Distinct vegetation response to drying and wetting trends across an aridity threshold

Abstract Aridity regulates the terrestrial ecosystem productivity in water-limited regions. The aridity index (AI) is often defined as ratio of annual precipitation to potential evapotranspiration. However, how drying and wetting influence vegetation response its characteristic along gradient remains unclear. Here, we examined trends AI normalized difference (NDVI) drylands East Asia from 1982 2015, which denoted response, respectively. results show that variability land area 1982–2015 was lower whole dryland than subtypes including hyper-arid, arid, semi-arid, dry sub-humid Drying were observed each interval a spatial gradient. Wetting are prevalent owing their magnitude twice those trends. Spatial variation shaped pattern trends; drier regions had smaller narrower ranges NDVI relative wetter A shift occurred at 0.4 AI. Distinct patterns change across threshold, transition region identified studied drylands. suggest changes might be masked by entire then leading failure recognizing transformation subtypes. This implies carbon storage prediction should consider avoid uncertainties due divergent different levels.