Effects of nitrogen deposition and soil fertility on cover and physiology of Cladonia foliacea (Huds.) Willd., a lichen of biological soil crusts from Mediterranean Spain

► We are providing evidence of the potential use of the crust-forming lichen Cladonia foliacea as biomarker of atmospheric N pollution in Mediterranean ecosystems of Europe, which are understudied with regard to this topic. ► Pigment concentration increased with N addition and FvFm, used as indicator of physiological status, showed a critical load above 40 kg N ha−1 y−1. ► Soil nitrate and pH were important in modulating responses to simulated N pollution and other soil parameters (micro-nutrients, water content, etc.) also explained variables of lichen physiology. ► We conclude that Cladonia foliacea could be used as biomarker and that responses to N are complex in heterogeneous Mediterranean-type landscapes.