The aim of this paper is to present the diversity of the lichen species on fruit trees (Malus sp., Pyrus sp., Prunus sp. and Cerasus sp.) growing in orchards in selected villages and towns in the Podlaskie Voivodeship. Fifty-six species of lichens were found. These were dominated by common lichens found on the bark of trees growing in built-up areas with prevailing heliophilous and nitrophilous species of the genera Physcia and Phaeophyscia. A richer lichen biota is characteristic of apple trees (52 species) and pear trees (36). Lichens of the apple trees constitute 78% of the biota of this phorophyte growing in the fruit orchards in Poland. Of the recorded species, only two (Ramalina farinacea, Usnea hirta) are covered by partial protection in Poland.
This study examines the occurrence of epigeic lichens on study plots located within different types of habitat near the Siemianowka retention reservoir in the Upper Narew Valley. The outcome of this research is a better understanding of epigeic lichens and the problems associated with their distribution and conservation.
The investigation of the less common and hence more interesting taxa found within the study area was based on species composition analyses of lichens in different habitats, the degree of recognition in North Eastern Poland and their conservation status as well as threats within the country. A total of 48 lichen species, mainly from the genus of Cladonia, were identified, which is a typical number for these types of habitat. 19% of the species growing on soil are classified as threatened and some of them have been recorded only within this study area. In total, 15 lichen species are under the strict or partial protection.
Monitoring of lichens as bioindicators of air pollution has been conducted in Sokółka. On the basis of the occurrence of indicator epiphytic and epilithic lichen species, the scale of lichen sensitivity for the city has been developed and lichen zones have been designated. The zone pattern was not of insular character, and as a result there was no “total lichen desert”. The distribution of lichen zones reflects the intensity of anthropogenic pressure within the town. The least favourable conditions for lichen growth have been recorded in the town centre, while the green areas have shown the most beneficial impact on the lichen test sites