Search

The study of animal communities is mainly concerned with how the groupings of species are distributed in nature and the ways in which the members of these communities assemble and interact with each other. Pianka suggested that animals partition environmental resources in three basic ways: temporally, spatially, and trophically. Such differences in activities separate the niches, reduce competition, and presumably allow the coexistence of a variety of species in the communities. The present work compares the spatial, trophic and temporal niches of four reptile species, two geckos (Tarentola mauritanica and Hemidactylus turcicus) and two lizards (Podarcis muralis and Podarcis siculus) living in a same roman-age archeological park situated area inside Rome metropolitan area (central Italy), and sharing the same two-dimensional habitat (the roman aqueduct walls). The results showed an overall overlap among species higher than expected by chance for all considered ecological dimensions except for the spatial resource related to the vertical position on the wall. Surprisingly, despite living in a two-dimension habitat would expect an increase of interspecific interaction rate, no partition was observed between species with the most convergent ecological requirements. Although our hypotheses about lizard communities structuring and interactions in the urban habitat require further investigation, we think that our lizard community is based more on the ecological needs of each species rather than on species' interactions. The observed spatial segregation between diurnal geckos and lizards would not support alone the interaction hypothesis. We speculated that the coexistence of ecologically overlapping species at the study area is allowed by a non-limiting availability of resources (above all food) that would result in the reduction of heterospecific competitive interactions and an overall wide overlap of resource use. [ABSTRACT FROM AUTHOR]

Based on long-term fieldwork, we report a descriptive SWOT (strengths, weaknesses, opportunities, and threats) analysis performed by a public agency that manages a protected area (PA) system in a densely populated area (Rome, central Italy) to highlight the core limits in this PA's management effectiveness. The key result of the analysis is that the limits of the management effectiveness and the obstacle in setting improvement strategies can be basically derived from the hierarchical command-and-control government approach and from the adopted management model. The main hindrance to the implementation of a multilevel collaborative management appears to be the “institutional stickiness” of the managing public agency in shifting from its hierarchical government approach to a governance one. Having observed the presence of operational gaps among the best solutions in the scholarly mainstream, the governing capability of the managing authority, and what happens in the field, we suggest that an answer to aligning these factors could be the creation of more fluid conditions for bottom–up initiatives—for instance, by monitoring the multibenefits of PAs for local communities or by making available to the public the economic evaluation of public goods.Environmental Practice 15:401–408 (2013) [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]