The Arctic tundra is warming rapidly, yet the exact mechanisms linking warming and observed ecological changes are often unclear. Understanding mechanisms of change requires long‐term monitoring of multiple ecological parameters. Here, we present the findings of a collaboration between government scientists, local people, park rangers, and academic researchers that provide insights into changes in plant composition, phenology, and growth over 18 yr on Qikiqtaruk‐Herschel Island, Canada. Qikiqtaruk is an important focal research site located at the latitudinal tall shrub line in the western Arctic. This unique ecological monitoring program indicates the following findings: (1) nine days per decade advance of spring phenology, (2) a doubling of average plant canopy height per decade, but no directional change in shrub radial growth, and (3) a doubling of shrub and graminoid abundance and a decrease by one‐half in bare ground cover per decade. Ecological changes are concurrent with satellite‐observed greening and, when integrated, suggest that indirect warming from increased growing season length and active layer depths, rather than warming summer air temperatures alone, could be important drivers of the observed tundra vegetation change. Our results highlight the vital role that long‐term and multi‐parameter ecological monitoring plays in both the detection and attribution of global change.

中文翻译：

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十八年的生态监测揭示了苔原植被变化的多种证据

北极苔原正在迅速变暖，但是将变暖和观测到的生态变化联系起来的确切机制通常是不清楚的。要了解变化的机制，就需要长期监控多个生态参数。在这里，我们介绍政府科学家，当地人，公园管理员和学术研究人员之间合作的发现，这些发现提供了对加拿大奇基夸鲁克-赫歇尔岛18年以上植物组成，物候和生长变化的见解。奇奇塔鲁克（Qikiqtaruk）是重要的重点研究地点，位于北极西部的纬向高灌木线。这个独特的生态监测程序表明以下发现：（1）春季物候每十年提前九天，（2）每十年平均植物冠层高度增加一倍，但灌木径向生长没有方向性变化，（3）灌木和类粉虫的丰度翻倍，并且每十年的裸地覆盖率减少一半。生态变化与卫星观测到的绿化同时发生，如果整合在一起，则表明由生长季节长度和活动层深度的增加引起的间接变暖，而不是仅使夏季气温变暖，可能是观察到的苔原植被变化的重要驱动力。我们的结果突出了长期和多参数生态监测在全球变化的发现和归因中所起的关键作用。而不是仅使夏季气温变暖，可能是观察到的冻原植被变化的重要驱动力。我们的结果突出了长期和多参数生态监测在全球变化的发现和归因中所起的关键作用。而不是仅使夏季气温变暖，可能是观察到的冻原植被变化的重要驱动力。我们的结果凸显了长期和多参数生态监测在全球变化的发现和归因中所起的关键作用。