Human pressure, parasitism and body condition in an insular population of a Mediterranean lizard

Many wild populations of lizards in the Mediterranean Basin inhabit small islands frequently visited by humans. Reptiles respond to humans as potential predators by escaping to refuges or by increasing antipredator behaviours which lead to a loss of body condition and may have important consequences for fitness. We assessed effects of human pressure on parasitism and body condition of the endangered insular lizard Podarcis lilfordi in Aire Island (Balearic Islands, Spain). Two areas differing in the number of visitors were compared at different seasons: spring, with almost no human pressure, and summer, when the major bulk of visitors arrive. Compared across seasons, the lizards from areas frequented by humans suffered a greater loss of body condition and showed a less parasitism reduction compared to individuals from the undisturbed area. Therefore, human disturbance seems to have deleterious effects on body condition and other fitness-related drivers, as parasitism. Results evidence important consequences of tourism for short- and long-term fitness of individuals and should be considered when designing conservation plans or management strategies.