互花米草与盐地碱蓬群落交错带土壤因子的梯度变化特征

【目的】研究互花米草(Spartina alterniflora)入侵对土壤因子的改造作用,以及土壤因子改变对互花米草生态入侵过程的影响。【方法】以江苏沿海滩涂湿地互花米草群落与和盐地碱蓬(Suaeda salsa)群落的交错带为研究对象,从互花米草群落到盐地碱蓬群落分6个生境梯度带,对各梯度带植物生长状况及表层(0~10 cm)、中层(≥10~30 cm)、下层(≥30~60 cm)3个层次土壤主要理化指标的梯度变化特征进行了研究。【结果】①各梯度带不同土壤层次间,除粒径、总磷,其他指标表层土壤性质与中下层差异显著。②植物群落特征和土壤因子分布在表层呈现出明显的梯度分布格局,与盐地碱蓬群落相比,互花米草群落表层土壤有较高的含水量、总有机碳、总氮含量及较低的盐度、容重和pH。③随着互花米草群落由内部向边缘带过渡,生物量、株高、盖度呈下降趋势,表层土壤含水量、总有机碳、总氮含量总体呈下降趋势,容重和pH 呈上升趋势,盐度、粒径、总磷含量没有明显的趋势变化。【结论】互花米草入侵对群落交错区土壤的改造效果在土壤表层明显,表现为显著增加土壤含水量、总有机碳和总氮量,降低pH、盐度和容重,而总有机碳、总氮含量随入侵时间的延长具累积效应,含水量、总有机碳、总氮等因子含量的增加可能会促进互花米草的相对竞争优势。

Distribution of soil factors across the habitat gradient of Spartina alterniflora and Suaeda salsa communities

【Objective】The purpose of this study was to investigate the effects of Spartina alterniflora invasion on dynamic changes in soil factors and how soil factors alter the invasion process of Spartina alterniflora. 【Method】 Samples were taken from the six gradient zones in the ecotone of Spartina alterniflora and Suaeda salsa communities at depths of 0-10, ≥10-30 and ≥30-60 cm, in Yancheng Coastal Wetland Jiangsu Province. We investigated the plant traits and analyzed the main soil factors. 【Result】 ① Soil factors at 0-10 cm, except the average particle size and total phosphorus, were significantly different from those at the other depths.② The surface soil factors and community characteristics displayed a gradient distribution pattern. Compared with S. salsa, the surface soil of Spartina alterniflora had higher soil water content, the total organic carbon, total nitrogen, and lower bulk density, salinity and pH.③ With the transition from the interior to the edge zone of the Spartina alterniflora community, plant biomass, height and coverage decreased. Surface soil water content, the total organic carbon and nitrogen generally decreased, while the bulk density and pH increased. Additionally, salinity, particle size and total phosphorus showed no significant differences among the different zones. 【Conclusion】 The invasion of Spartina alterniflora altered soil factors mainly in the surface layer, which included increased soil water content, total organic carbon, nitrogen, and reduced pH, bulk density and salinity. As the duration of invasion increased, the total organic carbon and nitrogen showed cumulative effects. The increase in soil water content, the total organic carbon and nitrogen may promote the comparatively competitive advantages of Spartina alterniflora.