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

Abstract

Within its range, the Caspian green lizard, Lacerta strigata, occurs in the Elburz Mountains (northern Iran) at elevations frombelow sea level to approximately 2700 m a.s.l. To determine the environmental factors affecting the distribution of this lizard, we usedan ensemble approach to model the distribution of the Caspian green lizard (Lacerta strigata) in Iran using four algorithms (generalizedboosted model, maximum entropy, generalized linear model, random forest). Results revealed that low-elevation habitats betweenthe 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 importantenvironmental variables influencing the distribution of the species. NDVI was likely the most important variable because it is anindicator of plant productivity, which presumably influences the availability of food resources such as insects. We also tested the validityof an old distribution record for the species near Shiraz in southwestern Iran. The results show that southwestern Iran is not ecologicallysuitable for the species. As our results highlighted that the NDVI strongly affects distribution of the species, we suggest protection ofvegetation cover in the habitat of the species for conservation of Lacerta strigata.