Hungry feral pigs are exacerbating climate change


None of the factors of ecological imperialism are more aggressive than wild boar. Wherever the Europeans attacked, from the Americas to Australia, their pigs accompanied them, and many fled to the countryside to wreak havoc.

These wild animals kill native plants and animals, spread disease, destroy crops, and alter the entire ecosystem with these behaviors. Now add climate change to their list of destructive ones. Pigs, in their endless search for food, pull the roots of plants out of the soil and turn them upside down like a farmer plowing the land.

According to Wired, scientists used to know that wild boar activity in the soil releases the carbon in which it is trapped, but researchers in Australia, New Zealand and the United States have now calculated how much wild boar is destroying land around the world. The authors conclude that the amount of carbon dioxide released into the atmosphere each year by wild boar activity is equivalent to the amount of emissions from more than one million cars. This shows how much land manipulation (which in this case is unintended) has exacerbated climate change. Christopher O’Brien, Says University of Queensland ecologist and author of a new article published in the journal Global Change Biology:

Every time you stir the soil, you emit greenhouse gases. For example, when you plow the land for agriculture or make extensive changes in land use through urbanization and deforestation.

The researchers knew that given the abundance of pigs in the wild, they should make matters worse, but no one had modeled it globally. The researchers in the new study tried to estimate the amount of emissions from wild boar activity by collecting previous models and data.

In this context, there was a model that showed wild boar populations around the world. Another researcher studied wild boar in Australia and provided information on how much damage this species causes to the soil. There were also estimates of carbon emissions from wild boar in Switzerland and China.

This type of sporadic study is associated with uncertainty. For example, no model can determine how many wild boars are in a given area at a given time. In addition, some soils release more carbon during degradation. Materials such as peat, which are made from dead plant material that has not been completely decomposed, are compacted in practice, thus releasing more carbon than other soils. The amount of carbon loss also depends on the soil microbiome, the bacteria and fungi that feed on the plant material.

Given the wide range of variables, the researchers simulated 10,000 maps of potential wild boar densities around the world and excluded areas of Europe and Asia where the native pig was found from their models (in other words, they only modeled locations in They were invasive wild boars.

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For each of the simulations, they randomly calculated the amounts of carbon emissions from pigs based on data from previous studies, which allowed them to combine variables in thousands of ways: If the number of pigs is this number and the amount of soil they destroy, this What is the amount, what amount of publications do they produce? As a result of these efforts, they were able to estimate the average gas emissions from pigs. Their model showed that around the world, invading feral pigs destroy between 14,000 and 48,000 square miles of land.

But wild pigs are not evenly distributed on the ground. While the Oceania (an area that includes Australia and the Polynesian Islands) makes up a small portion of the Earth’s surface, it has a large number of pigs. Meanwhile, peat soils are mainly located in the tropics. In parts of the ocean, such as tropical northern Queensland, there are significant amounts of carbon storage. The combination of the two means that 60% of all global emissions from soil degradation by wild boar are from Oceania.

However, researchers believe that their estimation is very conservative. This is because they did not take into account the emissions from farmland, which are so abundant that wild boars plunder them to find free food. According to their hypotheses, this type of soil is already degraded and emits carbon dioxide, so they did not want to double count.

In addition, researchers have only estimated where wild boar may be present, not where it will enter soon. According to O’Brien, the pest is spreading and they could potentially reach areas with high carbon reserves. Cat Todd Brown“He was not involved in the research,” said a biochemist from the University of Florida.

What the article shows is something that geologists have known for some time; Soil degradation as a result of the activities of living organisms plays an important role in soil emissions and soil respiration. You will also see similar effects with the movement of earthworms and any animals that dig the earth and disrupt the structure of the soil.

Of course, there is a fundamental difference between the two: Indigenous animals have long been involved in the ancient carbon cycle, but invasive species such as wild boar disrupt carbon-rich soil outside their historic habitats. Rich Connat“Disruption is an integral part of ecosystem function and carbon balance, but before that, I never considered the damage that wild boar can do,” said a scientist who studies the carbon cycle but did not participate in the study.

The question now is what to do about wild boar. They are very stubborn, have a high reproductive rate and eat a lot of food. It can be very difficult to eradicate them.

In 2005, helicopter gunners were forced to remove 5,000 pigs one by one off the island of Santa Cruz off the coast of California. It took 14 months and cost $ 5 million. This was while the island was there and the pigs were surrounded by water. In some areas, people have been able to trap these animals, but cooperation between local organizations is needed to make this work.

In addition, most eradication measures also produce carbon. “If we get on a helicopter and go after the pigs and shoot them, install traps or build fences, it also emits greenhouse gases,” says O’Brien. “Therefore, we have to consider these cases as well.”

At the moment, there is no cheap and easy solution. This means that wild boars continue to roam, releasing carbon that was once buried in the soil.

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