The C, N, and P concentrations of lichens globally

Lichens play irreplaceable roles in ecosystem biogeochemical cycling, such as nutrient input, retention, and release. Their nutrient status affects these roles, but our understanding of lichen nutrient content is fragmentary, hampering our ability to predict changes in lichen performance and functions under global change. We therefore performed a global analysis relating carbon (C), nitrogen (N), and phosphorus (P) concentrations with lichen attributes (photobiont, growth form, and substrate) and environmental factors (temperature, precipitation, vapor pressure deficit, and atmospheric N deposition). Photobiont and growth form largely determined lichen N and P concentrations, respectively. As expected, cyanolichens possessed the highest N, while foliose lichens had higher P than fruticose species. Lichen N increased with temperature and vapor pressure deficit but was unrelated to N deposition. These global-scale patterns of variation in lichen C, N, and P concentrations set a standard that more local patterns can compare against, while the summarized quantitative data allow better parameterizing terrestrial biogeochemical cycling models, which should urgently start to include non-vascular photoautotrophs.