Wherever land meets water, life abounds. In every country and all climatic zones, from polar regions to the tropics, and from the highest mountains to the oceans, wetlands provide natural resources for 40% of the world’s species and are vital for people too. Explore the different types of wetlands, what distinguishes them from one another and how they support people and nature below.
Peatlands are wetlands with a thick water-logged soil layer made up of dead and decaying plant material.
Peatlands include moors, bogs, mires, peat swamp forests and permafrost tundra. Peatlands represent half of the Earth’s wetlands and cover 3% of the global total land area. They are found all over the world.
Why are peatlands important?
Peatlands absorb heavy rainfall, providing protection against floods, and release water slowly, ensuring a supply of clean water throughout the year. Millions of people depend on peatlands for their livelihoods such as herding cattle, fishing, and farming. Tropical peat swamp forests are home to thousands of animals and plants, including many rare and critically endangered species such as the orangutan and Sumatran tiger. Peatlands contain twice as much carbon as the world’s forests. If managed well they can continue to sequester equally large amounts from the atmosphere.
Coasts and deltas
Wetlands in deltas and along coasts are connectors between marine, freshwater and terrestrial ecosystems
These wetlands include mangrove forests, salt marshes, seagrass beds, mudflats and even coral reefs! By regulating flows of water and sediment, they contribute to building robust and diverse coastlines.
Why are coasts and deltas important?
Coasts and deltas serve as ecological corridors that provide breeding grounds for fish and other marine fauna, stopover sites for millions of migratory birds, and hunting and grazing grounds for visiting megafauna from sharks to tigers. They store large amounts of carbon in biomass and soils – typically more than equivalent areas of rainforests. As fishing grounds, they sustain hundreds of millions of livelihoods, many of them directly dependent on wetland services. Coastal wetlands such as mangrove forests also provide vital protection from storms, floods and salt water intrusion and in some cases even seal level rise. A mangrove can reduce the destructive force of a tsunami by up to 90%.
Rivers and Lakes
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river.
Rivers originate as rain on high ground that flows downhill into creeks and streams. They connect to major wetland systems and deltas, which are found on the lower reaches of rivers, where the flow of water slows down and spreads out into expanses of wetlands and shallow water. Rivers and lakes are critical in arid and semi-arid areas, where wetlands are characterised by seasonal rainfall and wetlands that retain water long after the rest of the landscape has dried out. These wetlands include rivers, swamps, and lakes and springs that dry up for portions of the year. Dry regions are found in Asia, Australia, Africa, the Middle East and North and South America.
Why are rivers and lakes important?
Rivers and lakes serve as important sources of drinking water, food and irrigation for crops. River waters also recharge lakes and transport fertile sediments that enrich floodplains and marshes. Rivers also play an essential role as highways for transportation and commerce and as sources of energy. Rivers and lakes provide critical habitat for fish and other freshwater animals such as amphibians and shellfish.
High altitude wetlands
Glacial lakes, marshes, wet grasslands, peatlands and rivers at high altitude support unique ecosystems and services that sustain the livelihoods of people.
High altitude wetlands store water from rain and glacial melt, feed groundwater stores, trap sediments and recycle nutrients, enhancing both the quantity and quality of water.
Why are high altitude wetlands important?
High latitude wetlands are important stopping points for migratory birds and breeding grounds for birds, fish and amphibians. Their ability to promote vegetation growth lessens soil erosion and buffers water flow, providing a steady flow of water downstream while reducing the severity of disasters such as landslides, floods and droughts.
Wetlands are the main ecosystem in the Arctic. These peatlands, rivers, lakes, and shallow bays cover nearly 60% of the total surface area.
Arctic wetlands store enormous amounts of greenhouse gases and are critical for global biodiversity. They are also the main source of livelihoods for local indigenous peoples.
Why are Arctic wetlands important?
Arctic wetlands offer unique habitats to both plants and animals. For many migratory species the Arctic provides indispensable breeding and feeding areas. In addition to this, over four million people, including more than 30 different indigenous groups, live in the Arctic. People living in the Arctic depend on wetlands for fish and waterfowl hunting, harvesting of plants and as pastures for grazing. Arctic wetlands also contain enormous stocks of organic carbon in their soils, and are dependent on frozen permafrost for their ability to store carbon. As temperatures rise and the permafrost thaws, huge amounts of greenhouse gases may be released into the atmosphere.
Wetlands in cities or urban areas affect billions of people and have a huge impact on their surroundings and micro-climates.
Urban wetlands are essential habitats and provide range of benefits, including reducing urban flooding during monsoon or rainy seasons, securing water supply, safeguarding biodiversity, and locking away carbon.
Why are urban wetlands important?
Cities are expected to account for nearly 7 billion people or two-thirds of the total global population by the year 2050. The urbanisation process drives wetland loss, absorbing rural wetlands into the city and landfilling existing urban wetlands for industry or housing. This degradation of wetlands can lead to loss of biodiversity habitat, reduces water supply, increased risk of flooding, waterlogging, and carbon emissions – it also limits the capacity to absorb heat and regulate local climates. With climate change leading to more severe and frequent heat waves, cities can manage these by protecting, restoring and (in some cases) constructing urban wetlands and integrate them with other blue-green infrastructure.