14 DAY TRIAL // A group of investigators argues that it managed to uncover a new mechanism through which mass extinction events can be triggered. Their explanation does not require for massive volcanic eruptions or asteroids from outer space to play a role.
According to a study the group published in the December 29 issue of the open-access scientific journal PLoS ONE, it would appear that a large influx of invasive species may be sufficient to trigger such a phenomenon.
As these species make their way into new habitats, their sheer numbers simply stop the dominant natural process that leads to the formation of new species, therefore planting the seeds for a future mass extinction.
These results are nothing but bad news, considering the current state of Earth's ecosystems. Most habitats are struggling with biodiversity loss, but also with invasive species making their way into places where they were not supposed to exist.
This situation is similar, the team says, to what happened on our planet during a marine species extinction event that took place 378 to 375 million years ago, in the Late Devonian period.
Though Earth suffered no less than five major mass extinction events, this particular one really stands out from the crowd due to the fact that it managed to bring with it a nearly total environmental crash.
“We refer to the Late Devonian as a mass extinction, but it was actually a biodiversity crisis,” explains Ohio University expert Alycia Stigall, who was also the author of the PLoS ONE paper.
“This research significantly contributes to our understanding of species invasions from a deep-time perspective,” adds National Science Foundation (NSF) Division of Earth Sciences (DES) program director Lisa Boush.
“The knowledge is critical to determining the cause and extent of mass extinctions through time, especially the five biggest biodiversity crises in the history of life on Earth,” she adds.
“It provides an important perspective on our current biodiversity crises,” the NSF official adds. The DES, the American Chemical Society and the Ohio University sponsored the new study.
The main conclusion of the research was that natural processes such as vicariance and dispersal stopped entirely during the Late Devonian.
Vicariance occurs when a natural obstacle – the formation of a sea or a mountain chain – separate two populations of a species, which then go on to become separate species, unable to interbreed.
Dispersal is similar, except that a population subgroup simply moves to a new location, and never returns to its point of origin.
“Even if you can stop habitat loss, the fact that we've moved all these invasive species around the planet will take a long time to recover from because the high level of invasions has suppressed the speciation [formation of new species] rate substantially,” Stigall explains.
“The more we know about this process, the more we will understand how to best preserve biodiversity,” the expert concludes.