By uprooting carbon trapped in soil, wild pigs are releasing around 4.9 million metric tonnes (about 5.4 million tons) of carbon dioxide every year worldwide.
That’s the equivalent of 1.1 million cars.
Researchers used predictive population models, coupled with advanced mapping techniques, to pinpoint the climate damage wild pigs cause across five continents.
The globe’s ever-expanding population of feral pigs could be a significant threat to the climate, says Christopher O’Bryan of the University of Queensland.
“Wild pigs are just like tractors plowing through fields, turning over soil to find food. When soils are disturbed from humans plowing a field or, in this case, from wild animals uprooting, carbon is released into the atmosphere,” O’Bryan says.
“Since soil contains nearly three times as much carbon than in the atmosphere, even a small fraction of carbon emitted from soil has the potential to accelerate climate change.
“Our models show a wide range of outcomes, but they indicate that wild pigs are most likely currently uprooting an area of around 36,000 to 124,000 square kilometers (13,899 to 47,876 square miles), in environments where they’re not native.
“This is an enormous amount of land, and this not only affects soil health and carbon emissions, but it also threatens biodiversity and food security that are crucial for sustainable development.”
Using existing models on wild pig numbers and locations, the team simulated 10,000 maps of potential global wild pig density.
They then modeled the amount of soil area disturbed from a long-term study of wild pig damage across a range of climatic conditions, vegetation types, and elevations spanning lowland grasslands to sub-alpine woodlands.
The researchers then simulated the global carbon emissions from wild pig soil damage based on previous research in the Americas, Europe, and China.
Nicholas Patton, a PhD candidate at the University of Canterbury, says the research would have ramifications for curbing the effects of climate change into the future.
“Invasive species are a human caused problem, so we need to acknowledge and take responsibility for their environmental and ecological implications,” Patton says.
“If invasive pigs are allowed to expand into areas with abundant soil carbon, there may be an even greater risk of greenhouse gas emissions in the future. Because wild pigs are prolific and cause widespread damage, they’re both costly and challenging to manage.
“Wild pig control will definitely require cooperation and collaboration across multiple jurisdictions, and our work is but one piece of the puzzle, helping managers better understand their impacts.
“It’s clear that more work still needs to be done, but in the interim, we should continue to protect and monitor ecosystems and their soil which are susceptible to invasive species via loss of carbon,” says Patton.
The research appears in Global Change Biology.
Source: University of Queensland