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Temperature drives biodiversity

Date:
December 22, 2016
Source:
University of Würzburg
Summary:
Why is the diversity of animals and plants so unevenly distributed on our planet? An international research team of researchers has provided new data on this core issue of ecology. They found biodiversity to be driven by temperature.
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The diversity of plants and animals decreases as temperatures fall. This photo was taken on Mount Kilimanjaro at an altitude of around 3,800 meters.
Credit: Andreas Ensslin

The diversity of plants and animals in Earth's arctic regions is moderate. Tropical latitudes in contrast are teeming with different species where new organisms are being discovered all the time.

What is the cause of this uneven distribution? Why are the tropics home to more species than higher latitudes? "This question has intrigued ecologists for some time," says Professor Ingolf Steffan-Dewenter from the University of Würzburg's Biocenter. "Already about ten years ago, the publishers of Science declared this to be one of the 25 most important questions of science to be answered yet."

Several hypotheses circulating

To date, this core question has been subject to controversy. One hypothesis, for instance, is that the primary productivity of a habitat is ultimately decisive for the number of species living there. Simply put: "A larger cake can sustain more species than a small one," explains Würzburg ecologist Dr. Marcell Peters. Another hypothesis assumes that the rate of evolution and speciation depend on temperature. According to this assumption, more species thrive in a warmer climate than in a cold one.

So far, these hypotheses have been examined usually by focusing on selected groups of species: For example, the studies observed only birds, bees, ants or ferns and analysed their diversity in different regions of the world, e.g. in North America, Europe or along elevational gradients in the Alps. "Some studies supported one hypothesis, whereas others backed another assumption," Peters says and states that it is still a long way from establishing a "general rule" which ecologists are aiming for.

Unique study conducted at Mount Kilimanjaro

In the journal "Nature Communications" Peters and the team of the Research Unit "FOR1246" funded by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) now present a new study which is unique so far and is the synthesis of four years of working: "On Mount Kilimanjaro, one of Earth's largest climatic gradients, we observed so many animal and plant groups in parallel as never before," the researcher says.

Overall, the team examined eight groups of plants and 17 groups of animals, from bees to bats. 38 scientists from Germany, Tanzania and other countries participated in the large-scale study; they were supported by around 50 local drivers, carriers and other assistants. "We had to climb in mountainous areas for several days to reach the highest study sites," Peters says.

The area of study stretched from the savannahs at the foot of the mountain to the habitats at an altitude of 4,550 metres that barely sustain plants. The data across all groups were collected over the same areas and in the same period of time, respectively. "This approach allowed us to not only analyse the biodiversity of each individual group, but also that of whole communities."

Diversity increases with temperature

The study revealed that biodiversity in communities is mainly determined by temperature. The warmer it is, the greater the diversity. "The more groups of animals and plants you investigate in parallel, the greater the significance of temperature for explaining biodiversity, whereas the importance of all other variables decreases accordingly."

The scientists believe that this is strong evidence supporting the assumption that temperature is actually more decisive for distribution patterns of overall biodiversity than productivity or size of habitats.


Story Source:

Materials provided by University of Würzburg. Original written by Robert Emmerich. Note: Content may be edited for style and length.


Journal Reference:

  1. Marcell K. Peters, Andreas Hemp, Tim Appelhans, Christina Behler, Alice Classen, Florian Detsch, Andreas Ensslin, Stefan W. Ferger, Sara B. Frederiksen, Friederike Gebert, Michael Haas, Maria Helbig-Bonitz, Claudia Hemp, William J. Kindeketa, Ephraim Mwangomo, Christine Ngereza, Insa Otte, Juliane Röder, Gemma Rutten, David Schellenberger Costa, Joseph Tardanico, Giulia Zancolli, Jürgen Deckert, Connal D. Eardley, Ralph S. Peters, Mark-Oliver Rödel, Matthias Schleuning, Axel Ssymank, Victor Kakengi, Jie Zhang, Katrin Böhning-Gaese, Roland Brandl, Elisabeth K.V. Kalko, Michael Kleyer, Thomas Nauss, Marco Tschapka, Markus Fischer, Ingolf Steffan-Dewenter. Predictors of elevational biodiversity gradients change from single taxa to the multi-taxa community level. Nature Communications, 2016; 7: 13736 DOI: 10.1038/ncomms13736

Cite This Page:

University of Würzburg. "Temperature drives biodiversity." ScienceDaily. ScienceDaily, 22 December 2016. <www.sciencedaily.com/releases/2016/12/161222095844.htm>.
University of Würzburg. (2016, December 22). Temperature drives biodiversity. ScienceDaily. Retrieved May 27, 2017 from www.sciencedaily.com/releases/2016/12/161222095844.htm
University of Würzburg. "Temperature drives biodiversity." ScienceDaily. www.sciencedaily.com/releases/2016/12/161222095844.htm (accessed May 27, 2017).

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