The Atacama Desert is one of the driest and probably oldest deserts on Earth where
only a few extremophile organisms are able to survive. This study investigated two
terricolous and two epiphytic lichens from the fog oasis “Las Lomitas” within the
National Park Pan de Azúcar which represents a refugium for a few vascular desert
plants and many lichens that can thrive on fog and dew alone. Ecophysiological meas‐
urements and climate records were combined with molecular data of the mycobiont,
their green algal photobionts and lichenicolous fungi to gain information about the
ecology of lichens within the fog oasis. Phylogenetic and morphological investiga‐
tions led to the identification and description of the new lichen species Acarospora
conafii sp. nov. as well as the lichenicolous fungi that accompanied them and revealed
the trebouxioid character of all lichen photobionts. Their photosynthetic responses
were compared during natural scenarios such as reactivation by high air humidity
and in situ fog events to elucidate the activation strategies of this lichen community.
Epiphytic lichens showed photosynthetic activity that was rapidly induced by fog
and high relative air humidity whereas terricolous lichens were only activated by fog.