Exotic Populus taxa pose a threat to the success of riparian forest restoration in floodplain areas. We evaluated the impact of exotic Populus taxa on softwood riparian forest development along the river Common Meuse after introducing native Populus nigra and after the re-establishment of the natural river dynamics. We sampled 154 poplar seedlings that spontaneously colonized restored habitat and assessed their taxonomy based on diagnostic chloroplast and nuclear microsatellite markers. Furthermore, by using a paternity analysis on 72 seedlings resulting from six open pollinated P. nigra females, we investigated natural hybridization between frequently planted cultivated poplars and native P. nigra. The majority of the poplar seedlings from the gravel banks analyzed where identified as P. nigra; only 2% of the sampled seedlings exhibited genes of exotic poplar species. Similarly, the majority of the seedlings from the open pollinated progenies were identified as P. nigra. For three seedlings (4%), paternity was assigned to a cultivar of P. × canadensis. Almost two decades after reintroducing P. nigra, the constitution of the seed and pollen pools changed in the study area in favor of reproduction of the native species and at the expense of the exotic poplar species. This study indicates that, although significant gene flow form exotic poplars is observed in European floodplains, restoration programs of the native P. nigra can vigorously outcompete the exotic gene flows and strongly reduce the impact of exotic Populus taxa on the softwood riparian forest development.

异国情调 胡杨分类单元对洪泛区的河岸森林恢复成功构成威胁。我们评估了异国情调的影响胡杨 引进原生种后沿默兹河沿岸的软木河岸森林发展的分类单元 黑杨并重新建立了自然河流动力学。我们对154棵自发定居恢复的生境的杨树幼苗进行了采样，并根据诊断性叶绿体和核微卫星标记评估了它们的分类学。此外，通过对六个开放授粉的72株幼苗进行亲子关系分析黑黑松 雌性，我们调查了经常种植的栽培杨树和本地杨树之间的自然杂交 黑黑松。来自砾石滩的大部分杨树幼苗在分析中被确定为黑黑松; 抽样的幼苗中只有2％表现出外来杨树种的基因。同样，来自开放授粉后代的大多数幼苗被鉴定为黑黑松。对于三棵幼苗（占4％），将亲子关系分配给一个P. × 加拿大一枝黄花。重新引入后将近二十年黑黑松，种子和花粉池的组成在研究区域发生了变化，有利于本地物种的繁殖并以外来杨树物种为代价。这项研究表明，尽管在欧洲洪泛区中观察到了重要的基因流动形式，来自外来杨树，但当地人的恢复计划黑黑松 可以大大超越外来基因流，并大大降低外来基因的影响 胡杨 紫杉对软木河岸森林发展的影响。