A quarter of freshwater species face extinction, study finds

A new study is ringing alarm bells for freshwater species, finding nearly a quarter are at risk of extinction. 

The study, from researchers at the International Union for the Conservation of Nature (IUCN), named dams, farms, invasive species and pollution as responsible for the decline, Julia Jacobo reported for ABC News. 

The findings are “alarming,” Catherine Sayer, freshwater biodiversity lead at IUCN, told ABC News.

“We have about a quarter of species which are on their way to extinction if we don’t do anything to stop it,” she said.

The study, which assessed more than 23,000 freshwater species, broke down the impact of each threat:

• Dams block species from reaching habitats they previously used for breeding or feeding.
• Climate change threatens 18 percent of the freshwater species studied — a figure experts expect to grow.
• Pollution affects 54 percent of the threatened species studied.
• Agriculture, including land-use change and the use of pesticides and herbicides, affects 37 percent of the studied species.
• Invasive species and disease threaten 28 percent of the studied species.

Rivers, lakes and wetlands cover less than 1 percent of Earth’s surface yet support at least 10 percent of the planet’s species. Freshwater ecosystems also provide critical benefits including flood control, climate regulation and nutrient cycling, as well as sustaining local livelihoods and providing food and water to communities.

It’s estimated that monitored populations of freshwater species have fallen by 84 percent, and nearly one-third of freshwater ecosystems have been lost since 1970 due to human activities that degrade habitats and decrease water quality.

“Small, often unseen creatures like shrimp, crayfish and crabs living in lakes, rivers and ponds are easy to overlook,” said Stephanie Wear, who leads Conservation International’s Moore Center for Science. “Yet, they are essential to keeping these waterways healthy and supporting billions of people. It’s critical that we take this news seriously, and act to protect freshwater habitats for the wildlife that benefit our own well-being.”

For example, a Conservation International project in Mexico is providing a blueprint for how people can work with nature to create a more sustainable future.

On the outskirts of Mexico City, an ancient wetland system of lakes and canals built by the Aztecs to grow crops are also the only home to the endangered axolotl.

Over the years, this ecosystem has been drained and polluted; Conservation International is helping restore it by supporting farmers’ transition to pesticide-free farming and helping install biofilters to clean the water so these wetlands can thrive into the future.

Read the full story from ABC News here.

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.