A herbaceous plant is a plant that does not have any woody stems above the ground. Marshes are nutrient-rich wetlands which support a variety of reeds and grasses. The roots of the plant bind to the muddy soil and the slow water flow allows the plants to spread out across the marsh. Many marshes are freshwater and exist in areas with poor drainage—along streambeds, lakes, and ponds.
Since soil is constantly wet from flooding, marshes are extremely nutrient-rich and can support a wide variety of plant and animal life. Marshes can also be tidal, according to experts. Saltwater marshes are saturated every time the tide comes in from the ocean. There are some marshes that are fed by groundwater. Marshes also get saturated from rain water. As you can see a marsh and a swamp are not the same. The vegetation that grows in each is the main difference.
A swamp is filled with trees while a marsh does not normally have trees but is filled with grasses and other herbaceous plants. Marshes are typically not as deep as swamps as well.
Swamps may be divided into two major classes, depending on the type of vegetation present: shrub swamps and forested swamps. Swamps serve vital roles in flood protection and nutrient removal. Floodplain forests are especially high in productivity and species diversity because of the rich deposits of alluvial soil from floods. Many upland creatures depend on the abundance of food found in the lowland swamps, and valuable timber can be sustainably harvested to provide building materials for people.
Due to the nutrient-rich soils present in swamps, many of these fertile woodlands have been drained and cleared for agriculture and other development. Historically, swamps have been portrayed as frightening no-man's-lands. This perception led to the vast devastation of immense tracts of swampland over the past years, such as the destruction of more than half of the legendary Great Dismal Swamp of southeastern Virginia.
Forested swamps are found throughout the United States. They are often inundated with floodwater from nearby rivers and streams.
Sometimes, they are covered by many feet of very slowly moving or standing water. In very dry years they may represent the only shallow water for miles and their presence is critical to the survival of wetland-dependent species like Wood Ducks Aix sponsa , River Otters Lutra canadensis and Cottonmouth Snakes Agkistrodon piscivorus.
Bottomland hardwood swamp is a name commonly given to forested swamps in the south central United States. Shrub swamps are similar to forested swamps except that shrubby vegetation such as Buttonbush, Willow, Dogwood Cornus sp.
In fact, forested and shrub swamps are often found adjacent to one another. The soil is often water logged for much of the year and covered at times by as much as a few feet of water because this type of swamp is found along slow moving streams and in floodplains. Mangrove swamps are a type of shrub swamp dominated by mangroves that covers vast expanses of southern Florida. Bogs are one of North America's most distinctive kinds of wetlands.
They are characterized by spongy peat deposits, acidic waters and a floor covered by a thick carpet of sphagnum moss. Bogs receive all or most of their water from precipitation rather than from runoff, groundwater or streams. As a result, bogs are low in the nutrients needed for plant growth, a condition that is enhanced by acid forming peat mosses. There are two primary ways that a bog can develop: bogs can form as sphagnum moss grows over a lake or pond and slowly fills it terrestrialization , or bogs can form as sphagnum moss blankets dry land and prevents water from leaving the surface paludification.
Over time, many feet of acidic peat deposits build up in bogs of either origin. The unique and demanding physical and chemical characteristics of bogs result in the presence of plant and animal communities that demonstrate many special adaptations to low nutrient levels, waterlogged conditions, and acidic waters, such as carnivorous plants. Bogs serve an important ecological function in preventing downstream flooding by absorbing precipitation.
Bogs support some of the most interesting plants in the United States like the carnivorous Sundew and provide habitat to animals threatened by human encroachment. Bogs in the United States are mostly found in the glaciated northeast and Great Lakes regions northern bogs but also in the southeast pocosins.
Their acreage declined historically as they were drained to be used as cropland and mined for their peat, which was used as a fuel and a soil conditioner. Recently, bogs have been recognized for their role in regulating the global climate by storing large amounts of carbon in peat deposits. Bogs are unique communities that can be destroyed in a matter of days but require hundreds, if not thousands, of years to form naturally.
Northern bogs are generally associated with low temperatures and short growing seasons where ample precipitation and high humidity cause excessive moisture to accumulate. Therefore, most bogs in the United States are found in the northern states. Northern bogs often form in old glacial lakes. They may have either considerable amounts of open water surrounded by floating vegetation or vegetation may have completely filled the lake terrestrialization. The sphagnum peats of northern bogs cause especially acidic waters.
The result is a wetland ecosystem with a very specialized and unique flora and fauna that can grow in these conditions called acidophiles.
Moose, deer, and lynx are a few of the animals that can be found in northern bogs. The word pocosin comes from the Algonquin Native American word for "swamp on a hill.
Usually, there is no standing water present in pocosins, but a shallow water table leaves the soil saturated for much of the year. They range in size from less than an acre to several thousand acres located between and isolated from old or existing stream systems in most instances.
Because pocosins are found in broad, flat, upland areas far from large streams, they are ombrotrophic like northern bogs, meaning rain provides most of their water. Also like the bogs of the far north, pocosins are found on waterlogged, nutrient poor and acid soils. The soil itself is a mixture of peat and sand containing large amounts of charcoal from periodic burnings. These natural fires occur because pocosins periodically become very dry in the spring or summer.
The fires are ecologically important because they increase the diversity of shrub types in pocosins. The most common plants are evergreen trees Loblolly Bay, Red Bay and Sweet Bay , and evergreen shrubs titi, fetterbush and zenobia. Pocosins provide important habitat for many animals, including some endangered species like the red-cockaded woodpecker.
Salt marshes are coastal wetlands that are flooded and drained by salt water brought in by the tides. They are marshy because the soil may be composed of deep mud and peat.
Peat is made of decomposing plant matter that is often several feet thick. Peat is waterlogged, root-filled, and very spongy. Because salt marshes are frequently submerged by the tides and contain a lot of decomposing plant material, oxygen levels in the peat can be extremely low—a condition called hypoxia.
Hypoxia is caused by the growth of bacteria which produce the sulfurous rotten-egg smell that is often associated with marshes and mud flats.
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