Differential Responses of Lichen Symbionts to Enhanced Nitrogen and Phosphorus Availability: An Experiment with Cladina stellaris

Lichens can be both nitrogen- (N) and phosphorous- (P) limited and thus may be susceptible to nutrient enrichment. Nutrient enrichment with N and P may have differing impacts on the lichen structure because of different physiological responses of fungal and algal partners to these nutrients. The hypothesis was tested that the differential responses of lichen symbionts to enhanced availability of N and P is reflected in the lichen thallus structure and the wall-to-wall interface between the algal and fungal cells.