Featured Research

from universities, journals, and other organizations

What triggers mass extinctions? Study shows how invasive species stop new life

Date:
December 31, 2010
Source:
National Science Foundation
Summary:
An influx of invasive species can stop the dominant natural process of new species formation and trigger mass extinction events, according to new research. 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.

The ocean in Devonian times. A 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.
Credit: University of Michigan Museum of Paleontology

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.

Related Articles


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.

"This research significantly contributes to our understanding of species invasions from a deep-time perspective," said Lisa Boush, program director in the National Science Foundation (NSF)'s Division of Earth Sciences, which funded the research.

"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. It provides an important perspective on our current biodiversity crises."

The research suggests that the typical method by which new species originate--vicariance--was absent during this ancient phase of Earth's history, and could be to blame for the mass extinction.

Vicariance occurs when a population becomes geographically divided by a natural, long-term event, such as the formation of a mountain range or a new river channel, and evolves into different species. New species also can originate through dispersal, which occurs when a subset of a population moves to a new location.

In a departure from previous studies, Stigall used phylogenetic analysis, which draws on an understanding of the tree of evolutionary relationships to examine how individual speciation events occurred.

She focused on one bivalve, Leptodesma (Leiopteria), and two brachiopods, Floweria and Schizophoria (Schizophoria), as well as a predatory crustacean, Archaeostraca. These small, shelled marine animals were some of the most common inhabitants of the Late Devonian oceans, which had the most extensive reef system in Earth's history.

The seas teemed with huge predatory fish such as Dunkleosteus, and smaller life forms such as trilobites and crinoids (sea lilies). 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 main mode of speciation that occurs in the geological record is shut down during the Devonian," said Stigall. "It just stops in its tracks."

Of the species Stigall studied, most lost substantial diversity during the Late Devonian, and one, Floweria, became extinct. The entire marine ecosystem suffered a major collapse. Reef-forming corals were decimated and reefs did not appear on Earth again for 100 million years. The giant fishes, trilobites, sponges and brachiopods also declined dramatically, while organisms on land had much higher survival rates.

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.

In addition, the modern extinction rate exceeds the rate of ancient extinction events, including the event that wiped out the dinosaurs 65 million years ago.

"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.

Maintaining Earth's ecosystems, she suggests, would be helped by focusing efforts and resources on protection of new species generation. "The more we know about this process," Stigall said, "the more we will understand how to best preserve biodiversity."

The research was also funded by the American Chemical Society and Ohio University.


Story Source:

The above story is based on materials provided by National Science Foundation. Note: Materials may be edited for content and length.


Journal Reference:

  1. 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

Cite This Page:

National Science Foundation. "What triggers mass extinctions? Study shows how invasive species stop new life." ScienceDaily. ScienceDaily, 31 December 2010. <www.sciencedaily.com/releases/2010/12/101230100050.htm>.
National Science Foundation. (2010, December 31). What triggers mass extinctions? Study shows how invasive species stop new life. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2010/12/101230100050.htm
National Science Foundation. "What triggers mass extinctions? Study shows how invasive species stop new life." ScienceDaily. www.sciencedaily.com/releases/2010/12/101230100050.htm (accessed October 25, 2014).

Share This



More Plants & Animals News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Black Bear Cub Goes Sunday Shopping

Black Bear Cub Goes Sunday Shopping

Reuters - Light News Video Online (Oct. 23, 2014) Price check on honey? Bear cub startles Oregon drugstore shoppers. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Dances With Wolves in China's Wild West

Dances With Wolves in China's Wild West

AFP (Oct. 23, 2014) One man is on a mission to boost the population of wolves in China's violence-wracked far west. The animal - symbol of the Uighur minority there - is under threat with a massive human resettlement program in the region. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
Breakfast Debate: To Eat Or Not To Eat?

Breakfast Debate: To Eat Or Not To Eat?

Newsy (Oct. 23, 2014) Conflicting studies published in the same week re-ignited the debate over whether we should be eating breakfast. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins