鄱阳湖南矶湿地典型植被对水深和淹没频率的响应分析

Analysis of responses of typical vegetation in Nanji Wetland National Nature Reserve of Poyang Lake to water depth and submergence frequency

水文要素是控制湿地生态过程发展与演替的主要驱动因子,在湿地形成、发育、演替直至消亡全过程中起重要作用。湿地植被群落是湿地生态系统重要组成成分和主要初级生产者,其结构、功能和生态特征综合反映着湿地生态环境的基本特点和功能特性。本文以鄱阳湖南矶湿地国家级自然保护区为例,运用植被群落—水文要素丰度直方图和敏感性指数,分析探讨了保护区内5种典型湿地植被群落对水深和淹没频率两种水文要素的耐受性和敏感性。结果表明:不同植被群落对水深、淹没频率的耐受性和敏感性不同。其中:(1)虉草和蓼子草2种群落对水深的耐受性最强,南荻群落最弱;苔草群落对淹没频率的耐受性最强,蓼子草群落最弱。(2)相较于淹没频率,5种典型植被群落对水深的敏感性更强;(3)南荻群落对水深和淹没频率变化的敏感性最强,而蓼子草群落对水文要素变化的响应最不敏感。

Hydrological process is the main driving factor that controls the development and succession of wetland ecological process and plays an important role in the whole process of wetland formation, development,succession and demise. Wetland vegetation communities are the significant components and mainly primary producers of wetland ecosystem. Their structures, functions and ecological characteristics comprehensively reflect the basic features of the wetland ecological environment. In this paper, taking Nanji Wetland National Nature Reserve as an example,the authors analyzed the tolerances and sensitivities of the five typical wetland vegetation communities to hydrological features using histogram and sensitivity index. The results showed that the tolerances and sensitivities of different vegetation communities to water depth and submergence frequency were different:(1) the two communities of Phalaris and Polygonum criopolitanum had the strongest tolerance to water depth; on the contrary, the Triarrhena lutarioriparia community was the weakest; the Carex community was the most tolerant to the submergence frequency, while the Polygonum criopolitanum community was the weakest;(2) compared with submergence frequency, these five typical vegetation communities were more sensitive to water depth; and (3) Triarrhena lutarioriparia community was more sensitive to water depth and submergence frequency,while the sensitivities of Polygonum criopolitanum community to hydrologic features were the lowest.