Epiphytic and epixylic lichens in forests of the Šumava mountains in the Czech Republic; abundance and frequency assessments

Abstract

Extensive sampling of lichen diversity in forest habitats in the Sumava mountains consisted of 128 plots with 824 sampled objects (single trees, snags, logs, etc.). The survey enabled assessment of regional abundance and frequency of epiphytic and epixylic lichen species. 240 species were recorded with frequencies (i.e. number of plots in which each species was recorded) ranging from 1 to 123 and with total abundance scores (i.e. sum of abundances from all objects) ranging from 1 to 1304. Using the total abundance scores, each species was classified as either: rare (129 species), common (68) or abundant (43). We recognised six types of forest, one formed by human activity and five natural ones. Species richness in the natural forests were in decreasing order: beech forests (167 species), bog and waterlogged forests (147), montane spruce forests (124), ash-alder alluvial forests (92) and ravine forests (68). The relative order of the first four kinds is probably real, but the low number of species in ravine forests is a result of insufficient sampling. All species were characterized by their fidelity and specificity to each forest type. Each natural forest category has a group of species with high fidelity. Many species were recorded in only a single category of forest, which demonstrates that a rich regional lichen biota requires variability in forest types. Forest habitats formed by human impact, mostly plantations of coniferous trees, have fewer species, and distinctly fewer species with high fidelity, than any natural forest category. Throughout the region, mature spruce trees in montane spruce forests have been dying at a rapid rate for over 20 years. This has probably resulted in a decline in those lichens that require high humidity, and an increase of some epixylic lichens, especially nitrophilous species. We did not encounter all species previously recorded in forests in the region, but most of the species missing from our list are either rare or have specialised habitat requirements. In the Red List of the Czech Republic, we suggested changes in categories for 32 species.