摘要:地上生物量是反映湿地植物群落数量特征和生产能力的重要因子，内陆盐沼湿地植被地上生物量空间分布格局及其水盐响应机制，对湿地生态水文学研究具有重要的理论意义。采用湿地群落学调查和支持向量回归模型（SVR）相结合的方法，将苏干湖湿地划分为山洪区、泉水区等5个分区，研究了植被地上生物量的空间异质及其影响因素。结果表明：支持向量回归模型在内陆盐沼湿地植被地上生物量反演方面具有较高的拟合精度；苏干湖不同区域湿地植物群落地上生物量空间格局呈现出复杂的空间分异规律，对地下水埋深和土壤全盐量的响应也存在明显差异：河洪区的植被地上生物量随地下水埋深、土壤全盐量的增加呈先增大后减小的趋势，湖水区的植被地上生物量与地下水埋深呈显著正相关关系，而土壤全盐量则相反，山洪区的植被地上生物量随地下水埋深的增加呈先增大后减小的趋势，泉水区的植被地上生物量随地下水埋深的增加逐渐减小，台地区的植被地上生物量与地下水埋深和土壤全盐量均无显著相关性。苏干湖湿地不同等级植被地上生物量在空间上呈现出多斑块组成的镶嵌体结构形态，体现了湿地植物应对土壤水盐等环境因子变化的生态适应机制。



Abstract:The spatial distribution pattern of aboveground biomass of inland salt marsh wetland vegetation and its influencing factors have important theoretical significance for wetland ecological hydrology. Our study aimed to use wetland community survey and support vector regression (SVR) model to explore the spatial heterogeneity of aboveground biomass of vegetation and its influencing factors. The study site was located in Sugan Lake wetland at the northwestern end of Haizi Grassland, Akesai County, Gansu Province, China (94° 10' 33″-94° 14' 43″ E, 39° 01' 25″-39° 05' 32″ N), and the elevation is between 2795-2808 m. The study area is divided into 5 ecological functional areas based on differences in landscape, landforms, vegetation, water and soil resources, and ecological and environmental issues. We chose 425 plots randomly and set in the 5 ecological functional areas, each plot was set with 1 m×1 m quadrat. The species, coverage, height, density and aboveground biomass of all plants in the quadrat were measured, and repeated 3 times. The aboveground biomass data of 275 community quadrats were selected as the response variables of the model, and the remaining 150 data were selected as the test model variables, the aboveground biomass of vegetation in the whole area was inversely performed, and the influence of water and salt on it was analyzed. The results showed that support vector regression model had high fitting accuracy in the retrieval of aboveground biomass of inland salt marsh wetland vegetation, and the predicted values of the model and the field measured values were tested with significant positive correlation (P<0.01, R²=0.81). The spatial pattern of aboveground biomass of wetland plant communities in different regions of Sugan Lake presented complex spatial differentiation rules, and there were significant differences in response to groundwater depth and total salt content of soil:with the increase of groundwater depth and total salt content of soil, the aboveground biomass of vegetation in He-hong area first increased and then decreased; there was a significant positive correlation between the aboveground biomass of vegetation and groundwater depth in the Hu-shui area, while the total salt content of soil was the opposite; with the increase of groundwater depth, the aboveground biomass of vegetation in Shan-hong area first increased and then decreased; the aboveground biomass of vegetation in Quan-shui decreased with the increase of groundwater depth; there was no significant correlation between aboveground biomass of vegetation and groundwater depth and total salt content of soil in Tai-di area. This study reflects the ecological adaptation mechanism of wetland plants to the changes of environmental factors such as soil water and salt.





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