基于相位图分析法研究羊草与大针茅的种间竞争关系

Interspecific competition between Leymus chinensis and Stipa grandis based on the analysis of the phase diagrams

文中利用微分方程动力系统的理论,对经典的Lotka-Volterra模型进行改进和实证分析,建立了内蒙古典型草原区羊草与大针茅种间竞争的数学模型,分别绘制了2005年和2014年两年度羊草、大针茅生物量变化的相位图。结果表明:2005年的环境条件更有利于羊草生长,大针茅相对受到抑制;而2014年的环境条件更利于大针茅生长,羊草受到抑制。二者在总体生长趋势上具有补偿性,优势种和建群种的这种补偿作用,弥补了由于年度间降水、气温等气候条件改变所导致的生产力波动过大,有利于维护整个草原生态系统的稳定性。

By using the theory in dynamic system of differential equation we improved the classic Lotka - Volterra model and gave the empirical analysis. We established the mathematical model about moisture competition between Leymus chinensis and Stipa grandis on typical grassland of Inner Mongolia too. Phase diagrams of two grasses＇biomass in 2005 and 2014 were mapped. The results proved that the water condition in 2005 was more con- ducive to Leymus chinensis, and the growth of Stipa grandis was restricted, whereas the growth of Leymus chinensis was restricted in 2014. The general growth trends of the two grasses were in compensation. The compensation of the dominant species and the constructive species made up the big change of productivity caused by the change of precipitation, temperature and other climates conditions. It is helpful for the stability of the grassland ecosystem.