Invasive plants, such as kudzu, can accelerate the greenhouse effect by releasing carbon stored in soil into the atmosphere, researchers, including one of Indian-origin, have found.
The study by Clemson University scientists could have far-reaching implications for how we manage agricultural land and native ecosystems.
Plant ecologist Nishanth Tharayil and graduate student Mioko Tamura show that invasive plants can accelerate the greenhouse effect by releasing carbon stored in soil into the atmosphere.
Since soil stores more carbon than both the atmosphere and terrestrial vegetation combined, the repercussions for how we manage agricultural land and ecosystems to facilitate the storage of carbon could be dramatic.
In their study, Tamura and Tharayil examined the impact of encroachment of Japanese knot-weed and kudzu, two of North America's most widespread invasive plants, on the soil carbon storage in native ecosystems.
They found that kudzu invasion released carbon that was stored in native soils, while the carbon amassed in soils invaded by knot-weed is more prone to oxidation and is subsequently lost to the atmosphere.
The key seems to be how plant litter chemistry regulates the soil biological activity that facilitates the buildup, composition and stability of carbon-trapping organic matter in soil.
"Our findings highlight the capacity of invasive plants to effect climate change by destabilising the carbon pool in soil and shows that invasive plants can have profound influence on our understanding to manage land in a way that mitigates carbon emissions," Tharayil said.
Tharayil estimates that kudzu invasion results in the release of 4.8 metric tonnes of carbon annually, equal to the amount of carbon stored in 11.8 million acres of US forest.
This is the same amount of carbon emitted annually by consuming 540 million gallons of gasoline or burning 5.1 billion pounds of coal.
"Climate change is causing massive range expansion of many exotic and invasive plant species. As the climate warms, kudzu will continue to invade northern ecosystems, and its impact on carbon emissions will grow," Tharayil said.
The research was published in the journal New Phytologist.
