Changes in the Nardus grasslands in the (Sub)Alpine Zone of Western Carpathians over the last decades

Abstract

Nardus stricta dominated grassland is a specific habitat occurring on the nutrient-poor soils. Its large areas were formed as a result of livestock grazing. However, landscape management underwent significant changes over the last decades including grazing cessation. This triggered successional processes leading to considerable changes in floristic composition reported from numerous European regions. We focused on this phenomenon in the Western Carpathian high mountains, where the issue was not studied sufficiently. Our research, based on pairwise comparison of 19 historical and recent phytocoenological relevés, confirmed changes here. These include (i) decrease in cover of some diagnostic species of Nardetea strictae class, especially Nardus stricta, (ii) increase in competitively strong species with their high biomass productivity, (iii) shift in floristic composition indicating conversion of Nardion strictae vegetation into other communities, especially those of Loiseleurio-Vaccinietea class, (iv) increase in Shannon-Wiener index values and (v) enrichment of originally oligotrophic grasslands with some nutrient-demanding species, mainly at lower altitudes and decrease in light-demanding species.