Lichens in Reunion Island

Usnea lichen growing on trees in Reunion Island. Lichens are composite organisms resulting of a symbiotic association between a fungus and a photosynthetic partner, such as a green alga or a cyanobacterium. Usnea is very sensitive to air pollution, especially sulfur dioxide, which makes it an interesting biomarker for air quality.

Thanks to Valentin Duflot for the trek across Mafat and CIlaos cirques where the picture was taken.