Effects of road dust on vegetation composition and surface chemistry of three ombrotrophic peatlands in eastern Canada
Effects of road dust on vegetation composition and surface chemistry of three ombrotrophic peatlands in eastern Canada
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道路灰尘对加拿大东部三个雨养泥炭地植被组成和表面化学的影响
DOI：
10.1016/j.geoderma.2023.116665
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发表时间：
2023-11
期刊：
影响因子：
6.1
通讯作者：
Xiaoyu Li;Julie Talbot;James King;Meng Wang
中科院分区：
文献类型：
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作者：
Xiaoyu Li;Julie Talbot;James King;Meng Wang
粉尘沉降可以给营养有限的泥炭地施肥，并影响泥炭地的植物群落和生态系统功能，但道路局部粉尘对泥炭地的影响研究很少。本文研究了加拿大魁省东部rivire -au- tonnerre （RT）、Chemin de l'Anse-de-la-Grande-Pointe （GP）和Kegaska （KEG）三个共养泥炭地的植被组成和地表化学（植被、地表泥炭和地下水化学）对不同化学成分水平的道路粉尘沉积的响应。在每个地点，沿着主要风向的样带，从路边开始并垂直于路边，以距离砾石（未铺设的）道路250米的间隔进行采样。我们发现，在所有三个站点中，地表泥炭的灰分含量在离道路最近的地方最高，并且随着距离的增加呈指数下降，直至距离道路200 m。在KEG，道路粉尘沉积量最大，且磷含量最丰富，灰分含量在3个站点中最高，且随着距离道路的远近，灰分含量下降最快。在KEG，随着距离道路的增加，叶面组织和表层泥炭中碳(C)、氮(N)和磷的化学计量质量比（C:N、C:P和N:P）显著增加，而且苔藓对道路粉尘沉降的化学反应比灌木更敏感。KEG的总溶解磷浓度较高，离公路较近。在中度道路粉尘沉积的GP， C:N、C:P和N:P比值随距离的显著增加只在地表泥炭中发现，而在叶面组织中则没有。由于GP道路粉尘中碳酸盐矿物的存在，靠近道路的地下水钙（Ca）浓度和pH值较高，导致植被覆盖度明显下降，尤其是苔藓，从而导致NO3−淋滤增加。相比之下，在道路粉尘沉积量最低的RT，沿着采样样带只发现了一些表面化学的清晰变化模式。总体而言，我们的研究结果表明，砾石道路粉尘可能是邻近泥炭地的重要局部营养来源，并影响其植被组成和表面化学成分，这取决于道路粉尘的数量及其化学成分，特别是其钙和磷含量。
Dust deposition can fertilize nutrient-limited peatlands and affect their plant assemblages and ecosystem functions, but the effects of local road dust on peatlands have seldom been studied. Here, we investigate the responses of vegetation composition and surface chemistry (vegetation, surface peat, and groundwater chemistry) at three ombrotrophic peatlands: Rivière-au-Tonnerre (RT), Chemin de l'Anse-de-la-Grande-Pointe (GP), and Kegaska (KEG) in eastern Québec, Canada, to varying levels of road dust deposition with differential chemical composition. At each site, a transect aligned with the dominant wind direction, starting at and perpendicular to the roadside, was sampled at increasing intervals up to 250 m away from the gravel (unpaved) road. We find that the ash content of surface peat is highest closest to the roads at all three sites and decreases exponentially with increasing distance up to 200 m away from the roads. At KEG, with the highest amount of, and the most phosphorus (P) rich, road dust deposition, the ash content is highest among the three sites, decreasing most rapidly with distance away from the road. The stoichiometric mass ratios of carbon (C), nitrogen (N) and P, i.e., C:N, C:P, and N:P, in foliar tissues and surface peat increase significantly with distance away from the road at KEG, and mosses are found to be more responsive in terms of foliar chemistry than shrubs to the road dust deposition. A higher concentration of total dissolved phosphorus at KEG is found closer to the road. At GP, having a moderate amount of road dust deposition, significant increases in C:N, C:P, and N:P ratios with distance are found only in surface peat but not in foliar tissues. Due to the presence of carbonate minerals in the road dust of GP, the calcium (Ca) concentration and pH value of groundwater closer to the road are higher, leading to an obvious loss of vegetation coverage, especially mosses, and a consequent increase in NO3−leaching. In contrast, at RT, having the lowest amount of road dust deposition, only a few clear variation patterns in surface chemistry are found along the sampling transect. Overall, our results suggest that dust from gravel roads can be an important localized source of nutrients for adjacent peatlands and influence their vegetation composition and surface chemistry, depending on the amount of road dust and its chemical composition, especially its contents in Ca and P.