Habitat patches of green shield-moss (Buxbaumia viridis) host diverse set of bryophytes and lichens of conservation concern: case study from hemiboreal Estonia

Abstract

Green shield-moss Buxbaumia viridis is an epixylic forest bryophyte threatened in several European countries. In Estonia, the species belongs to the strictest protection category since 2004 and therefore, around each species localities the habitat patch is delineated and excluded from any logging activity. The aim of the current study was to survey do habitat patches of B. viridis entail other species of conservation concern (SPEC) and if they do, to evaluate specificity of such additional protection value. Standardised stand-scale survey of bryophytes and lichens in 12 habitat patches of B. viridis revealed in total 60 SPEC species (37 lichen and 23 bryophytes). Woodland indicator species and/or dead-wood specialists dominated among SPEC bryophytes and red-listed epiphytic species among SPEC lichens, but legally protected bryophytes and lichens were scarce. Comparison with the dataset collected with the same survey protocol from 12 forest sites not inhabited by B. viridis (but being potentially suitable habitats for the species in terms of forest site type and age) showed lower total SPEC richness (48 species) but no significant difference on mean SPEC number per plot. However, lichens SPEC composition differed between site groups. This indicates, that at least in European hemiboreal region, where clear-felling based forestry is prevailing, logging-free zone around all localities of B. viridis can provide simultaneous protection for diverse set of SPEC bryophytes and lichens, which are often inconspicuous and legally not strictly protected at the national level. In the current study also the presence of gemmae of B. viridis was confirmed for the first time in Estonia.