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产生的重要因素。但是，目前尚不清楚生物量生产如何与湿地地区的洪水模式联系起来。我们利用测站数据，数字高程模型，植被调查数据和Landsat 8图像来研究洪水的平均淹没深度（AID）和淹没持续时间（IDU）对Po阳地区植被的季节末生物量的影响特别是三峡大坝运行后的湖泊湿地。湿地植被的季节末生物量在AID和IDU梯度上均呈高斯分布。对于湿地植被生物量生产而言，最有利的洪水条件是AID为3.9至4.0 m，IDU为39％至41％。对于AID较低（<3.9 m; IDU < 39％）的季节末生物量值呈正相关，而对于AID较高（4.0 m; IDU> 41％）的地点，季节末生物量值呈负相关。三峡大坝投入运行后，Po阳湖湿地的AID和IDU特征的洪灾格局得到了明显缓解，整个湿地植被生物量的变化趋势混合。与1980-2002年相比，由缓和洪灾引起的下表面季末生物量的增加远远超过了较高表层的季末生物量的减少，导致季末生物量增加。自2003年以来为1.0％–6.7％。