2021-11-26

Science: there are frequent fires all over the world. The reason is that animals are extinct?

By yqqlm yqqlm

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more than 8000 koalas have been killed by wildfires in Australia. Netizens: directly endangered a species

wildfires burned into the fire waterfall of the world heritage Blue Mountain National Park in Australia

Australian wildfires are rampant, but the Australian Prime Minister is determined not to eliminate the New Year Fireworks Show

and the more growing Eucalyptus in Australia once again contributed to the fire Because many parts of Eucalyptus contain oil, there are more combustibles falling on the ground, which further promotes the spread of the fire

therefore, both factors are well understood. However, another reason you can’t think of is also related to wildfires, that is, herbivores. A new study in science has found that the extinction of herbivores may have ignited one wildfire after another around the world

Science: there are frequent fires all over the world. The reason is that animals are extinct?

the research is inspired by the observation of local herbivores and ecological changes in the past. For example, there are a large number of herbivores in Serengeti Plain in southern Tanzania. However, when their number decreases, the frequency of fire will also increase. Of course, the specific mechanism is also very simple. The feeding behavior of herbivores will reduce the amount of combustibles and avoid fire

can this conclusion be extrapolated to the world? The past extinction of large animals gives researchers a great opportunity to explore this problem

the Quaternary extinction from 50000 to 6000 years ago made the iconic herbivores such as mammoths, large bison and ancient wild horses disappear. Yale University cooperated with Utah natural history museum to compile the species and specific extinction time of extinct herbivores in this period

data show that the proportion of herbivores extinct in South America is the largest, and about 83% of the populations have disappeared. In addition, 68 per cent of herbivores were lost in North America, 44 per cent in Australia and 22 per cent in Africa

at the same time, the research team made statistics on the stratigraphic charcoal records of 161 long grass areas, which can reflect the combustion of biomass in different periods

by comparing the two schedules, the researchers found that the extinction of large herbivores is directly proportional to the occurrence of fire, and the more serious the extinction of herbivores, the greater the increase of fire range. For example, fires in South and North America are very serious, while grassland fire activities in Australia and Africa have hardly changed

Science: there are frequent fires all over the world. The reason is that animals are extinct?(1)

the research points out that this frequent fire phenomenon is mainly related to the accumulation of combustibles such as hay and leaves on the ground. For example, some animals foraging on trees (such as large sloth) also died out in the same period, However, their disappearance has little impact on the fire in forest areas

“the extinction of large herbivores will lead to a series of consequences,” said Dr. Allison Karp, the first author of the new study. The predator system will collapse, the plants that rely on herbivores to spread seeds will disappear, and even cause raging fires all over the world. “Studying these effects will help us understand how herbivores shape ecosystems.”

with the withdrawal of large herbivores from the ecosystem, frequent fires have directly reshaped the grassland ecosystem, and the grazing resistant grass in the past has gradually disappeared. Animals adapted to the new environment also began to rise, including species such as livestock

the new study also makes researchers think about the relationship between the migration of herbivorous livestock and the occurrence of wildfires. “If we want to predict fires, we must pay close attention to these interactions,” said Carla staver, an associate professor at Yale University and corresponding author of the study