Breeding bird assemblages in a Mediterranean mature beech forest: evidence of an intra-seasonal stability M. Ferraguti • C. Battisti • L. Luiselli • L. Zangari • M. A. Bologna Received: 13 April 2012 / Accepted: 14 September 2012 / Published online: 5 October 2012 Ó Accademia Nazionale dei Lincei 2012 Abstract In this study, we obtained data on the structure of two intra-seasonal breeding bird assemblages of a Mediterranean low-altitude beech forests (about 400 m a.s.l.), an ecosystem type of high eco-biogeographic interest and little known in this sense. We sampled 22 breeding bird species (20 sedentary species and two long migrants) with the point count method. Both mean values of species richness and abundance increased from March– April to May–June periods, but differences were not sig- nificant. The Shannon diversity index showed a weak increase between early and late spring. We observed an increase of a, b and c-diversity values from early to late spring. Diversity dominance curves showed a partial coincidence between the two intra-seasonal periods, with a significant difference in slope. Although our low-altitude beech forest showed a relatively low number of species, we observed higher values of total abundance when compared with other beech forests of Central Italy at higher altitude. As a confirmation, our null model analyses of niche overlap revealed no non-random patterns of the temporal distribution of sightings, thus widely supporting the general hypothesis that the bird assemblages of low-altitude beech forests are indeed stable intra-seasonally. The only observed differences between assemblages in the two intra- seasonal periods are limited to the occurrence of two migrant species in the late-spring assemblage (Oriolus oriolus and Upupa epops) that change the slope of the relative diversity/dominance curve (significant different to the early spring curve). Although previous research high- lighted the role of altitude in influencing species richness and abundance, this is the first study to analyze the intra- seasonal structure of bird assemblages inhabiting Medi- terranean beech forests at low altitude. Keywords Diversity/dominance curves Á Seasonal variation Á Bird assemblages Á Mediterranean beech forest Á Central Italy 1 Introduction European beech forests represent quite stable ecosystems diffused at low (northern and central Europe) or middle- high (southern Europe) elevation, from Sweden to northern Sicily and from the Iberian Peninsula to north-western Turkey. These ecosystems are characterized by specific bird assemblages (Farina 1980; Van Dorp and Opdam 1987; Farina 1995; Kropil 1996; Korn ˇan 2004; Korn ˇan and Adamik 2007; Fusco and Tellini Florenzano 2008; Battisti et al. 2010). In the Mediterranean region, there are few examples of beech forests located at relatively low altitude (i.e., lower than 600 m a.s.l.). Due to peculiar ecological and bioclimatic constraints (Anzalone 1961; Hofmann 1991; Manzi 1991; Blasi 1994), these ecosystems are of high biogeographic and conservation value. Electronic supplementary material The online version of this article (doi:10.1007/s12210-012-0206-0) contains supplementary material, which is available to authorized users. M. Ferraguti Á L. Zangari Á M. A. Bologna Dipartimento di Biologia Ambientale, Universita ` Roma Tre, viale Marconi 446, 00146 Rome, Italy C. Battisti (&) Environment Service, Province of Rome (‘‘Protected areas-regional parks’’), via Tiburtina 691, 00159 Rome, Italy e-mail: c.battisti@provincia.roma.it L. Luiselli Centre of Environmental Studies ‘Demetra s.r.l.’, via Olona 7, 00198 Rome, Italy 123 Rend. Fis. Acc. Lincei (2013) 24:1–5 DOI 10.1007/s12210-012-0206-0