Analysis and Comparison of the Ecological Niche of Two Endemic Species of the Genus Diploglossus (Sauria: Diploglossidae)

Of all the Cuban reptile species, lizards have the greatest richness and diversity. Among them, little is known about the natural history of the species of the genus Diploglossus, so that studies on their ecological niche would provide relevant and novel information about their ecology. Because of that, we proposed to characterize the climatically suitable areas of D. delasagra and D. nigropunctatus and to evaluate the niche overlap between them. We compiled information from 123 georeferenced presence records. Bioclimatic variables of WorldClim were used as predictive variables for the generation of ecological niche models in Maxent program. The final averaged models were binarized to generate presence-absence maps with the ArcGis program. The models obtained were evaluated as useful and excellent according to the difference between the training and testing AUC values, reflecting their high predictive capacity. The contribution of the variables to the resulting models varied between the two species, and in both cases the variables derived from temperature were those with the greatest contribution. The climatically suitable areas completely included the areas of known presence and included other areas. The potential distribution areas of the climate niche for both species showed very different distribution patterns, being higher for D. delasagra (221 123.84 km2) and smaller for D. nigropunctatus (6 173.82 km2). The Principal Components Analysis showed a very low niche overlap between the species, being D. delasagra the one with the greatest ecological plasticity and D. nigropunctatus the one with the least, the latter with preference of environments with lower values of seasonality in temperatures and a regime of abundant rainfall all year. The ecological niche breadth was also described using the B1 index in the ENMTools program, and the position and amplitude of the niche along the climatic axes. The Discriminant Analysis showed 95.24% of correct classifications, so there is no overlap between the ecological niches of both species. In conclusion, D. delasagra presents a wide distribution with respect to D. nigropunctatus, restricted to the main mountainous massifs of the east of Cuba, and both niches differ in environmental requirements and amplitude, defined by different variables.