BACKGROUND Invasions by non-native plants contribute to loss of ecosystem biodiversity and productivity, modification of biogeochemical cycles, and inhibition of natural regeneration of native species. Japanese stiltgrass (Microstegium vimineum (Trin.) A. Campus) is one of the most prevalent invasive grasses in the forestlands of Tennessee, United States. We measured the extent of invasion, identified potential factors affecting invasion, and quantified the relative importance of each factor. We analyzed field data collected by the Forest Inventory and Analysis Program of the U.S. Forest Service to measure the extent of invasion from 2005 to 2011 and identified potential factors affecting invasion during this period using boosted regression trees. RESULTS Our results indicated that presence of Japanese stiltgrass on sampled plots increased 50% (from 269 to 404 plots) during the time period. The probability of invasion was correlated with one landscape condition (elevation) (20.5%) and five forest features (including tree species diversity, basal area, stand age, site productivity, and natural regeneration) (79.5%). Boosted regression trees identified the most influential (highly correlated) variables as tree species diversity (30.7%), basal area (22.9%), elevation (20.5%), and stand age (16.7%). Our results suggest that Japanese stiltgrass is likely to continue its invasion in Tennessee forests. CONCLUSIONS The present model, in addition to correlating the probability of Japanese stiltgrass invasions with current climatic conditions and landscape attributes, could aid in the on-going development of control strategies for confronting Japanese stiltgrass invasions by identifying vulnerable areas that might emerge as a result of likely changes in climatic conditions and land use patterns.

中文翻译：

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林下动荡：影响日本踩草入侵美国田纳西州林地的因素。

背景技术非本地植物的入侵导致生态系统生物多样性和生产力的丧失，生物地球化学循环的改变以及天然物种自然再生的抑制。日本高跷（Microstegium v​​imineum（Trin。）A. Campus）是美国田纳西州林地中最普遍的入侵草之一。我们测量了入侵的程度，确定了影响入侵的潜在因素，并量化了每个因素的相对重要性。我们分析了美国林业局森林调查与分析计划收集的现场数据，以测量2005年至2011年的入侵程度，并使用增强回归树确定了此期间影响入侵的潜在因素。结果我们的结果表明，在这段时间内，采样地上日本高跷草的存在增加了50％（从269处增加至404处）。入侵的可能性与一种景观条件（海拔）（20.5％）和五种森林特征（包括树种多样性，基础面积，林分年龄，立地生产力和自然更新）（79.5％）相关。增强型回归树确定了最具影响力（高度相关）的变量，包括树种多样性（30.7％），基础面积（22.9％），海拔（20.5％）和林分年龄（16.7％）。我们的结果表明，日本高跷可能会继续在田纳西州的森林中入侵。结论本模型除了将日本踩草入侵的可能性与当前气候条件和景观属性相关联之外，