鄱阳湖典型洲滩湿地土壤环境因子对植被分布影响研究

湿地植被生长的影响因素包括非生物因素和生物因素两部分。其中,非生物因素中对湿地植被格局影响较大的主要是水文和土壤环境因子,也是当今湿地生态水文过程研究的热点和重点。通过研究鄱阳湖典型洲滩湿地4种植物群落带下各土壤环境因子的含量变化特征,结合研究区20个植被样方的典范对应分析(Canonical Correspondence Analysis,CCA)排序,分析了鄱阳湖典型洲滩湿地主要土壤环境因子及其对植被分布的影响。结果表明:不同植被群落下的全氮含量有明显差异,依次为苔草带藜蒿-狗牙根带芦苇-苔草带苔草-虉草带;总有机碳与全氮含量大小在不同植被群落带的分异趋势相同,二者存在极显著相关关系;土壤全磷含量随植被群落不同的变化规律不明显;随植被群落带离湖泊水体距离逐渐减小,土壤中速效钾含量有增大的趋势,但程度较小。鄱阳湖典型洲滩湿地土壤有机碳与全氮、有效磷呈极显著相关关系,土壤含水量与土壤有效磷呈显著负相关关系,有效磷与全氮呈极显著相关关系。土壤含水量是影响鄱阳湖湿地研究区植被分布的最主要因素,土壤pH、全钾含量也是影响湿地植被分布的重要土壤环境因子。

Effects of soil environmental factors on vegetation distribution in shoaly wetlands typical to Poyang Lake

Both abiotic factors and biological factors affect growth of wetland vegetation. Of the former hydrological and soil environmental factors are the major ones and hence the hot spots and focal points of the research on wetland eco-hydrological processes. Investigations were carried out of variation of various soil environment factors in content in shoaly wetlands typical to the Poyang Lake under four different kinds of plant communities, and CCA (Canonical correspondence analysis) ordination was performed of the 20 vegetation sampling plots in the research zone, for analysis of major soil environment factors in the shoaly wetlands and their effects of vegetation distribution. Results show that the soils under four kinds of vegetation communities differed sharply in total nitrogen content, displaying an order of Carex cinerascen< Artemisia selengens Cynodon dactylon< Phragmites communis Carex cinerascen< Phalaris arundinace Carex cinerascen, and demonstrated a similar trend in variation of total organic carbon, for these two were significantly positively related. They did not have any significant trend of variation in soil total P content. With the increasing distance of the shoaly wetlands from the water body of the lake, content of readily available K in the soils showed an increasing trend, but not great in extent. Soil total nitrogen and soil available phosphorus was closely related to soil organic carbon and soil available P was significantly negatively related to soil moisture content, while content of available phosphorus was significantly related to total nitrogen. To sum up, soil moisture content is the major factor and soil pH sand total potassium content are also important ones among the soil environment factors affecting distribution of vegetation on wetland soils.