Tidal marsh wetlands in the Yellow River Delta provide valuable eco-services to the local population and global ecology. However, this area is suffering from serious degradation under the stresses of social development and climate change. Hydrological connectivity, a new framework in hydrology and ecology, has been proposed as the main factor affecting the ecological processes in coastal wetlands; however, its role in hydrology–soil–vegetation interactions remains unclear. In this study, we parametrically quantified the hydrological connectivity in the tidal marsh wetlands and analyzed its relationship with Phragmites australis, one of the dominant species in this area. Our results showed threshold-like effects on the interaction between hydrological connectivity and P. australis on the plot scale. When biomass is lower than 2.2 kg m⁻², the population density and structure size were found to increase with hydrological connectivity. When the biomass is higher than the threshold, the plots disconnected hydrologically because of high water consumption. Compared with soil chemistry, salinity, and water soil content, hydrological connectivity in the surface soil layer is more strongly linked to the plant traits and spatial structure in the tidal marsh wetlands due to the narrow ranges of other variables. Based on the Best on previous study and our analysis, we do not recommend dense plantation of P. australis, especially near the freshwater sources in the tidal marsh, because of its high reproduction ability and competitive nature, which may cut the freshwater connectivity off, lowering the richness of plant species and habitat diversity.

中文翻译：

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潮汐沼泽湿地水文连通性与优势植物种群相互作用的阈值效应

黄河三角洲的潮汐沼泽湿地为当地人口和全球生态提供了宝贵的生态服务。然而，在社会发展和气候变化的压力下，该地区正在遭受严重的退化。水文连通性是水文学和生态学的一个新框架，被认为是影响沿海湿地生态过程的主要因素；然而，它在水文-土壤-植被相互作用中的作用仍不清楚。在这项研究中，我们参数量化了潮汐沼泽湿地的水文连通性，并分析了其与该地区优势物种之一芦苇的关系。我们的结果显示了对水文连通性和P之间相互作用的阈值效应。澳大利亚在情节尺度上。当生物量低于2.2 kg m ^{-2 时}，发现种群密度和结构大小随着水文连通性而增加。当生物量高于阈值时，由于耗水量高，地块在水文上断开。与土壤化学、盐度和水土含量相比，由于其他变量的范围较窄，表层土壤的水文连通性与潮汐沼泽湿地的植物性状和空间结构的联系更加紧密。根据先前研究的最佳结果和我们的分析，我们不建议密集种植P。澳大利亚，尤其是靠近潮汐沼泽淡水源的地方，由于其繁殖能力强和竞争性强，可能会切断淡水的连通性，降低植物物种的丰富度和栖息地的多样性。