Extinction of grazers led to grassland fires around the world: study

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From the past 50,000 years to the past 6,000 years, some of the world’s largest animals such as the giant bison, woolly mammoth and ancient horses have become extinct. According to a recent study, these were grazing species and their loss led to a global increase in grassland fire activity. The research has been published in the ‘Science Journal’.

Working with the Utah Museum of Natural History, Yale scientists have compiled lists of large extinct mammals and their approximate dates of extinction on four continents. The data showed that South America had lost the most grazers (83 percent of all species), followed by North America (68 percent). These losses were significantly higher than in Australia (44 percent) and Africa (22 percent).

They then compared these results with the records of fire activity revealed in lake sediments. Using charcoal records from 410 global sites, which provided a historical record of regional fire activity across continents, they found that fire activity increased after fire extinctions. mega-grazers. The continents that lost more grazers (South America, then North America) experienced a greater increase in fire activity, while the continents that experienced lower extinction rates (Australia and Africa) saw little change in prairie fire activity. “These extinctions resulted in a cascade of consequences,” said Allison Karp, postdoctoral associate in the Department of Ecology and Evolutionary Biology at Yale and corresponding author of the article.

“Studying these effects helps us understand how herbivores are shaping global ecology today,” she added. Widespread extinctions of megaherbivores have had major impacts on ecosystems, ranging from the collapse of predators to the loss of fruit trees that once depended on herbivores for their dispersal.

But Karp and lead author Carla Staver, associate professor of ecology and evolutionary biology at Yale School of Arts and Sciences, questioned whether there was an increase in fire activity in ecosystems as well. of the world, especially from an accumulation of dry grass, leaves, or wood caused by the disappearance of giant herbivores. They found that in the prairies, grass-fueled fires had increased. However, Karp and Staver noted that many species of ancient navigators – such as mastodons, diprotodons, and giant sloths, which foraged on shrubs and trees in wooded areas – also became extinct during the same period. period, but their losses had less of an impact on the fires. in wooded areas.

Grassland ecosystems around the world have been transformed after the loss of grazing tolerant grasses due to the loss of herbivores and an increase in fires. New grazers, including livestock, had finally adapted to the new ecosystems. That’s why scientists should consider the role of grazing cattle and wild grazers in fire mitigation and climate change, the authors said.

“This work really highlights how important grazers can be in shaping fire activity,” Staver said. “We need to pay close attention to these interactions if we are to accurately predict the future of fires,” Staver added. (ANI)

(This story was not edited by Devdiscourse staff and is auto-generated from a syndicated feed.)

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