Wild pigs are one of the most damaging invasive species on Earth, suggests a new study. By pulling up the carbon trapped in the soil, they release almost 4.9 million metric tonnes of carbon dioxide annually across the globe.
This is the first study that calculates the global extent of this and its implications for carbon emissions.
Scientists used predictive population models to pinpoint the climate damage caused by wild pigs across five continents along with advanced mapping techniques.
The models showed a wide range of outcomes, yet they indicate that wild pigs are most likely to uproot an area of around 36,000 to 124,000 square kilometers in environments where they’re not native.
This is an enormous amount of land. It threatens biodiversity and food security that are crucial for sustainable development.
UQ’s Dr. Christopher O’Bryan said, “When soils are disturbed from humans ploughing a field or, in this case, from wild animals uprooting, carbon is released into the atmosphere.”
“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.”
Scientists 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 various climatic conditions, vegetation types, and elevations spanning lowland grasslands to sub-alpine woodlands.
Based on the previous research in the Americas, Europe, and China, scientists simulated the global carbon emissions from wild pig soil damage.
University of Canterbury Ph.D. candidate Nicholas Patton said, “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.”
“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 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.”
The study was conducted by the University of Canterbury, the University of Queensland, and the University of Canberra.
- Christopher J. O’Bryan, et al. Unrecognized threat to global soil carbon by a widespread invasive species. Global Change Biology, 2021; DOI: 10.1111/gcb.15769