Habitat preference of the endangered species Crambe tataria (Brassicaceae) from Romania

Abstract

Crambe tataria is a protected species, thermophilic relict in Europe and steppe postglacial relict in Romania. In the past three decades, the size of C. tataria populations has been significantly reduced, and the geographical distribution of these populations is fragmented. Despite its status, there is insufficient data on the environmental conditions of this priority species. This study aimed to identify the main plant communities with C. tataria and the relationships between their floristic composition and environmental variables. The floristic composition based on 211 phytocoenological relevés from the Romanian Grasslands Database (164 relevés; EU-RO-008) and personal data (47 relevés). The vegetation groups were identified using hierarchical agglomerative clustering methods. Detrended correspondence analysis (DCA) and canonical correlation analysis (CCA) evaluated the relationship between floristic composition and environmental variables. Climatic variables were represented by the environmental variables. The analysis of the floristic composition was performed based on the presence/absence matrix. The vegetation analysis indicated that C. tataria grows and persists in a limited number of plant communities, with a preference for the Arrhenatherion elatioris, Festucion valesiacae, Stipion lessingianae, Cirsio-Brachypodion pinnati, Danthonio-Brachypodion and Prunion fruticosae. The most important variable that influences the floristic composition is the elevation. The analyzed populations prefer alkaline soils rich in nitrogen, phosphorus, and potassium. Arsenic and lead were also present in high concentrations. Investigations have shown that in addition to the Festuco- Brometea the phytocoenoses of C. tataria identified belong to the Molinio-Arrhenatheretea, and Rhamno-Prunetea classes. The areas occupied by xerophilic meadows of the Festuco-Brometea are in different stages of degradation due to overgrazing, particularly in north-eastern Romania.