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"Marshland" redirects here. Marsh_sentence_0

For the 2014 film, see Marshland (film). Marsh_sentence_1

For the locality in Australia, see Marshlands, Queensland. Marsh_sentence_2

For other uses, see Marsh (disambiguation). Marsh_sentence_3

A marsh is a wetland that is dominated by herbaceous rather than woody plant species. Marsh_sentence_4

Marshes can often be found at the edges of lakes and streams, where they form a transition between the aquatic and terrestrial ecosystems. Marsh_sentence_5

They are often dominated by grasses, rushes or reeds. Marsh_sentence_6

If woody plants are present they tend to be low-growing shrubs, and then sometimes called carrs. Marsh_sentence_7

This form of vegetation is what differentiates marshes from other types of wetland such as swamps, which are dominated by trees, and mires, which are wetlands that have accumulated deposits of acidic peat. Marsh_sentence_8

Basic information Marsh_section_0

Marshes provide a habitat for many species of plants, animals, and insects that have adapted to living in flooded conditions. Marsh_sentence_9

The plants must be able to survive in wet mud with low oxygen levels. Marsh_sentence_10

Many of these plants, therefore, have aerenchyma, channels within the stem that allow air to move from the leaves into the rooting zone. Marsh_sentence_11

Marsh plants also tend to have rhizomes for underground storage and reproduction. Marsh_sentence_12

Common examples include cattails, sedges, papyrus and sawgrass. Marsh_sentence_13

Aquatic animals, from fish to salamanders, are generally able to live with a low amount of oxygen in the water. Marsh_sentence_14

Some can obtain oxygen from the air instead, while others can live indefinitely in conditions of low oxygen. Marsh_sentence_15

Marshes provide habitats for many kinds of invertebrates, fish, amphibians, waterfowl and aquatic mammals. Marsh_sentence_16

Marshes have extremely high levels of biological production, some of the highest in the world, and therefore are important in supporting fisheries. Marsh_sentence_17

Marshes also improve water quality by acting as a sink to filter pollutants and sediment from the water that flows through them. Marsh_sentence_18

Marshes (and other wetlands) are able to absorb water during periods of heavy rainfall and slowly release it into waterways and therefore reduce the magnitude of flooding. Marsh_sentence_19

The pH in marshes tends to be neutral to alkaline, as opposed to bogs, where peat accumulates under more acid conditions. Marsh_sentence_20

Types of marshes Marsh_section_1

Marshes differ depending mainly on their location and salinity. Marsh_sentence_21

Both of these factors greatly influence the range and scope of animal and plant life that can survive and reproduce in these environments. Marsh_sentence_22

The three main types of marsh are salt marshes, freshwater tidal marshes, and freshwater marshes. Marsh_sentence_23

These three can be found worldwide and each contains a different set of organisms. Marsh_sentence_24

Salt marshes Marsh_section_2

Main articles: Salt marsh, Brackish marsh, and Tidal marsh Marsh_sentence_25

Saltwater marshes are found around the world in mid to high latitudes, wherever there are sections of protected coastline. Marsh_sentence_26

They are located close enough to the shoreline that the motion of the tides affects them, and, sporadically, they are covered with water. Marsh_sentence_27

They flourish where the rate of sediment buildup is greater than the rate at which the land level is sinking. Marsh_sentence_28

Salt marshes are dominated by specially adapted rooted vegetation, primarily salt-tolerant grasses. Marsh_sentence_29

Salt marshes are most commonly found in lagoons, estuaries, and on the sheltered side of shingle or sandspit. Marsh_sentence_30

The currents there carry the fine particles around to the quiet side of the spit and sediment begins to build up. Marsh_sentence_31

These locations allow the marshes to absorb the excess nutrients from the water running through them before they reach the oceans and estuaries. Marsh_sentence_32

These marshes are slowly declining. Marsh_sentence_33

Coastal development and urban sprawl has caused significant loss of these essential habitats. Marsh_sentence_34

Freshwater tidal marshes Marsh_section_3

Main article: Tidal marsh Marsh_sentence_35

Although considered a freshwater marsh, this form of marsh is affected by the ocean tides. Marsh_sentence_36

