It could take Earth’s freshwater ecosystems millions of years to recover from the damage inflicted upon them by humans, according to the results of a new study. The research also revealed that gastropods living in these environments are going extinct at a rate three orders of magnitude higher than occurred during the mass extinction event that wiped out the dinosaurs.
Earth’s many ecosystems are incredibly complex and remarkably fragile. The expansion and industrialization of the human race has triggered mass habitat destruction, the introduction of pollution and invasive species, and has prompted a steady but dramatic shift in our planet’s climate.
These factors have led to countless species being listed as endangered, while others have been driven to complete extinction. The situation has become so dire that many members of the scientific community say we have entered a 6th mass extinction.
A new study, published in the journal Communications Earth & Environment, sought to estimate how long it will take Earth’s freshwater ecosystems to recover from their current plight, and compares the modern day crisis with that of the Cretaceous-Paleogene mass extinction that decimated the dinosaur population.
The international team of scientists behind the study, which was led by members from the Justus Liebig University Giessen, focused on the living and fossilized remains of freshwater gastropod species that inhabited Europe in the last 200 million years.
Gastropods, which include snails and slugs, are some of the most diverse groups of animals living in freshwater environments. They also have one of the best preserved fossil records, which makes them an excellent group to observe when examining extinction and recovery.
Data from a grand total of 3,387 living and fossil specimens was used by the team to estimate the emergence rate of new species during the last 200 million years – a value known as speciation – and the rate of extinction.
The researchers then went on to estimate how long it took for gastropods to recover from the Cretaceous-Paleogene mass extinction event that wiped out 76 percent of all animal species on Earth some 66 million years ago.
It was discovered that the asteroid strike that set in motion the downfall of the dinosaurs triggered a high rate of extinction in the 5.4 million years following the event. Furthermore, according to the study authors, it took a further 6.9 million years before the balance between speciation and extinction leveled out.
Disturbingly, the data also revealed that the rate of extinction for modern day freshwater snail species in Europe is around three orders of magnitude higher than was the case during the Cretaceous-Paleogene mass extinction. According to the study, a third of current freshwater species are forecast to have gone extinct by the year 2120.
"Even if our impact on the world's biota stops today, the extinction rate will likely stay high for an extended period of time," says Dr. Thomas A.Neubauer, lead author of the new study. "Considering that the current biodiversity crisis advances much faster than the mass extinction event 66 million years ago, the recovery period may be even longer. Despite our short existence on Earth, we have assured that the effects of our actions will outlast us by millions of years."
The paper has been published in the journal Communications Earth & Environment.
Source: Naturalis Biodiversity Center