Adventive species Asclepias syriaca L. in disturbed grassland from western Romania.
Asclepias syriaca L. (common milkweed) is an adventive invasive species in Europe original from North America. The species became more frequent in Western Romania as weed in crops and pastures. Having in view the problems created by the invasion of common milkweed in some areas from Hungary we have considered important to take in consideration the presence of it in the studied area. Researches were developed in 2017-2019 period on a grassland from Pecica (Arad County) from the territory of the National Parc Lunca Mureşului. There were delimited three areas of vegetation with different features, respectively permanent grassland, grassland invaded with indigo bush (Amorpha fruticosa L.) and transition area, the last one being placed between the previous two and presenting scattered shrubs on the surface. The focus of the research was to investigate the existence of relationship between some vegetation features and the participation rate of common milkweed in the vegetation sward. The obtained results showed that the vegetation type has a highly significant influence on Asclepias syriaca contribution (CS%).