Menu

Productivity Paradox

During the last ice age, there wasn’t much plant matter to eat on northern steppes, but herbivorous woolly mammoths were abundant. How did they survive?

Jun 1, 2018
Jim Daley

MAMMOTH APPETITE: Scientists strive to understand how large animals in northerly climes subsisted on limited vegetation. WIKIMEDIA COMMONS/FLYING PUFFIN

EDITOR'S CHOICE IN ECOLOGY

The paper
D. Zhu et al., “The large mean body size of mammalian herbivores explains the productivity paradox during the Last Glacial Maximum,” Nat Ecol Evol, 2:640-49, 2018.

A PALEONTOLOGY PARADOX
During the Last Glacial Maximum, global temperatures and atmospheric carbon levels were less than ideal for vegetation to grow in the northern hemisphere, but the fossil record shows that herbivorous woolly mammoths were plentiful in unglaciated regions—a discrepancy termed the “productivity paradox.”

MODEL MAMMOTHS
An international team of researchers approached the problem by modeling plant cover based on climate, the water cycle, and other variables, and incorporating the presence of large grazing animals. The scientists tested the model on a variety of modern ecosystems involving grazers, and found that its predictions of grass cover generally matched observations. For the Ice Age scenario, it was the mammoths’ large bodies and relatively efficient metabolisms that allowed them to survive on sparse vegetation, says coauthor Nicolas Viovy, an informatics engineer and biogeochemist at Versailles Saint-Quentin-en-Yvelines University in France.

TOP-DOWN OR BOTTOM-UP?
Love Dalén, a paleogeneticist at the Swedish Museum of Natural History, says the paradox really boils down to whether vegetation limited the abundance of grazers or vice versa. The new study rests on the assumption that mammoths controlled the abundance of vegetation, he says, but it’s still an open question as to whether that was the case.

RUMINATE ON IT
How the mammoths digested plant matter is also important in solving the paradox, says Danielle Fraser, a paleobiologist at the Canadian Museum of Nature. “I would have been interested to see how the model would differ if they included the digestive physiology of mammoths,” which were relatively efficient “hindgut fermenters,” she says. Viovy says the team plans to continue improving the model to account for more variables like this one.

February 2019

Big Storms Brewing

Can forests weather more major hurricanes?

Marketplace

Sponsored Product Updates

Bio-Rad Releases First FDA-Cleared Digital PCR System and Test for Monitoring Chronic Myeloid Leukemia Treatment Response
Bio-Rad Releases First FDA-Cleared Digital PCR System and Test for Monitoring Chronic Myeloid Leukemia Treatment Response
Bio-Rad Laboratories, Inc. (NYSE: BIO and BIOb), a global leader of life science research and clinical diagnostic products, today announced that its QXDx AutoDG ddPCR System, which uses Bio-Rad’s Droplet Digital PCR technology, and the QXDx BCR-ABL %IS Kit are the industry’s first digital PCR products to receive U.S. Food and Drug Administration (FDA) clearance. Used together, Bio-Rad’s system and kit can precisely and reproducibly monitor molecular response to treatment in patients with chronic myeloid leukemia (CML).
Bio-Rad Showcases New Automation Features of its ZE5 Cell Analyzer at SLAS 2019
Bio-Rad Showcases New Automation Features of its ZE5 Cell Analyzer at SLAS 2019
Bio-Rad Laboratories, Inc. (NYSE: BIO and BIOb) today showcases new automation features of its ZE5 Cell Analyzer during the Society for Laboratory Automation and Screening 2019 International Conference and Exhibition (SLAS) in Washington, D.C., February 2–6. These capabilities enable the ZE5 to be used for high-throughput flow cytometry in biomarker discovery and phenotypic screening.
Andrew Alliance and Sartorius Collaborate to Provide Software-Connected Pipettes for Life Science Research
Andrew Alliance and Sartorius Collaborate to Provide Software-Connected Pipettes for Life Science Research
Researchers to benefit from an innovative software-connected pipetting system, bringing improved reproducibility and traceability of experiments to life-science laboratories.
Corning Life Sciences to Feature 3D Cell Culture Technologies at SLAS 2019
Corning Life Sciences to Feature 3D Cell Culture Technologies at SLAS 2019
Corning Incorporated (NYSE: GLW) will showcase advanced 3D cell culture technologies and workflow solutions for spheroids, organoids, tissue models, and applications including ADME/toxicology at the Society for Laboratory Automation and Screening (SLAS) conference, Feb. 2-6 in Washington, D.C.