Department of Biological Sciences, University of Calgary, Calgary, AB, Canada.
J Anim Ecol. 2019 Jan;88(1):154-163. doi: 10.1111/1365-2656.12905. Epub 2018 Oct 22.
Spatially separated populations of the same species often exhibit correlated fluctuations in abundance, a phenomenon known as spatial synchrony. Dispersal can generate spatial synchrony. In nature, most individuals disperse short distances with a minority dispersing long distances. The effect of occasional long distance dispersal on synchrony is untested, and theoretical predictions are contradictory. Occasional long distance dispersal might either increase both overall synchrony and the spatial scale of synchrony, or reduce them. We conducted a protist microcosm experiment to test whether occasional long distance dispersal increases or decreases overall synchrony and the spatial scale of synchrony. We assembled replicate 15-patch ring metapopulations of the protist predator Euplotes patella and its protist prey Tetrahymena pyriformis. All metapopulations experienced the same dispersal rate, but differed in dispersal distance. Some metapopulations experienced strictly short distance (nearest neighbour) dispersal, others experienced a mixture of short- and long distance dispersal. Occasional long distance dispersal increased overall spatial synchrony and the spatial scale of synchrony for both prey and predators, though the effects were not statistically significant for predators. As predicted by theory, dispersal generated spatial synchrony by entraining the phases of the predator-prey cycles in different patches, a phenomenon known as phase locking. Our results are consistent with theoretical models predicting that occasional long distance dispersal increases spatial synchrony. However, our results also illustrate that the spatial scale of synchrony need not match the spatial scale of the processes generating synchrony. Even strictly short distance dispersal maintained high spatial synchrony for many generations at spatial scales much longer than the dispersal distance, thanks to phase locking.
同一物种的空间上分离的种群通常表现出丰度的相关波动，这种现象称为空间同步性。扩散可以产生空间同步性。在自然界中，大多数个体进行短距离扩散，少数个体进行长距离扩散。偶尔的长距离扩散对同步性的影响尚未得到检验，理论预测也存在矛盾。偶尔的长距离扩散可能会增加整体同步性和同步性的空间尺度，也可能会降低它们。我们进行了原生动物微观实验，以测试偶尔的长距离扩散是否会增加或减少整体同步性和同步性的空间尺度。我们组装了原生动物捕食者 Euplotes patella 和其原生动物猎物 Tetrahymena pyriformis 的重复 15 个斑块环复合种群。所有复合种群都经历相同的扩散率，但扩散距离不同。一些复合种群经历严格的短距离（最近邻）扩散，而另一些则经历短距离和长距离扩散的混合。偶尔的长距离扩散增加了猎物和捕食者的整体空间同步性和同步性的空间尺度，尽管对于捕食者来说，这种影响在统计学上并不显著。正如理论预测的那样，扩散通过使不同斑块中的捕食者-猎物周期相位锁定，产生了空间同步性。我们的结果与预测偶尔的长距离扩散增加空间同步性的理论模型一致。然而，我们的结果也表明，同步性的空间尺度不一定与产生同步性的过程的空间尺度相匹配。即使是严格的短距离扩散，也由于相位锁定，在比扩散距离长得多的空间尺度上维持了许多代的高空间同步性。
