Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study reports on declines in ecosystem productivity fueled by nitrogen-induced species loss

04.07.2013
Humans have been affecting their environment since the ancestors of Homo sapiens first walked upright, but never has their impact been more detrimental than in the 21st century.

"The loss of biodiversity has much greater and more profound ecosystem impacts than had ever been imagined," said David Tilman, professor of ecology, biodiversity and ecosystem functioning at UC Santa Barbara's Bren School of Environmental Science & Management.


Caption: This is the Cedar Creek Ecosystem Science Reserve in central Minnesota where the study took place. Credit: Forest Isbell

Human-driven environmental disturbances, such as increasing levels of reactive nitrogen and carbon dioxide (CO2), have multiple effects, including changes in biodiversity, species composition, and ecosystem functioning. Pieces of this puzzle have been widely examined but this new study puts it all together by examining multiple elements. The results were published July 1 in the Proceedings of the National Academy of Sciences.

According to the team's recent findings, adding nitrogen to grasslands led to an initial increase in ecosystem productivity. However, that increase proved unsustainable because the increased nitrogen resulted in a loss of plant diversity. "In combination with earlier studies, our results show that the loss of biodiversity, no matter what might cause it, is a major driver of ecosystem functioning," said Tilman.

The study analyzed 30 years of field data from the Nitrogen Enrichment Experiment in order to determine the temporal effect of nitrogen enrichment on the productivity, plant diversity, and species composition of naturally assembled grasslands at the Cedar Creek Ecosystem Science Reserve in central Minnesota. The results showed that while nitrogen enrichment initially increased plant productivity, eventually this effect declined, especially in the plots that received the most fertilizer. These returns diminished over time because fertilizing also drove declines in plant diversity.

In fact, the continuous addition of nitrogen fertilizer led to a loss of the dominant native perennial grass, Schizachyrium scoparium, which decreased productivity twice as much as did random species loss in a nearby biodiversity experiment. In contrast, elevated CO2 didn't decrease or change grassland plant diversity in any way and consistently promoted productivity over time.

According to the authors, previous studies have underestimated the impact of biodiversity on ecosystem functioning. "Many people expect that only rare or subordinate species will be lost and that their loss will have negligible effects on ecosystem functioning," says lead author Forest Isbell, a postdoctoral associate in the Department of Ecology, Evolution & Behavior at the University of Minnesota in Saint Paul. "But we found that the most common species were lost under fertilization, creating a substantial decrease in productivity over time."

Furthermore, the results of this study show that changes in biodiversity can be important intermediary drivers of the long-term effects of human-caused environmental changes on ecosystem functioning. For example, accounting for the effects of nitrogen on plant diversity could improve predictions of the long-term impacts of nitrogen on productivity. While the researchers expect their results will be relevant in other ecosystems, they also hope to explore the practical implications of their results for sustaining forage yields in diverse pastures and hay meadows. In particular, they hope to determine whether maintaining plant diversity over time can sustain the productivity of these managed grasslands.

This research was supported by grants from Department of Energy Program for Ecosystem Research, the Department of Energy National Institute for Climatic Change Research, the National Science Foundation Long-Term Ecological Research Program, the National Science Foundation Biocomplexity Coupled Biogeochemical Cycles Program, the National Science Foundation Long-Term Research in Environmental Biology Program, and by the University of Minnesota.

Julie Cohen | EurekAlert!
Further information:
http://www.ucsb.edu

More articles from Studies and Analyses:

nachricht Researchers simplify tiny structures' construction drip by drip
12.11.2018 | Princeton University, Engineering School

nachricht Mandibular movement monitoring may help improve oral sleep apnea devices
06.11.2018 | Elsevier

All articles from Studies and Analyses >>>

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

Massive impact crater from a kilometer-wide iron meteorite discovered in Greenland

15.11.2018 | Earth Sciences

When electric fields make spins swirl

15.11.2018 | Physics and Astronomy

Discovery of a cool super-Earth

15.11.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>