Department of Biology, University of New Mexico, Albuquerque, NM, USA.
The Rocky Mountain Biological Laboratory, Crested Butte, CO, USA.
Ecol Lett. 2021 Sep;24(9):1930-1942. doi: 10.1111/ele.13829. Epub 2021 Jun 26.
Although rarely experimentally tested, biotic interactions have long been hypothesised to limit low-elevation range boundaries of species. We tested the effects of herbivory on three alpine-restricted plant species by transplanting plants below (novel), at the edge (limit), or in the centre (core) of their current elevational range and factorially fencing-out above- and belowground mammals. Herbivore damage was greater in range limit and novel habitats than in range cores. Exclosures increased plant biomass and reproduction more in novel habitats than in range cores, suggesting demographic costs of novel interactions with herbivores. We then used demographic models to project population growth rates, which increased 5-20% more under herbivore exclosure at range limit and novel sites than in core habitats. Our results identify mammalian herbivores as key drivers of the low-elevation range limits of alpine plants and indicate that upward encroachment of herbivores could trigger local extinctions by depressing plant population growth.
虽然很少进行实验测试，但生物相互作用长期以来一直被假设为限制物种在低海拔地区的分布范围。我们通过将植物移植到当前海拔范围以下（新颖）、边缘（极限）或中心（核心），并对地上和地下哺乳动物进行围栏隔离，来测试食草动物对三种高山限制植物物种的影响。在范围极限和新栖息地中，食草动物的破坏程度大于范围核心。与范围核心相比，在新栖息地中，围栏隔离增加了植物生物量和繁殖更多，这表明与食草动物的新相互作用存在人口成本。然后，我们使用人口模型来预测种群增长率，在范围极限和新地点，与核心栖息地相比，食草动物围栏隔离下的种群增长率增加了 5-20%。我们的研究结果表明，哺乳动物食草动物是高山植物低海拔分布范围的关键驱动因素，并表明食草动物的向上侵袭可能通过降低植物种群增长率而导致局部灭绝。
