private lands Landscaping for birds and wildlife

More by Margaret C. Brittingham, Ph.D.