The effects of agricultural land-use history on non-native plant invasion in Bent Creek Experimental Forest in 2006

The researchers considered the effects of agricultural land-use legacies on the distribution of non-native invasive plants a century after abandonment in a watershed in western North Carolina, USA. The study was conducted at the Bent Creek Experimental Forest (BCEF) 15 km southwest of Asheville, North Carolina, USA, in the Pisgah National Forest. Forest sites that were previously in cultivation and abandoned ca. 1905 were compared with nearby reference sites that were never cultivated. The most common invasive plants were Celastrus orbiculatus Thunb., Microstegium vimineum Trin., and Lonicera japonica Thunb. (Kuhman, Pearson, and Turner 2011). Disentangling the cause–effect relationships between land-use history, the biotic community, and the abiotic template presents a challenge, but understanding the role of land-use legacies may provide important insights regarding the mechanisms underlying the establishment and spread of invasive plants in forest ecosystems (Kuhman, Pearson, and Turner 2011). A total of 86 plots were established at Bent Creek Experimental Forest during the summer of 2006. Specifically, the study was conducted between June and August 2006. Half of these were established in historic agricultural plots and half in reference plots that were not formerly used for agriculture (pasture or rowcrops) based on the 1941 Forest Service Report by William Nesbitt and the appended land-use history map (History of early settlement and land use on the Bent Creek Experimental Forest Buncombe County, NC. 1941). Historic agriculture and reference plots were paired based on similarities in topography and bedrock geology (typically in relatively close proximity to one another). Within sites, two plots were established, one adjacent to the road and one 50 m away from the road (labeled as "A" and "B", respectively, in the "Plot #").研究人员考察了美国北卡罗来纳州西部某流域内，农田利用遗留效应在弃耕一个世纪后对外来入侵植物分布的影响。本研究的实施地点位于美国北卡罗来纳州阿什维尔西南15公里处的本特溪实验林（Bent Creek Experimental Forest, BCEF），地处皮斯加国家森林公园范围内。研究将1905年左右弃耕的既往耕作林地样区与邻近的未耕作参照样区进行对比。本研究中最常见的入侵植物为南蛇藤（Celastrus orbiculatus Thunb.）、莠竹（Microstegium vimineum Trin.）以及忍冬（Lonicera japonica Thunb.）（Kuhman、Pearson与Turner, 2011）。厘清土地利用历史、生物群落与非生物生境基底之间的因果关系是一项挑战，但理解农田利用遗留效应的作用，或可为森林生态系统中入侵植物定植与扩散的潜在机制提供重要见解（Kuhman、Pearson与Turner, 2011）。2006年夏季，研究人员在本特溪实验林共设置86个样地，具体调查时段为2006年6月至8月。其中一半样地设于历史农业样区，另一半设于既往未用于农业（牧场或条播作物田）的参照样区，划分依据为威廉·内斯比特1941年发布的《林务局报告》及附带的土地利用历史地图《北卡罗来纳州邦科姆县本特溪实验林早期定居与土地利用史》（1941年）。历史农业样区与参照样区根据地形与基岩地质的相似性进行配对，通常二者间距较近。在每个样区内设置两个样地：一个紧邻道路，另一个距道路50米，在“样地编号”中分别标记为“A”与“B”。