Scaling relations in food webs.
Scaling relations in food webs.
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DOI：
10.1103/physreve.73.041903
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发表时间：
2006-04
期刊：
影响因子：
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通讯作者：
Loide Barbosa;A. C. E. Silva;J. K. L. D. Silva
中科院分区：
文献类型：
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作者：
Loide Barbosa;A. C. E. Silva;J. K. L. D. Silva
在过去的三十年里，研究人员试图确定食物网结构中的普遍模式。最近有人提出，表征大型和小型食物网能量传输效率的指数eta可能具有一个普适值（eta = 1.13）。在这项工作中，我们建立了一个一般的生成树与一个固定数量的营养物种和水平，这个指数的上下界。当物种的数量很大时，上下限都等于1，这意味着结果eta = 1.13是由于有限尺寸效应，这个指数的值取决于网络的大小。我们还评估分析和数值的指数eta的分层和随机网络。在所有情况下，指数eta取决于营养物种的数量K，当K很大时，我们有eta->1。此外，这一结果适用于任何固定数量M的营养级。
In the last three decades, researchers have tried to identify universal patterns in the structure of food webs. It was recently proposed that the exponent eta characterizing the efficiency of the transport of energy in large and small food webs might have a universal value (eta = 1.13). In this work we establish lower and upper bounds for this exponent in a general spanning tree with a fixed number of trophic species and levels. When the number of species is large, the lower and upper bounds are equal to 1, implying that the result eta = 1.13 is due to finite-size effects and that the value of this exponent depends on the size of the web. We also evaluate analytically and numerically the exponent eta for hierarchical and random networks. In all cases the exponent eta depends on the number of trophic species K, and when K is large we have that eta-->1. Moreover, this result holds for any fixed number M of trophic levels.