Cyanobacteria and Cyanobacterial Lichens from Inselbergs of the Ivory Coast, Africa

Abstract

Abstract:This study focuses on the saxicolous lichens and cyanobacteria of the open, exposed rock surface of inselbergs. Twenty‐three species of cyanobacteria and 17 cyanobacterial lichen species (“cyanolichens”) from several inselbergs and other rocky outcrops of three major climatic regions, savanna, transition zone and rain forest, are reported from the Ivory Coast. Inselbergs are isolated and frequently mountains consisting of Precambrian granites or gneisses that abruptly rise from the surrounding plains. Cyanobacteria were found to be the dominating organisms on all rock surfaces. The lichens found mainly belong to the family Peltulaceae and a few were present from the family Lichinaceae. Nine species of the cyanolichens and most of the cyanobacteria are new for the Ivory Coast. A gradient in total species number (cyanolichens and cyanobacteria) occurs from the savanna to the rain forest, with a decrease in species number towards the rain forest. Saxicolous cyanobacterial lichens reached a higher species number in the savanna type ecosystem (11) than on inselbergs in the rain forest (7). The cyanolichens and cyanobacteria found are characteristic for larger, light‐exposed rock surfaces and species like P. congregate, P. lingulata, P. tortuosa and P. umbilicata preferentially occur on the granite or sandstone of inselbergs.