摘要

The population density of three lacertid lizards (Podarcis sicula, Podarcis muralis, Lacerta viridis) was studied along several transects crossing agro-forest habitats in Mediterranean central Italy. Overall, seven transects, in three different wooded patches, were walked for lizards. Distance sampling (with uniform model design) was applied to the dataset in order to calculate population size, dispersion, and coefficient of variation at each site. In order to detect which factors may influence lizard density, a Generalized Linear Model (GLZ; multinomial distribution and cumulative log link function) was built, with environmental variables and density of predators' variables being included in the model as covariates (scale predictor). Density of the three lizard species differed significantly among study sites, evidencing species-specific responses to local patch conditions. None of the environmental variables taken separately in the GLZ model influenced significantly the lizard densities, whereas lizards densities showed species-specific response to the considered environmental variables. The largest species (L. viridis) showed the highest density in the fragment with the most irregular shape and largest wood size, whereas the two smaller Podarcis species presented their highest population density in the site with the smallest wood patch and with a very low snake density. Density of P. sicula was negatively correlated with both the woodland area and Colubridae density, and was positively correlated with woodland shape (i.e. with circularity).

  • 出版日期2011-12