THE RELATIONSHIP OF VEGETATION TO METHANE EMISSION AND HYDROCHEMICAL GRADIENTS IN NORTHERN PEATLANDS
THE RELATIONSHIP OF VEGETATION TO METHANE EMISSION AND HYDROCHEMICAL GRADIENTS IN NORTHERN PEATLANDS
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DOI：
10.2307/2261594
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发表时间：
1995-06-01
影响因子：
5.5
通讯作者：
BUBIER, JL
中科院分区：
文献类型：
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作者：
BUBIER, JL
1描述了加拿大中北部粘土带地区和魁北克拉布拉多海槽的亚北极地区的一系列森林和开阔的泥炭地的苔藓植物和维管束植物区系。通过分类(TWINSPAN)、去势对应分析(DCA)和典型对应分析(CCA)分析了两个泥炭地的植物区系格局及其与甲烷(CH4)排放、水文和水化学的关系。2尽管两个泥炭地的植被地貌、化学和地质不同，但水化学(pH、Ca、Mg、K-corr)和水文学解释了两个泥炭地的大部分物种分布。在粘土带，苔藓植物主要对地下水位位置作出反应，其次是水化学作用；维管束植物区系则相反。拉布拉多海槽的苔藓植物和维管束的排列比北方更相似。3尽管亚北极地区的CH4排放量低于北方地区，但两个地区的平均CH4通量与平均地下水位高度相关(r(2)=0.73)，而与水化学不相关。最高的CH4排放量(季节平均值大于或等于100mgm(-2)d(-1))出现在隆起的沼泽和有图案的沼泽池塘，那里的泥炭正在退化。4北方和亚北极地区CH4通量、平均地下水位位置和物种分布之间的关系是相似的。苔藓植物通常比维管植物更好地预测CH4通量，但在受灾地区的某些物种除外(如Carer spp)。苔藓植物也是地下水位长期平均位置的更好指标，反映了季节内甲烷产生和氧化的相对区域。在维管植物分析中，灌木覆盖指示了亚北极沼泽急剧分化的串-翼池地形中的干燥条件和低CH4通量，但在灌木和树木较普遍的北方地区较干燥的丘陵-中空微地形中，灌木覆盖对CH4排放的预测较小。总体而言，草本植物或莎草覆盖并不能指示这两个地区的CH4通量。
1 The bryophyte and vascular flora were described for a range of forested and open peatlands in the mid-boreal Clay Belt region of Canada, and in the subarctic region of the Labrador Trough, Quebec. The floristic patterns and their relationships to methane (CH4) emission, hydrology and water chemistry were analysed with classification (TWINSPAN), detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA).2 Despite differences in vegetation physiognomy, chemistry, and geology, water chemistry (pH, Ca, Mg, K-corr) and hydrology explain most of the species distribution in both peatland regions. In the Clay Belt, bryophytes respond primarily to water table position, and secondarily to water chemistry; the reverse is true for the vascular flora. The bryophyte and vascular ordinations are more similar to each other in the Labrador Trough than in boreal sites.3 Although CH4 emissions are lower in subarctic than in boreal sites, mean CH4 flux is strongly correlated with mean water table position (r(2) = 0.73) in both regions, but is not correlated with water chemistry. The highest CH4 emissions (seasonal mean greater than or equal to 100 mg m(-2) day(-1)) occur in raised bog and patterned poor fen pools where the peat mat is degrading.4 The relationships among CH4 flux, mean water table position, and species distribution are similar in both boreal and subarctic regions. Bryophytes are generally better predictors of CH4 flux than vascular plants, except for certain species in flooded sites (e.g. Carer spp.). Bryophytes are also better indicators of the long-term average position of the water table, reflecting relative zones of methane production and oxidation over the season. In the vascular plant analyses, shrub cover indicates dry conditions and low CH4 flux in the sharply differentiated string-flark-pool topography of the subarctic fens, but is less predictive of CH4 emission in the drier hummock-hollow microtopography at boreal sites where shrubs and trees are more pervasive. Overall herbaceous or sedge cover is not indicative of CH4 flux in either region.