Wetland

Wetlands are special places where the ground is covered or soaked with water, either all the time or for part of the year. They sit between dry land and water bodies, like lakes or rivers, and the plants and animals there have adapted to live in these watery conditions. Because of this unique environment, wetlands are some of the most alive places on Earth, home to many different kinds of plants and animals.

You can find wetlands all over the world, except in Antarctica. They can hold fresh, salty, or a mix of both kinds of water. There are many types of wetlands, such as marshes, which have tall grasses and reeds, and swamps, which have trees and shrubs. Other types include mangrove forests near the ocean and bogs, which get their water from rain.

Wetlands are very important for people and the planet. They help clean water by catching harmful substances, protect shorelines from storms, and control flooding. They also help fight climate change by storing carbon. However, many wetlands are under threat from human activities like building, pollution, and draining the land for farming. Protecting wetlands is important for keeping both nature and people safe and healthy.

Definitions and terminology

Main article: Classification of wetlands

A wetland is an area of land that is often filled with water. This water can be on the surface or just below the ground, and it stays there for at least part of the year. Wetlands are special because they are a mix between dry land and water bodies, with plants and animals that have adapted to life in wet conditions.

Wetlands can be found all around the world, in many different climates. They may be in warm places, cold places, or everywhere in between. Some wetlands are always wet, while others are only wet for part of the year. There are many types of wetlands, including marshes, swamps, bogs, and fens, each with its own unique plants and animals.

Processes

Wetlands can look very different depending on where they are and what affects them, like the shape of the land, how water moves, and what plants grow there. Important things that change wetlands include how fertile the soil is, natural events that disturb the area, and animals that eat plants. When dead plants build up in waterlogged soil, special types of wetlands called bogs and fens form.

The biggest thing that creates wetlands is water flooding the land or keeping the soil very wet for long periods. This flooding decides if the wetland will have plants usually found in water, in marshes, or in swamps. Other factors that matter include soil richness, natural disturbances, competition among plants, animals eating plants, and salt in the water. When dead plants collect in these wet areas, they create bogs and fens. Water gets into wetlands mainly from rain, surface water like rivers, and water underground. Water leaves wetlands through evaporation, flowing over the land, and moving underground. How water moves through a wetland changes how much water stays there and for how long. The land's shape and what lives there affect how water behaves in wetlands. The amount of oxygen and carbon dioxide in wetland water depends on temperature, air pressure, and mixing with outside air. Wetlands usually get water that contains materials from the soil, except for special bogs that get water only from rain. Bogs get most of their water from rain and the air, so their water has few minerals. Other wetlands get water from underground or tides, so they have more nutrients and minerals. Fens get water from both rain and underground sources, so their water can range from acidic with few minerals to having lots of calcium and magnesium.

Biology

Wetlands are special places where plants, animals, and tiny organisms like bacteria and fungi live. The most important thing about wetlands is how long they stay flooded with water. Other factors, like how fertile the soil is or how salty the water is, also matter. Plants and animals in wetlands can change with the seasons or depending on how often the area floods.

Wetlands have four main types of plants. Some plants grow completely underwater, like seagrasses and eelgrass, and they help provide food and homes for small creatures. Other plants float on the water's surface, such as duckweeds. Plants like cattails and sedges grow up out of the water. When trees and shrubs grow in wet soil, the area is called a swamp. Swamps can have just one type of tree, like silver maple swamps, or many different kinds of trees, like in the Amazon basin.

Ecosystem services

Further information: Ecosystem service

Wetlands provide many important benefits to people and nature. They help control floods by storing extra water, clean water by trapping pollutants, and give homes to many animals and plants. Wetlands also support fishing, farming, and even provide materials for building and medicine.

Wetlands are valuable because they save money. Instead of building expensive dams or water treatment plants, healthy wetlands naturally do these jobs. They protect coastlines from big waves and storms, refill underground water supplies, and even help prevent soil erosion. Without wetlands, we would need to spend a lot more money to keep our water clean and our lands safe.

