High Atmospheric CO Concentration Mitigates Drought Effects on an Important Grassland Weed in South America.

The differential growth and yield response of plant species to rising carbon dioxide concentrations and climatic change may alter species diversity within biomes. The Pampa Biome in South America is an important grassland biome of agronomic and environmental importance. (Chirca) is one of the most important weeds in natural pasture areas widely distributed in southern South America and can adversely affect livestock production.