USDA Forest Service Pacific Northwest Research Station, 161 East 1st Avenue, Door 8, Anchorage, AK 99501, USA.
Environ Monit Assess. 2013 May;185(5):3931-57. doi: 10.1007/s10661-012-2841-4. Epub 2012 Sep 8.
Introduced plant species have significant negative impacts in many ecosystems and are found in many forests around the world. Some factors linked to the distribution of introduced species include fragmentation and disturbance, native species richness, and climatic and physical conditions of the landscape. However, there are few data sources that enable the assessment of introduced species occupancy in native plant communities over broad regions. Vegetation data from 1,302 forest inventory plots across 24 states in northeastern and mid-western USA were used to examine and compare the distribution of introduced species in relation to forest fragmentation across ecological provinces and forest types, and to examine correlations between native and introduced species richness. There were 305 introduced species recorded, and 66 % of all forested plots had at least one introduced species. Forest edge plots had higher constancy and occupancy of introduced species than intact forest plots, but the differences varied significantly among ecological provinces and, to a lesser degree, forest types. Weak but significant positive correlations between native and introduced species richness were observed most often in intact forests. Rosa multiflora was the most common introduced species recorded across the region, but Hieracium aurantiacum and Epipactus helleborine were dominant in some ecological provinces. Identifying regions and forest types with high and low constancies and occupation by introduced species can help target forest stands where management actions will be the most effective. Identifying seemingly benign introduced species that are more prevalent than realized will help focus attention on newly emerging invasives.
引入的植物物种在许多生态系统中具有显著的负面影响，并且在世界各地的许多森林中都有发现。一些与引入物种分布相关的因素包括破碎化和干扰、本地物种丰富度以及景观的气候和物理条件。然而，很少有数据源可以评估引入物种在原生植物群落中的占有情况，特别是在广阔的地区。利用来自美国东北部和中西部 24 个州的 1302 个森林清查样地的植被数据，研究了引入物种在生态省和森林类型之间与森林破碎化的分布关系，并检验了本地和引入物种丰富度之间的相关性。共记录了 305 种引入物种，66%的森林样地至少有一种引入物种。森林边缘样地的引入物种恒定性和占有性高于完整森林样地，但这种差异在不同生态省之间存在显著差异，在一定程度上也存在于不同森林类型之间。在完整森林中，本地和引入物种丰富度之间通常存在较弱但显著的正相关关系。该地区最常见的引入物种是多花蔷薇，但在一些生态省，橙头草和 Epipactus helleborine 是优势物种。确定具有高恒定性和引入物种占有性的地区和森林类型，可以帮助确定需要采取管理措施的森林林分，从而提高管理措施的效果。确定那些比实际更为普遍的看似良性的引入物种，将有助于关注新出现的入侵物种。
