Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Climate change: Diseqilibrium will become the norm in the plant communities of the future

01.07.2013
Global climate change will induce large changes to the plant communities on Earth

The forest we are used to looking at is not at all in equilibrium. Since the Ice Age, a number of plants have been 'missing' in Northern Europe, i.e. species that have not yet arrived.


Heartleaf Oxeye is an example of a species that has not yet returned to Northern Europe since the last Ice Age, but which we have helped along by planting in our gardens. Here it was found in the Danish countryside.

Credit: Photo: Jens-Christian Svenning, Aarhus University

The same applies in many other parts of the world. Similarly, there is evidence that -- even today -- it often takes a very long time before plants follow when glaciers retreat, or the climate changes. In future, such disequilibrium will become the norm in the plant communities on Earth. This has been demonstrated by a new synthesis carried out by two researchers at Aarhus University -- Professor of Biology Jens-Christian Svenning and Assistant Professor Brody Sandel.

Professor Svenning explains: "In the climate debate, even researchers have had a tendency to overlook the fact that ecological dynamics can be slow. However, our forests take an extremely long time to adapt. For example, we still have a small amount of small-leaved lime in Denmark, which has held on since the warm period during the Bronze Age, i.e. about 3000 years. Perhaps it will now get another chance to spread when the summers once more get warmer. However, such expansion would take a long time, as lime is not a particularly fast-growing tree or particularly good at dispersing, even under optimum conditions. The climate will change considerably in the course of a single tree generation so we should not assume that the forest we're looking at in a given place is suitable for the climate. Future climate will constantly shift, which will increasingly result in these strange situations of disequilibrium."

Even fast spreaders such as some invasive exotic plants remain in disequilibrium for decades or centuries. Shown here is a Norway maple, a highly invasive tree species in North America that may nevertheless still take many decades to spread across even small landscapes.

Photo: Lennarth Skov Espersen, http://www.fotoinaturen.dk.

The challenges we face

"Consequently, if you're trying to practise natural forest management with natural regeneration, you may see completely different plants regenerating compared with what you had before, because the climate has shifted to become suitable for another set of species. This also makes it challenging to adhere to a management plan granting preservation status to a particular type of nature at a certain site. At such a site, the existence of a large number of fully grown specimens of an endangered species is no guarantee that there will be a next generation.

This would be challenging for everyone -- for the managers, for the people who use the countryside in one way or another, and also for the researchers who are used to working with ecosystems that are much more balanced. Plant life and ecosystems will become much more dynamic and often out of sync with the climate.

We're causing so many changes to the climate, but at the same time nature is SO slow. Just think of a tree generation. Our entire culture is based on something that was, if not in complete equilibrium, then at least relatively predictable. We're used to a situation where flora, fauna and climate are reasonably well matched. In future, this equilibrium will shift on an ongoing basis, and there will be plenty of mismatches. That's what we'll have to work with."

Professor Svenning also calls for caution: "With nature in such a state of disequilibrium, human introduction of new species will play a key role. Take cherry laurel, for example, which we see in many gardens in Denmark. It's ready to spread throughout the Danish countryside. If it were to migrate unaided from its nearest native site in South-East Europe to Denmark, it would take thousands of years. Horticulturists now help it along. This will help the species survive, but can also cause northern species in Denmark to become extinct more rapidly. The cherry laurel is an evergreen, and if it disperses on the forest floor, it may create too much shade for the existing flora on the forest floor to survive. At the same time, the disequilibrium presents the advantage that such dispersal will take decades despite the contribution of horticulturists," Professor Svenning concludes.

Cherry laurel is another example of a species that has not yet returned to Northern Europe since the last Ice Age, but which we have helped along by planting in our gardens. Here it was found in the English countryside. Photo: Jens-Christian Svenning, Aarhus University.

For more information, please contact

Professor Jens-Christian Svenning
Department of Bioscience
Aarhus University
+45 8715 6571/2899 2304
svenning@biology.au.dk
Disequilibrium vegetation dynamics under future climate change. J-C. Svenning and B. Sandel, American Journal of Botany 100(7), 2013.

Jens-Christian Svenning | EurekAlert!
Further information:
http://www.biology.au.dk

More articles from Earth Sciences:

nachricht Global study of world's beaches shows threat to protected areas
19.07.2018 | NASA/Goddard Space Flight Center

nachricht NSF-supported researchers to present new results on hurricanes and other extreme events
19.07.2018 | National Science Foundation

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Global study of world's beaches shows threat to protected areas

19.07.2018 | Earth Sciences

New creepy, crawly search and rescue robot developed at Ben-Gurion U

19.07.2018 | Power and Electrical Engineering

Metal too 'gummy' to cut? Draw on it with a Sharpie or glue stick, science says

19.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>