What Triggers Mass Extinctions? Study Shows How Invasive Species Stop New Life

ScienceDaily (Dec. 31, 2010) — An influx of invasive species can stop the dominant natural process of new species formation and trigger mass extinction events, according to research results published December 29 in the journal PLoS ONE. The study of the collapse of Earth’s marine life 378 to 375 million years ago suggests that the planet’s current ecosystems, which are struggling with biodiversity loss, could meet a similar fate.

Although Earth has experienced five major mass extinction events, the environmental crash during the Late Devonian was unlike any other in the planet’s history. The actual number of extinctions wasn’t higher than the natural rate of species loss, but very few new species arose. “We refer to the Late Devonian as a mass extinction, but it was actually a biodiversity crisis,” said Alycia Stigall, a scientist at Ohio University and author of the PLoS ONE paper.

[…]The first forests and terrestrial ecosystems appeared during this time; amphibians began to walk on land. As sea levels rose and the continents closed in to form connected land masses, however, some species gained access to environments they hadn’t inhabited before. The hardiest of these invasive species that could thrive on a variety of food sources and in new climates became dominant, wiping out more locally adapted species. The invasive species were so prolific at this time that it became difficult for many new species to arise.

[…]The study is relevant for the current biodiversity crisis, Stigall said, as human activity has introduced a high number of invasive species into new ecosystems.

“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 rate substantially,” Stigall said.

For the complete ScienceDaily article see: http://www.sciencedaily.com/releases/2010/12/101230100050.htm

Journal Reference: Anna Stepanova, Alycia L. Stigall. Invasive Species and Biodiversity Crises: Testing the Link in the Late Devonian. PLoS ONE, 2010; 5 (12): e15584 DOI: 10.1371/journal.pone.0015584