Refugial habitats of paleoendemic Picea omorika: soil and plant attributes

Refugial habitats occupied by palaeoendemic species provide valuable insights into the adaptive strategies of populations shaped by long-term climatic and environmental change. They also help to assess the conservation potential of refugia under future climate scenarios. In this study, two refugia of Picea omorika on Mount Tara, Serbia, Trenice (S) on serpentine substrate and Vranjak (NS) on non-serpentine substrate, were investigated in terms of soil properties (both under natural and climate-simulated conditions) and plant traits (leaf stoichiometry and morphophysiological traits). The soils at the two sites differed significantly in terms of nutrient content, total organic carbon, moisture content and trace metal concentrations, while the pH values were similar and both had a high Ca:Mg ratio. Serpentine (S) and non-serpentine (NS) populations differed significantly in trace metal concentrations in needles, soil-to-leaf stoichiometric patterns, morphophysiological traits and water status. The serpentine population had higher values in traits associated with a conservative strategy, such as specific leaf mass, relative water content and leaf thickness, suggesting a potential for better adaptation to future climatic conditions. Soil incubation in the climate chamber showed that trace metal concentrations remained stable, while other physico-chemical properties changed in different ways. Our findings highlight the importance of considering site-specific conditions and integrating more ecosystem indices (geological substrate, edaphic factors, functional plant traits) into climate-driven species distribution models.