Native vs. Invasive Plants in a CO₂-Enrched World

According to Lei et al. (2011), it has been found that "elevated CO₂ may promote the growth of some invasive species compared to native species," but they note that "the generality of this prediction and the mechanisms with which nonnative plants outperform natives is mostly unknown." Hence, they write that "it is important to study how physiological differences among native and invasive species interact with predicted changes in atmospheric composition."

In a study designed to do just that, Lei et al. grew well-watered individual seedlings of invasive Eupatorium adenophorum, its native conspecific, and a native congener (E. japonicum) in 5-liter pots filled with 4 kg of homogenized forest topsoil placed within closed-top chambers out-of-doors in southwest China at the Ailaoshan Station for Subtropical Forest Ecosystem Studies (24°32'N, 101°01'E) for a period of three months under ambient and double-ambient atmospheric CO₂ concentrations, while measuring various plant properties and physiological processes both during and at the end of the experiment.

With respect to their findings, the six scientists report that "CO₂ enrichment increased relative growth rate by 8, 14, and 11% in invasive E. adenophorum, its native conspecific, and native E. japonicum, respectively; and they state that "the interactions between plant material and CO₂ treatment were not significant for relative growth rate and biomass," while additionally indicating that "all studied materials responded similarly to CO₂ enrichment."

So what doe these findings imply? Simply stated, in the words of Lei et al., "the results suggest that CO₂ enrichment might not aggravate E. adenophorum invasion in the future."