Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


A resourceful approach to climate research: Alpine ibex horns and old hay shed light on how grassland reacts to climate change

How do plant ecosystems react to rising concentrations of the greenhouse gas CO2 in the atmosphere over the long term? This fundamental question is becoming increasingly pressing in light of global climate change.

Researchers from the Chair of Grassland Science at the Technische Universität München (TUM) have now - for the first time worldwide - taken up this issue for grasslands. The scientists found their answers in two unlikely places: in horns of Alpine ibex from Switzerland and in 150-year-old hay from England.

Researchers studying the reactions of trees to rising CO2 concentration in the atmosphere have it easy. Since trees store the carbon they absorb in wood, all they need to do is take core samples from tree trunks. A centenarian oak will reveal how it coped with the incipient climate change over a period of a hundred years in its annual rings. "However, the grassland vegetation we work with is grazed or dies off in a matter of months and decomposes," explains Prof. Hans Schnyder, who is doing research in the field of grasslands at the Center for Life and Food Sciences Weihenstephan at the TUM. The Swiss scientist nonetheless wanted to establish out how economically grasslands deal with water when temperatures rise and the carbon dioxide concentration in the air increases.

Important in this context is that all plants absorb CO2 from the atmosphere. At the same time they transpire water vapor to cool their sunlit leaves. Both processes run via the stomata, tiny pores in the leaves, the opening size of which plants can regulate. During longer periods of drought plants close the stomata to curb water loss, albeit at the expense of CO2 absorption. Laboratory experiments show that, for a given stoma aperture, an artificial increase of ambient CO2 leads to a temporary increase in the absorption capacity for the gas. However, to ascertain the actual change of water use efficiency in grassland vegetation over the course of the last century, Prof. Schnyder had to find grassland time series comparable in length to those of trees.

This is where the team turned their sights to the Alpine ibex horn collection at the Museum of Natural History in Bern. Ibex store isotopic information in their horns that reflects the water use of the vegetation they consume. The TUM researchers went at the museum collection, which covers the years 1938 to 2006, with a carving knife, to remove tiny samples from the horns. Since ibex horns also have annual rings, the grassland researchers were able to use the samples to draw conclusions about temporal changes in the grassland vegetation of the Bernese Alps where the ibex had grazed.

A unique specimen archive at the research station Rothamsted in England eventually enabled a comparison with a second grassland region. The "Park Grass Experiment" - the longest running ecological grassland experiment worldwide - was initiated in Rothamsted over 150 years ago. Since 1857 specimens have been archived there to allow future generations of scientists to gain long-term insights into the local ecosystem using modern research methods. And indeed, the TUM scientists were able to benefit from the hay specimens dating as far back as 150 years. Once again analyzing the isotope signature, they could infer how the English grassland vegetation had utilized the water over the years.

The Weihenstephan researchers thus determined the individual isotope composition of the grassland vegetation in both the Bernese Alps and in the British lowlands over extended periods of time: more than 69 years based on the horns, and as far back as 150 years using the hay specimens. In a second step this data was lined up with climate data, e.g. air temperature and aridity, of the respective region. The result: In both locations the intrinsic water-use efficiency of the grassland vegetation rose over the years. This implies that the plants improved their water storage potential as temperatures rose and the level of CO2 in the atmosphere increased. Based on these results the TUM scientists have now, for the first time ever, managed to demonstrate the long-term effects of anthropogenic climate change on the water-use efficiency of grasslands.

There were, however, also differences between the two locations. In Switzerland the effective water-use efficiency of the Alpine meadows remained unchanged in spite of the increased intrinsic water-use efficiency of the grassland. This was because, overall, the air had become drier and warmer as a result of the climate change. In England the scientists found evidence for this effect only during the fall. In the spring though - which in Rothamsted is no drier today than it was 150 years ago - the water storage potential of grassland vegetation had a real effect. This insight will help to further improve climate simulations. In the past, complex simulation models that included vegetation had to rely on estimates where grassland was concerned. The scientists at the TU München have now succeeded in prying open this climate research black box.

Prof. Hans Schnyder
Chair of Grassland Science
Center of Life and Food Sciences
Technische Universität München
Tel. 08161 / 71-5165
Free Pictures:
Barbosa ICR, Köhler I, Auerswald K, Lüps P, Schnyder H (2009) Last-century changes of alpine grassland water-use efficiency - a reconstruction through carbon isotope analysis of a time-series of Capra ibex horns. Global Change Biology, DOI: 10.1111/j.1365-2486.2009.02018.x

Köhler IH, Poulton PR, Auerswald K, Schnyder H (2009) Intrinsic water-use efficiency of temperate semi-natural grassland has increased since 1857: an analysis of carbon isotope discrimination of herbage from the Park Grass Experiment. Global Change Biology, DOI: 10.1111/j.1365-2486.2009.02067.x

Barbosa ICR, Kley M, Schäufele R, Auerswald K, Schröder W, Filli F, Hertwig S, Schnyder H (2009) Analysing the isotopic life history of the alpine ungulates Capra ibex and Rupicapra rupicapra rupicapra through their horns. Rapid Communications in Mass Spectrometry (RCM) 23, 2347-2356.

Dr. Ulrich Marsch | idw
Further information:

More articles from Ecology, The Environment and Conservation:

nachricht Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide

nachricht Malaysia's unique freshwater mussels in danger
27.09.2016 | The University of Nottingham Malaysia Campus

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: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

The gene of autumn colours

27.10.2016 | Life Sciences

Polymer scaffolds build a better pill to swallow

27.10.2016 | Life Sciences

Greater Range and Longer Lifetime

26.10.2016 | Power and Electrical Engineering

More VideoLinks >>>