A global study by Colorado State University professor Melinda Smith and other university scientists found that the effects of extreme drought on grasslands and shrublands have been underestimated. The study, published in Proceedings of the National Academy of Sciences, quantified the impact of extreme drought on grassland and shrubland ecosystems across six continents with unprecedented detail. The experiment represented the first baseline understanding of the potential losses of plant productivity in these ecosystems.
Grasslands and shrublands cover millions of acres of land in Colorado and account for a significant portion of the state’s land area. The reduction in plant growth after a single 1-in-100-year drought event was found to be 60% greater than previously reported losses. The research also demonstrated the variability in drought response across grassland and shrubland ecosystems.
The International Drought Experiment utilized rainfall manipulation structures to experimentally reduce precipitation for a full growing season. The study demonstrated that drier and less diverse sites, such as those in Colorado, are most vulnerable to drought, with extreme droughts resulting in substantial losses across the globe.
As Earth’s climate continues to change, short-term droughts of extreme intensity are expected to become more common. The team is currently examining data collected over four years to assess multiyear drought impacts globally. The findings offer insight into the potential ecological consequences of extreme droughts and highlight the vulnerabilities of grassland and shrubland ecosystems as a result of climate change.