Great Wetlands of the World

Protecting an undervalued natural treasure

By Esri's StoryMaps team

Eight photos, each circular in the shape and differing in size, form a collage showing different wetland environments, or inhabitants of wetlands. Note that all the photos in this story are framed within a circle. The cover images include: Green trees packed densely along the shore of calm water. Two people in a small fishing boat, one is holding up two large fish. Satellite image of wetlands that experience seasonal flooding as the current water patterns show thin rivers of water surrounded by dark green vegetation in the areas where the water flows in the wet season. Tall, thin coniferous and deciduous trees with a river flowing in the background. An aerial view of dozens of small ponds surrounded by green grasslands. A jaguar lurks under trees in a sandy area surrounded by tree branches. Two white geese with black wings flying across a clear blue sky. An aerial view of a horseshoe bend in a river winding through a forest on a bright day with cumulus clouds in the background.

Wetlands are perhaps nature's least appreciated landscapes.

Left image: A marshland landscape with brown and green grasses in the foreground and foothills in the background. Right image: An aerial view of a river delta with areas of green islands surrounded by rivers.

Many of us may think of swamps, marshes, and bogs as mosquito-infested mudholes. In fact, they're vital to the health of ecosystems, maintenance of water quality, reduction of flood impacts, and moderation of climate change. And they're places of beauty.

Left image: Satellite image of a river delta during the dry season. The thin rivers wind through the dark green delta area. Right image: A small child leans over a bucket in a shallow river, with fishing boats visible in the background

Scroll to explore the world's largest wetland areas. Throughout the tour you'll learn about some of the myriad benefits of wetlands.

Large area of central Russia, stretching from Kazakhstan in the south to the Kara Sea in the north and several hundred kilometers wide.

West Siberia Lowlands

This million-square-mile corner of Siberia is drained by the Ob and the Yenisey rivers and forms the world's largest wetland complex. Much of it is tundra, or peatland, underlain by permafrost. Shown here, braided channels of the Ob River flow slowly northward toward the Arctic Ocean.

Overhead view of a river with a horseshoe bend that meanders through a forest as puffy clouds float in the sky in the background.

Wetlands benefits: water quality

Wetlands improve water quality by acting as natural filters, removing pollutants and storing sediment.

The Amazon River Basin

The Amazon, by far the world's largest river by volume of water, drains a large basin that includes an extensive, rain forested floodplain. These wetland areas are uniquely adapted to seasonal flooding; water levels can fluctuate by 30 feet or more in a single year.

In this view, the Madeira River (left) adds its waters to the already-mighty Amazon.

Green trees packed densely along the shore of calm water.

Wetlands benefits: biodiversity

Wetlands, especially in the tropics, provide habitat-supporting, highly diverse ecosystems. More than 2,000 fish species, for instance, are native to the Amazon.

The Hudson Bay Lowlands

The third largest wetland in the world borders the southern shores of Hudson Bay. The waterlogged region is still in the process of rebounding following the withdrawal of the Laurentide Ice Sheet at the end of the last Ice Age.

Two white geese with black-tipped wings fly across a clear blue sky.

Wetlands benefits: climate moderation

Wetlands help moderate climate by storing vast amounts of carbon in soils and partially decayed plant matter. Wetland plants also actively remove carbon from the atmosphere.

Locator map showing a roundish area in western Africa that includes areas of northwest D R Congo, and northeast Congo.

The Congo River Basin

Largely unknown due to their inaccessibility and proximity to conflict zones, the region's extensive swamps drain into the braided Congo River, second only to the Amazon in the volume of its discharge. Seen here, the Congo widens upstream from Kinshasa, DRC.

An overhead view of a river delta with areas of green islands surrounded by rivers.

Wetlands benefits: reduced erosion

Wetlands stabilize shorelines, reducing erosion more effectively and less expensively than engineering solutions.

Locator map showing a range covering most of the Northwest Territories in north central Canada.

Mackenzie River Basin

The twisted channels of the Mackenzie River's vast delta drain into the Arctic Ocean. The Mackenzie Basin includes extensive peatlands and supports wildlife, including large herds of migratory caribou.

