Ground-ivy (Glechoma hederacea L., Lamiaceae) habitats in NE Slovenia: floristic, chorological and syntaxonomic diversity

Ground-ivy (Glechoma hederacea L.) is a widespread stoloniferous plant that grows in several ecologically diverse habitats: in the open, at the forest edge, and in understorey. The vegetation of ground-ivy habitats was studied in NE Slovenia in terms of floristic richness and diversity, biological spectrum, phytogeography and syntaxonomy. We identified five clusters of ecologically distinct habitats with the occurrence of ground-ivy, differentiated according to environmental conditions and flora composition: eutrophic forest edges, trampled habitats, forests, which are divided into two groups with different soil moisture, and meadows. The habitats were assessed using Ellenberg indicator values, thus confirming the ecological differentiation of ground-ivy habitats. Ground-ivy coexists with 169 plant species from 49 families. The highest plant species richness and Shannon diversity is found in meadows (100 plant species), while the lowest diversity is found in trampled habitats (12 plant species). Plant species coexisting with ground-ivy belong to 10 geoelements of which circumboreal, sub-cosmopolitan, Euro-Caucasian and Eurasian geoelements are represented in all habitats. The most represented life form is the hemicryptohytes with up to 88 % of all species per relevé. The syntaxon Molino-Arrhenatheretea dominates in the meadows, the shrub species of the forest edges belong to the syntaxon Rhamno-Prunetea, while Querco-Fagatea predominates in the forests. Ruderal species of the syntaxon Stellarietea mediae occurred in all habitats except in the understorey where light is a limiting factor. A non-negligible proportion of species belongs to Galio-Urticetea, a community characteristic of eutrophic forest edges, an optimal habitat for ground-ivy