Decreasing control of precipitation on grassland spring phenology in temperate China

Aim Vegetation phenology is highly sensitive to climate change. The timing of spring phenology in temperate grasslands is regulated primarily by temperature and precipitation. The aim of this study was to determine whether the primary factor regulating vegetation phenology has changed under ongoing climate change and the underlying mechanisms. Location Temperate semi-dry grasslands in China. Time period 1982-2015. Major taxa studied Temperate grassland. Methods We extracted start of season (SOS) dates using five standard methods from satellite-derived normalized difference vegetation index (NDVI) data and determined the primary factor regulating spring phenology using partial correlation analysis. Results The SOS date did not change significantly during the entire 1982-2015 study period in these semi-dry grasslands, but interannual variability increased significantly from the first subperiod [1982-1998, 8.8 +/- 1.1 days (mean +/- SE)] to the second subperiod (1999-2015, 10.3 +/- 1.1 days). Interestingly, we found that the primary factor regulating SOS shifted from precipitation during 1982-1998 to temperature during 1999-2015. Specifically, we found that during the first period, the SOS in 67.5% of the study area was determined by precipitation (mean partial correlation coefficient, r = 0.58 +/- 0.16), but during the second period the main regulating factor in 75.0% of the study area was temperature (r = 0.61 +/- 0.14). Main conclusions The change in the primary driver of spring phenology was attributed mainly to significant increases in preseason precipitation. Our study highlights that the response of spring phenology to climatic factors might change under ongoing climate change. This shift should be addressed in phenology models to simulate grassland phenology better, in addition to its impact on carbon and water cycles in future climate conditions.

Publication year:2021

Keywords:A1 Journal article

BOF-keylabel:yes

Accessibility:Open