Impacts of climate change on the Taraxacum mongolicum growing season in the temperate zone of eastern China

Using leaf unfolding and leaf coloration data of a widely distributed herbaceous species, Taraxacum mongolicum, we detected linear trends of the growing season and identified responses of the growing season to temperature at 52 stations from 1990 to 2009. Across the temperate zone of eastern China, the growing season beginning date advanced nonsignificantly, while the growing season end date was delayed significantly at a rate of 3.2 days per decade and the growing season length was prolonged significantly at a rate of 5.5 days per decade. At individual stations, linear trends of the beginning date correlate negatively with linear trends of spring temperature, whereas linear trends of the end date and length correlate positively with linear trends of autumn temperature and annual mean temperature. Moreover, linear trends of the growing season are also closely related to responses of the growing season to temperature and geo-location parameters. Regarding to growing season response to temperature, a 1°C increase in spring temperature may induce an advancement of 2.1 days in the beginning date of the growing season, while a 1°C increase in autumn temperature may cause a delay of 2.3 days in the end date of the growing season, and a 1°C increase in annual mean temperature may result in an extension of 8.7 days in the length of the growing season over the research region. At individual stations, response of the beginning date to spring temperature depends obviously on local annual mean temperature and geo-location parameters. Namely, a 1°C increase in spring temperature may induce a larger advancement of the beginning date at warmer locations with smaller latitudes and longitudes than at colder locations with larger latitudes and longitudes, while a 1°C increase in spring temperature may cause a larger advancement of the beginning date at higher altitudes than at lower altitudes.