Divergent responses of vegetation aboveground net primary productivity to rainfall pulses in the Inner Mongolian Plateau, China

Abstract

The differential responses of vegetation types to rainfall pulses are still not fully understood in the Inner Mongolian Plateau. This study firstly investigated the hierarchical responses of vegetation aboveground net primary productivity (ANPP) to rainfall pulses in the Inner Mongolian Plateau using Normalized Difference Vegetation Index (NDVI) as a proxy. Forty-eight independent rainfall events were selected between 2000 and 2013 for three study sites within a precipitation gradient transect. Results of the threshold-delay model revealed that vegetation in the Gobi desert and Typical steppe responded much faster with 3.6 ± 2.0 day and 6.4 ± 4.6 day, respectively, contrast with a durable response in Desert steppe (10.2 ± 6.5 day). Desert steppe had the highest upper threshold of rainfall (80.2 mm), which was about two-fold of Gobi desert (36.1 mm) and Typical steppe (41.2 mm). Pulse size, timing, soil texture and plant functional type (PFT) were the main drivers that influenced the rate and magnitude of vegetation responses. The results highlight the differential responses of vegetation types to rainfall pulses in the Inner Mongolian Plateau and may contribute to a better understanding of the impact of changing rainfall patterns on vegetation dynamics in arid and semiarid regions.