Environmental predictors for the distribution of the Caspian green lizard, Lacerta strigata Eichwald, 1831, along elevational gradients of the Elburz Mountains in northern Iran

Within its range, the Caspian green lizard, Lacerta strigata, occurs in the Elburz Mountains (northern Iran) at elevations from below sea level to approximately 2700 m a.s.l. To determine the environmental factors affecting the distribution of this lizard, we used an ensemble approach to model the distribution of the Caspian green lizard (Lacerta strigata) in Iran using four algorithms (generalized boosted model, maximum entropy, generalized linear model, random forest). Results revealed that low-elevation habitats between the Elburz Mountains and the Caspian Sea are the most suitable habitats for the species. The normalized difference vegetation index (NDVI), annual precipitation (both with positive relationships), and altitude (with a negative relationship) were the most important environmental variables influencing the distribution of the species. NDVI was likely the most important variable because it is an indicator of plant productivity, which presumably influences the availability of food resources such as insects. We also tested the validity of an old distribution record for the species near Shiraz in southwestern Iran. The results show that southwestern Iran is not ecologically suitable for the species. As our results highlighted that the NDVI strongly affects distribution of the species, we suggest protection of vegetation cover in the habitat of the species for conservation of Lacerta strigata.