Forest age and topographic position jointly shape the species richness and composition of vascular plants in karstic habitats

Abstract

Key message: Dolines may provide important safe havens for many plant species and play a key role in maintaining biodiversity. The combined effects of forest age and topographic position influence the biodiversity patterns of these unique habitats. Forest managers, conservationists, and researchers need to work together in order to maintain the species richness and composition of these habitats under environmental changes. Context: Dolines are the most prominent geomorphological features in many karst landscapes that may provide important microhabitats for many species. Aims: We aim to contribute to a better understanding of how forest age and topographic position influence the plant species richness and composition of vascular plants within doline habitats. Methods: We studied the effects of forest age (four age classes: from 5- to 10-year-old stands to more than 90-year-old stands), topographic position (south-facing slope, bottom, and north-facing slope), and their interaction on the distribution of vascular plants and mean Ellenberg indicator values in dolines using detrended correspondence analysis and mixed-effects models. Diagnostic species for the forest age classes and topographic positions were also determined. Results: Different groups of vascular plant species usually showed significant preferences for certain topographic positions and/or forest age classes in dolines. In general, the number of species in all studied groups of plants increased after a few years of canopy removal. The number of plant species in almost all groups was lowest in dolines covered with 40–45-year-old forests. The moist and nutrient-rich doline bottoms covered with 90–120-year-old forests harboured many climate change vulnerable plant species. Conclusions: Forest age and topographic position considerably influence the species richness and composition of vascular plants in dolines; therefore, forest managers and conservationists need to consider their potential impacts when evaluating the effects of climate warming on karst landscapes.