Dai Xue, Yu Zhongbo, Yang Guishan, Wan Rongrong
State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing, China.
College of Hydrology and Water Resources, Hohai University, Nanjing, China.
Front Plant Sci. 2020 Oct 16;11:521358. doi: 10.3389/fpls.2020.521358. eCollection 2020.
Flooding is an important factor influencing the biomass production of vegetation in natural wetland ecosystems. However, how biomass production is linked to flooding patterns in wetland areas remains unclear. We utilized gauging station data, a digital elevation model, vegetation survey data, and a Landsat 8 image to study the effects of average inundation depth (AID) and inundation duration (IDU) of flooding on end-of-season biomass of vegetation in Poyang Lake wetland, in particular, after operation of Three Gorges Dam. The end-of-season biomass of wetland vegetation showed Gaussian distributions along both the AID and IDU gradients. The most favorable flooding conditions for biomass production of vegetation in the wetland had an AID ranging from 3.9 to 4.0 m and an IDU ranging from 39% to 41%. For sites with a lower AID (<3.9 m; IDU < 39%), the end-of-season biomass values were positively related, whereas for sites with a higher AID (4.0 m; IDU > 41%), the end-of-season biomass values were negatively related. After the operation of the Three Gorges Dam, flooding patterns characterized by AID and IDU of the Poyang Lake wetland were significantly alleviated, resulting in a mixed changing trend of vegetation biomass across the wetland. Compared with 1980-2002, the increase of end-of-season biomass in lower surfaces caused by the alleviated flooding pattern far exceeded the decrease of end-of-season biomass in higher surfaces, resulting in an end-of-season biomass increase of 1.0%-6.7% since 2003. These results improved our understanding of the production trends of vegetation in the wetland and provided additional scientific guidance for vegetation restoration and wetland management in similar wetlands.
洪水是影响自然湿地生态系统中植被生物量生产的一个重要因素。然而，湿地地区生物量生产与洪水模式之间的联系仍不明确。我们利用测量站数据、数字高程模型、植被调查数据和陆地卫星8号图像，研究了洪水的平均淹没深度（AID）和淹没持续时间（IDU）对鄱阳湖湿地植被季末生物量的影响，特别是三峡大坝运行之后的影响。湿地植被的季末生物量沿AID和IDU梯度均呈高斯分布。湿地植被生物量生产最有利的洪水条件是AID在3.9至4.0米之间，IDU在39%至41%之间。对于AID较低（<3.9米；IDU<39%）的地点，季末生物量值呈正相关，而对于AID较高（>4.0米；IDU>41%）的地点，季末生物量值呈负相关。三峡大坝运行后，鄱阳湖湿地以AID和IDU为特征的洪水模式得到显著缓解，导致整个湿地植被生物量呈现混合变化趋势。与1980 - 2002年相比，洪水模式缓解导致低地势区域季末生物量的增加远远超过高地势区域季末生物量的减少，自2003年以来季末生物量增加了1.0% - 6.7%。这些结果增进了我们对湿地植被生产趋势的理解，并为类似湿地的植被恢复和湿地管理提供了更多科学指导。
