Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study finds predators have outsized influence over habitats

15.06.2012
A grasshopper's change in diet to high-energy carbohydrates while being hunted by spiders may affect the way soil releases carbon dioxide into the atmosphere, according to Yale and Hebrew University researchers in Science.

Grasshoppers like to munch on nitrogen-rich grass because it stimulates their growth and reproduction. But when spiders enter the picture, grasshoppers cope with the stress from fear of predation by shifting to carbohydrate-rich plants, setting in motion dynamic changes to the ecosystem they inhabit.

"Under stressful conditions they go to different parts of the grocery store and choose different foods, changing the makeup of the plant community," said Oswald Schmitz, a co-author of the study,"Fear of Predation Slows Plant-Litter Decomposition," and Oastler Professor of Population and Community Ecology at the Yale School of Forestry & Environmental Studies (F&ES).

The high-energy, carbohydrate diet also tilts a grasshopper's body chemistry toward carbon at the expense of nitrogen. So when a grasshopper dies, its carcass breaks down more slowly, thus depriving the soil of high-quality fertilizer and slowing the decomposition of uneaten plants. Microbes in the soil require a lot of nitrogen to function and to produce the enzymes that break down organic matter.

"It only takes a slight change in the chemical composition of that animal biomass to fundamentally alter how much carbon dioxide the microbial pool is releasing to the atmosphere while it is decomposing plant organic matter," said Schmitz. "So this shows that animals could potentially have huge effects on the global carbon balance because they're changing the way microbes respire organic matter."

The researchers found that the rate at which the organic matter of leaves decomposed increased between 60 percent and 200 percent in stress-free conditions relative to stressed conditions, which they consider "huge." "Climate and litter quality are considered the main controls on organic-matter decomposition, but we show that aboveground predators change how soil microbes break down organic matter," said Mark Bradford, a co-author of the study and assistant professor of terrestrial ecosystem ecology at F&ES.

Schmitz added: "What it means is that we're not paying enough attention to the control that animals have over what we view as a classically important process in ecosystem functioning."

The researchers took soil from the field, put it in test tubes and ground up grasshopper carcasses obtained either from predation or predation-free environments. They then sprinkled the powder atop the soil, where the microbes digested it. When the grasshopper carcasses were completely decomposed, the researchers added leaf litter and then measured the rate of leaf-litter decomposition. The experiment was then replicated in the field at Yale Myers Forest in northeastern Connecticut.

"It was a two-stage process where the grasshoppers were used to prime the soil, and then we measured the consequences of that priming," said Schmitz.

Schmitz said that the effect of animals on ecosystems is disproportionately larger than their biomass would suggest. "Traditionally people have thought animals had no important role in recycling of organic matter, because their biomass is relatively small to all of that plant material that's entering ecosystems," he said. "We need to pay more attention to the role of animals because in an era of biodiversity loss we're losing many top predators and larger herbivores from ecosystems."

The other co-authors Michael Strickland, a Yale postdoctoral associate who is joining the faculty at Virginia Tech this fall, and Dror Hawlena, a senior lecturer at the Alexander Silberman Institute of Life Sciences at the Hebrew University of Jerusalem and former postdoctoral associate in Schmitz's lab.

David DeFusco | EurekAlert!
Further information:
http://www.yale.edu

More articles from Studies and Analyses:

nachricht Do microplastics harbour additional risks by colonization with harmful bacteria?
05.04.2018 | Leibniz-Institut für Ostseeforschung Warnemünde

nachricht Rutgers-led innovation could spur faster, cheaper, nano-based manufacturing
14.02.2018 | Rutgers University

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Magnetic nano-imaging on a table top

20.04.2018 | Physics and Astronomy

Start of work for the world's largest electric truck

20.04.2018 | Interdisciplinary Research

Atoms may hum a tune from grand cosmic symphony

20.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>