The current biodiversity crisis, often called the sixth mass extinction, is one of the critical challenges we face in the 21st century. Many species are threatened with disappearance, mainly as a direct or indirect consequence of human impact. Among the main causes of the rapid decline in Earth’s biota are: habitat destruction, climate change, overexploitation, pollution and invasive species.
Now, a new study suggests that the current rate of decline in biodiversity in freshwater ecosystems exceeds the late Cretaceous extinction that decimated the dinosaur population and the damage being done to ecosystems will take millions of years to undo.
Species are dying faster than ever
A team of researchers led by the University of Giessen (Germany) wanted to know how quickly species were disappearing from Earth and how long it would take them to recover. To do this, they focused on the freshwater species that are among the most threatened. They created a database of thousands of species of living and fossilized snails from Europe (gastropods) covering the last 200 million years. Gastropods, which include snails and slugs, are some of the most diverse groups of animals that live in freshwater environments. They also have one of the best-preserved fossil records, making them an excellent group to watch when examining extinction and recovery.
They examined 3,387 living and fossil specimens. Experts found that freshwater species declined faster than expected after the asteroid that struck Earth 66 million years ago. But this was nothing compared to their estimates of future extinction rates. Scientists believe that the current extinction event will kill species at an average rate three times that of the last event. By 2120, a third of living freshwater species could be extinct.
“Species loss leads to changes in species communities and, in the long run, this affects entire ecosystems. We depend on the functioning of freshwater environments to maintain human health, nutrition, and freshwater supplies, ”says Thomas A. Neubauer, lead author of the new study.