Tall, thin coniferous and deciduous trees cover the landscape accompanied by a river flowing in the background.

Wetlands benefits: groundwater

Wetlands can recharge aquifers, underground reservoirs that are vital water supply sources for countless farms and cities.

A locator showing an area in southern Brazil on the border with Bolivia and just north of Paraguay.

The Pantanal

Southern Brazil's famous wetland complex features seasonally-flooded savannas and forests that harbor a highly diverse wildlife community. A top predator is the jaguar.

A jaguar lurks under trees in a sandy area surrounded by tree branches.

Wetlands benefits: watersheds

They are essential to health of watersheds. Destruction of wetlands reduces the overall health and quality of river systems.

A locator showing the area in the south-central United States surrounding the southern part of the Mississippi River stretching from the border of the southern tip of Illinois, a sliver of Kentucky, Missouri, Tennessee, the eastern quarter of Arkansas, the western border of Mississippi, and the eastern and southern parts of Louisiana.

The Mississippi Alluvial Plain

The lower Mississippi Valley has been highly modified by human activities, including erection of levees and flood control structures, and development of forests into farmlands. This has reduced the rate at which the river meanders and spawns oxbow lakes.

Satellite image of wetlands that experience seasonal flooding as the current water patterns show thin rivers of water surrounded by dark green vegetation in the areas where the water flows in the wet season.

Wetlands benefits: agriculture

Wetlands produce useful commodities, including rice, fish, shellfish, cranberries, and other crops.

The Lake Chad Basin

Lake Chad's shallow waters intermix with marshy wetlands. The lake has shrunk significantly since the 1960s. The lake and its wetlands are of vital economic importance to Chad and neighboring countries including Niger, Nigeria, and Cameroon.

A small child leans over a bucket in a shallow river. Fishing boats are visible in the background.

Wetlands benefits: economy

Many species of economically valuable fish spawn in wetlands.

The Nile River Basin

The familiar, downstream reaches of the Nile flow northward through the Sahara. The river is fed to a large extent by the Sudd, a far less-known but sprawling wetland area in South Sudan drained by the White Nile.

Two people in a small fishing boat, one is holding up two large fish.

Wetlands benefits: reduced flooding

Wetlands reduce the severity of floods by temporarily storing and slowly releasing flood waters.

A locator map showing the North American Prairie Pothole range stretching from the southeast quadrant of Alberta, Canada, across the southern half of Saskatchewan, the lower southwest corner of Manitoba, and crossing into the United States covering much of North Dakota, the eastern half of South Dakota and diagonally bisecting the state of Minnesota almost reaching the border with Wisconsin on the east, and dipping into Iowa on the south.

North American Prairie Potholes

The upper great plains of the U.S. and Canada are pocked with thousands of glacially carved depressions that collectively comprise one of the planet's great wetland complexes. Plants and animals adapt to constantly-changing water levels in these pocket wetlands.

An aerial view of dozens of small ponds surrounded by green grasslands.

Wetlands benefits: nesting habitat

Like many wetlands, the prairie potholes provide nesting habitat for huge populations of ducks and songbirds.

The Magellanic Moorland

Interspersed among the forests, glaciers, peaks, and waterways of southern South America are the peat wetlands of Patagonia. Collectively some 17,000 square miles in extent, the moorlands thrive in the region's cool, wet, windy climate.

A marshland landscape with brown and green grasses in the foreground and foothills in the background.

Wetlands benefits: recreation

Wetlands provide recreational opportunities, including kayaking, canoeing, and wildlife observation.

Wetlands of international importance

More than 150 nations have agreed to protect designated wetlands under the Ramsar Convention, a treaty named after the Iranian city where the agreement was drafted. The treaty went into effect in 1975 and currently covers more than 2,200 sites.

Ramsar wetlands around the world

This map locates the Ramsar wetlands; pop-ups summarize their size, "social use," and threats. Size of circles is proportional to wetland extents.

Thousands of additional wetlands across the globe face a variety of threats. More than half of U.S. and European wetlands have already been lost to development, draining, and other activities.