Am Nat. 2020 Feb;195(2):216-230. doi: 10.1086/706913. Epub 2019 Dec 18.
Many species show synchronous fluctuations in population size over large geographical areas, which are likely to increase their regional extinction risk. Here we examine how the degree of spatial synchrony in population dynamics is affected by trophic interactions using a two-species predator-prey model with spatially correlated environmental noise. We show that the predator has a larger spatial scale of population synchrony than the prey if the population fluctuations of both species are mainly determined by the direct effect of stochastic environmental variations in the prey. This result implies that in ecosystems regulated from the bottom up, the spatial scale of synchrony of the predator population increases beyond the scale of the spatial autocorrelation in the environmental noise and in the prey fluctuations. Harvesting the prey increases the spatial scale of population synchrony of the predator, while harvesting the predator reduces the spatial scale of the population fluctuations of its prey. Hence, the development of sustainable harvesting strategies should also consider the impact on unharvested species at other trophic levels as well as human perturbations of ecosystems, whether the result of exploitation or an effect on dispersal processes, as they can affect food web structures and trophic interactions over large geographical areas.
许多物种在大地理区域内表现出种群规模的同步波动，这可能会增加它们在区域内灭绝的风险。在这里，我们使用具有空间相关环境噪声的两种群捕食者-猎物模型来研究种群动态的空间同步程度如何受到营养相互作用的影响。我们表明，如果两个物种的种群波动主要由猎物中随机环境变化的直接影响决定，则捕食者的种群同步空间尺度大于猎物。这一结果意味着，在自下而上调节的生态系统中，捕食者种群的同步空间尺度会超过环境噪声和猎物波动的空间自相关尺度。猎物的收获增加了捕食者种群同步的空间尺度，而捕食者的收获则减少了其猎物种群波动的空间尺度。因此，可持续收获策略的制定还应考虑到对其他营养级未收获物种的影响，以及人类对生态系统的干扰，无论是由于开发还是对扩散过程的影响，因为它们会影响食物网结构和大地理区域内的营养相互作用。
