Abstract:Global temperatures are increasing, and, in particular, global minimum temperatures are increasing faster than maximum temperatures. Because temperature is a key factor hat controls the growth and distribution of vegetation, and there is no a priori reason to assume that ecosystems will respond similarly to changes in minimum and maximum temperatures, it is very important to explore the ecological consequences of global warming on terrestrial communities.
The Leymus chinensis grassland is a dominant ecosystem of Inner Mongolia, and this region is very vulnerable to global climate change. We analyzed a long term climate and vegetation data base (1981-1994) for Inner Mongolia to examine the characteristics and the ecological consequences of temperature changes on Leymus chinensis grasslands. The results showed that temperatures increased and minimum temperatures, especially winter minimum temperatures, increased faster than maximum and average temperatures. There were no significant relationships between winter minimum temperatures and diversity indices (Simpson index and Shannon-wiener index), species saturation, and aboveground net primary productivity (ANPP) at the community scale. At the species level, the importance value and ANPP of most species had no significant relationship with winter minimum temperatures, except for Agropyron michnoi, Heteropappus altaicus and Carex duriuscula, all of which showed significant negative relationships. Because these are important species in this grassland community, the results suggest that the structure and function of the L. chinensis grassland community could be altered if winter minimum temperatures continue to increase. Thus, the identification of key elements of temperature change is very important for understanding and predicting the impacts of global warming to L. chinensis grassland communities.