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L’avifauna nidificante in due aree Prealpine del Friuli: Val d’Alba (Moggio Udinese, Udine) e Val Còlvera (Frisanco, Pordenone)

1989; eScholarship Publishing, University of California; Volume: 13; Linguagem: Italiano

10.21426/b613110317

1594-7629

Paolo De Franceschi, Sandro Di Bernardo Angelo,

Species Distribution and Climate Change

BIOGEOGHAPHIA - vol. XIII — 1987 Biogeografla delle Alpi Sud-Orienta/i L’avifauna nidificante in due aree Prealpine del Friuli: Val d’Alba (Moggio Udinese, Udine) e Val Colvera (Frisanco, Pordenone) PAOLO DE FRANCESCI-II(q‘) — ANGELO SANDRO DI BERNARDOU7‘) (*) Mureo Civico dzq Storzkz Nmfumle dz’ Verona (*q‘) Mz'I2zLtter0 Agrztoltum e Foreste, Uflicio Ammz'mktmzz'o/16 Forestcz dzq Tm'vz'sz'o, Ttzrvz'5z'0 (Udme) SUMMARY Censuses of bird breeding in mixed woods and open habitats were made during 1976-78 in Val d’Alba and during 1973-74 in Val Colvera. In Val Alba 94 species of birds were censused of which 82 were found as breeding species. In Val Colvera 114 species of birds were censused of which 93 as breeding ones. In the latter area, the species belonging to the Mediterranean and European-Turkestanian faunal type (Voous, 1960) represent 17.2% of all breeeding species (only 12.2% in the former). 14 species of birds, lacking in Val d’Alba, bred in Val Qolvera, between them, there are species belonging to the Cosmopolitan (1), Holarctic (1), of the Old World (3), Palearctic (3), European (3), European-Turkestanian (2) and Mediterranean (1) faunal type. 1 8 species of birds are present in Val d’Alba and absent in val Colvera, 6 of them belong to the g-Iolaxctic, Palearctic and Palaeornontane faunal type. Only 2 species belong to the European-Turkestanian aunal type. The differences between these two bird community structures are to ascribe to ecological factors rather than to biogeographical factors. Most of the species belonging to the Mediterranean and European- Turkestanian faunal type, are linked to the open and dry habitats, where hazel, ash and oaks grow more aboundant. Such a composition of the vegetation is better represented in Val Colvera than in Val d’Alba and this can explain the differences found in the two bird community structures. 1 MATERIALI E METODI La raccolta dei dati relativi alle due Valli prese in considerazione e partita da punti di Vista diversi e con finalita diverse. L’indagine sull’aVifauna della Val Colvera aveva lo scopo di individuare le specie nidificanti, rnigratrici ed accidentali ma poneva particolare attenzione nella raccolta dei clati relativi all’ecologia del sito di nidificazione delle specie piu frequenti 0 pin facilmente contattabilj durante la ricerca sul campo. Le visite all’interno dell’area presa in esarne non seguivano percio regolarmente dei percorsi prefissati ma portavano il 1-ilevatore a vagabondare all’interno dei diversi habitat presenti nella Val Colvera e particolarmente nel bosco ceduo. L’indagine condotta nella Val d’Alba (e nell’alta Valle del Rio Simon) pur avendo lo scopo di determinate le caratteristiche dell’avifauna in essa presen- te, si e sviluppata prevalentetnente lungo alcuni percorsi campione preceden- ternente stabiliti. Cio si e reso necessario-a Causa della notevole diversita di 781