Researchers at the Senckenberg have discovered a feedback in 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 species loss 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.
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
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.
The press release and images are available for download at www.senckenberg.de/presse
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
Sabine Wendler | Senckenberg Forschungsinstitut und Naturmuseen
Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
17.01.2017 | Earth Sciences
17.01.2017 | Materials Sciences
17.01.2017 | Architecture and Construction