Variation in species assemblages due to micro-topographic features and flow regime determine vegetation carbon stock in floodplain wetlands. We tested this hypothesis in Chatla—a tropical floodplain wetland located in northeast India. Five sampling stations characterized by contrasting micro-topographic and flow parameters were selected in the wetland for study. Species composition, assemblage pattern, and vegetation carbon stock were studied in these stations during three flood phases, i.e., early, middle, and late flood phases following standard methods. Univariate and multivariate statistics were used to determine the relationship between the selected environmental parameters, plant species assemblages, and vegetation carbon stock of the wetland. Thirty-one species of herbs and five species of shrubs were recorded from the five stations in Chatla floodplain wetland. Flow regime characterized by water flow velocity and discharge showed substantial variations across the stations. These parameters in turn are related to variations in the micro-topographic characteristics namely depth, width, and cross-sectional area of the stations. Plant species composition and abundance differed significantly with respect to micro-topography and flow regime as revealed by the cluster diagram. The canonical correspondence analysis revealed strong association of plant species assemblages with the micro-topography and flow regime within the wetland. Multiple regression analysis revealed a significant positive relationship of the vegetation carbon stock with the water discharge. Spatial variation in plant species diversity because of micro-topography and flow regime determines the vegetation carbon stock in floodplain wetlands. Modification of these parameters by anthropogenic activities such as mining and quarrying may potentially influence the carbon stocking potential of seasonal floodplain wetlands. Therefore, appropriate measures should be taken to maintain the integrity of the natural topographic features of such wetlands.

中文翻译：

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微观形貌和流态导致的物种组合变化控制着季节性洪泛区湿地的植被碳储量

由于微观地形特征和流态的不同，物种组合的变化决定了洪泛区湿地的植被碳储量。我们在位于印度东北部的热带洪泛区湿地Chatla中检验了这一假设。在湿地中选择了五个具有相反微地形和流量参数特征的采样站进行研究。按照标准方法，在三个洪水阶段，即早期，中期和晚期洪水阶段，研究了这些站的物种组成，组合模式和植被碳储量。单变量和多变量统计量用于确定所选环境参数，植物物种组合和湿地植被碳储量之间的关系。在查特拉河漫滩湿地的五个站点中记录了31种草药和5种灌木。以水流速和流量为特征的流态在各站之间显示出很大的变化。这些参数又与微观地形特征的变化有关，即站的深度，宽度和横截面积。如簇图所示，植物的种类组成和丰度在微观形貌和流动方式方面有显着差异。典型的对应分析表明，植物物种集合与湿地内的微形貌和流动状态密切相关。多元回归分析表明，植被碳储量与排水量之间存在显着的正相关关系。由于微观地形和水流状况，植物物种多样性的空间变化决定了洪泛区湿地的植被碳储量。人为活动（例如采矿和采石）对这些参数的修改可能会影响季节性洪泛区湿地的碳储存潜力。因此，应采取适当的措施来保持此类湿地自然地形特征的完整性。