Null model analysis of community structure reveals that patch quality influences the conservation of complex bird communities in Mediterranean habitats

Abstract

The bird communities of the Presidential Estate of Castelporziano (Rome, Italy) were studied to determine their structure in a set of different natural habitats. This study area presents a complex ecosystem, formed by a mosaic of different habitats and their ecotones, having a high biodiversity level. Wetlands housed the highest number of bird species followed by oak forests. Bird communities of Castelporziano are characterized by high degrees of richness and complexity. Null model analyses revealed that the bird community was not randomly organized by Randomization Algorithm 2 (thus denoting that the generalist-specialist nature of the species reduced ecological similarity) nor by Randomization Algorithm 3 and Randomization Algorithm 4 (thus denoting that the types of resources utilized did not reduce ecological similarity). Based on this study, we will not only focus on conservation levels of single habitats for Mediterranean birds, but also modify the classical approach of ‘fragmentation biology’ with a new approach where the natural quality of all patches is evaluated with appropriate statistical tools.