Early warnings of regime shift when the ecosystem structure is unknown.
Early warnings of regime shift when the ecosystem structure is unknown.
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DOI：
10.1371/journal.pone.0045586
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Carpenter SR
中科院分区：
文献类型：
--
作者：
Brock WA;Carpenter SR
有时可以利用监测数据发现生态系统动态的突然变化。使用非参数的方法，假设基本结构的知识最少，我们计算单独的估计的漂移（确定性）和扩散（随机）组件的一般动态过程，以及一个指标的条件方差。理论和模拟结果表明，非参数条件方差在临界转变之前上升。非参数扩散也上升，在真正的扩散函数涉及临界转变（有时称为噪声诱导转变）的情况下。因此，通过比较条件方差和扩散函数的时间序列，可以区分噪声诱导跃迁和其他类型的临界跃迁。蒙特卡洛分析表明，在生态系统转型前，各指标总体上呈上升趋势，但随着生态系统接近转型点，各指标的不确定性变大。
Abrupt changes in dynamics of an ecosystem can sometimes be detected using monitoring data. Using nonparametric methods that assume minimal knowledge of the underlying structure, we compute separate estimates of the drift (deterministic) and diffusion (stochastic) components of a general dynamical process, as well as an indicator of the conditional variance. Theory and simulations show that nonparametric conditional variance rises prior to critical transition. Nonparametric diffusion rises also, in cases where the true diffusion function involves a critical transition (sometimes called a noise-induced transition). Thus it is possible to discriminate noise-induced transitions from other kinds of critical transitions by comparing time series for the conditional variance and the diffusion function. Monte Carlo analysis shows that the indicators generally increase prior to the transition, but uncertainties of the indicators become large as the ecosystem approaches the transition point.