Transient responses of North-American grasslands to changes in climate

TitleTransient responses of North-American grasslands to changes in climate
Publication TypeJournal Article
Year of Publication1996
AuthorsCoffin D.P., Lauenroth WK
JournalClimate Change
Start Page269
Date Published10/01/1996
Keywordschanges in climate, North-American grasslands, Transient responses

Our objective was to evaluate the transient responses of grasslands in the central grassland region of North America to changes in climate. We used an individual plant-based gap dynamics simulation model (STEPPE-GP) linked with a soil water model (SOILWAT) to evaluate the effects of changes in climate on the composition and structure of grassland vegetation. Five functional types of plants were simulated based upon lifeform, physiology, and rooting distribution with depth. C3 and C4 perennial grasses with either a shallow or deep rooting distribution, and deeply rooted C3 shrubs were simulated under current climatic conditions and under a GFDL climate change scenario for nine sites representative of the temperature and precipitation regimes in the grassland region.

Although vegetation at the sites responded differently to climate change, shifts in functional types occurred within 40 years of the start of the climate change. C4 grasses increased in dominance or importance at all sites with a change in climate, primarily as a result of increases in temperature in all months at all sites. The coolest sites that arc currently dominated by C3 grasses were predicted to shift to a dominance by C4 grasses, whereas sites that are currently dominated by C4 grasses had an increase in importance of this functional type with a change in climate. Current annual temperature was the best predictor of changes in C3 biomass, and C3 and C4 biomass combined; current annual precipitation was the best predictor of changes in C4 biomass. These predicted shifts in dominance and importance of C3versus C4 grasses would have important implications for the management of natural grasslands as well as the cultivation of crops in the central grassland region.