黄河河口盐沼植被分布、多样性与土壤化学因子的相关关系

Relationships between salt marsh vegetation distribution/diversity and soil chemical factors in the Yellow River Estuary,China

以黄河河口盐沼实地调查的67个样地19个植物种的重要值,运用双向指示种分析将黄河河口盐沼植被分为柽柳-翅碱蓬+补血草+碱蓬群落、翅碱蓬群落、柽柳-芦苇+翅碱蓬群落、芦苇群落、穗状狐尾藻+芦苇群落和旱柳-芦苇+荻群落。利用典范对应分析(CCA)分析了土壤盐分、pH、Na+、K+、Ca2+、Mg2+、Cl-、全氮、全磷、全碳、有机质等11个土壤化学因子与黄河河口盐沼植被分布的相关关系。CCA排序结果表明,土壤盐分和土壤pH是影响黄河河口盐沼植被分布的主要土壤化学因子。CCA排序第一轴与土壤盐分呈显著正相关关系(P<0.001),第二轴主要和土壤pH呈显著负相关关系(P<0.001)。柽柳-翅碱蓬+补血草+碱蓬群落排列于排序图的右上部,与生境土壤中高含盐量及中等pH相对应,穗状狐尾藻+芦苇群落和芦苇群落分布于第一排序轴的最左端,主要与土壤低含盐量相关,翅碱蓬群落位于第二排序轴的下侧,与较高的土壤pH相关,柽柳-芦苇+翅碱蓬群落和旱柳-芦苇+荻群落,土壤pH和盐分均较低。通过物种丰富度R、香农维纳多样性H′、物种均匀度E等指数与土壤化学因子的相关分析,发现黄河河口盐沼植物物种多样性与土壤盐分没有呈现出与土壤盐分很好的负相关关系,物种丰富度R、香农维纳多样性H′、物种均匀度E均与土壤盐分呈现显著正相关关系;R、H′与土壤pH呈现出十分显著的负相关关系;R、H′与土壤Ca2+、Mg2+含量呈现极为显著正相关关系。

Relationships between salt marsh vegetation distribution/diversity and soil chemical factors in the Yellow River Estuary, China was analyzed. Field survey was carried out from Sept. to Oct. , 2006. The vegetation of 67 sampling sites was investigated. Plant cover values and densities were recorded and five soil samples were collected randomly from a depth of 0- 20cm in each sampling site. All together 11 soil chemical factors （soil salinity, soil pH, Na ^＋ , K^＋ , Ca^2＋ , Mg^2＋ , Cl^-, total nitrogen, total phosphorus and total carbon） were mensurated in the lab. As a primary analysis, TWINSPAN （Two Way Indicator Speceis Analysis） was performed to compartmentalize all the sampling sites into different plant associations. Seven associations of salt marsh vegetation in the Yellow River Estuary were obtained： Ass. Tamarix chinensis-Suaeda salsa ＋ Limonium sinense ＋ Suaeda glauca, Ass. Suaeda salsa, Ass. Tamarix chinensis-Phragmites australis ＋ Suaeda salsa, Ass. Phragmites australis, Ass. Myriophyllum spicatum ＋ Phragmites australis, Ass. Salix matsudana-Phragmites australis ＋ Triarrhena sacchariflora. The roles of all measurated soil chemical factors on the vegetation distribution patterns were detected by Canonical Corresponding Analysis. And soil salinity and soil pH turned up to be the main determinants. Soil salinity showed a significant positive correlation with CCA axis 1 and soil pH significant negative with axis 2. Ass. Tamarix chinensis-Suaeda salsa ＋ Limonium sinense ＋ Suaeda glauca composed of salt tolerant species dominated the up right part of the CCA ordination chart, which indicated a high soil salinity but moderate soil pH. Ass. Myriophyllum spicatum ＋ Phragmites australis and Ass. Phragmites australis dominated the negative end of CCA axis 1 mainly correlated negatively with soil salinity. Ass. Suaeda salsa ditributed on the negative end of axis 2 indicating a high soil pH, and Ass. Salix matsudana-Phragmites australis ＋ Triarrhena sacchariflora, and Ass. Tamarix chinensis-Phragmites australis ＋ Suaeda salsa distributed on the up left part of the ordination chart negatively correlated with both soil salinity and pH. Spearman correlation coefficients were calculated between soil chemical factors and species richness （R）, Shannon-Weiner diversity （H＇） and Pielou evenness （E）. This revealed us a significant positive correlation between R, H＇, E and soil salinity and a significant negative correlation between soil pH and H＇, E. However, soil Ca^2＋ and Mg^2＋ seemed to play a more important role in determining the diversity. Reasons were detailed in Discussion.