Spatial and Seasonal Variation in Rain Use Efficiency in Semiarid Grasslands of Inner Mongolia

Rain use efficiency (RUE) is an important indicator for identifying the response of plant production to variation in precipitation patterns, especially in semiarid ecosystem grasslands of Inner Mongolia. We have investigated the response and spatial patterns of RUE to precipitation patterns based on five years (2006, 2007, 2008, 2012, and 2013) of records from semiarid ecosystem sites across Inner Mongolia. Our results showed that RUEADM was lowest in the wettest year (2012) and highest in the year following the driest year (2008). There was no significant correlation between RUEADM and RUETDM in typical and desert steppe. RUETDM was strongly correlated with both annual precipitation (AP) and growing season precipitation (GSP) compared to RUEADM. RUEADM, therefore, cannot be used in place of RUETDM. RUEADM increased with species richness. The relationship between RUEADM and species richness was significantly correlated in meadow steppe, typical steppe, and desert steppe. Our findings can shed light on the spatial utilization pattern of seasonal rainfall in semiarid grassland ecosystems