摘要
近20年来,洞庭湖湿地的湖草面积大幅度减少,退化严重.为寻求湖草的恢复途径,本文以位于洞庭湖丁字堤的短尖苔草为对象,依高程差划分成7条样带,调查了63个样方的植被特征(株高、盖度、密度、生物量、多样性指数)和土壤理化特征(土壤有机碳、全氮、全磷、土壤容重、土壤含水量).结果表明:除多样性指数先下降后升高外,其余生物学指标均随高程增加呈现倒"U"型分布,即靠近水域(低海拔区)和堤岸(高海拔区)的苔草长势较差,而位于中间的苔草长势较好;土壤容重随高程增加而增加,土壤含水量的变化则相反,土壤有机碳和全氮含量均呈中海拔区高、低和高海拔区低的分布规律.主成分分析表明,影响苔草生物量的关键因子依次为土壤有机碳含量、氮含量、含水量和土壤容重.可见,提高土壤肥力和保持适当的土壤含水量可能是短尖苔草恢复的有效途径.
In recent 20 years, the area of lake grass has been drastically reduced and degraded. In order to search for reasonable recovery ways of the lake grass, the vegetational characteristics （ plant height, coverage, density, biomass and biodiversity index） and soil physico-chemical characteristics （ soil organic carbon, SOC ; total nitrogen, TN ; total phosphorus, TP; soil bulk density and moisture ） were investigated in the Carex brevicuspis community from 63 sampling plots in 7 samphng belts along an elevation gradient in Dingzidi, East Dongting Lake. All biological characteristics showed an inverted ＂U＂ distribution pattern along with increasing elevation, except for diversity in- dex, which showed a tendency of increasing at first and then decreasing. Plant growth was inhibited near water body （ low elevation region） and levee （ high elevation region）. In contrast, the interme- diate elevation region had a favorable condition for plant growth For soil physical properties, soil water moisture decreased but soil bulk density increased along with increasing elevation. However, SOC and TN contents were higher in the intermediate elevation region and lower in both low and high elevation regions. TP content was fluctuant along with increasing elevation. The principal com- ponent analysis （PCA） showed that the key factors influencing biomass of C. brevicuspis were soil C and N contents, soil moisture and bulk density. These results indicated that increasing soil fertility and maintaining proper soil moisture might be efficient to recover the vegetation of C. brevicuspis.
出处
《应用生态学报》
CAS
CSCD
北大核心
2014年第3期745-751,共7页
Chinese Journal of Applied Ecology
基金
国家重点基础研究发展计划项目(2012CB417005)
国家自然科学基金项目(31170342)资助
关键词
洞庭湖湿地
苔草群落
环境因子
主成分分析
Dongting Lake wetland
Carex brevicuspis
soil environmental factor
principal component analysis.
