Nagaishi Ellie, Takemoto Kazuhiro
Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Iizuka, Fukuoka 820-8502, Japan.
R Soc Open Sci. 2018 Sep 12;5(9):180706. doi: 10.1098/rsos.180706. eCollection 2018 Sep.
It is theorized that a mutualistic ecosystem's resilience against perturbations (e.g. species extinction) is determined by a single macroscopic parameter (network resilience), calculable from the network. Given that such perturbations occur owing to environmental changes (e.g. climate change and human impact), it has been predicted that mutualistic ecosystems that exist despite extensive environmental changes exhibit higher network resilience; however, such a prediction has not been confirmed using real-world data. Thus, in this study, the effects of climate change velocity and human activities on mutualistic network resilience were investigated. A global dataset of plant-animal mutualistic networks was used, and spatial analysis was performed to examine the effects. Moreover, the potential confounding effects of network size, current climate and altitude were statistically controlled. It was demonstrated that mutualistic network resilience was globally influenced by warming velocity and human impact, in addition to current climate. Specifically, pollination network resilience increased in response to human impact, and seed-dispersal network resilience increased with warming velocity. The effect of environmental changes on network resilience for plants was remarkable. The results confirmed the prediction obtained based on the theory and imply that real-world mutualistic networks have a structure that increases ecosystem resilience against environmental changes. These findings will enhance the understanding of ecosystem resilience.
从理论上讲，互利共生生态系统对干扰（如物种灭绝）的恢复力由一个单一的宏观参数（网络恢复力）决定，该参数可从网络中计算得出。鉴于此类干扰是由环境变化（如气候变化和人类影响）引起的，据预测，尽管环境发生了广泛变化但仍存在的互利共生生态系统具有更高的网络恢复力；然而，这一预测尚未通过实际数据得到证实。因此，在本研究中，调查了气候变化速度和人类活动对互利共生网络恢复力的影响。使用了全球动植物互利共生网络数据集，并进行了空间分析以检验其影响。此外，还对网络规模、当前气候和海拔的潜在混杂效应进行了统计控制。结果表明，除了当前气候外，互利共生网络恢复力在全球范围内还受到变暖速度和人类影响的影响。具体而言，传粉网络恢复力随人类影响而增加，种子传播网络恢复力随变暖速度而增加。环境变化对植物网络恢复力的影响显著。这些结果证实了基于该理论得出的预测，并意味着现实世界中的互利共生网络具有一种结构，可增强生态系统对环境变化的恢复力。这些发现将增进对生态系统恢复力的理解。
