Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Trees and shrubs invading critical grasslands, diminish cattle production

19.08.2014

Researchers discover rapid change in ecosystem services

Half of the Earth's land mass is made up of rangelands, which include grasslands and savannas, yet they are being transformed at an alarming rate. Woody plants, such as trees and shrubs, are moving in and taking over, leading to a loss of critical habitat and causing a drastic change in the ability of ecosystems to produce food — specifically meat.


Grasslands are being transformed at an alarming rate as woody plants, such as trees and shrubs, take over. This is leading to a loss of critical habitat and causing a drastic change in the ability of ecosystems to produce food. This is one example near the Santa Rita mountains in Arizona.

Credit: Osvaldo Sala

Researchers with Arizona State University's School of Life Sciences led an investigation that quantified this loss in both the United States and Argentina. The study's results are published in today's online issue of the scientific journal Proceedings of the National Academy of Sciences (PNAS).

"While the phenomenon of woody plant invasion has been occurring for decades, for the first time, we have quantified the losses in ecosystem services," said Osvaldo Sala, Julie A. Wrigley Chair and Foundation Professor with ASU's School of Life Sciences and School of Sustainability. "We found that an increase in tree and shrub cover of one percent leads to a two percent loss in livestock production." And, woody-plant cover in North America increases at a rate between 0.5 and two percent per year.

In recent years, the U.S. government shelled out millions of dollars in an effort to stop the advance of trees and shrubs. The U.S. Natural Resources Conservation Service spent $127 million from 2005-2009 on herbicides and brush management, without a clear understanding of its economic benefit.

The research team used census data from the U.S. and Argentina to find out how much livestock exists within the majority of the countries' rangelands. In both countries, the team studied swaths of rangeland roughly the size of Texas — approximately 160 million acres each. These lands support roughly 40 million heads of cattle. Researchers also used remote sensors to calculate the production of grasses and shrubs. And, to account for the effects of different socioeconomic factors, researchers quantified the impact of tree cover on livestock production in two areas of the world that have similar environments, but different level of economic development.

Surprisingly, the presence of trees explained a larger fraction of livestock production in Argentina than in the US.

"What's happening in Argentina seems to be a much narrower utilization of rangelands," added Sala. "The land there is mostly privately-owned and people who have ranches are producing predominantly meat to make a profit. But in the U.S., many people who own ranches don't actually raise cattle. They are using the land for many other different purposes."

While ranchers clearly depend on grasslands to support healthy livestock, ecosystems also provide a range of other services to humans. Stakeholders such as conservationists, farmers, builders, government entities and private landowners, depend on the land for a variety of reasons and each has different values and land use needs.

Why are trees and shrubs taking over grasslands? There are several hypotheses as to why woody plant encroachment is happening. Fire reduction, grazing intensity, climate change, and increased carbon dioxide in the atmosphere are some widely held beliefs as to the cause. However, Sala's study is focused not on the cause, but rather on the cost of this change to people.

"For each piece of land, there are different people who have an interest in that land and they all have different values. And, they are all okay," said Sala. "However, in order to negotiate how to use the land and to meet the needs of these different stakeholders, we need concrete information. We now know how much increase in tree cover is affecting the cattle ranchers."

Sala and his colleagues hope that the information found in their study will be used to inform discussions as policy makers and other stakeholders negotiate changes in land use. Researchers who took part in the study include Sala and Billie Turner II with ASU, José Anadón with City University of New York, and Elena Bennett with McGill University. National Academies Keck Futures Initiative and the U.S. National Science Foundation funded the study.

###

ASU's School of Life Sciences is an academic unit of the College of Liberal Arts and Sciences.

Sandra Leander | Eurek Alert!
Further information:
http://www.asu.edu

Further reports about: Arizona Foundation ecosystems grasslands livestock meat rangelands savannas shrubs stakeholders

More articles from Ecology, The Environment and Conservation:

nachricht Managing an endangered river across the US-Mexico border
18.07.2016 | International Institute for Applied Systems Analysis (IIASA)

nachricht The European pet trade is jeopardising the survival of rare reptile species
13.07.2016 | Helmholtz-Zentrum für Umweltforschung - UFZ

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: Newly discovered material property may lead to high temp superconductivity

Researchers at the U.S. Department of Energy's (DOE) Ames Laboratory have discovered an unusual property of purple bronze that may point to new ways to achieve high temperature superconductivity.

While studying purple bronze, a molybdenum oxide, researchers discovered an unconventional charge density wave on its surface.

Im Focus: Mapping electromagnetic waveforms

Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.

Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...

Im Focus: Continental tug-of-war - until the rope snaps

Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases

Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...

Im Focus: A Peek into the “Birthing Room” of Ribosomes

Scaffolding and specialised workers help with the delivery – Heidelberg biochemists gain new insights into biogenesis

A type of scaffolding on which specialised workers ply their trade helps in the manufacturing process of the two subunits from which the ribosome – the protein...

Im Focus: New protocol enables analysis of metabolic products from fixed tissues

Scientists at the Helmholtz Zentrum München have developed a new mass spectrometry imaging method which, for the first time, makes it possible to analyze hundreds of metabolites in fixed tissue samples. Their findings, published in the journal Nature Protocols, explain the new access to metabolic information, which will offer previously unexploited potential for tissue-based research and molecular diagnostics.

In biomedical research, working with tissue samples is indispensable because it permits insights into the biological reality of patients, for example, in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

GROWING IN CITIES - Interdisciplinary Perspectives on Urban Gardening

15.07.2016 | Event News

SIGGRAPH2016 Computer Graphics Interactive Techniques, 24-28 July, Anaheim, California

15.07.2016 | Event News

Partner countries of FAIR accelerator meet in Darmstadt and approve developments

11.07.2016 | Event News

 
Latest News

Newly discovered material property may lead to high temp superconductivity

25.07.2016 | Materials Sciences

Did you know that UV light helps to ensure safe bathing during the summer months?

25.07.2016 | Power and Electrical Engineering

Hey robot, shimmy like a centipede

22.07.2016 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>