Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China.
College of Forestry, Northeast Forestry University, Harbin 150040, China.
Sci Total Environ. 2019 May 20;666:1169-1177. doi: 10.1016/j.scitotenv.2019.02.265. Epub 2019 Feb 21.
Understanding wetland vegetation phenology and its response to climate change is important to predict the changes of wetland vegetation in wetland regions. Using the NDVI and climate data, this work studied the spatiotemporal change of start date of vegetation growing season (SOS) and explored the possible effects of climate change on the SOS over freshwater marshes of Northeast China. The results showed that the SOS significantly advanced by 0.52 day per year throughout the freshwater marshes of Northeast China during 2001 to 2016. The significant advancing of SOS was mainly concentrated in freshwater marshes of the Khingan Mountains (the Greater Khingan Mountains and the Lesser Khingan Mountains) and central arid or semi-arid regions (Songnen plain and Liaohe plain) in Northeast China. By contrast, there were weak delay trends of SOS in freshwater marshes of Eastern Inner Mongolia region, and Sanjiang plain. We found that precipitation was a dominant factor determining the SOS in arid or semi-arid regions (Songnen plain and Liaohe plain), while temperature played a bigger role in determining the SOS in Sanjiang plain and three cold mountains of the Northeast China. During the study period, increasing precipitation in the winter and spring contributed to advancing SOS in Songnen plain and Liaohe plain; the decrease of temperature from December to April explain the delaying SOS in freshwater marshes of Sanjiang Plain; the weak warming of temperature between November and May account for the advancing SOS of freshwater marshes in three cold mountains. In freshwater marshes of cold and the most arid region of Northeast China (Eastern Inner Mongolia), the SOS was influenced by both precipitation and temperature. Decreasing precipitation between January and April, as well as temperature decreases in March and April explain the delay of SOS in freshwater marshes of Eastern Inner Mongolia region.
理解湿地植被物候及其对气候变化的响应对于预测湿地植被在湿地地区的变化非常重要。本研究利用 NDVI 和气候数据，研究了植被生长季节开始日期（SOS）的时空变化，并探讨了气候变化对中国东北淡水沼泽区 SOS 的可能影响。结果表明，2001 年至 2016 年期间，中国东北淡水沼泽区的 SOS 显著提前了 0.52 天/年。SOS 的显著提前主要集中在中国东北的大兴安岭（大兴安岭和小兴安岭）和中部干旱或半干旱地区（松嫩平原和辽河平原）。相比之下，在内蒙古东部地区和三江平原的淡水沼泽区，SOS 则呈现出较弱的延迟趋势。研究发现，降水是决定干旱或半干旱地区（松嫩平原和辽河平原）SOS 的主导因素，而温度在决定三江平原和中国东北三寒山区的 SOS 方面发挥了更大的作用。在研究期间，冬季和春季降水的增加导致了松嫩平原和辽河平原 SOS 的提前；12 月至 4 月的温度下降解释了三江平原 SOS 的延迟；11 月至 5 月之间温度的微弱变暖导致了中国东北三寒山区淡水沼泽区 SOS 的提前。在中国东北寒冷和最干旱地区（内蒙古东部）的淡水沼泽区，SOS 受到降水和温度的共同影响。1 月至 4 月降水减少以及 3 月和 4 月温度下降解释了内蒙古东部地区淡水沼泽区 SOS 延迟的原因。
