Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, N-1432 Ås, Norway.
Sci Rep. 2016 Jun 1;6:27225. doi: 10.1038/srep27225.
Herbivore cycles are often synchronized over larger areas than what could be explained by dispersal. In Norway, the 3-4 year lemming cycle usually show no more than a one-year time lag between different regions, despite distances of up to 1000 km. If important food plants are forced to reallocate defensive proteins in years with high seed production, spatially synchronized herbivore outbreaks may be due to climate-synchronized peaks in flowering. Because lemming peaks are expected to occur one year after a flowering peak, and the formation of flower buds is induced in the year before flowering, a two-year time lag between flower-inducing climate events and lemming peaks is predicted. At Hardangervidda, South Norway, the probability that a year was a population peak year of lemming during 1920-2014 increased with increasing midsummer atmospheric pressure two years earlier, even when the number of years since the previous peak was accounted for.
食草动物的周期通常比扩散所能解释的范围更大。在挪威，3-4 年的旅鼠周期通常在不同地区之间没有超过一年的时间滞后，尽管距离长达 1000 公里。如果重要的食物植物在种子产量高的年份被迫重新分配防御性蛋白质，那么空间上同步的食草动物爆发可能是由于开花期气候同步达到高峰。由于旅鼠高峰预计在开花高峰后的一年出现，而花芽的形成是在开花前一年诱导的，因此可以预测到诱导气候事件和旅鼠高峰之间存在两年的时间滞后。在南挪威的哈当厄高原，1920-2014 年间，一个年份成为旅鼠种群高峰年份的概率随着两年前仲夏大气压力的增加而增加，即使考虑到前一个高峰以来的年份数。
