White T C R
School of Agriculture Food and Wine, Waite Agricultural Research Institute, The University of Adelaide, Glen Osmond, South Australia 5064, Australia.
Biol Rev Camb Philos Soc. 2008 Aug;83(3):227-48. doi: 10.1111/j.1469-185X.2008.00041.x.
More and more studies are demonstrating that populations of animals - from herbivores to top predators, vertebrates and invertebrates - are limited by their food, and that the availability of this food is dictated by the weather. Satellite monitoring is revealing how cyclic and quasi-cyclic climatic patterns, like the El Niño Southern Oscillation and the North Atlantic Oscillation, are driving and synchronising these weather-driven changes in the supplies of food. Changes in the amount of food available operate to limit the abundance of populations largely through their influence on the survival of the very young: the Achilles heel of all populations. Any individual organism struggles to use whatever resources it can get from a mostly inhospitable environment to maximise the proliferation of its genes. Each level of a food chain is thus dependent upon, and pressing hard against the limits set by the one below. The resulting intra- and inter-specific interactions produce a multitude of complex outcomes, that significantly influence the dynamics of populations, but do not determine their ultimate size. There is no density-dependent regulation of abundance. Intra-specific competition does not determine the size of populations, it only decides which few individuals gain access to the limited food. Nor do predators regulate their prey. They, too, are limited by their food, and the abundance and quality of food is dictated by the weather.
越来越多的研究表明，从食草动物到顶级食肉动物、脊椎动物和无脊椎动物等各类动物种群都受到食物的限制，而且这种食物的可获得性取决于天气。卫星监测正在揭示诸如厄尔尼诺南方涛动和北大西洋涛动等周期性和准周期性气候模式是如何驱动并同步这些由天气引发的食物供应变化的。可获得食物量的变化主要通过影响幼崽的存活来限制种群数量：这是所有种群的致命弱点。任何个体生物都在努力利用它能从大多并不适宜生存的环境中获取的资源，以最大限度地增加其基因的繁衍。因此，食物链的每一个层级都依赖于下一层级，并紧紧受制于下一层级所设定的限制。由此产生的种内和种间相互作用会产生众多复杂的结果，这些结果会显著影响种群动态，但并不能决定种群的最终规模。不存在与密度相关的数量调节机制。种内竞争并不能决定种群规模，它只是决定了少数个体能够获取有限的食物。捕食者也不会调节它们的猎物数量。它们同样受到食物的限制，而食物的数量和质量取决于天气。
