Promiscuity in Lichens Follows Clear Rules: Partner Switching in Cladonia Is Regulated by Climatic Factors and Soil Chemistry

Climatic factors, soil chemistry and geography are considered as major factors affecting lichen distribution and diversity. To determine how these factors limit or support the associations between the symbiotic partners, we revise the lichen symbiosis as a network of relationships here. More than one thousand thalli of terricolousCladonialichens were collected at sites with a wide range of soil chemical properties from seven biogeographical regions of Europe. A total of 18 OTUs of the algal genusAsterochlorisand 181 OTUs ofCladoniamycobiont were identified. We displayed all realized pairwise mycobiont–photobiont relationships and performed modularity analysis. It revealed four virtually sep…