The study on the lichen diversity of the Tossal Gros (Arbeca, les Garrigues), a hill located within the sicoric territory, and surronded by several sorts of crops, has yield a catalog of 56 species, two of them are new quotation for Catalonia. The features of the lichen composition, dominated by crustose species with a trebouxioid alga as a photobiont, show up the huge stress that affects the area; not only the drought due to climatic conditions, but also the strong anthropic activity being developed for centuries. This second contribution to the lichen biota of the sicoric territory represents an increase for the area. Up to now, there was only a catalogue from an area wit a low protected regime, Espai Natural Protegit dels Secans de Mas de Melons Alfès. Tossal Gros and the aforementioned area just share a 23.6 % of species; however, both areas have a very similar composition in terms of functional traïts. Key words: drought, functional traits, lichenized Ascomycota, Mediterranean.