Lorenzo Rugiero and Luca Luiselli
Luca Luiselli and Lorenzo Rugiero
Null models are an essential tool for investigating structure in natural communities of animals, including reptiles. In this paper, we studied the assembly structure of a lizard community constituted by four species (Lacerta bilineata, Podarcis muralis, P. sicula, Chalcides chalcides) along 25 different transects, each 300 m long and representing a specific habitat type, in five independent urban green areas in Rome, central Italy. Lacerta bilineata was observed in 92% of the total transects (n = 25), P. muralis in 100%, P. sicula in 72%, and C. chalcides in 52%. Based on the number of lizards observed along the various transects, it seemed that each species was linked especially to particular habitat types within each study area, but that the habitat types frequented by each species were not necessarily exactly the same across the study areas. Null model analyses revealed that the lizard community was not randomly organized in four of five study areas by RA2 (thus denoting that the generalist-specialist nature of the species reduced ecological similarity) but not by RA3 algorithms (thus denoting that the types of resources used did not reduce ecological similarity). Thus, the community structure was due mainly to the different specialist-generalist nature of the various co-occurring species.
Massimo Capula, Lorenzo Rugiero and Luca Luiselli
Godfrey C. Akani, Godfrey C. Akani, Fabio Petrozzi, Godfrey C. Akani, Fabio Petrozzi, Lorenzo Rugiero, Godfrey C. Akani, Fabio Petrozzi, Lorenzo Rugiero, Gabriel H. Segniagbeto, Godfrey C. Akani, Fabio Petrozzi, Lorenzo Rugiero, Gabriel H. Segniagbeto and Luca Luiselli
The diet composition of rainbow lizards (Agama agama complex) populations was studied by feces analysis at eight distant places across a mega-transect in the Gulf of Guinea (West Africa), covering three countries: Togo, Benin and Nigeria. The effects of geography (= linear distance between study sites) and local conditions (using the mean annual rainfall as a proxy of the site-specific conditions) on dietary similarity of rainbow lizards were tested. Rainbow lizards were mainly insectivorous at all sites. Multivariate analyses identified four main groups of localities in terms of diet diversity indexes, with populations inhabiting forest towns tending to have less prey taxa richness than conspecifics from more arid areas, which instead had higher dietary evenness. Food niche overlap between populations was high among populations (range 0.631-0.940, ), and decreased with increases in the difference of mean annual rainfall between sites. There was no effect of the geographic distance on the similarity in diet composition between populations. A UPGMA dendrogram revealed a geographic trend in terms of presence/absence of the various prey types in the diets, with all the Nigerian study sites forming one cluster, whereas Lomé and Cotonou, two cities situated within the Dahomey Gap, being grouped apart. Overall, rainfall of the various sites seems to be more important than geographic distance for determining the taxonomic diet composition similarity of these lizards.
Silvia Del Vecchio, Lorenzo Rugiero, Luca Luiselli, Massimo Capula and Russell L. Burke
Although research on habitat use and habitat selection is essential for understanding population ecology and behavior, most such zoological studies have used only general habitat categories describing main habitat features instead of using modern plant ecological approaches. Here, we analyze Testudo hermanni microhabitat use at a coastal Mediterranean site in central Italy by modeling tortoise presence/absence at three spatial scales, using a logistic regression design and quantitative vegetation and plant community analysis to reveal correlates of tortoise habitat use on a fine scale. Our analyses showed that only a few plant species among the many present, and these on a very small spatial scale, are important determinants of tortoise presence and site selection. We also find that tortoises chose a paradoxical combination of high levels of bare soil and high total vegetation cover. This suggests that these tortoises are selecting small patches of habitat in a matrix of less desirable habitat. Our findings also have important implications for habitat management, in that increasing the number of habitat patches containing the few significant plants is likely to be desirable, whereas increasing the size of such patches is probably less relevant.
Leonardo Vignoli, Marco A. Bologna, Silvia Manzini, Lorenzo Rugiero and Luca Luiselli
Attributes of basking sites are important elements to study in management plans of threatened freshwater turtles. Here, we analyzed the basking-site characteristics of European pond turtle (Emys orbicularis) populations in a Mediterranean territory of central Italy (Tolfa Mountains, Latium). We used logistic regression and Principal Components Analysis to characterize 29 presence sites versus 61 random sites, through 16 descriptive variables recorded within a 5 m radius from the sighting/target spot. Our analyses revealed that some variables (i.e. water turbidity, presence of small coves, submerged vegetation, and emergent tree-trunks) were those that influenced most strongly the presence of turtles on potential basking sites. Maintenance of deadwood in water and preservation of submerged aquatic vegetation should be included in the management planning for this turtle species in central Italy.
Gaetano Aloise, Lorenzo Rugiero, Arianna Ceccarelli, Sophia Valenti, Luca Luiselli and Massimo Capula
The snakes of the Mediterranean regions are in general characterised as wide ranging with relatively unspecialised ecological traits (e.g., feeding ecology and diet composition). The few endemic snake species with a narrow range can be of great interest to control whether the relative ecological non-specialization is truly general for Mediterranean snakes or if, on the contrary, those species with a small range are so because of their more specialised ecology. Here, we study the case of the Italian Aesulapian snake, Zamenis lineatus, which is endemic to southern Italy and the island of Sicily, and that has been for long time considered merely as a subspecies of the widespread Zamenis longissimus. We studied the diet of this species in the wild, and also examined snout-vent length and head length in several museum vouchers in order to highlight the eventual morphometric correlates of diet composition. Our results showed (i) a diet based on small mammals and birds, (ii) an evident ontogenetic shift in diet composition (from ectotherms to endotherms), and (iii) a lack of significant intersexual difference in diet composition. In addition, morphometric data revealed no intersexual differences in average snout-vent-length or head length. The general implications of these results are discussed. We conclude that, based on this study case, Zamenis lineatus feeding ecology was very similar to that of the widespread and ecological generalist Zamenis longissimus, and this is contrary to the hypothesis that endemic, narrowly distributed Mediterranean snakes may be more specialist than their widespread counterparts.