Michigan Technological University, 1400 Townsend Drive, Houghton, MI, 49931, USA.
USDA Forest Service, Northern Research Station, 1 Gifford Pinchot Dr., Madison, WI, 53726, USA.
J Environ Manage. 2021 Oct 15;296:113090. doi: 10.1016/j.jenvman.2021.113090. Epub 2021 Jul 10.
Peatlands play a critical role in terrestrial carbon (C) storage, containing an estimated 30% of global soil C, despite occupying only 3% of global land area. Historic management of peatlands has led to widespread degradation and loss of important ecosystem services, including C sequestration. Legacy drainage features in the peatlands of northern Minnesota, USA were studied to assess the volume of peat and the amount of C lost in the ~100 years since drainage. Using high-resolution Light Detection and Ranging (LiDAR) data, we measured elevation changes adjacent to legacy ditches to model pre-ditch surface elevations, which were used to calculate peat volume loss. We established relationships between volume loss and site characteristics from existing geographic information systems datasets and used those relationships to scale volume loss to all mapped peatland ditches in northern Minnesota (USA). We estimated that 0.165 ± 0.009 km of peat have been lost along almost 4000 km of peatland ditches. Peat loss upslope of ditches was significantly less than downslope (P < 0.001). Mean width of the entire ditch-effect zone was 333 ± 8.32 m. Using our volume loss estimates, literature estimates of oxidation, and mean bulk density and peat C% values from Minnesota peatlands, we calculate a total historic loss 3.847 ± 0.364 Tg C. Assuming a constant oxidation rate during the 100 years since drainage, euic and dysic peatlands within the ditch effect zone have lost 0.26 ± 0.08 and 0.40 ± 0.13 Mg C ha yr, respectively, comparable to IPCC estimates. Our spatially-explicit peat loss estimates could be incorporated into decision support tools to inform management decisions regarding peatland C and other ecosystem services.
泥炭地在陆地碳（C）储存中发挥着关键作用，尽管仅占全球土地面积的 3%，但其估计包含了全球土壤碳的 30%。历史上对泥炭地的管理导致了广泛的退化和重要生态系统服务的丧失，包括 C 的固存。本研究对美国明尼苏达州北部的泥炭地中的历史排水特征进行了研究，以评估自排水以来的 100 年间泥炭的体积和 C 的损失量。利用高分辨率的激光雷达（LiDAR）数据，我们测量了邻近历史沟渠的高程变化，以模拟沟渠前的地表高程，从而计算出泥炭体积的损失。我们建立了体积损失与现有地理信息系统数据集的站点特征之间的关系，并利用这些关系将体积损失扩展到明尼苏达州北部所有 mapped 泥炭地沟渠。我们估计，在近 4000 公里的泥炭地沟渠中，有 0.165±0.009 公里的泥炭已经流失。沟渠上游的泥炭损失明显小于下游（P<0.001）。整个沟渠效应带的平均宽度为 333±8.32 米。利用我们的体积损失估计值、文献中关于氧化的估计值以及明尼苏达州泥炭地的平均体积密度和泥炭 C%值，我们计算出了一个历史上总损失 3.847±0.364Tg C。假设在排水后的 100 年期间，氧化速率保持不变，沟渠效应带内的 euic 和 dysic 泥炭地分别失去了 0.26±0.08 和 0.40±0.13 Mg C ha yr，与 IPCC 的估计值相当。我们的空间上明确的泥炭损失估计值可以纳入决策支持工具中，以告知泥炭地 C 和其他生态系统服务的管理决策。
