Phytocoenological and Ecogeographical study of Salvia nutans in Romania

Salvia nutans is a steppe relict species, characteristic of the West Palearctic steppe and forest-steppe. It is vulnerable to overgrazing and the conversion of grasslands into arable land. Due to these anthropogenic impacts, the species is endangered in some locations in Romania. In this context, the study aims to find the plant associations in which the species occurs and the environmental factors that explain the floristic composition. For the vegetation analysis, 870 relevés were used, and the data were analyzed in JUICE programme, applying the modified TWINSPAN algorithm for clustering. The floristic composition data and environmental variables were used for the multivariate analyses. Salvia nutans was recorded most frequently in the Festuco-Brometea class, the Festucetalia valesiacae order, the Stipion lessingianae alliance, and the Jurineo transylvanicae-Stipetum pulcherrimae and Allio albidi-Stipetum lessingianae associations. Canonical Correlation Analysis indicates that annual precipitation (BIO12) explained most of the variation in floristic composition. S. nutans occurs predominantly on steep slopes with southwest aspects and at an average elevation of 359 m. The species occurs in moderately acidic to slightly alkaline soils, with moderate phosphorus and high potassium concentrations. Salvia nutans is related to topographic and edaphic conditions, showing its role as an indicator species for continental, xerophilic grasslands. Given its vulnerability to land-use changes, S. nutans should be included in long-term monitoring programs to assess population dynamics.