The adaptability of vegetation productivity to precipitation variability determines its resistance in central asian grassland ecosystems

The aboveground net primary production (ANPP) and precipitation use efficiency (PUE) play essential roles in governing the carbon and water cycles of grassland ecosystems, but the associations among the ANPP, PUE and climate variation remain a subject of controversy in the grasslands of Central Asia. In this study, the variability in grassland ANPP and PUE in the Central Asian region was investigated based on ANPP (2002–2019) estimated by a machine learning model. In Central Asian grasslands, the average values of ANPP and PUE were 92.76 g m⁻² yr ⁻¹ and 0.42 g m⁻² mm⁻¹, respectively. A positive relationship was observed between ANPP and precipitation in the Central Asian region, indicating the role of precipitation in grassland productivity improvement; however, the relationship is not a simple linear relationship. Compared with the semiarid region, grasslands in the arid region (precipitation <200 mm) had a higher PUE and showed a lower sensitivity of ANPP to precipitation. The analysis of interannual variability in PUE and ANPP resistance suggested that the ability to regulate PUE will significantly impact grassland resistance to environmental changes in arid and semiarid ecosystems. This study provides new perspectives for comprehending the variations in ANPP and PUE among arid and semiarid grasslands of the Central Asian region.