Ackland G J, Gallagher I D
School of Physics, The University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, UK.
Phys Rev Lett. 2004 Oct 8;93(15):158701. doi: 10.1103/PhysRevLett.93.158701.
Conventional ecological models show that complexity destabilizes foodwebs, suggesting that foodwebs should have neither large numbers of species nor a large number of interactions. However, in nature the opposite appears to be the case. Here we show that if the interactions between species are allowed to evolve within a generalized Lotka-Volterra model such stabilizing feedbacks and weak interactions emerge automatically. Moreover, we show that trophic levels also emerge spontaneously from the evolutionary approach, and the efficiency of the unperturbed ecosystem increases with time. The key to stability in large foodwebs appears to arise not from complexity per se but from evolution at the level of the ecosystem which favors stabilizing (negative) feedbacks.
传统生态模型表明，复杂性会使食物网不稳定，这意味着食物网不应有大量物种或大量相互作用。然而，在自然界中情况似乎恰恰相反。我们在此表明，如果允许物种间的相互作用在广义的洛特卡 - 沃尔泰拉模型中演化，那么这种稳定反馈和弱相互作用会自动出现。此外，我们还表明，营养级也会从这种演化方法中自发出现，并且未受干扰的生态系统的效率会随时间增加。大型食物网稳定的关键似乎并非源于复杂性本身，而是源于生态系统层面有利于稳定（负）反馈的演化。
