The spread of alien species with the expansion of road networks and increasing traffic is a well-known phenomenon globally. Besides their corridor effects, road maintenance practices, such as the use of de-icing salts during winter facilitate the spread of halophyte (salt tolerant) species along roads. A good example is Plantago coronopus, a mainly coastal halophyte which has started spreading inland from the Atlantic and Mediterranean coastal habitats, recently reaching even Central European countries (e.g. Hungary). Here we studied the spread of this halophyte and tried to identify factors explaining its successful dispersion along roads, while also comparing native and non-native roadside occurrences with regard to altitude of the localities, size of roadside populations and frequency of roadside occurrences. We completed a comprehensive literature review and collected more than 200 reports of occurrence from roadsides spanning a total of 38 years. During systematic sampling the frequency of the species along roads was significantly higher in the Mediterranean (native area), than along Hungarian (non-native area) roads, however the average number of individuals at the sampling localities were very similar, and no significant difference could be detected. Using a germination experiment, we demonstrate that although the species is able to germinate even at high salt concentrations, salt is not required for germination. Indeed salt significantly decreases germination probability of the seeds. The successful spread of the species could most likely be explained by its remarkably high seed production, or some special characteristics (e.g. seed dimorphism) and its ability to adapt to a wide range of environmental conditions. Considering the recent and rapid eastward spread of P. coronopus, occurrences in other countries where it has not been reported yet can be predicted in coming years.

随着道路网络的扩大和交通量的增加，外来物种的传播是全球众所周知的现象。除了走廊效应之外，道路维护实践，例如在冬季使用除冰盐，促进了盐生植物（耐盐）物种在道路上的传播。一个很好的例子是车前草，主要是沿海盐生植物，已开始从大西洋和地中海沿海栖息地向内陆扩散，最近甚至到达中欧国家（例如匈牙利）。在这里，我们研究了这种盐生植物的传播，并试图确定解释其沿道路成功扩散的因素，同时还比较了本地和非本地路边发生的地方海拔、路边种群规模和路边发生频率。我们完成了全面的文献回顾，收集了 200 多份路边发生的报告，时间跨度为 38 年。在系统采样期间，地中海（本土地区）道路沿线物种的频率明显高于匈牙利（非本土地区）道路沿线，然而，采样地点的平均个体数非常相似，没有检测到显着差异。使用发芽实验，我们证明尽管该物种即使在高盐浓度下也能发芽，但发芽不需要盐。事实上，盐会显着降低种子的发芽概率。该物种的成功传播很可能是由于其非常高的种子产量，或一些特殊的特征（例如种子二态性）及其适应各种环境条件的能力。考虑到最近和迅速向东蔓延 我们证明，尽管该物种即使在高盐浓度下也能发芽，但发芽不需要盐。事实上，盐会显着降低种子的发芽概率。该物种的成功传播很可能是由于其非常高的种子产量，或一些特殊的特征（例如种子二态性）及其适应各种环境条件的能力。考虑到最近和迅速向东蔓延 我们证明，尽管该物种即使在高盐浓度下也能发芽，但发芽不需要盐。事实上，盐会显着降低种子的发芽概率。该物种的成功传播很可能是由于其非常高的种子产量，或一些特殊的特征（例如种子二态性）及其适应广泛环境条件的能力。考虑到最近迅速向东蔓延P. coronopus，可以预测在未来几年发生在其他尚未报告的国家。