Temperature Sensitivity of Aboveground Production in Semi-Arid Grasslands

Precipitation has been shown to have a strong positive correlation with aboveground net primary productivity (ANPP) in grasslands and has been at the forefront in climate change research in grasslands. However, evidence suggests that especially at the local level, there may be additional controlling variables, such as temperature, that help explain variability in ANPP in grasslands. To better understand the importance of temperature in grasslands and how it alters ecosystem functioning, we examine how much the variation in temperature can explain the variation of ANPP. We observed seven sites located along a south-north temperature gradient in the Central Plains, from New Mexico to Montana. We analyzed the relationships between temperature and precipitation (growing season and annual) and above ground primary productivity of current year's growth by functional type. Analysis shows that when precipitation is held constant, the relationship between temperature and ANPP is negatively correlated with ANPP. It also appears that when examining these relationships across functional groups, some are more sensitive to alterations in climatic patterns. These results suggest that increasing global temperatures will alter grassland ANPP and species composition. This will affect the forage availability and amount of carbon sequestration that grasslands provide, which could further contribute to climate change. These results highlight the importance of including temperature in climate change models for grasslands.