Barlow Kathryn M, Mortensen David A, Drohan Patrick J, Averill Kristine M
Department of Plant Science, The Pennsylvania State University, PA, 16802, USA.
Department of Plant Science, The Pennsylvania State University, PA, 16802, USA.
J Environ Manage. 2017 Nov 1;202(Pt 1):208-216. doi: 10.1016/j.jenvman.2017.07.005. Epub 2017 Jul 20.
Vegetation removal and soil disturbance from natural resource development, combined with invasive plant propagule pressure, can increase vulnerability to plant invasions. Unconventional oil and gas development produces surface disturbance by way of well pad, road, and pipeline construction, and increased traffic. Little is known about the resulting impacts on plant community assembly, including the spread of invasive plants. Our work was conducted in Pennsylvania forests that overlay the Marcellus and Utica shale formations to determine if invasive plants have spread to edge habitat created by unconventional gas development and to investigate factors associated with their presence. A piecewise structural equation model was used to determine the direct and indirect factors associated with invasive plant establishment on well pads. The model included the following measured or calculated variables: current propagule pressure on local access roads, the spatial extent of the pre-development road network (potential source of invasive propagules), the number of wells per pad (indicator of traffic density), and pad age. Sixty-one percent of the 127 well pads surveyed had at least one invasive plant species present. Invasive plant presence on well pads was positively correlated with local propagule pressure on access roads and indirectly with road density pre-development, the number of wells, and age of the well pad. The vast reserves of unconventional oil and gas are in the early stages of development in the US. Continued development of this underground resource must be paired with careful monitoring and management of surface ecological impacts, including the spread of invasive plants. Prioritizing invasive plant monitoring in unconventional oil and gas development areas with existing roads and multi-well pads could improve early detection and control of invasive plants.
自然资源开发导致的植被清除和土壤扰动，再加上外来入侵植物繁殖体的压力，会增加植物受入侵的脆弱性。非常规油气开发通过井场、道路和管道建设以及交通流量增加产生地表扰动。人们对由此对植物群落组装产生的影响知之甚少，包括入侵植物的扩散。我们的研究在宾夕法尼亚州覆盖马塞勒斯和尤蒂卡页岩层的森林中进行，以确定入侵植物是否已扩散到非常规天然气开发所形成的边缘栖息地，并调查与其存在相关的因素。使用分段结构方程模型来确定与井场上入侵植物定殖相关的直接和间接因素。该模型包括以下测量或计算变量：当地通路目前的繁殖体压力、开发前道路网络的空间范围（入侵繁殖体的潜在来源）、每个井场的井数（交通密度指标）以及井场使用年限。在调查的127个井场中，61%至少有一种入侵植物物种存在。井场上入侵植物的存在与通路的当地繁殖体压力呈正相关，与开发前的道路密度、井数和井场使用年限呈间接正相关。美国大量的非常规油气储备正处于开发初期。这种地下资源的持续开发必须与对地表生态影响的仔细监测和管理相结合，包括入侵植物的扩散。在有现有道路和多井场的非常规油气开发区优先进行入侵植物监测，可改善对入侵植物的早期发现和控制。
