Climate warming enhances precipitation sensitivity of flowering phenology in temperate steppes on the Mongolian Plateau

Abstract

The phenological sensitivity of terrestrial plants to precipitation change (precipitation sensitivity, Sp) and whether Sp is affected by climatic warming remain largely unknown. A four-year (2015–2018) field experiment with warming and increased/decreased precipitation was conducted to investigate the impacts of climate change on Sp in three dominant temperate grasslands (i.e., desert, typical, and meadow steppes) on the Mongolian Plateau of Northern China. Results showed that Sp of flowering phenology to reduced and increased precipitation was symmetric in each of the three steppes. Experimental warming stimulated Sp by 0.30 day/(10 mm· °C) over the three steppes, however, by 1.20 day/(10 mm· °C) in the desert steppe, which could be primarily attributed to enhanced dependences of Sp on soil moisture and normalized difference vegetation index (NDVI) during the flowering stage. These findings suggest that warming has the greater potential to stimulate Sp of phenological events in arid rather than semiarid and mesic grasslands and that Sp is jointly controlled by soil water availability and community development indicated by NDVI in different flowering stages in temperate grasslands. Considering the above two factors in phenology models will promote robust prediction of grassland reproductive phenology in temperate regions under concurrent climate warming and changing precipitation.