Breeding land birds across the Greek islands: a biogeographic study with emphasis on faunal similarity, species–area relationships and nestedness

Abstract

We investigated the biogeography of 102 breeding land bird species reported on 77 islands in the Aegean archipelago. For the first time, we prepared a complete as possible dataset concerning the land birds of the Aegean islands. The overall insular avifauna has been treated as a unit to find out certain ecological patterns. We examined the faunal similarity using recent distribution data, studied the species–area relationships (SARs) and tested land bird biotas for nested patterns. A significant SAR was identified for land bird species richness of the Aegean islands and for most of the island subdivisions. The surface area of the available Aegean islands explained 79% of the variance in species richness and the overall z value was 0.305, in general suggesting a high degree of island isolation. The z values of the log–log species–area regression varied significantly among island groups and ranged between 0.100 and 0.329. We found that the overall slope of the species–area curve was steeper than those of terrestrial invertebrates (i.e., centipedes, darkling beetles). The land bird fauna on the Aegean islands was nested, whereas Crete and its satellite islands was the least-nested island group. Insectivores and seedeaters contributed differently to land bird assemblages with the former showing a more reliable nested arrangement than the latter. In most cases, the rank of breeding bird species, as determined by the nestedness metric, was negatively correlated with island area and/or maximum altitude.