What You Need to Know

…are like giant sponges.

They prevent flooding. During heavy rains, they collect and hold water. They also protect coastal areas from storms that can wash away beaches and communities.

…act as water treatment facilities.

They filter and clean water. Chemicals found in fertilizer often wash into wetlands. Wetland plants, fungi, and algae absorb these harmful chemicals. Other pollutants sink to the bottom. There they are buried in soil.

…are homes for many species.

Many plant and animal species depend on wetlands for their survival.

Two-thirds of the fish eaten worldwide depend on wetlands during their life cycle.

…are diverse ecosystems.

Wetlands cover only five percent of the United States. Yet more than one-third of threatened or endangered species in the U.S. live only in wetlands. An additional 20 percent use wetlands during their lives.

…are important to people.

Nearly 400 million people live close to wetlands. People depend on them. They use wetlands to grow crops like rice. Wetlands are also used for fun. People fish and boat on them. In fact, Americans spend more than $100 billion on wetland activities every year.

wetlands face many threats

As much as half the world’s wetlands have disappeared since 1900, despite their value to people and wildlife.


Development often changes wetlands by removing vegetation. Then wetlands are filled or drained to build houses and roads.

Invasive Species

The introduction of non‑native plants and animals causes native species to compete. If native species die off, the ecosystem gets disrupted.


Wetland soil is often made into land for farming. The runoff from nearby farmland can hurt wetlands.

Climate Change

The rise in sea levels has been caused by climate change. As a result, many coastal wetlands may be permanently flooded.