Floristic diversity in relation to geomorphological and climatic factors in the subalpine-alpine belt of the Rodna Mountains (the Romanian Carpathians)

Abstract

As a part of the GLORIA-EUROPE project, the floristic diversity, frequency and species coverage in relation to the main ecological gradients (altitude,aspect) were studied in the alpine pasture (Primulo-Caricetum curvulae, Oreochloo-Juncetum trifidi) and subalpine dwarf shrub communities (Rhododendro myrtifolii - Vaccinetum) of the four summits from the Pietrosul Rodnei massif (Romanian Carpathians). Floristic diversity is higher in the plant communities from lower altitude summits (Golgota, Gropile), while it decreases in communities, to higher summits (Buhaiescu, Rebra). For each 100 m increase in the altitude of subalpine-alpine summits, a decrease of approximately 10% was found in the number of vascular plant species. Arctic-Alpine species (Carex curvula, Juncus trifidus, Hieracium alpinum, Oreochloa disticha, etc.) and a Carpatho-Balkanic regional species (Rhododendron myrtifolium) have the highest frequency and coverage in these plant communities. In northern and eastern slope areas, where the vegetation cover is 15-30% lower than on western and southern slopes and the soil temperature is generally 1-3°C lower during the vegetative season (June-August), the mean number of species per square meter is 25% higher than in southern and western slope areas.