**1. Introduction**

Water is an important resource for all living beings. Therefore, the use of water and its supply from sources are very important. Wetlands are an ecosystem from mangrove to subarctic peatlands that have affected human. The earliest civilizations were established near the river, lake, and floodplains [1]. The Mesopotamian civilization is authoritatively accepted to have started around 4000–3500 BC between the Euphrates and Tigris River. The other ancestral civilization, Egypt, commenced in the Nile Valley at around 3200 BC. This represents the importance of the water and wetlands. The fact that people are in these regions is a reflection of how important it is for biotic diversity. Therefore, wetlands are a very critical ecosystem, and some of them are the most productive habitats.

Wetlands occur where the water table is at or near the surface of the land or where the land is covered by water [2]. Wetlands are the only ecosystems for whose conservation an international convention (Ramsar Convention) had been adopted as early as 1971. Ramsar Convention defined wetlands as "areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six meters" [2]. Wetlands have about 6% of the earth although they play an important role in hydrology and include mangroves, peatlands and marshes, rivers and lakes, deltas, floodplains and flooded forests, and even coral reefs. A wetland is a generalized concept including coastal wetlands. It exists in every climatic region, ranging from the polar zones to the arid zones.

Many wetlands are transitional area between aquatic and terrestrial ecosystems. These ecosystems are divided into two groups depending on the quantity of water: permanent and temporal flooded. Since wetlands are distributed in many different habitats on earth, they

reflect different responses and behaviors to environmental changes. Therefore, wetland classification is important, and differences can be found. It is basically divided into natural and human-made constructed wetlands. In general, abiotic environmental factors, habitat differences, and biotic factors are considered to have a wide range of classification. Physical, chemical, and sediment quality determine wetland functions and classification. These situations classify its types [3].

temporal variation. For these reasons, positive and negative feedback mechanisms at the wetland are critical control systems. Therefore, the wetland is considered as holistic ecosystem perspective from its basin scale. Odum and Soto–Ortiz [8, 9] concluded that the natural balance is not a steady state and has a homeorhesis. As shown in **Figure 1**, the feedback mechanism occurs to control the wetland ecosystem dynamics. In the natural ecosystems, feedback control processes are repeated between environmental factors and population growth rates in their carrying capacities. However, when the human population intervenes and extremely uses wetlands, this tolerance is destructed, and ecosystems wander off their homeorhesis.

Introductory Chapter: Wetland Importance and Management

http://dx.doi.org/10.5772/intechopen.82456

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The exponential human population growth reflects why environmental problems appear suddenly [10]. Due to the excess use of wetlands in different ways in time, wetlands have lost

**Figure 1.** Comparison of natural wetlands (a) and human effects on wetlands (b). Many complex relationships exist in a wetland. Ecosystem feedback control mechanisms play a critical role in the functioning of wetland balance (homeorhesis).

Wetland ecosystems rapidly get worse due to various reasons. The environmental quality gradually deteriorates, and biotic diversity decreases in these habitats. It is estimated that more than 50% of specific wetland types in Europe, North America, Australia, and New Zealand were modified or changed during the twentieth century [4, 5]. Coastal wetland ecosystems are under extreme pressure, and it is estimated that about 35% of mangrove have been lost during the last two decades due to increasing agricultural area, deforestation, and freshwater reduction [6, 7].

Monitoring is the long-term regular observation and recording of current and altering situations. In the environmental assessment, these data were utilized to evaluate wetlands based on decision-making and planning processes. Consequently, wetland surveys have possessed a multidisciplinary perspective. The fact that the recognition of wetlands supplies many values for people and is an important case for global conservation has led to an increase in research and management activity.
