Featured Research

from universities, journals, and other organizations

Earth In Midst Of Sixth Mass Extinction: 50% Of All Species Disappearing

Date:
October 21, 2008
Source:
University of California - Santa Barbara
Summary:
The Earth is in the midst of the sixth mass extinction of both plants and animals, with nearly 50 percent of all species disappearing, scientists say. Which plants should be a top priority to conserve? Researchers say the most genetically unique species are the ones that have the greatest importance in an ecosystem.

Buttercups. Losing the buttercup, where it occurs in grasslands, would have a much bigger impact on the system than losing a daisy or a sunflower, for example.
Credit: iStockphoto/Mark Goddard

The Earth is in the midst of the sixth mass extinction of both plants and animals, with nearly 50 percent of all species disappearing, scientists say.

Because of the current crisis, biologists at UC Santa Barbara are working day and night to determine which species must be saved. Their international study of grassland ecosystems, with flowering plants, is published in the Proceedings of the National Academy of Sciences.

"The current extinction event is due to human activity, paving the planet, creating pollution, many of the things that we are doing today," said co-author Bradley J. Cardinale, assistant professor of ecology, evolution and marine biology (EEMB) at UC Santa Barbara. "The Earth might well lose half of its species in our lifetime. We want to know which ones deserve the highest priority for conservation."

He explained that the last mass extinction near the current level was 65 million years ago, called the Cretaceous Tertiary extinction event, and was probably the result of a meteor hitting the Earth. It is best known for the extinction of non-avian dinosaurs, but massive amounts of plant species became extinct at that time as well.

According to the current study, the most genetically unique species are the ones that have the greatest importance in an ecosystem. These are the ones that the scientists recommend be listed as top priority for conservation.

"Given that we are losing species from ecosystems around the world, we need to know which species matter the most –– and which we should pour our resources into protecting," said first author Marc W. Cadotte, postdoctoral fellow at UCSB's National Center for Ecological Analysis and Synthesis (NCEAS).

Cadotte, Cardinale, and co-author Todd Oakley, an EEMB associate professor, put together a "meta-analysis" of approximately 40 important studies of grassland ecosystems around the world. They reconstructed the evolutionary history among 177 flowering plants used in these studies by comparing the genetic makeup of the plants.

The scientists found that some species are more critical than others in preserving the functions of ecosystems and that these species tend to be those that are genetically unique. Therefore, they are looking to evolutionary history for guidance in conservation efforts and in understanding the potential impacts of species loss.

Recent studies show that ecological systems with fewer species generally produce less biomass than those with more species. Less plant biomass means that less carbon dioxide is absorbed from the atmosphere and less oxygen is produced. So, as the biomass of plants plummets around the globe, the composition of gasses in the atmosphere that support life could be profoundly affected. Additionally, there are fewer plants for herbivorous animals to eat. Entire food chains can be disrupted, which can impact the production of crops and fisheries.

The loss of species that are not closely related to other species in the ecosystem reduces productivity more than the loss of species with close relatives. And the more genetically distinct a species is, the more impact it has on the amount of biomass in an ecosystem.

"Losing a very unique species may be worse than losing one with a close relative in the community," said Oakley. "The more evolutionary history that is represented in a plant community, the more productive it is."

Cadotte explained that the buttercup is a very unique species, evolutionarily. Losing the buttercup, where it occurs in grasslands, would have a much bigger impact on the system than losing a daisy or a sunflower, for example. The latter species are closely related. Each could therefore help fill the niche of the other, if one were to be lost. The daisy and sunflower also have a more similar genetic make-up.

"These 40 studies are showing the same thing for all plants around the world," said Cardinale. "It is not a willy-nilly conclusion. This study is very robust. It includes studies of plants that are found throughout the U.S., Europe, and Asia. We can have a high degree of confidence in the results. And the results show that genetic diversity predicts whether or not species matter."


Story Source:

The above story is based on materials provided by University of California - Santa Barbara. Note: Materials may be edited for content and length.


Cite This Page:

University of California - Santa Barbara. "Earth In Midst Of Sixth Mass Extinction: 50% Of All Species Disappearing." ScienceDaily. ScienceDaily, 21 October 2008. <www.sciencedaily.com/releases/2008/10/081020171454.htm>.
University of California - Santa Barbara. (2008, October 21). Earth In Midst Of Sixth Mass Extinction: 50% Of All Species Disappearing. ScienceDaily. Retrieved July 22, 2014 from www.sciencedaily.com/releases/2008/10/081020171454.htm
University of California - Santa Barbara. "Earth In Midst Of Sixth Mass Extinction: 50% Of All Species Disappearing." ScienceDaily. www.sciencedaily.com/releases/2008/10/081020171454.htm (accessed July 22, 2014).

Share This




More Plants & Animals News

Tuesday, July 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

San Diego Zoo Welcomes New, Rare Rhino Calf

San Diego Zoo Welcomes New, Rare Rhino Calf

Reuters - US Online Video (July 21, 2014) An endangered black rhino baby is the newest resident at the San Diego Zoo. Sasha Salama reports. Video provided by Reuters
Powered by NewsLook.com
Shark Sightings a Big Catch for Cape Tourism

Shark Sightings a Big Catch for Cape Tourism

AP (July 21, 2014) A rise in shark sightings along the shores of Chatham, Massachusetts is driving a surge of eager vacationers to the beach town looking to catch a glimpse of a great white. (July 21) Video provided by AP
Powered by NewsLook.com
$23.6 Billion Awarded To Widow In Smoking Lawsuit

$23.6 Billion Awarded To Widow In Smoking Lawsuit

Newsy (July 20, 2014) Cynthia Robinson claims R.J. Reynolds Tobacco Company hid the health and addiction risks of its products, leading to the death of her husband in 1996. Video provided by Newsy
Powered by NewsLook.com
A Centuries' Old British Tradition Is Far from a Swan Song

A Centuries' Old British Tradition Is Far from a Swan Song

AFP (July 19, 2014) As if it weren't enough that the Queen is the Sovereign of the UK and 15 other Commonwealth realms, she is also the owner of all Britain's unmarked swans. Duration: 02:18 Video provided by AFP
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:
from the past week

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