Multi-decadal patterns of vegetation succession after tundra fire on the Yukon-Kuskokwim Delta, Alaska
Multi-decadal patterns of vegetation succession after tundra fire on the Yukon-Kuskokwim Delta, Alaska
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阿拉斯加育空-库斯科奎姆三角洲苔原火灾后植被演替的多年代际模式
DOI：
10.1088/1748-9326/ab5f49
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发表时间：
2020
影响因子：
6.7
通讯作者：
S. Natali
中科院分区：
文献类型：
--
作者：
G. Frost;R. Loehman;L. Saperstein;M. Macander;P. Nelson;D. Paradis;S. Natali
阿拉斯加的育空-库斯库温三角洲（YKD）是北极冻土带生物群落中最温暖的地区之一，冻土带火灾在其高地地区很常见。本文结合野外测量、Landsat观测和冻土带植物功能类型（PFTs）的定量覆盖图，对1971-1972年、1985年、2006-2007年和2015年发生过大面积野火的云南高原地衣为主的冻土带进行了火灾后的多年代际演替和景观变化特征分析。未燃烧冻土带地衣丰富，地衣覆盖率低与历史火灾密切相关。虽然我们观察到一些演替模式与早期在阿拉斯加苔原上的工作一致，但其他模式则不是。在我们研究的景观中，很大比例的火前苔藓覆盖和地表泥炭倾向于在火中存活，这有利于现有维管植物的生存，限制了种子补充的机会。尽管在1985年和1971-1972年的火灾中灌木覆盖比未燃烧的苔原高得多，但高灌木（> ~ 0.5 m）很少，PFT图显示火灾后灌木增加的程度和持续时间在景观尺度上具有很高的变异性。火灾引起了高原冻土带物种组成和结构的持续变化，但地衣为主的燃料和厚厚的地表泥炭似乎限制了严重火灾和伴随的土壤变化的可能性。2006-2007年的土壤融化深度比未燃烧的冻土带深约10厘米，但与1985年和1971-1972年的未燃烧冻土带相似。从历史上看，YKD上很少发生重复火灾，植被的功能多样性在火灾后的几十年内得到恢复。我们的发现为预测和监测YKD和其他地区的火后冻土带演替提供了基础。
Alaska’s Yukon-Kuskokwim Delta (YKD) is one of the warmest parts of the Arctic tundra biome and tundra fires are common in its upland areas. Here, we combine field measurements, Landsat observations, and quantitative cover maps for tundra plant functional types (PFTs) to characterize multi-decadal succession and landscape change after fire in lichen-dominated upland tundra of the YKD, where extensive wildfires occurred in 1971–1972, 1985, 2006–2007, and 2015. Unburned tundra was characterized by abundant lichens, and low lichen cover was consistently associated with historical fire. While we observed some successional patterns that were consistent with earlier work in Alaskan tussock tundra, other patterns were not. In the landscape we studied, a large proportion of pre-fire moss cover and surface peat tended to survive fire, which favors survival of existing vascular plants and limits opportunities for seed recruitment. Although shrub cover was much higher in 1985 and 1971–1972 burns than in unburned tundra, tall shrubs (>0.5 m height) were rare and the PFT maps indicate high landscape-scale variability in the degree and persistence of shrub increase after fire. Fire has induced persistent changes in species composition and structure of upland tundra on the YKD, but the lichen-dominated fuels and thick surface peat appear to have limited the potential for severe fire and accompanying edaphic changes. Soil thaw depths were about 10 cm deeper in 2006–2007 burns than in unburned tundra, but were similar to unburned tundra in 1985 and 1971–1972 burns. Historically, repeat fire has been rare on the YKD, and the functional diversity of vegetation has recovered within several decades post-fire. Our findings provide a basis for predicting and monitoring post-fire tundra succession on the YKD and elsewhere.
影响因子：
13.5
作者：
Raynolds, Martha K.;Walker, Donald A.;Troeva, Elena
通讯作者：
Troeva, Elena