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Sanz-Aguilar A.,CSIC - Donana Biological Station | Sanz-Aguilar A.,CSIC - Mediterranean Institute for Advanced Studies | De Pablo F.,Institute Menorqui Destudis Ime | Donazar J.A.,CSIC - Donana Biological Station
Oecologia | Year: 2015

Large terrestrial long-lived birds (including raptors) are typically sedentary on islands, even when they are migratory on the mainland. Density-dependent variation in the age at first breeding has been described as responsible for the long-term persistence of long-lived bird populations on islands. However, sedentary island populations may also benefit from higher survival rates derived from the absence of migration costs, especially for young individuals. Thus, sedentary island populations can mimic a natural experiment to study migration costs. We estimated the age-dependent survival of two sedentary raptors on the island of Menorca (Egyptian vultures Neophron percnopterus and red kites Milvus milvus) and compared these estimates with those reported for other migratory and sedentary populations. In Menorca, Egyptian vultures, but not red kites, showed low levels of human-related mortality resulting in extremely high survival probabilities, probably due to different diet choices and behavioral patterns. Juvenile Egyptian vultures and red kites in the studied population had lower survival probabilities than adults. This difference, however, was smaller than those reported for mainland migrant populations, which showed a lower juvenile survival rate. In fact, between-population comparisons suggested that survival of the young in migrant populations may be triggered by mortality factors in wintering areas. In contrast, adult survival may respond to mortality factors in breeding areas. Our results suggest that raptor species that become sedentary on islands may benefit from higher pre-breeder survival prospects in comparison with their mainland migrant counterparts. This fact, in combination with an earlier age at first reproduction, may facilitate their persistence. © 2015, Springer-Verlag Berlin Heidelberg. Source

Dettori C.A.,University of Cagliari | Loi M.C.,University of Cagliari | Brullo S.,University of Catania | Fraga i Arguimbau P.,Institute Menorqui Destudis Ime | And 2 more authors.
Flora: Morphology, Distribution, Functional Ecology of Plants | Year: 2016

The giant fennel Ferula communis L. is a circum-Mediterranean complex characterized by a great morphological variability, and comprising several species and subspecies. In this work, we used AFLP markers to investigate the pattern of genetic variation of the F. communis complex in the Tyrrhenian area and to compare the levels of genetic diversity between the widespread F. communis and the Corso-Sardinian endemic congener F. arrigonii.Our study indicates fairly high levels of genetic diversity for all populations (Fragpoly = 58.2-88%; Hj = 0.186-0.313), with no significant differences between F. arrigonii and F. communis. The genetic structure is only partially coherent with the geographic provenance of the populations: while individuals of F. arrigonii constituted a separate genetic group, the individuals of F. communis were partitioned into three main genetic clusters. These corresponded respectively to F. communis subsp. glauca, to populations from Tunisia and Gozo Island, and to all populations from the rest of the investigated areas; this last cluster was characterized by a marked substructure. © 2016 Elsevier GmbH. Source

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