Song Yan-Yan, Zhang Qi, Jiang San-Yuan, Guo Yu-Yin
Key Laboratory of Watershed Geographic Science, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
Hydrology Bureau of Poyang Lake in Jiangxi Province, Jiujiang 332800, Jiangxi, China.
Ying Yong Sheng Tai Xue Bao. 2021 Jan;32(1):123-133. doi: 10.13287/j.1001-9332.202101.018.
Groundwater level directly affects soil water content, which in turn impacts the growth, distribution, and succession of wetland vegetation. Based on the groundwater monitoring data during 2014 to 2018, we analyzed the inter- and intra-annual variations in groundwater level of the wetland in Poyang Lake. We set up a groundwater numerical model to investigate the spatial patterns of groundwater flow field and distribution of groundwater depth. The relationship between groundwater depth and distribution of typical vegetation was explored with Gaussian regression analysis. Results showed that groundwater level of the wetland showed inter-annual variation, with the trend highly consistent to the changes in lake water level. There was a lag of one month between the inter-annual change in groundwater depth and the seasonal distribution of precipitation. The annual groundwater level showed a decreasing trend from upstream to downstream. The range of groundwater depth in upstream area of the wetland was narrower (0.1-1.1 m) than that of the downstream area (0.1-5.6 m). The groundwater flow field was directed from the hilly upstream area to the relatively flat downstream lake area, with the flow direction consistent with the change in elevation. The ground-water depth decreased with decreasing distance to the lake water body, with an average value of 2.07 m in the study are. The optimal groundwater depths for the growth of , and communities were 1.1, 3.7 and 5.7 m, respectively. The typical vegetation distribution showed different responses to groundwater depth. The ecological width of communities was larger than the and communities. The three types of community were overlapped in ecological niche when the groundwater depth ranged 1.1-5.7 m. The vegetation distribution index of decreased rapidly, that of increased firstly and then decreased, while that of increased continually to the maximum and began to decrease when the groundwater depth reached 5.7 m.
地下水位直接影响土壤含水量，进而影响湿地植被的生长、分布和演替。基于2014年至2018年的地下水监测数据，我们分析了鄱阳湖湿地地下水位的年际和年内变化。我们建立了一个地下水数值模型，以研究地下水流场的空间格局和地下水深度分布。采用高斯回归分析方法探讨了地下水深度与典型植被分布之间的关系。结果表明，湿地地下水位呈现年际变化，其趋势与湖泊水位变化高度一致。地下水深度的年际变化与降水的季节分布之间存在一个月的滞后。年地下水位从上游到下游呈下降趋势。湿地上游地区的地下水深度范围（0.1 - 1.1米）比下游地区（0.1 - 5.6米）窄。地下水流场从上游丘陵地区流向相对平坦的下游湖区，水流方向与海拔变化一致。地下水位随着与湖泊水体距离的减小而降低，研究区域内的平均值为2.07米。苔草、芦苇和南荻群落生长的最佳地下水深度分别为1.1米、3.7米和5.7米。典型植被分布对地下水深度表现出不同的响应。苔草群落的生态幅大于芦苇和南荻群落。当地下水深度在1.1 - 5.7米范围内时，这三种群落的生态位存在重叠。苔草的植被分布指数迅速下降，芦苇的植被分布指数先上升后下降，而南荻的植被分布指数持续上升至最大值，当地下水深度达到5.7米时开始下降。
