Extinction threatens nearly a quarter of all freshwater species

Tired Earth

By The Editorial Board

Freshwater ecosystems cover less than 1% of Earth's surface, but are vital for life on this planet. New research reveals that damage to these environments is pushing freshwater animals to the edge of extinction, with 24% of species in danger of being wiped out.

Thousands of fish, crab and dragonfly species could become extinct in the coming decades—and many more could follow.

A landmark assessment of the health of nearly 24,000 freshwater species found that just under a quarter are at risk of extinction. Of these, almost 1,000 species are considered Critically Endangered, with 200 having potentially been lost already.

These numbers may only represent the tip of the iceberg, with scientists lacking the information needed to properly understand the extinction risk of thousands of species. Catherine Sayer, the lead author of the study, says that urgent action is needed to understand and protect these animals.

"Lack of data on freshwater biodiversity can no longer be used as an excuse for inaction," she says. "Freshwater landscapes are home to 10% of all known species on Earth and key for billions of people's safe drinking water, livelihoods, flood control and climate change mitigation, and must be protected for nature and people alike."

The findings of the study appear in the journal Nature.

What challenges do freshwater habitats face?

While fresh, clean water is vital for all life on land, freshwater ecosystems are some of the most threatened on Earth. Freshwater environments are being put under pressure as demand for food, water and resources increases.

Wetlands in particular, including bogs, mangroves and saltmarshes, are bearing the brunt of these losses. It's estimated that an area the size of India—a staggering 3.4 million square kilometers—of wetland has been lost since 1700.

The loss of wetlands harms far more than just the animals and plants that live there, as it also limits our ability to fight climate change and stop flooding.

Freshwater sources are also suffering from a cocktail of different challenges. An increase in water abstraction and dams on rivers are reducing the available habitat for wildlife. Some rivers, like the Colorado River, no longer even reach the sea.

The animals that persist in these reduced habitats are then impacted by sewage, industrial and plastic pollution. Yet, despite the rising risk to these species, freshwater environments are significantly understudied compared to the oceans.

Dr. Topiltzin Contreras MacBeath, a co-author of the study, says that this needs to change if we are to ensure that freshwater species have the best chance of survival.

"It is essential that freshwater species data are actively included in conservation strategies and water use management to support healthy freshwater ecosystems," Dr. MacBeath says. "Increased investment in measuring and monitoring freshwater species is needed to ensure conservation action and water use planning is based on the latest information."

Source : phys.org