As for the first time in 2019 the ‘Floristisch-soziologische Arbeitsgemeinschaft (FlorSoz)’ introduces the ‘Plant Community of the Year 2020’ for Germany. The FlorSoz proposal aims to alert the public that the conservation of endangered plant communities and their biodiversity is essential. For the year 2020 the plant community of mat-grass swards (Narduss stricta grassland) has been selected. Similar to other plant communities on nutrient-poor sites, Narduss grassland is highly endangered and in some regions on the brink of extinction. We focus on Nardus grassland of the lowland to montane levels with the characteristic Violenion caninae suballiance (named after Viola canina, the Heath Dog-violet). The sites of Violenion caninae communities are not fertilized and depend on extensive grazing, but there are also mat-grass swards which are mown once a year. Nardus grasslands host many threatened species, e.g., Arnica montana (Arnica) and Antennaria dioica (Mountain Everlasting). The decline of Nardus grassland is not only due to abandonment, afforestation, outdoor activities and construction measures, but also due to changes in the structure and species composition through eutrophication by either direct manuring or by atmospheric nitrogen input. Eutrophication causes local decline or extinction of low-competitive, often endangered species which are replaced by ubiquists, mostly highly competitive species. For management, long-term conservation practices like extensive grazing or cutting once a year are essential. We give an outline of Nardus grassland as an endangered habitat type and summarize its current state of ecological and phytosociological research. In particular we take up the issue of conservation, including the loss of Narduss grasslands and their restoration. Effective conservation depends on an integrative nature-conservation approach, using suitable management practices.