The Impact of Spatial and Temporal Dimensions of Disturbances on Ecosystem Stability
The Impact of Spatial and Temporal Dimensions of Disturbances on Ecosystem Stability
复制标题
扰动的时空维度对生态系统稳定性的影响
DOI：
10.1101/429100
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发表时间：
2018
影响因子：
3
通讯作者：
M. Loreau
中科院分区：
文献类型：
--
作者：
Yuval R. Zelnik;J. Arnoldi;M. Loreau
生态系统不断面临时空特征不同的干扰，但关于这些特征如何影响生态系统的恢复和持久性，即生态系统的稳定性，人们知之甚少。我们通过考虑三个具有不同局部动力的生态系统模型来解决这个问题，并询问它们的稳定性特性如何依赖于扰动的空间和时间特性。我们通过扰动的空间范围来衡量扰动的空间维度，同时控制扰动的总体强度，并通过随机扰动事件的平均频率来衡量扰动的时间维度。我们的模型表明，由于扩散中介的救援效应，扰动后恢复平衡的程度强烈依赖于扰动的程度。然后，我们揭示了由重复扰动引起的时间变异性与从孤立扰动事件中恢复之间的直接关系。虽然这可能意味着生态系统响应对干扰频率的微小依赖，但我们发现只有在频率阈值以下才是正确的，这取决于干扰空间特征和生态系统动力学。超过这一阈值，响应发生质的变化，表现出扰动区域的空间集群，导致变异性增加，甚至失去具有替代稳定状态的生态系统的持久性。因此，跨越干扰的空间维度可以探测生态系统的潜在动态。此外，有必要同时考虑干扰的空间和时间维度，以预测可能产生戏剧性后果的生态系统反应的类型，例如制度变化。
Ecosystems constantly face disturbances which vary in their spatial and temporal features, yet little is known on how these features affect ecosystem recovery and persistence, i.e. ecosystem stability. We address this issue by considering three ecosystem models with different local dynamics, and ask how their stability properties depend on the spatial and temporal properties of disturbances. We measure the spatial dimension of disturbances by their spatial extent while controlling for their overall strength, and their temporal dimension by the average frequency of random disturbance events. Our models show that the return to equilibrium following a disturbance depends strongly on the disturbance’s extent, due to rescue effects mediated by dispersal. We then reveal a direct relation between the temporal variability caused by repeated disturbances and the recovery from an isolated disturbance event. Although this could suggest a trivial dependency of ecosystem response on disturbance frequency, we find that this is true only up to a frequency threshold, which depends on both the disturbance spatial features and the ecosystem dynamics. Beyond this threshold the response changes qualitatively, displaying spatial clusters of disturbed regions, causing an increase in variability, and even the loss of persistence for ecosystems with alternative stable states. Thus, spanning the spatial dimension of disturbances can allow probing of the underlying dynamics of the ecosystem. Furthermore, considering spatial and temporal dimensions of disturbances in conjunction is necessary to predict the type of ecosystem responses that can have dramatic consequences, such as regime shifts.