植物残体干扰对黄河河口高潮滩盐沼芦苇生长的促进作用

为研究植物残体干扰对黄河河口高潮滩盐沼芦苇生长的影响，在黄河河口高潮滩盐沼中分别选择典型的植物残体干扰斑块和未受干扰的自然群落，调查了其中芦苇（Phragmites australis）的形态特征及其种群的密度和生物量，并取样测定了土壤盐度、含水量、容重等土壤物理、化学性质，运用方差分析方法研究了植物残体干扰对芦苇的形态特征及其种群的密度和生物量的影响以及对土壤性质的影响。结果表明，植物残体干扰斑块中芦苇种群的密度、生物量等明显高于未受干扰的自然群落，芦苇的形态特征也明显优于未受干扰的自然群落。这说明植物残体干扰对芦苇生长产生了明显的促进作用。在植物残体干扰斑块中，土壤盐度、容重显著低于自然群落，说明植物残体干扰对黄河河口高潮滩盐沼芦苇的生长起到的促进作用，可能是通过改善土壤环境，缓解物理胁迫而产生的。

Facilitation of Phragmites australis Growth by Wrack Disturbance in High Salt Marsh

In this paper, the role of wrack disturbance in mediating P.australis growth in a high salt marsh in the Yellow River Estuary, China, was investigated. P.australis density, biomass and morphology traits (stem height, basal area, number of green leaves, leaf length, leaf width and leaf area) were measured in typical patches of wrack disturbance and in natural communities. Soil cores were collected from these two habitats, and soil salinity, water content and bulk density were determined in laboratory. A series of ANOVAs were conducted to test differences in performances of P.australis and edaphic factors between the two habitats. Both P.australis density and biomass were significantly higher in patches of wrack disturbance than those in natural communities, and stem height, basal area, number of green leaves, leaf length, leaf width and leaf area of P.australis were significantly larger in patches of wrack disturbance than those in natural communities, indicating facilitative effects of wrack disturbance on P.australis growth. Soil salinity and bulk density were significantly lower in patches of wrack disturbance than those in natural communities, indicating that wrack disturbance may facilitate P.australis growth through alleviating physical stresses. These data suggest that wrack disturbance play a facilitative role in mediating P.australis growth in high marshes in the Yellow River Estuary, China. This finding is consistent with several previous studies while differ from a few others in other salt marsh sites. As suggested previously, one reason for the variations in the role of wrack disturbance among sites is probably that physical environment, such as climate-induced salinity patterns, varies among sites. In future studies, the precise mechanisms of mediations of wrack disturbances and how wrack disturbances interact with other environmental factors should be investigated to improve our understanding of marsh plant organization.