The effects of network topology, climate variability and shocks on the evolution and resilience of a food trade network
The effects of network topology, climate variability and shocks on the evolution and resilience of a food trade network
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DOI：
10.1371/journal.pone.0213378
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发表时间：
2019-03-26
期刊：
影响因子：
3.7
通讯作者：
Dermody, Brian J.
中科院分区：
文献类型：
--
作者：
Dolfing, Alexander G.;Leuven, Jasper R. F. W.;Dermody, Brian J.
未来的气候变化将增加粮食生产和粮食贸易网络的可变性。然而，气候多变性和突然冲击对通过贸易获得资源的影响及其随后对人口增长的影响在很大程度上是未知的。在这里，我们研究了资源的可变性和网络拓扑结构对获得资源和人口增长的影响，使用一个模型，在贸易网络中的资源可用性限制的人口增长。资源在网络中根据供应和节点（即城市或国家）之间的距离进行重新分配。节点处的资源随时间变化，波动参数模拟已知气候变率引起的生物量生产变化。资源的随机扰动被应用于研究单个节点和整个系统的弹性。该模型表明，资源的重新分配增加了网络可以支持的最大人口（承载能力）。承载能力的波动取决于资源变化的幅度和频率：幅度越大，频率越低，波动就越大。研究表明，网络拓扑结构是决定网络节点承载能力的关键因素。在更大的网络中，承载能力增加，并且网络中的资源分配变得更加平等。最中心的节点比具有较低中心度的节点实现更高的承载能力。此外，中心节点不太容易受到长期资源变化和冲击的影响。这些见解可用于了解如何在气候多变性增加的情况下保持全球公平获取资源。
Future climate change will impose increased variability on food production and food trading networks. However, the effect of climate variability and sudden shocks on resource availability through trade and its subsequent effect on population growth is largely unknown. Here we study the effect of resource variability and network topology on access to resources and population growth, using a model of population growth limited by resource availability in a trading network. Resources are redistributed in the network based on supply and the distance between nodes (i.e. cities or countries). Resources at nodes vary over time with wave parameters that mimic changes in biomass production arising from known climate variability. Random perturbations to resources are applied to study resilience of individual nodes and the system as a whole. The model demonstrates that redistribution of resources increases the maximum population that can be supported (carrying capacity) by the network. Fluctuations in carrying capacity depend on the amplitude and frequency of resource variability: fluctuations become larger for increasing amplitude and decreasing frequency. Our study shows that topology is the key factor determining the carrying capacity of a node. In larger networks the carrying capacity increases and the distribution of resources in the network becomes more equal. The most central nodes achieve a higher carrying capacity than nodes with a lower centrality. Moreover, central nodes are less susceptible to long-term resource variability and shocks. These insights can be used to understand how worldwide equitable access to resources can be maintained under increasing climate variability.