Seasonal climate drivers of peak NDVI in a series of Arctic peatlands.
Seasonal climate drivers of peak NDVI in a series of Arctic peatlands.
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一系列北极泥炭地 NDVI 峰值的季节性气候驱动因素。
DOI：
10.1016/j.scitotenv.2022.156419
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Crichton KA
中科院分区：
文献类型：
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作者：
Crichton KA
植物覆盖和生产力的变化对于推动北极土壤碳动态和固存非常重要，特别是在泥炭地。众所周知，北极变暖趋势导致植物生产力、范围和群落组成发生变化，但仍需要更多数据来提高对所涉及的复杂控制和过程的理解。在这里，我们通过比较高峰生长季 NDVI（来自 Landsat 5 和 7 的归一化植被指数数据）与欧洲和加拿大高北极和低北极地区含有泥炭地的九个地点的季节平均天气数据（温度、降水和融雪时间），评估植物生产力对 1985 年至 2020 年间气候变化的响应。我们发现，春季（泥炭占主导地位的相关性为 0.36，马赛克相关性为 0.39；泥炭的 MLR 系数为 0.20，马赛克的相关性为 0.29）、夏季（0.47，0.42；0.18，0.17）和秋季前（0.35，0.25；0.33，0.27）温度与我们站点的峰值生长季 NDVI 相关。 1985年和2020年，春雪纷飞 融化时间（0.42，0.45；0.25，0.32）也很重要，生长季节的可用水量可能因地点而异。根据回归树，在预测泥炭为主的地区的最高旺季生产力时，温暖的秋季（9月至10月至11月）比温暖的夏季（6月至7月至8月）更重要。与土壤过程相关的机制可以解释前秋条件对生产力的重要性。我们进一步发现，这些北极泥炭地的生产力峰值增幅与周围非泥炭地为主的植被相当。北极泥炭地及其周围生产力的提高表明，随着未来变暖，土壤碳固存可能会增加，但需要进一步的工作来测试这在最近泥炭积累和范围的观察中是否明显。
Changes in plant cover and productivity are important in driving Arctic soil carbon dynamics and sequestration, especially in peatlands. Warming trends in the Arctic are known to have resulted in changes in plant productivity, extent and community composition, but more data are still needed to improve understanding of the complex controls and processes involved. Here we assess plant productivity response to climate variability between 1985 and 2020 by comparing peak growing season NDVI (Normalised Difference Vegetation Index data from Landsat 5 and 7), to seasonal-average weather data (temperature, precipitation and snow-melt timing) in nine locations containing peatlands in high- and low-Arctic regions in Europe and Canada. We find that spring (correlation 0.36 for peat dominant and 0.39 for mosaic; MLR coefficient 0.20 for peat, 0.29 for mosaic), summer (0.47, 0.42; 0.18, 0.17) and preceding-autumn (0.35, 0.25; 0.33, 0.27) temperature are linked to peak growing season NDVI at our sites between 1985 and 2020, whilst spring snow melt timing (0.42, 0.45; 0.25, 0.32) is also important, and growing season water availability is likely site-specific. According to regression trees, a warm preceding autumn (September–October–November) is more important than a warm summer (June–July–August) in predicting the highest peak season productivity in the peat-dominated areas. Mechanisms linked to soil processes may explain the importance of previous-Autumn conditions on productivity. We further find that peak productivity increases in these Arctic peatlands are comparable to those in the surrounding non-peatland-dominant vegetation. Increased productivity in and around Arctic peatlands suggests a potential to increased soil carbon sequestration with future warming, but further work is needed to test whether this is evident in observations of recent peat accumulation and extent.