Wetlands

Where land and water meet, and life multiplies.

Marshes, swamps, bogs and mangroves — land that is flooded or waterlogged for part of the year.

Overview

Wetlands are places where water covers the soil or keeps it saturated for at least part of the year. They range from freshwater marshes and swamp forests to peat bogs and salty mangroves on tropical coasts. They act like sponges, storing floodwater, filtering pollution and providing breeding grounds for fish, amphibians and birds.

Climate

Found in almost every climate; what defines them is water, not temperature.

Where it is found

Worldwide — from river deltas and floodplains to coastal mangroves and northern bogs.

Vegetation

Reeds, sedges, water lilies, mosses in bogs and salt-tolerant mangrove trees on tropical coasts.

Living conditions

Water: Soil is saturated or flooded for at least part of the year.
Oxygen: Waterlogged soils are low in oxygen, so plants need special adaptations.
Salinity: Fresh, brackish or salt water, depending on the wetland.

Key facts

Water: Flooded or saturated for part of the year (Definition)
Salinity: Fresh, brackish or salt water
Seasonality: Many wetlands flood and dry with the seasons

How the ecosystem works

Nurseries: Fish, amphibians and birds breed in sheltered shallow water.
Filters: Plants and microbes remove nutrients and pollutants from water.
Carbon stores: Peat and mangrove soils store large amounts of carbon.

Food web

Producers: Red mangrove, Reeds & sedges, Venus flytrap
Herbivores: Insects & snails, Capybaras
Predators: Jaguar, Bald eagle, Axolotl
Decomposers: Bacteria, Fungi

Biodiversity

Wetlands support a large variety of life for their size — especially birds, amphibians and fish — and even carnivorous plants that get nutrients from insects.

Threats

Drainage — Wetlands are drained for farming, cities and roads.
Pollution — Fertilisers and waste water upset the balance of life.
Dams & diversions — Changing river flows starves wetlands of water.
Invasive species — Introduced plants and fish crowd out native species.

Conservation

Wetlands protect against floods, clean water and store carbon. Restoring them is one of the most effective nature-based solutions for both people and wildlife.

Protecting remaining wetlands from drainage.
Restoring natural water flows.
Replanting mangroves on degraded coasts.