Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Climate change effect on plant communities is buffered by large herbivores, new research suggests

20.02.2013
Can existing ecological communities persist intact as temperatures rise?

This is a question of increasing relevance in the field of climate change and is the focus of a new study to be published in the journal Proceedings of the Royal Society of London on 20 February. The study suggests that the answer to this question may have as much to do with the biological interactions that shape communities as with the effects of climate change itself.

The study's insights are based on a novel approach by Eric Post, a Penn State University professor of biology, who simulated climate change and integrated the effects of large, plant-eating mammals in a 10-year arctic field experiment. The results of the research suggest that plant communities in the Arctic are more likely to resist destabilization by climate change if populations of caribou, musk ox, and other large herbivores remain intact. "The study demonstrates that grazing by these large herbivores maintains plant species diversity, while warming reduces it," Post said. "Plant communities with lower diversity display a greater tendency toward instability under warming, a pre-cursor to the loss of such communities."

Post explained that climate-change research in the 1980s and 1990s was focused primarily on how fluctuations in such factors as temperature, precipitation, and nutrient availability directly affected plant communities. "That research was important and enlightening, but what it did not emphasize were the indirect effects of climate change -- how interactions among species may shape the responses of those species to warmer temperatures," Post said. "If the planet continues to warm by 1.5-to-3.0 degrees Celsius over the next century, as the models predict, we need to know not only what the warming will do to plants and animals directly, but also how species' interactions may influence those effects of warming."

Post began the study in a remote, low-Arctic plant community near Kangerlussuaq, Greenland in 2002. To simulate the effects of the 1.5-to-3.0-degrees-Celsius warming that is predicted to occur over the next century, he erected special warming chambers -- cone-shaped hollow structures that create a greenhouse effect. Some areas on which these warming chambers were placed were left open to grazing by caribou and musk ox -- two ecologically important large herbivores in the Arctic -- while separate 800-square-meter areas that also received warming chambers were fenced off to exclude the animals. In this way, Post created two very different environments: one in which plants and herbivores continued to live together as the temperatures climbed within the warming chambers; the other in which the animals were not present and the plants were left ungrazed.

"The study tested a classic ecological hypothesis, but with a new angle," Post said. "Ecologists have argued for decades over whether species-rich plant communities are more stable, and, hence, persistent in the face of environmental disturbance, than species-poor communities. This study added a layer of complexity by asking whether large herbivores contribute to the diversity-stability relationship in a climate-change context."

After 10 years of careful observation of the Kangerlussuaq, Greenland plant communities, Post found that the grazed and ungrazed sections of land did indeed fare quite differently in their responses to warmer temperatures. "This study confirmed that caribou and musk ox act as a buffer against the degradative effects of warming on plant species diversity," Post said. He found that shrubs such as willow and birch became the dominant plants in response to warming where the herbivorous animals were excluded from the ecosystem. "When these shrubs expand in the plant community, they tend to shade their neighbors, and the build-up of leaf litter around the shrubs tends to cool the soil surface, reducing the availability of soil nutrients for other plants," Post said. "As a result, shrubs can quickly out-compete other plants and reduce species diversity in the process. On the other hand, in those areas where caribou and musk ox were able to graze freely, shrub responses to warming were muted, and species diversity within the plant community was maintained."

Post said the take-home message from his study is that, in a warming climate, intact populations of large herbivores may be crucial to the maintenance of plant-community diversity and to the persistence of existing plant communities. "What this experiment suggests is that factors that threaten the persistence of large herbivores may threaten the plant communities they exist in, as well. Conservation of these herbivores in the rapidly changing Arctic will require careful mediation of interacting stressors such as human exploitation, mineral extraction, and the direct effects of climate change," Post said.

Post said that the next step in his research will be to study the contribution of plant diversity to long-term stability of carbon dynamics in the atmosphere and in the soil.

The research was funded by the National Geographic Society's Committee for Research and Exploration, with additional funding from the Office of Polar Programs at the U.S. National Science Foundation.

[ Katrina Voss ]

CONTACTS

Barbara Kennedy (PIO) science@psu.edu, 814-863-4682

Eric Post esp10@psu.edu
IMAGES
High-resolution images associated with this research are online at http://www.science.psu.edu/news-and-events/2013-news/Post2-2013.

CAPTIONS

(for all images): Eric Post, Penn State University

IMAGE CAPTIONS (top to bottom on the webpage listed above)

Image 1: An adult male caribou in Greenland.
Image 2: Two adult male muskoxen in Greenland.
Image 3: Inland ice shelves in Greenland.
Image 4: To study how ecological communities react to rising temperatures, Eric Post erected special warming chambers to simulate a greenhouse effect in a remote, low-Arctic plant community near Kangerlussuaq, Greenland.
Image 5: An adult male muskox in Greenland.
Image 6: Adult male caribou in Greenland.
Image 7: Two adult male muskoxen in Greenland.
Image 8: A cotton-grass plant grows in Greenland.
Image 9: Inland ice shelves in Greenland.
GRANT NUMBERS
National Geographic Society (7442-03)
National Science Founcation (DEB-0124031)

Barbara Kennedy | EurekAlert!
Further information:
http://www.psu.edu

More articles from Ecology, The Environment and Conservation:

nachricht Despite government claims, orangutan populations have not increased. Call for better monitoring
06.11.2018 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

nachricht Increasing frequency of ocean storms could alter kelp forest ecosystems
30.10.2018 | University of Virginia

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

Im Focus: Coping with errors in the quantum age

Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly

The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

The dawn of a new era for genebanks - molecular characterisation of an entire genebank collection

13.11.2018 | Life Sciences

Fish recognize their prey by electric colors

13.11.2018 | Life Sciences

Ultrasound Connects

13.11.2018 | Awards Funding

VideoLinks
Science & Research
Overview of more VideoLinks >>>