“Trophic Downgrading of Planet Earth,” a review paper that will be published on July 15, 2011, in the journal Science, concludes that the decline of large predators and herbivores in all regions of the world is causing substantial changes to Earth’s terrestrial, freshwater, and marine ecosystems.
The paper claims that the loss of apex consumers from ecosystems “may be humankind’s most pervasive influence on nature.” The research was funded primarily by the Institute for Ocean Conservation Science at Stony Brook University with support from The Pew Charitable Trusts. The paper is co-authored by the Institute’s executive director, Dr. Ellen K. Pikitch, and the lead author is Dr. James A. Estes, professor of ecology and evolution at the University of California at Santa Cruz.
The review, conducted by an international team of 24 scientists, illuminates the patterns and far-reaching impacts of predation and herbivory on the structure and dynamics of global ecosystems. The researchers relied on both experimental and observational evidence, which provides a strong basis for their conclusions.
“By looking at ecosystems primarily from the bottom up, scientists and resource managers have been focusing on only half of a very complex equation,” said Dr. Estes. “These findings demonstrate that top consumers in the food web are enormous influencers of the structure, function, and biodiversity of most natural ecosystems.”
Apex consumers include animals such as big cats, wolves, bison, sharks, and great whales, and are typically large, long-lived, and not amenable to laboratory experiments. As a result, the effects of removing them from ecosystems are not easy to document. The team of scientists reviewed an accumulation of theoretical and empirical evidence on how the decline of top predators and herbivores has affected Earth’s ecosystems on land, in freshwater, and in the ocean. Their findings suggest that “trophic downgrading” – the ecological consequences of losing large apex consumers from nature – causes extensive cascading effects in ecosystems worldwide, especially when exacerbated by factors such as land use practices, climate changes, habitat loss, and pollution.
“Our review of existing studies clearly shows that a top-down cascading effect in natural systems is both powerful and widespread,” said Dr. Estes. “There is an urgent need for interdisciplinary research to forecast how a continued loss of top level consumers will further harm the planet’s ecosystems.”
• Industrial whaling in the 20th century resulted in the loss of large numbers of plankton-consuming great whales, which are now known to sequester carbon into the deep sea through deposition of feces. The result has been the transfer of approximately 105 million tons of carbon into the atmosphere that would have been absorbed by whales, contributing to climate change.
“We must assume going forward that significant changes to the ecosystem are occurring when large predators and herbivores are removed from the top of the food web, and, thus, that efforts to manage and conserve nature must include these animals,” said Dr. Pikitch. “An old paradigm has shifted, and those who question this theory now have the burden to prove otherwise.”
Editor’s Notes: For a copy of “Trophic Downgrading of Planet Earth,” please contact the AAAS Office of Public Programs at 202-326-6440 or email@example.com.Photos are available by request and can be downloaded from the Internet:
Wolf in Yellowstone: http://www.flickr.com/photos/oregonstateuniversity/5159133703/
The Institute for Ocean Conservation Science at Stony Brook University is dedicated to advancing ocean conservation through science. The Institute transforms real-world policy while pursuing serious science, both of which are essential for ocean health. For more information, go to www.oceanconservationscience.org.
Cindy Yeast | Newswise Science News
Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel
Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)
A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.
In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...
A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.
By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...
Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
23.02.2018 | Physics and Astronomy
23.02.2018 | Health and Medicine
23.02.2018 | Physics and Astronomy