Young boy fishing in Tonle Sap at sunset.

Freshwater Ecosystems

The areas on which humanity depends for its most precious resource are under increasing pressure.


Fresh water is the lifeblood of our planet, and freshwater ecosystems connect people with the resources they need to thrive. But when rivers, lakes and wetlands are degraded, their ability to provide reliable supplies of clean water — and to support the species on which millions of people depend — is threatened.

The planet’s freshwater ecosystems are in crisis: Research found that populations of monitored freshwater species have fallen by 84 percent and nearly one-third of wetland ecosystems have been lost since 1970 due to human activities that degrade habitats and decrease water quality.

But despite their vital contributions to humans and biodiversity, freshwater ecosystems receive only a small percentage of the funding dedicated to nature conservation, explained Robin Abell, a co-author of a recent review of these findings published in the journal Science, who leads Conservation International’s freshwater work.

“Freshwater ecosystems connect headwaters with oceans, land with water and people with the resources they need to thrive,” Abell said. “However, they have historically been ignored during the development of conservation initiatives such as protected areas and other management interventions.”

“Freshwater and terrestrial conservation need to go hand-in-hand to receive the full suite of benefits that nature can provide,” she said. “This will require strong policy that recognizes the connections between terrestrial and freshwater systems and that treats those systems as equal in importance.”


What Are the Issues?

Our Solutions

We work to protect and restore the freshwater ecosystems around the world that supply critical services to the people who depend on them most. Grounded in sound science, our projects offer innovative solutions that can serve as models for conservation anywhere on Earth. Given the link between nature and human well-being, we build bridges between conservation and development, providing leaders at all levels with the information they need to understand the true value of nature’s benefits.


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Related conservation news from the field

News spotlight: Cities turn to nature to revive their rivers

© Daniel Uribe

Editor's note: News about conservation and the environment is made every day, but some of it can fly under the radar. In a recurring feature, Conservation News shares a recent news story that you should know about.

Around the world, rivers have been treated like repositories of trash and toxic runoff — some so heavily polluted that they caught on fire. Now, cities from Australia to Europe to North America are turning to nature to restore their waterways by introducing plants typically found in wetland ecosystems. 

Floating wetlands, as they’re called, harness the natural ability of plants to filter contaminants while “giving scientists an opportunity to study environments that have long been ignored,” Susan Cosier reported for Yale Environment 360

What is a floating wetland? Exactly what it sounds like: An artificial platform with aquatic plants that has been engineered to float on waterways — often very polluted ones. It’s becoming an increasingly popular way for cities to help wipe out the toxic legacies of their waterways.

Like a natural wetland, floating wetlands contain plants, bacteria and algae that reduce contaminants from stormwater and absorb agricultural nutrients that can choke out aquatic life. A single acre of floating wetland can take up the equivalent of up to 6 hectares (15 acres) worth of nutrient pollution from urban development, Max Rome, a doctoral student at Northeastern University, told Yale Environment 360.

Other research suggests that floating wetlands can also filter some of the chemicals found in the acidic water that drains from metal mines and other dangerous contaminants linked to reproductive issues and cancer.

While they aren’t the sole answer to urban waterways’ woes, engineered wetlands could be a useful tool to improve water quality.

Further reading: Expert: Ending the global water crisis ‘starts in your back yard’

The constructed wetlands were created by the people in Xiadong Village.Constructed wetlands created by the people in Xiadong Village, China. ©Conservation International

The planet’s freshwater ecosystems are in crisis — 80 percent of wastewater worldwide goes untreated, with major impacts on human health and natural habitats. 

In southern China’s Dongjiang River, where wastewater treatment facilities are limited, Conservation International is working with local partners to tap into nature to improve community-based water stewardship. Two villages in the Dongjiang River Basin have constructed wetlands that move contaminated water through shallow septic tanks and into natural ecosystems, such as marshes, which absorb pollutants and filter the water. 

The constructed wetlands now treat up to 9,000 tons of sewage in the villages before returning the water to the river. At the same time, they provide habitat for native waterfowl, fish, frogs, insects and other species, said Weiling Wu, who runs Conservation International’s program on the Dongjiang River.

“Since the project began, we have seen a rise in the amount of wildlife in the area,” Wu said. “With clean water, the animals can thrive at the same time that we are creating freshwater infrastructure to help people.”

Read the full story here.

Further reading: In China, engineered wetlands remove waste from fresh water

Mary Kate McCoy is a staff writer at Conservation International. Want to read more stories like this? Sign up for email updates. Also, please consider supporting our critical work.

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