Climate and Grazing Effects on the Biomass and Photosynthetic Capacity of Dominant Species in Mongolia Steppe Communities

Abstract

Global climate change and grazing are the key factors affecting plant productivity in steppe regions of Mongolia. It is important to separate the impacts of these factors and to assess the contribution of each factor to the biomass of pastoral plants. Here, we studied the grazing and climate impact on biomass and functional traits in three dominant species of Mongolian steppe plant communities: Artemisia frigida Willd., Stipa krylovii Roshev., and Kochia prostrata (L.) Schrad. Both aridity and grazing significantly influenced the biomass of the studied species but the direction and scope of the changes were species-specific. Grazing had no effect on leaf mass per area (LMA), photosynthesis (A max ) and the content of photosynthetic pigments. An increase in climate aridity resulted in enhancing A max for C 4 -plant K. prostrata, but its decline in C 3 -species A. frigida and S. krylovii. K. prostrata showed the decrease in leaf dry matter content (LDMC) and water-use efficiency (WUE) under grazing. The authors conclude that: (1) both climate aridity and grazing have a significant influence on plant productivity and that they act on different groups of functional traits and (2) plants' response to the combined effect of these factors depends on the functional properties of the species.