Quantitative integration of factors that potentially affect exotic species richness and abundance at multiple spatial scales is relatively scarce in the literature. Our aim was to address this gap by evaluating the relative importance of the biotic community, abiotic factors, and landscape characteristics on the establishment and spread of native and exotic plant species. We assessed the effect of these factors on exotic and native species richness and abundance, and used regression tree and variation partitioning analyses to evaluate how these predictors interact to favor or limit exotic and/or native species. We found that landscape filters were especially important for the arrival of both native and exotic species, whereas biotic factors seemed to regulate the abundance of plant species once they were present within the system. However, the combined effects of different types of predictors explained the largest fraction of total variation in all models regarding exotic species. Furthermore, significant predictor variables had opposite effects on native versus exotic species at both local and landscape scales, which suggests that some ecosystem properties affect native and exotic species differently. Exotic species richness and abundance were increased by low values of native species cover and diversity, high landscape heterogeneity and edge density, human disturbances (e.g., mowing and soil disruption), land use activities (e.g., developed and agricultural areas), and proximity to transportation systems, especially highways. However, exotic species were less common in areas with low anthropogenic disturbance, where natural disturbances seemed to favor native plant species.

在多个空间尺度上潜在影响外来物种丰富度和丰度的因素的定量整合在文献中相对较少。我们的目标是通过评估生物群落，非生物因素和景观特征对本地和外来植物物种的建立和传播的相对重要性来解决这一差距。我们评估了这些因素对外来和本地物种的丰富度和丰度的影响，并使用回归树和变异分区分析来评估这些预测因素如何相互作用，以支持或限制外来和/或本地物种。我们发现景观过滤器对于本地和外来物种的到来特别重要，而一旦生物因子存在于系统中，生物因素似乎就可以调节植物物种的丰度。然而，在有关外来物种的所有模型中，不同类型的预测变量的综合影响解释了总变异的最大部分。此外，重要的预测变量对本地和外来物种在地方和景观尺度上都有相反的影响，这表明某些生态系统特性对本地和外来物种的影响不同。外来物种的丰富度和丰富度因以下原因而增加：本地物种的覆盖率和多样性低，景观异质性和边缘密度高，人为干扰（例如割草和土壤破坏），土地利用活动（例如发达和农业地区）以及邻近地区运输系统，尤其是高速公路。但是，在人为干扰较低的地区，外来物种较少见，那里的自然干扰似乎偏向本地植物物种。