Local snow melt and temperature-but not regional sea ice-explain variation in spring phenology in coastal Arctic tundra
Local snow melt and temperature-but not regional sea ice-explain variation in spring phenology in coastal Arctic tundra
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DOI：
10.1111/gcb.14639
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发表时间：
2019-07-01
影响因子：
11.6
通讯作者：
Hollister, Robert D.
中科院分区：
文献类型：
--
作者：
Assmann, Jakob J.;Myers-Smith, Isla H.;Hollister, Robert D.
北极正在经历剧烈的环境变化，地表温度迅速上升，海冰加速减少，积雪状况不断变化，所有这些都影响着苔原植物的物候。尽管有这些变化，但北极地区春季物候趋势没有全球一致的方向。虽然春天在一些地方提前了，但在其他地方，春天推迟了或没有变化，突出了大量无法解释的变化。在这里，我们测试的相对重要性，当地的温度，当地的融雪日期和区域春季下降海冰范围作为控制春季物候在不同地点和物种的变化。春季落叶和开花（平均跨度：18年）的长期时间序列的趋势是高度可变的14个冻原物种在我们的四个研究地点在阿拉斯加，加拿大和格陵兰岛的北极海岸，从每十年10.06天的进展，每十年1.67天的延迟。春季气温和海冰范围的春季下降日在所有站点（平均每十年1摄氏度和每十年21天，分别），但只有那些网站的进步，在融雪（平均每十年提前5天）也有推进物候。春季植物物候的变化最好解释融雪日期（平均效应：0.45天提前物候每提前一天融雪），并在较小程度上，平均春季温度（平均效应：2.39天提前物候每摄氏度）。与以往在不同空间尺度上研究海冰和物候的研究相反，在我们的分析中，海冰范围的区域春季下降并不能预测任何物种或地点的春季物候。我们的研究结果强调，苔原植被对全球变化的反应比对变暖的直接反应更为复杂，并强调了积雪融化作为苔原春季物候的当地驱动因素的重要性。
The Arctic is undergoing dramatic environmental change with rapidly rising surface temperatures, accelerating sea ice decline and changing snow regimes, all of which influence tundra plant phenology. Despite these changes, no globally consistent direction of trends in spring phenology has been reported across the Arctic. While spring has advanced at some sites, spring has delayed or not changed at other sites, highlighting substantial unexplained variation. Here, we test the relative importance of local temperatures, local snow melt date and regional spring drop in sea ice extent as controls of variation in spring phenology across different sites and species. Trends in long-term time series of spring leaf-out and flowering (average span: 18 years) were highly variable for the 14 tundra species monitored at our four study sites on the Arctic coasts of Alaska, Canada and Greenland, ranging from advances of 10.06 days per decade to delays of 1.67 days per decade. Spring temperatures and the day of spring drop in sea ice extent advanced at all sites (average 1 degrees C per decade and 21 days per decade, respectively), but only those sites with advances in snow melt (average 5 days advance per decade) also had advancing phenology. Variation in spring plant phenology was best explained by snow melt date (mean effect: 0.45 days advance in phenology per day advance snow melt) and, to a lesser extent, by mean spring temperature (mean effect: 2.39 days advance in phenology per degrees C). In contrast to previous studies examining sea ice and phenology at different spatial scales, regional spring drop in sea ice extent did not predict spring phenology for any species or site in our analysis. Our findings highlight that tundra vegetation responses to global change are more complex than a direct response to warming and emphasize the importance of snow melt as a local driver of tundra spring phenology.