Morphometric versus genetic variation in the Eurasian Reed Warbler Acrocephalus scirpaceus in Italy

ABSTRACT

Capsule

The Eurasian Reed Warbler Acrocephalus scirpaceus from breeding sites in Italy has little genetic variability in the mitochondrial cytochrome b gene but shows morphological variation suggesting isolation of some populations.

Aims

To investigate the morphometric and genetic trait variation of Eurasian Reed Warbler populations at a large temporal and spatial scale.

Methods

We analysed morphometric traits and the mitochondrial cytochrome b (cyt b) gene of samples collected over 25 years, from populations at seven sites across the Italian peninsula and islands.

Results

While we found no genetic differences, we detected significantly smaller body sizes in individuals breeding in Sicily and Sardinia compared to those from mainland Italy. There were also significant body size differences between two Sicilian populations: one larger breeding on the southern coast and the other smaller at an inner highland site.

Conclusion

The morphometric data, together with the site fidelity of individuals, are consistent with there being isolation of some populations. Specifically, our results are consistent with an example of polyphenism, morphological plasticity, in the populations of the main Italian islands, Sicily and Sardinia.

Acknowledgements

The corresponding regional Administrations and the ISPRA authorized Vincenzo Cavaliere, Natalino Cuti, Carlo Giannella, Renzo Ientile, Bruno Massa, Sergio Nissardi and Carla Zucca to ring Reed Warblers and to collect their feathers. We are very grateful to the late Roberto Ientile, who contributed much to the first elaboration of capture/recovery at Gela and Vendicari. A special thank goes to BirdLife/LIPU, the body managing the ‘Biviere di Gela’ Nature Reserve, to the Dipartimento Sviluppo Rurale e Territoriale of Regione Siciliana, manager of ‘Oasi faunistica di Vendicari’ Nature Reserve, the Province of Enna, manager of ‘Lake Pergusa’ Nature Reserve, the Province of Palermo, manager of ‘Ustica Island’ Nature Reserve, the managers of the Natural Regional Park Molentargius-Saline, and the WWF Campania, manager of the ‘Oasi di Persano’, whose staff allowed and supported the study. We also thank the following ringers: Mario Bonora, Giovanni Cumbo, Roberto De Carli, Antonino Di Lucia, Alessio Farioli, Andrea Galimberti, Raffaele Gemmato, Carlo Giannella, Andrea Ravagnani, Giuseppe Rossi, Massimo Sacchi and the Zagreb Ringing Scheme. For help in the field, we also thank Filadelfio Brogna, Paolo Galasso, Alessandra Linares, Oscar Lisi, Alessandro Marletta and Nicolò Pitti. Salvo Surdo provided us with some useful bibliographic references.

Disclosure statement

No potential conflict of interest was reported by the author(s).