From Lawns to Wastelands: Moss Diversity Patterns Across Urban Grasslands

Questions Although urban vascular plant communities are increasingly understood, urban moss communities remain largely unknown. This study investigates grassland bryophyte community composition against various urban environmental gradients. Location We sampled 58 grasslands, ranging from lawns to meadows and wastelands, in the metropolitan area of Strasbourg, France. Methods Moss communities were analyzed for species richness, frequencies, and the proportions of acrocarpous and pleurocarpous species in relation to landscape fragmentation, soil parameters, and management pressures. Results Urban bryophyte diversity increases with the sand percentage in the topsoil layer and decreases with nitrogen percentage, considered indicators of soil aridity and decreases with soil fertility, respectively, and particularly for acrocarpous species. The impact of vegetation management on mosses varies according to the practices involved, with higher diversity observed in wastelands and reduced richness in lawns. The ratio of acrocarpous species declines as the cover of vascular plants increases. Conclusion Urban environments, including wastelands, should be more carefully considered in regional moss diversity inventories.