Navigation Links
Predators have outsized influence over habitats
Date:6/15/2012

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 research results published this week in the journal 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, scientists have found.

"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 paper and an ecologist at Yale University.

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.

"This study casts a new light on the importance of predation in natural communities," said Saran Twombly, program director in the National Science Foundation's Division of Environmental Biology, which funded the research.

"A clever suite of experiments shows that the dark hand of predation extends all the way from altering what prey eat to the nutrients their decomposing bodies contribute to soil."

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.

"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 also an ecologist at Yale.

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 from environments either with or without grasshopper predators.

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 measured the rate of leaf-litter decomposition.

The experiment was then replicated in the field at the Yale Myers Forest in northeastern Connecticut.

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

The effect of animals on ecosystems is disproportionately larger than their biomass would suggest.

"Traditionally people thought that animals had no important role in recycling of organic matter, because their biomass is relatively small compared to the plant material that's entering ecosystems," Schmitz said.

"We need to pay more attention to the role of animals, however. In an era of biodiversity loss we're losing many top predators and larger herbivores from ecosystems."


'/>"/>
Contact: Cheryl Dybas
cdybas@nsf.gov
703-292-7734
National Science Foundation
Source:Eurekalert  

Related biology news :

1. T cells hunt parasites like animal predators seek prey, a Penn Vet-Penn Physics study reveals
2. Loss of predators in Northern Hemisphere affecting ecosystem health
3. Dinosaur fossil: Even specialized predators didnt turn down free meals
4. New evidence that many genes of small effect influence economic decisions and political attitudes
5. Fat outside of arteries may influence onset of coronary artery disease
6. BUSM researchers identify genes that influence hippocampal volume
7. Circadian rhythms have profound influence on metabolic output, UCI study reveals
8. Plastic trash altering ocean habitats, Scripps study shows
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Predators have outsized influence over habitats
(Date:3/30/2017)... , March 30, 2017 Trends, opportunities and ... and behavioral), by technology (fingerprint, AFIS, iris recognition, facial ... and others), by end use industry (government and law ... financial and banking, and others), and by region ( ... , Asia Pacific , and the ...
(Date:3/28/2017)... PUNE, India , March 28, 2017 ... (Analog, IP, Biometrics), Hardware (Camera, Monitors, Servers, Storage Devices), ... Maintenance), Vertical, and Region - Global Forecast to 2022", ... 30.37 Billion in 2016 and is projected to reach ... 15.4% between 2017 and 2022. The base year considered ...
(Date:3/24/2017)... 24, 2017 The Controller General of Immigration from ... Abdulla Algeen have received the prestigious international IAIR Award for the ... Continue Reading ... ... Controller Abdulla Algeen (small picture on the right) have received the IAIR ...
Breaking Biology News(10 mins):
(Date:4/26/2017)... (PRWEB) , ... April 26, 2017 , ... ... be demonstrating its new Bioflash MailGuardtm mail security screening solution at the National ... The Bioflash MailGuard system provides a fast, highly accurate, easy to use and ...
(Date:4/25/2017)... Yorba Linda, Ca (PRWEB) , ... April 25, 2017 , ... ... latest webinar in the series will explore the laboratory testing for DIC in order ... a serious hypercoagulable disorder which can occur in hospitalized patients resulting in a high ...
(Date:4/25/2017)... ... April 25, 2017 , ... Dr. Robert G. Schwartz, the ... announced today that acclaimed physiatrist Matthew Terzella, MD, has joined the practice as ... Dr. Terzella completed his residency in Physical Medicine and Rehabilitation at UMDNJ-Robert Wood ...
(Date:4/24/2017)... Labs announced today the offer of whole genome sequencing (WGS) ... individuals have been able to access WGS at $1,000, this ... EUR 1,000. The sequencing includes bioinformatics analysis and ... informed decisions about disease monitoring, prevention, nutrition, exercise, health monitoring ... ...
Breaking Biology Technology: