Frequency of occurrence of a set of water-related bird species in an archipelago of remnant marshlands of Central Italy

Abstract

In an archipelago of marshland fragments in Central Tyrrhenian Italy, we calculated the frequency of occurrence (i.e., the probability that an individual of a sensitive species occurs in a fragment of determined size area) of a set of water-related breeding bird species. Only one species (Cettia cetti) occurred in marshland fragments within the 0–1 size area class while all species were present in larger size classes. Acrocephalus scirpaceus is the only species that showed a significant increase in frequency of occurrence moving from 0–1 to 1–10 ha size area classes. However, our study supports the hypothesis that the frequency of occurrence of several other area-sensitive species (e.g., Tachybaptus ruficollis, Ixobrychus minutus, Gallinula chloropus, Fulica atra) increases toward larger size area classes, although these trends here are not significant. Therefore, the frequency of occurrence of these species should be a focus of further research in a wider range of marshland fragments. These results will be useful in terms of wetland management implications (e.g., selection of suitable fragments for sensitive species).