滨江湿地植被生态系统能量流动模型与稳定性分析

Collapsible model and stability analysis of energy flux process of vegetation ecosystem in Binjiang wetland

为加强对镇江市滨江湿地的优化管理,改善湿地功能和效益,提高湿地生产量,采用样方法调查滨江湿地植被的组成、种类和外貌,并对太阳能辐射环境,优势植物种群的净光合速率、呼吸速率和初级生产力,群落的生物量及热值进行测定;基于1997—2006年的气象数据,定量计算湿地植被吸收、固定、积累、转化和利用太阳辐射能的能量流动过程;应用系统分析方法建立滨江湿地植被生态系统能量流动的数学模型并进行稳定性分析。结果表明:太阳辐射能在植被生长季内(3月1日—10月31日)到达滨江湿地的太阳总辐射能为3 522.36 MJ/m2,以此为100%计算,植被层吸收能量1 608.66 MJ/m2,占45.67%;在被吸收的能量中,仅有133.50 MJ/m2的能量通过植物光合作用固定成为湿地植物群落的净生产量,为3.79%;而用于湿地植物群落的年能量积累量为80.31 MJ/m2,占2.28%,折合光能利用效率1.87%。根据李亚普诺夫稳定性原理,该系统能量流动过程的平衡态具有渐近稳定性。

To study the relevant relationship between the energy flux of a wetland ecosystem and the wetland vegetation has important economical and social effects to the optimal management and the improvement of the amount of production of the wetland. Based on the data of year 1997-2006 on energy flux through an vegetation ecosystem at south bank of Mount Beigu-Dadonggou in Binjing wetland, Zhenjiang city in middle and lower Yangtze River Plain, where the studies on the structure and functions of ecosystem have been carried out, T the radiation energy environment, photosynthesis and respiration rate, productivity, biomass and the dynamics of calorific value and its energy production of dominant plant community were measured and analyzed by survey of wetland vegetation ecosystem. The result shows that the whole sunshine radiant energy reached Binjing wetland vegetation ecosystem is about 3 522.36 MJ/m^2 （ 100% ） annually, 45.67% of which is absorbed by vegetation （about 1 608.66 MJ/m^2 ） only 3.79% is used for net biomass that plant fixed by photosynthesis （about 133.50 M J/m^2）; 2.28% for biomass accumulation, （80.31 MJ/m^2）. The efficiency for solar energy utilization in Binjiang wetland was 1.87% （from March, 1 to October, 31）. By simplifying the process, we established a collapsible model for the energy flux process, The stability analysis showed that the stability mechanism of the equilibrium state obeyed the negative feedback one. It was found that the ecosystem at present was in a state of deviating from its balance of energy flux, which has a progressive stability. The energy flux through the ecosystem is being in a transition from a labile state to a stable state of balance.