Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN, United States.
Sci Rep. 2019 Jan 18;9(1):214. doi: 10.1038/s41598-018-36804-3.
Increased road-building activity in the arctic has the potential to impact adjacent ecosystems. Roads in permafrost regions are often built atop insulative gravel pads that generate dust plumes, altering soil chemistry and ecosystem function of nearby tundra. Here, we measure edaphic and vegetation characteristics along transects of decreasing dust deposition perpendicular to the Dalton Highway in northern Alaska. We quantify the impact of dust deposition on normalized difference vegetation index (NDVI), a proxy for aboveground plant biomass. Deposition of calcium carbonate-rich dust declined from 1.625 grams m day immediately adjacent to the road, to negligible levels 625 meters away. Along these transects from the road, we found declines in soil moisture and temperature, thaw depth, shrub height, and foliar nitrogen content, indicating that tundra roads create corridors with edaphic conditions favorable to vascular plant growth. At sites nearest the road, dust deposited on leaf surfaces reduced measured NDVI values by 0.24 by blocking reflectance properties of the underlying leaves. Our findings on the impacts of roads and dust deposition on adjacent tundra may aid planning of future infrastructure projects. We caution that dust deposition may negatively bias NDVI-based estimates of plant biomass, especially where unpaved roads are common.
北极地区道路建设活动的增加有可能对相邻的生态系统产生影响。在永久冻土地区的道路通常建在隔热砾石垫上，这些砾石垫会产生尘埃羽流，改变附近冻原的土壤化学和生态系统功能。在这里，我们沿着阿拉斯加北部道尔顿高速公路垂直的递减尘埃沉积的横断面测量土壤和植被特征。我们量化了尘埃沉积对归一化差异植被指数（NDVI）的影响，NDVI 是地上植物生物量的替代物。富含碳酸钙的尘埃沉积量从紧邻道路的 1.625 克/米/天下降到 625 米外可忽略不计的水平。在这些从道路延伸的横断面中，我们发现土壤水分和温度、融深、灌木高度和叶片氮含量下降，表明冻原道路形成了有利于维管植物生长的土壤条件走廊。在靠近道路的地方，尘埃沉积在叶片表面，通过阻挡底层叶片的反射特性，使测量的 NDVI 值降低了 0.24。我们关于道路和尘埃沉积对邻近冻原影响的发现可能有助于规划未来的基础设施项目。我们警告说，尘埃沉积可能会对基于 NDVI 的植物生物量估计产生负面影响，尤其是在未铺砌道路很常见的地方。
