Rare shady chasmophytic habitat communities (8210) in Ukraine

Abstract

The characteristics of shadow chasmophytic habitats on shady calcareous rocks in forest conditions are described. For such communities, the forest canopy primarily acts as a shading factor that determines microclimate, humidity and light levels. The characteristic species of the calcareous rock communities are affected by shade and microclimate but are also broadly defined by the properties of the rock type, topography and aspect and are to some extent independent of the development of forest ecosystems. These communities can be found in deciduous forests of the Carpinion betuli, Fagion sylvaticae and Tilio-Acerion alliances, where they are confined to steep calcareous rock faces and cliffs, with a diameter of rocks of more than 2 m. A particular characteristic of these communities is the high abundance of ferns: Asplenium trichomanes, A. ruta-muraria, A. viridis, Phyllitis scolopendrium, Cystopteris fragilis, Polypodium vulgare, a dense cover of bryophytes that occur as mats over rocks, and a low or insignificant contribution of vascular plants. Syntaxonomically, these communities belong to the Polypodietea class (Ctenidio-Polypodietalia vulgaris order, Ctenidio-Polypodion vulgaris alliance) and belong to four informal communities (Isothecium alopecuroides-Polystichum braunii, Porella platyphylla-Asplenium ruta-muraria, Pseudanomodon attenuatus-Chrysosplenium alternifolium and Pedinophyllum interruptum-Polystichum aculeatum). We evaluated indices of environmental parameters according to the synphytoindication method using Didukh’s scales. According to this methodology, an assessment of the threat impacts and indicators of sociological significance shows that the habitat belongs to a rare type (II class), and therefore requires specific conservation measures.