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24 November 2016
Hoch hinaus: Forscher untersuchen Klima- und Landnutzungswandel am Kilimandscharo...
06 October 2016
The great feeding-frenzy: Species-rich food webs produce biomass more efficiently...
28 September 2016
Geological Society of America ehrt Direktor des Senckenberg Forschungsinstituts Frankfurt...
15 September 2016
For 20 Million Years, the Diversity of Large Terrestrial Mammals Depended on Plant Growth...
08 September 2016
Gene analyses reveal that there are not one, but four giraffe species...
06 September 2016
Age Before Youth: Older Cranes Lead the Way to New Migration Patterns...
18 August 2016
Greater biodiversity in grasslands leads to higher levels of ecosystem services...
20 July 2016
Are forests of the future at risk?...
12 July 2016
Ruhe im Genom...
28 June 2016
Mee(h)r Wissen über den Regen – Neue Methode ermöglicht genauere Rekonstruktion...
16 June 2016
Das Ei, das aus der Kälte kam – Wie sich Tigermücken für den Winter rüsten...
24 May 2016
Frankfurter Biologin wird Mitglied der Nationalen Akademie der Wissenschaften...
18 April 2016
Invasive Arten: Wer kommt als nächstes?...
24 March 2016
Wald in Europa: mehr Arten, mehr Nutzen. Homogenisierung von Wäldern führt zu geringerer Ökosystemleistung...
22 March 2016
Borreliose: Übertragung durch Mückenstich? Einheimische Mücken sind potentielle Vektoren für Lyme-Borreliose...
17 February 2016
Evolution auf Betriebstemperatur. In warmen Regionen entwickeln sich Lebewesen schneller...
16 February 2016
Rheinzufluss mit tropischen Parasiten ...
15 January 2016
Researchers uncover multiple adaptations to temperature in birds and mammals...
The great feeding-frenzy: Species-rich food webs produce biomass more efficiently
Frankfurt, Germany, October 06th, 2016. Researchers at the Senckenberg have discovered a feedback in complex food webs: species-rich ecosystems favor large, heavy animals. Even though this increases the amount of plants consumed, the plant biomass remains approximately at the same level as in species-poor ecosystems. This is due to the fact that in species-rich ecosystems, plant communities develop whose growth is more energetically efficient. The extent of biomass production in species-rich ecosystems is more stable and thereby predictable whereas the loss of species leads to unpredictable deficiencies, which would have to be compensated by humans, according to the paper, published today in “Nature Communications.”
On a daily basis, ecosystems reflect the maxim “Eat or be eaten” on a large scale. Plants form the basis of the food chains and are consumed by herbivores, which in turn serve as prey for the carnivores. And even these carnivores may fall victim to larger animals. Many of these predators near the top of the food chain are generalists; some will occasionally also eat plant material. This leads to the establishment of dense food webs, which contain numerous complex feeding relationships. But what happens when the animal diversity decreases?
A team around Dr. Florian Schneider from the Senckenberg Research Center for Biodiversity and Climate developed a new mathematical model that computes these very connections. “Using a computer, we simulated 20,000 ecosystems and the feeding processes that occur in each of them; from ecosystems that only contain a few species of animals and plant to systems with more than one hundred species. In the beginning, it is still open which species and what number of individuals of each animal and plant species will survive until the end. A species’ body mass is the decisive factor, since it not only determines the amount of food (in animals) and the metabolism, but in particular the feeding preference, as well,” explains Schneider.
Despite an increase in herbivores, the plants’ biomass production remains stable
The results are surprising, for even in the presence of many different herbivorous animals, plants produced the same amount of biomass as in simulations with a low diversity of herbivore species. This was the case even though with increasing animal species diversity, both the amount of plants consumed as well as the intra-guild predation increased. This reconciles two previously opposing schools of thought. It was assumed that high animal diversity generates positive effects as the dominant consumption of animal prey lessens the pressure on plant biomass, or they are more exploitative on plants, since the numerous different animal species, due to their various preferences, consume more plant species.
Species loss favors lightweights
In the model, both scenarios occur simultaneously because changes in the number of species also lead to changes in the composition of the species communities. When the overall number of animal species is lower, this favors smaller species with a lower body mass. Species-rich ecosystems, on the other hand, tend to be profitable for larger animals at the top of the food chain. “Overall, the total weight of animals in species-rich ecosystems is therefore higher than in species-poor ecosystems,” says Schneider. “Moreover, species-rich ecosystems contain a higher number of slow-growing, larger plants.”
Plants regrow more efficiently in species-rich ecosystems
This is efficient, since compared to smaller species, larger plants use less energy during the growth process, e.g., through respiration. Therefore, the more species-rich an animal community is, the more energetically efficient is the plants’ biomass production. The increased loss of biomass to consumption by larger animals is thus compensated by a reduction in plant community metabolism. This enables plants to maintain their level of biomass at an approximately equal level in species-poor as well as species-rich ecosystems.
Species extinction makes biomass production harder to predict
However not all is well in the end because human-induced species loss caused impacts the predictability of biomass production. “Our simulations show that species-rich ecosystems produce biomass at a relatively stable, predictable level. In species-poor ecosystems, on the other hand, two scenarios are likely; i.e., much more or much less biomass is produced. In many ways, the well-being of humans depends on the reliability of biomass production. Species richness therefore leads to greater security,” Schneider sums up.
Food webs are made up of many dynamic feeding relationships; for example herbivore aphids feed on Ground Elder and are themselves eaten by hoverfly larvae. At the same time, ants, being larger than the larvae, prey on the aphids’ predators. Copyright: Bernhard Seifert
Press images may be used at no cost for editorial reporting, provided that the original author’s name is published, as well. The images may only be passed on to third parties in the context of current reporting.
Dr. Florian D. Schneider
Senckenberg Biodiversity and Climate Research Centre
Tel. +49 (0)69 7542 1914
Senckenberg Biodiversity and Climate Research Centre
Tel. +49 (0)69 7542 1818
Schneider, Florian D., Brose, U., Rall, B.C. and Guill, C. (2016): Animal diversity and ecosystem functioning in dynamic food webs, Nature Communications. Doi: 10.1038/ncomms12718
To study and understand nature with its limitless diversity of living creatures and to preserve and manage it in a sustainable fashion as the basis of life for future generations – this has been the goal of the Senckenberg Gesellschaft für Naturforschung (Senckenberg Nature Research Society) for almost 200 years. This integrative “geobiodiversity research” and the dissemination of research and science are among Senckenberg’s main tasks. Three nature museums in Frankfurt, Görlitz and Dresden display the diversity of life and the earth’s development over millions of years. The Senckenberg Nature Research Society is a member of the Leibniz Association. The Senckenberg Nature Museum in Frankfurt am Main is supported by the City of Frankfurt am Main as well as numerous other partners. Additional information can be found at www.senckenberg.de.
2016 is the Leibniz year. On the occasion of the 370th birthday and the 300-year death anniversary of polymath Gottfried Wilhelm Leibniz (*7/1/1646 in Leipzig, † 11/14/1716 in Hanover), the Leibniz Association is organizing an extensive topical year. Under the title “The best of all possible worlds” – a Leibniz quote – it brings into focus the diversity and timeliness of the subject matter currently studied by the scientists at the 88 Leibniz institutions across the Federal Republic of Germany. www.bestewelten.de
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