Distribution and Diversity of Lichens Species at Selected Sites within Sulaymaniyah Province, Iraq

Abstract

The objectives of this research are to study the distribution, diversity, and relative dominance of lichen species on rock and tree bark at a few sites in Sulaymaniyah. A fifteen species of lichens were observed, with an obvious difference in occurrence and abundance of the two substrate types. The findings showed that the distribution and diversity of lichen communities on rocks was more balanced with Circinaria calcarea having the highest relative dominance of 12.5% and several species with moderate contributions. Lichen community on tree bark, in contrast, had a high dominance pattern with Physcia stellaris contributing to 47.1%, which demonstrated its high adaptability to the conditions of the bark . These variations were closely linked to the environmental conditions especially substrate pH. The rock substrates were mainly alkaline, more favorable to a wider variety of calcicolous species, whereas tree bark conditions were acidic and reduced the diversity of species and increased the domination of a limited number of tolerant taxa. Also, climatic conditions like temperature and relative humidity helped in determining the distribution of lichens as they affected the environment and the suitability of growth. This interplay between environmental variables and substrate properties were important in shaping lichen community structure.