Department of Environmental Sciences, University of Virginia, Charlottesville, Virginia, USA.
Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA.
Ecol Lett. 2022 May;25(5):1189-1201. doi: 10.1111/ele.13991. Epub 2022 Mar 4.
Spatial synchrony may be tail-dependent, that is, stronger when populations are abundant than scarce, or vice-versa. Here, 'tail-dependent' follows from distributions having a lower tail consisting of relatively low values and an upper tail of relatively high values. We present a general theory of how the distribution and correlation structure of an environmental driver translates into tail-dependent spatial synchrony through a non-linear response, and examine empirical evidence for theoretical predictions in giant kelp along the California coastline. In sheltered areas, kelp declines synchronously (lower-tail dependence) when waves are relatively intense, because waves below a certain height do little damage to kelp. Conversely, in exposed areas, kelp is synchronised primarily by periods of calmness that cause shared recovery (upper-tail dependence). We find evidence for geographies of tail dependence in synchrony, which helps structure regional population resilience: areas where population declines are asynchronous may be more resilient to disturbance because remnant populations facilitate reestablishment.
空间同步性可能依赖于尾部，也就是说，当种群丰富时比稀缺时更强，反之亦然。这里，“依赖于尾部”是指分布具有一个由相对低值组成的下尾部和一个由相对高值组成的上尾部。我们提出了一个一般理论，说明环境驱动因素的分布和相关结构如何通过非线性响应转化为依赖于尾部的空间同步性，并在加利福尼亚海岸线的巨型海带中检验了理论预测的经验证据。在受保护的区域，当波浪相对强烈时，海带会同步下降（下尾部依赖），因为低于一定高度的波浪对海带几乎没有损害。相反，在暴露的区域，海带主要通过平静期同步，这导致了共同的恢复（上尾部依赖）。我们发现了同步性中尾部依赖的地理证据，这有助于构建区域种群的恢复力：种群下降不同步的区域可能对干扰更有弹性，因为残余种群有助于重新建立。