Disturbances and human impacts

Wetlands can be affected by many different changes, both from nature and from people. These changes can include things like too much rain or not enough rain, or humans building things, taking too many fish, or polluting the water. These changes can hurt the plants and animals that live in wetlands.

Some big problems for wetlands include pollution that makes the water too rich in nutrients, harmful chemicals, and too much dirt. When wetlands are turned into dry land for farming or building, it can hurt the environment. Building walls to hold back water can also cause more flooding later. Taking too many fish from wetlands can also be a big problem, especially in places where fish farming is common.

Conservation

Wetlands have often been drained for building or farming, and sometimes flooded to make lakes or produce power. Many important farms were once wetlands. But since the 1970s, people have worked harder to protect wetlands because they are important for nature. Sadly, about 65–70% of wetlands have disappeared since 1900. To keep wetlands healthy, we need to reduce changes that harm them.

Wetlands are important for the people who live near them. Research in places like Malawi and Zambia shows that we can farm in wet areas called dambos without hurting them. These projects helped grow lots of food, taught better farming ways, and found smart ways to manage water for watering crops.

Main articles: Ramsar Convention and List of Ramsar wetlands of international importance

The Ramsar Convention is an agreement between countries to help protect important wetlands all around the world. Its goals are to list these special wetlands and make sure they are used wisely. This means sometimes limiting who can visit and teaching people why wetlands are valuable, not empty land. The convention works with groups like Birdlife International, the IUCN, the International Water Management Institute, Wetlands International, and the World Wide Fund for Nature to share knowledge, study wetlands, and support protection efforts.

Restoration

Restoration helps bring wetlands back to their natural state after they have been disturbed. Ecologists use different methods depending on how much the wetland has been damaged. One way is to let the wetland heal on its own by stopping further harm and helping it recover naturally. Another method involves some human help, like adding soil or plants, especially when the wetland needs more support to recover. The most involved method is building a new wetland from the ground up, which is often used to help manage water and support wildlife in cities. Traditional knowledge from local communities can also guide restoration by focusing on the connections between different parts of the wetland.

Main article: Constructed wetland

Climate change aspects

Wetlands play an important role in our planet's climate. When wetlands like peat swamp forests are damaged, stored carbon is released into the air as carbon dioxide, which contributes to climate change. This happens often in Southeast Asia, where peatlands are drained and burned.

Restoring wetlands can help fight climate change. Wetlands can trap carbon from the air and store it, which helps reduce the amount of carbon dioxide in the atmosphere. They also help protect coastlines and control water levels, which is especially important as climate change causes more extreme weather like floods and droughts.

Valuation

Wetlands are important to communities because they provide many useful services. To understand their value, people first map where wetlands are located and then study what jobs they do, like cleaning water or giving animals homes. This helps decide which wetlands need protection or care.

There are quick ways to check how healthy a wetland is. These methods use simple questions and checklists to give a score, helping people know which wetlands are most important. This is useful when decisions need to be made fast or when there are many wetlands to study. Scientists also watch wetlands over time to see if they are staying healthy or getting worse, using tools like satellites and maps to keep an eye on them from far away.

Legislation

Each country has its own rules to help protect wetlands. In the United States, wetlands are areas that stay wet enough to support special plants that like soggy soil. These rules help protect wetlands under laws like the Clean Water Act. Some states, like Massachusetts and New York, have their own slightly different rules.

In Canada, there are also policies to protect wetlands, with each province and territory having its own guidelines to keep these important areas safe.

Examples

See also: List of Ramsar Wetlands of International Importance, Mediterranean wetlands, List of Ramsar wetland sites in Pakistan, and List of Ramsar sites in Australia

Some of the biggest wetlands in the world are the swamp forests in the Amazon River basin, the peatlands on the West Siberian Plain, the Pantanal in South America, and the Sundarbans in the Ganges-Brahmaputra delta. These places are important homes for many plants and animals because they are often flooded or very wet.