Zustand und Entwicklungsperspektiven der Populationen von Salvia pratensis L. im Zentrum und Südwesten Luxemburgs

This article provides an overview of the extant populations of Salvia pratensis in the south-west and centre of Luxembourg. The occurrence of meadow sage has decreased significantly over the last three decades, which prompted an analysis of the fitness of the existing populations to draw conclusions for conservation measures. This study was conducted as a part of the SICONA project ‘Nearest neighbours’ and aims to contribute to the conservation and connectivity of the remaining populations. To this end, 97 formerly known populations were analysed as to the presence of meadow sage, of which only 55 could be verified. Parameters of growth and reproduction as well as land-use characteristics were recorded in 20 populations, divided into three size classes. Small populations were mainly found at sites without protected biotope status, whereas populations of intermediate and high population size were almost completely restricted to protected habitat types. However, presence or absence of contractual nature conservation scheme was not related to population size. Furthermore, the majority of the measured fitness parameters showed visible distinctions between population size classes. However, these distinctions were not statistically significant due to the relatively small sample size of studied populations. Additionally, a number of site-specific ecological factors significantly influenced plant traits. Plant height was positively related to soil nutrient content, i.e. plant available phosphorus and nitrogen. There was a statistical tendency for an increased proportion of flowering plants in relation to plant available nitrogen, whereas germination rate was negatively influenced by phosphorus. These results must however be viewed in the context of overall species loss as a result of increased nutrient input (fertilisation and eutrophication) and the dominance of highly competitive species, and cannot be interpreted as a general positive effect of fertilisation on the conservation of Salvia populations and the habitat-typical species community. Plant height differed between habitat types, with plants growing taller in meadows without protected biotope status, likely due to competition, and small plants occurring mainly in dry calcareous grasslands, due to reduced water and nutrient availability. Furthermore, a positive effect of grazing regimes compared to mowing on flowering traits was observed, likely due to the avoidance of meadow sage by cattle. The results demonstrate vegetation-specific developments which are discussed and interpreted in terms of habitat preferences and competitive behaviour of meadow sage. Apart from the propagation of Salvia-plants, reintroduction measures and the establishment of stepping-stone populations, we recommend the extensive management of species-rich grassland without fertilisation and the expansion of cooperation with farmers to conserve and (re)connect the remaining populations in a long view.