High-mountain phylogeography in the Balkan Peninsula: isolation pattern in a species of alpine siliceous grasslands and its possible background

Abstract Although the Balkan Peninsula belongs to most mountainous regions of Europe, phylogeographic structure its alpine flora remains insufficiently understood, especially for species distributed both in western and eastern parts Peninsula. We analyzed Campanula orbelica , a endemic typical high-mountain siliceous grasslands, based on population genetic structure, climatic niche modeling at species- intraspecific level, hindcasting back Last Glacial Maximum (LGM; 20 kya). Our data reveal clear pattern with three geographically coherent groups: (i) divergent spatially restricted lineage Pirin mountains (east), (ii) neighboring Rila other massifs (Rhodopes, Stara Planina, Vitoša), (iii) disjunct Scardo-Pindhic range (Šar Planina Korab) west. This indicates multiple refugia isolated evolutionary centers within mountains, part as likely ancestral area, an early dispersion into region, which formed main geographical disjunction. The divergence was only partly correlated isolation, dispersal barriers, or shifts, suggesting contrasting isolation/dispersal dynamics various range. Climatic overlap low among vs. groups, correlates longest spatial distance significant divergence, while characteristic subset adjacent niche. High populations also not persistent gaps potential distributions but hypothetically may have been triggered by diversified (limestone/silicate) bedrock conditions. results highlight need surveys Peninsula, assess biogeographical relevance isolation patterns definition evolutionarily important units flora.