However, without the stresses of salinity at work in its saltwater counterpart, the diversity of the plants and animals that live in and use freshwater tidal marshes is much higher than in salt marshes. Marsh_sentence_37

The most serious threats to this form of marsh are the increasing size and pollution of the cities surrounding them. Marsh_sentence_38

Freshwater marshes Marsh_section_4

Main articles: Freshwater marsh, Wet meadow, Vernal pool, and Dry lake Marsh_sentence_39

Ranging greatly in both size and geographic location, freshwater marshes make up the most common form of wetland in North America. Marsh_sentence_40

They are also the most diverse of the three types of marsh. Marsh_sentence_41

Some examples of freshwater marsh types in North America are: Marsh_sentence_42

Wet meadows Marsh_section_5

Wet meadows occur in areas such as shallow lake basins, low-lying depressions, and the land between shallow marshes and upland areas. Marsh_sentence_43

They also occur on the edges of large lakes and rivers. Marsh_sentence_44

Wet meadows often have very high plant diversity and high densities of buried seeds. Marsh_sentence_45

They are regularly flooded but are often dry in the summer. Marsh_sentence_46

Vernal pools Marsh_section_6

Vernal pools are a type of marsh found only seasonally in shallow depressions in the land. Marsh_sentence_47

They can be covered in shallow water, but in the summer and fall, they can be completely dry. Marsh_sentence_48

In western North America, vernal pools tend to form in open grasslands, whereas in the east they often occur in forested landscapes. Marsh_sentence_49

Further south, vernal pools form in pine savannas and flatwoods. Marsh_sentence_50

Many amphibian species depend upon vernal pools for spring breeding; these ponds provide habitat free from fish which eat the eggs and young of amphibians. Marsh_sentence_51

An example is the endangered gopher frog (Rana sevosa). Marsh_sentence_52

Similar temporary ponds occur in other world ecosystems, where they may have local names. Marsh_sentence_53

However, the term vernal pool can be applied to all such temporary pool ecosystems. Marsh_sentence_54

Playa lakes Marsh_section_7

Playa lakes are a form of shallow freshwater marsh that occurs in the southern high plains of the United States. Marsh_sentence_55

Like vernal pools, they are only present at certain times of the year and generally have a circular shape. Marsh_sentence_56

As the playa dries during the summer, conspicuous plant zonation develops along the shoreline. Marsh_sentence_57

Prairie potholes Marsh_section_8

Prairie potholes are found in the northern parts of North America as the Prairie Pothole Region. Marsh_sentence_58

These landscapes were once covered by glaciers, and as a result shallow depressions were formed in great numbers. Marsh_sentence_59

These depressions fill with water in the spring. Marsh_sentence_60

They provide important breeding habitats for many species of waterfowl. Marsh_sentence_61

Some pools only occur seasonally while others retain enough water to be present all year. Marsh_sentence_62

Riverine wetlands Marsh_section_9

Many kinds of marsh occur along the fringes of large rivers. Marsh_sentence_63

The different types are produced by factors such as water level, nutrients, ice scour, and waves. Marsh_sentence_64

Embanked marshlands Marsh_section_10

Main article: Tidal marsh Marsh_sentence_65

Large tracts of tidal marsh have been embanked and artificially drained. Marsh_sentence_66

They are usually known by the Dutch name of polders. Marsh_sentence_67

In Northern Germany and Scandinavia they are called , Marsch or marsk, in France marais maritime. Marsh_sentence_68

In the Netherlands and Belgium they are designated as marine clay districts. Marsh_sentence_69

In East-Anglia the embanked marshes are also known as Fens. Marsh_sentence_70

Restoration Marsh_section_11

Some areas of the world have already lost 90% of their wetlands, including marshes. Marsh_sentence_71

They have been drained to create agricultural land or filled to accommodate urban sprawl. Marsh_sentence_72

Restoration is the process of returning marshes to the landscape to replace those lost in the past. Marsh_sentence_73

Restoration can be done on a large scale, such as by allowing rivers to flood naturally in the spring, or on a small scale by returning wetlands to urban landscapes. Marsh_sentence_74

See also Marsh_section_12

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