Lichens are sensitive to a lot of changes in their habitat. Thus they are used as biomonitors for many influences caused by human activity in the environment. The role of the lichens as indicators of the human influences in forest ecosystems is shown with the help of two examples. The diversity and abundance of epiphytic lichens is important for the assessment of ecosystems according to the categories of nature conversation. Keywords : Lichens, influences of anthropogenic factors, forest ecosystems, conservation.