Arctic greening from warming promotes declines in caribou populations.
Arctic greening from warming promotes declines in caribou populations.
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DOI：
10.1126/sciadv.1601365
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发表时间：
2017-04
期刊：
影响因子：
13.6
通讯作者：
Hausner VH
中科院分区：
文献类型：
--
作者：
Fauchald P;Park T;Tømmervik H;Myneni R;Hausner VH
一个更加绿色的北极并没有使驯鹿受益;由于变暖而导致的苔原植被的变化与驯鹿群的减少有关。北美的迁徙苔原驯鹿群遵循十年的人口周期，丰富的驯鹿的浏览可以预期抵消目前气候驱动的环极苔原生物群落中灌木的扩张。我们证明，在北冰洋的海冰覆盖提供了一个强烈的信号，气候引起的变化对邻近的驯鹿夏季范围，优于其他气候指数解释驯鹿植物动态。我们没有发现驯鹿丰富的植被生物量的负面影响的证据。相反，我们发现了一个强大的自下而上的影响，其中一个温暖的气候有关减少海冰增加了植物生物量的夏季牧场，沿着矛盾的下降驯鹿种群。这一结果表明，这种气候引起的绿化一直伴随着牧场质量的恶化。北美北极地区的灌木扩张涉及具有强大抗浏览防御的植物物种。因此，我们的研究结果可能是一个早期的信号，气候驱动的转变，在驯鹿植物的相互作用，从一个系统与低植物生物量调制周期驯鹿种群占主导地位的非食用灌木和减少成群的迁徙驯鹿。
A greener Arctic does not benefit caribou; the shift in tundra vegetation due to warming is associated with declining caribou herds. The migratory tundra caribou herds in North America follow decadal population cycles, and browsing from abundant caribou could be expected to counteract the current climate-driven expansion of shrubs in the circumpolar tundra biome. We demonstrate that the sea ice cover in the Arctic Ocean has provided a strong signal for climate-induced changes on the adjacent caribou summer ranges, outperforming other climate indices in explaining the caribou-plant dynamics. We found no evidence of a negative effect of caribou abundance on vegetation biomass. On the contrary, we found a strong bottom-up effect in which a warmer climate related to diminishing sea ice has increased the plant biomass on the summer pastures, along with a paradoxical decline in caribou populations. This result suggests that this climate-induced greening has been accompanied by a deterioration of pasture quality. The shrub expansion in Arctic North America involves plant species with strong antibrowsing defenses. Our results might therefore be an early signal of a climate-driven shift in the caribou-plant interaction from a system with low plant biomass modulated by cyclic caribou populations to a system dominated by nonedible shrubs and diminishing herds of migratory caribou.