水生态食物链多平衡态问题的理论研究  

The euilibrium states of food-chain of aqua-ecosystem

作　　者：林振山[1] Li Larry 

机构地区：[1]南京师范大学地理科学学院,南京210097 [2]Ecological Complexity and ModelingLab,University of California,Riverside

出　　处：《生态学报》2003年第10期2066-2072,共7页Acta Ecologica Sinica

基　　金：国家"十五"资助项目;国家"2 11"工程重大资助项目;江苏省"333工程"资助项目~~

摘　　要：生态食物链的多平衡态问题关系到生态多样性。由于生态食物链复杂的非线性过程 ,使得该问题的理论研究困难重重。建立了一个生态食物链的准三分子模型 ,并讨论了系统的定态解及其稳定性。研究结果表明 :(1 )在定态里 ,浮游植物的密度正比于溶解营养物的密度、光合作用过程的速率 ,而反比于游泳掠夺者的捕食速率 ;(2 )如果溶解营养物的密度和光合作用过程的速率都很小 ,或者掠夺者的捕食速率过大 ,系统将是不稳定的 ;(3)生态食物链系统是一空间有序的结构 。The Trimolecular model or Brusselator, first introduced by Prigogine Brussels school of thermodynamics, is one of the simplest models of a nonlinear chemical system for which the relative concentration of the constituents can oscillate in time, or can exhibit nonlinear waves. It possesses two initial “reservoirs”, two intermediates and two “final products”. Spatially varying steady states, temporally oscillating homogeneous states and nonlinear traveling waves in the system, which only become stable far from equilibrium, have been called dissipative structure by I. Prigogine because their very existence depends on dissipative processes. Here we developed a modified-Brusselator to show how the spatio-temporally self-organized pattern can be formed in a simple food chain. Our analyses of this model indicate that: (1) at the steady state, the density of zooplankton is proportional to the concentration of dissolved nutrients and the rate of photosynthesis, and is inverse proportional to the predating rate of top predators; the normal modes with wave number tend to stabilize the ecosystem; (2) if the concentration of dissolved nutrients is smal l, the rate of photosynthesis and predating rate of zooplankton are very small or the predating rate of the top predator is very large, the system is unstable; (3) the change of the density of zooplanktons always lags a phase behind any change of phytoplankton; and (4) both explicit forms of the steady-state solutions and the time-dependent solutions show that spatio-temporal pattern formed in this ecosystem is dissipative structure. As we move away from equilibrium, new macroscopic modes (dissipative structures) can suddenly appear in this food chain, leading to dramatic new macroscopic behavior.

关 键 词：准三分子模型 生态系统 食物链 定态 稳定性 

分 类 号：Q141[生物学—生态学]