LOW ALTITUDE GLACIAL RELICTS IN THE ROMANIAN FLORA

Abstract

Glacial relicts represent isolated populations of cold-adapted species, remnants of their past extensive distribution at southern latitudes that have survived in situ far from their current main areal since the Ice Age ended. We hereby aim to identify, based on a numerical evaluation that uses a scoring system applied for 14 ecological and biogeographic criteria, putative glacial relicts occurring in lowland wetlands from the Romanian part of the Carpathian Region. Our selection of (sub) species for evaluation includes mainly cold-adapted plants occurring in wetland areas of the intra-mountain depressions and peripheral lowland areas, while those occurring mostly in the high mountain areas of the Carpathians were excluded. As a result, of 171 evaluated taxa, 74 are considered to possess stronger lowland glacial relict features in the Romanian flora. Furthermore, based on the evaluation of their distribution in Romania, we highlight the hotspots of richness, rarity and range limit for these taxa. Both richness and rarity indices calculated for the 74 glacial relicts displayed the highest values in the Eastern Carpathians, probably linked to the wider development in this region of intra-mountain depressions harboring extensive wetlands. In addition, several potential refugia have been identified based on the distribution of very rare taxa in the north-eastern part of the Apuseni Mountains and the eastern part of the Southern Carpathians (Bucegi Mountains). The distribution of range limit populations of glacial relicts in Romania outlines two well-demarcated areas, one in the southern part of the Eastern Carpathians and the second in the western part of the Southern Carpathians, along deep intra-mountain valleys and depressions. Due to their limited, isolated distribution and the fragility of wetland habitats in which they occur, populations of glacial relicts are more prone to be affected by impacts generated by human activities and climate change. Therefore, our study can also serve as a useful tool for enhancing conservation efforts by highlighting the lowland wetland areas harboring a high number of cold-adapted relict populations that require careful monitoring and urgent protection measures.