Contrasting changes in surface waters and barrens over the past 60 years for a subarctic forest–tundra site in northern Manitoba based on remote sensing imagery
Contrasting changes in surface waters and barrens over the past 60 years for a subarctic forest–tundra site in northern Manitoba based on remote sensing imagery
复制标题
基于遥感图像的马尼托巴省北部亚北极森林苔原地区过去 60 年地表水和贫瘠之地的变化对比
DOI：
10.1139/cjes-2012-0162
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发表时间：
2013
影响因子：
1.4
通讯作者：
Tvera, Andrea
中科院分区：
文献类型：
--
作者：
Umbanhowar, Charles;Camill, Philip;Edlund, Mark;Geiss, Christoph;Durham, Wesley;Kreger, Dahna;Molano, William;Raskob, Charlie;Stocker, Mary;Tvera, Andrea
北极和亚北极地区的变暖加剧，导致水生和陆地生态系统的范围、生产力和组成发生广泛变化。对遥感图像的分析记录了池塘和湖泊的数量和面积的区域变化，以及高地灌木和小树覆盖范围的扩大。为了更好地了解土壤梯度的长期变化，我们比较了1956年（航空照片）和2008-2011年（高分辨率卫星图像）之间的水体和干旱贫瘠地（>100 m2）的数量和面积，这些地点位于马尼托巴Nejanilini湖附近（59.559°N，97.715°W）。在现代景观中，水体和荒地的数量相似（分别为1162和1297），但水体更大（平均分别为3.1 × 104和681 m2），占表面积的17%，而荒地占0.4%。在过去的60年里，尽管小型水体（<1 000平方米）的数量减少了30%，但水的总表面积没有显著变化（16.7%-17.1%）。然而，数量和面积的贫瘠减少（55%和67%，分别）在所有大小类。这些变化与北极因气温和降水量增加而变绿的现象是一致的。小型水体的丧失表明，潮湿的苔原地区可能正在变干，如果这是真的，可能对碳平衡产生重要影响。我们的观测结果可能是冬季条件变化的结果，再加上该地区永久冻土层冰含量低，这在一定程度上解释了气候变化的区域变化。
Intensified warming in the Arctic and Subarctic is resulting in a wide range of changes in the extent, productivity, and composition of aquatic and terrestrial ecosystems. Analysis of remote sensing imagery has documented regional changes in the number and area of ponds and lakes as well as expanding cover of shrubs and small trees in uplands. To better understand long-term changes across the edaphic gradient, we compared the number and area of water bodies and dry barrens (>100 m2) between 1956 (aerial photographs) and 2008–2011 (high-resolution satellite images) for eight ∼25 km2sites near Nejanilini Lake, Manitoba (59.559°N, 97.715°W). In the modern landscape, the number of water bodies and barrens were similar (1162 versus 1297, respectively), but water bodies were larger (mean 3.1 × 104versus 681 m2, respectively) and represented 17% of surface area compared with 0.4% for barrens. Over the past 60 years, total surface area of water did not change significantly (16.7%–17.1%) despite a ∼30% decrease in numbers of small (<1000 m2) water bodies. However, the number and area of barrens decreased (55% and 67%, respectively) across all size classes. These changes are consistent with Arctic greening in response to increasing temperature and precipitation. Loss of small water bodies suggests that wet tundra areas may be drying, which, if true, may have important implications for carbon balance. Our observations may be the result of changes in winter conditions in combination with low permafrost ice content in the region, in part explaining regional variations in responses to climate change.