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The loss of ancient herbivores caused an increase in global fires

Mammoth. Credit: Tracy O (Flickr) via Wikimedia Commons

From 50,000 to 6,000 years ago, many of the world’s largest animals were extinct, including mammoths, giant bison, and iconic grassland herbivores such as ancient horses.The loss of these grazing species has caused a dramatic increase in fire activity in the world’s grasslands, according to a new Yale-led study published in the journal on November 26. Chemistry..


Scientists at Yale University have worked with the Natural History Museum of Utah to summarize the extinct large mammals on four continents and their approximate dates of extinction. Data show that South America lost the most herbivores (83% of all species), followed by North America (68%). These losses were significantly higher than in Australia (44%) and Africa (22%).

These findings were then compared to records of fire activity revealed in lake sediments. Using charcoal records from 410 global sites that provided historical records of fire activity in the region of the entire continent, they found that fire activity increased after the extinction of the Megaglazer. On continents that lost more herbivores (South America, then North America), the extent of fire increased significantly, but on less extinct continents (Australia and Africa), there was little change to grassland fire activity. Was not seen.

“These extinctions have led to a series of consequences,” said Allison Carp, a postdoctoral fellow in ecology and evolutionary biology at Yale University and the corresponding author of the paper. “Study of these effects will help us understand how herbivores shape today’s global ecosystems.”

The widespread extinction of mega-herbivores has had a major impact on ecosystems, from the collapse of predators to the loss of fruit-bearing trees that once depended on herbivores for dispersal. However, Carp and senior author Carla Staver, associate professor of ecology, Evolutionary biology The Faculty of Arts and Sciences at Yale University wondered if fire activity in the world’s ecosystems also increased, especially due to the accumulation of dry grass, leaves, or trees caused by the loss of giant herbivores. I did. They found an increase in grass-fueled fires in grasslands.

However, Karp and Staver are looking at many ancient browser species that forage shrubs and trees, such as mastodons, diprotodons, and giant sloths. Treeed area— Extinct at the same time, but the loss was due to the less impact on fires in the woodlands.

Grassland ecosystems around the world have changed after the loss of grazing-tolerant grasses due to the loss of herbivores and increased fires. New herders, including livestock, eventually adapted to the new ecosystem.

Therefore, scientists need to consider the role of grazing in livestock and wild grazing. fire Mitigation and climate change, the author said. “This work really emphasizes how important a wrangler is to shape. Fire activity“If you want to accurately predict the future of a fire, you need to pay close attention to these interactions,” says Staver.


Creative management of grazing with a small fire


For more information:
Allison Carp, Global Response of Fire Activities to the Extinction of Late Quaternary Herbivores, Chemistry (2021). DOI: 10.1126 / science.abj1580.. www.science.org/doi/10.1126/science.abj1580

Provided by
Yale University

Quote: The loss of ancient herbivores caused an increase in global fires (November 25, 2021). Obtained from https://phys.org/news/2021-11-loss-ancient-grazers-triggered-global.html on November 25, 2021

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The loss of ancient herbivores caused an increase in global fires

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