Comparación de los patrones de selección del lugar de nidificación de distintas especies rapaces simpátridas, como herramienta para su conservación

In this study the nest–site selection patterns of four tree–nesting sympatric raptor species in Dadia National Park (Greece) were compared in order to provide a sound conservation tool for their long–term management in the area. The species studied were the Black vulture (Aegypius monachus), the Lesser–spotted eagle (Aquila pomarina), the Booted eagle (Hieraaetus pennatus) and the Goshawk (Accipiter gentilis). Twenty–six variables illustrating the landscape context and vegetation structure of nesting sites were analysed. Multivariate–ANOVA and Discriminant Function Analysis were used to test for significant differentiations in nest–site characteristics among the species. The species studied were initially differentiated by geomorphology and distance to foraging areas. Once these were determined their nesting areas were established according to forest structure. Our results indicate that forest management should integrate the preservation of mature forest stands with sparse canopy and forest heterogeneity in order to conserve suitable nesting habitats for the raptors. Specific conservation me asures such as restriction of road construction should be implemented in order to protect the active nests and provisions should be made for adequate nesting sites for the Black vulture, which is sensitive to human disturbance. Key words: Sympatric raptors, Discriminant analysis, Nesting habitat separation, Conservation guidelines.En este estudio se han comparado los patrones de selección del lugar de nidificación de cuatro especies de rapaces simpátridas que construyen sus nidos en los árboles, en el Dadia National Park (Grecia), con el fin de obtener una buena herramienta de conservación para su gestión a largo plazo en esta zona. Las especies estudiadas fueron el Buitre Negro (Aegypius monachus), el Águila Pomerana (Aquila pomarina), el Aguililla Calzada (Hieraaetus pennatus) y el Azor Común (Accipiter gentilis). Se analizaron 26 variables que ilustraban el contexto paisajístico y la estructura de la vegetación de los lugares de nidificación. Se utilizaron el ANOVA multivariante y el Análisis de Función Discriminante para comprobar las diferencias significativas en las características de los lugares de nidificación según las especies. En primer lugar, las especies estudiadas se diferenciaron en cuanto a la geomorfología y la distancia a los lugares de alimentación. Una vez determinados ambos parámetros, se establecieron sus áreas de nidificación según la estructura forestal. Nuestros resultados indican que la gestión forestal debería integrar la conservación de zonas de bosque maduro con un dosel escaso y la heterogeneidad forestal, para conservar hábitats de nidificación adecuados para estas rapaces. Deberían tomarse medidas específicas de conservación tales como la restricción de construcción de carreteras, para la protección de los nidos activos y se debería proveer de lugares adecuados para la nidificación del buitre negro, que es muy sensible a la presencia humana. Palabras clave: Rapaces simpátridas, Análisis discriminante, Clasificación de hábitats de nidificación, Pautas de conservación

Food and feeding ecology of Gull-billed terns (Gelochelidon nilotica) in Greece

Le régime de la Sterne hansel Gelochelidon nilotica a été étudié par analyse des pelotes de régurgitation dans trois zones humides de Grèce, le delta de l'Evros (1985-87), Alyki Kitrous (1989) et Messolonghi (1989). Dans la première localité, les insectes, et en particulier les Coléoptères, constituent les proies principales, les autres taxons (Mollusques bivalves, Crustacés, Poissons téléostéens, Reptiles, Mammifères) n'ayant qu'une importance secondaire. A Alyki, ce sont les Orthoptères qui prédominent. A Messolonghi, les crabes arrivent en tête, suivis par les insectes (Orthoptères et Coléoptères principalement), puis les proies de moindre importance (Arachnides, Amphibiens, Poissons téléostéens). Les indices de diversité trophique varient d'une année à l'autre dans le delta de l'Evros. Contrairement à ce qui a été suggéré antérieurement, la diversité du régime de la Sterne hansel est indépendante de la latitud

Modelling nesting habitat as a conservation tool for the Eurasian black vulture (Aegypius monachus) in Dadia nature reserve, northeastern Greece.

Abstract The Eurasian black vulture (Aegypius monachus) is a globally endangered species, vulnerable in Europe and endangered in Greece. We modelled its nesting preferences in Dadia reserve, northeastern Greece using logistic models at multi-scale level combined by Bayesian statistics. Compared with the random sites, the vultures nested at trees with greater diameter (DBH), lower height, and lower total number of trees around the nest tree, steeper slopes and greater distance from forest roads. Our results indicate that conservation and management guidelines for black vultures must aim: (1) to preserve old, isolated mature trees in the reserve, (2) to maintain the zones of strict protection as vulture sanctuary, including most of the suitable nesting habitat, (3) to protect the apparently suitable but still unused habitat in the rest of the reserve from disturbance and logging, (4) to monitor any changes in habitats and use our models to evaluate and predict their effect on vulture nesting in the reserve

Use of the Drana lagoon (Evros Delta, Greece) by threatened colonially nesting waterbirds and its selection of the Shelduck Tadorna tadorna in Evros Delta, Greece possible restoration

Abstract Six species of waterbirds nested colonially on small islands in the Drana saltwater lagoon in the Evro

Breeding ecology of the avocet (Recurvirostra avosetta L.) in the Evros delta (Greece)

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Food and feeding ecology of Gull-billed Terns (Gelochelidon nilotica) in Greece

A study of the diet of Gull-billed Terns was carried out by analysis of regurgitated pellets during the breeding season in three Greek coastal wetlands : Evros Delta (1985-1987), Alyki Kitrous (1989) and Messolonghi (1989). In the Evros Delta, insects, especially Coleoptera, were the most important prey ; non-insect taxa (Bivalvia, Crustacea, Osteichthyes, Reptilia and Mammalia) were much less important. At Alyki, insects, especially Orthoptera, were the predominant prey whereas other prey items (Bivalvia, Amphibia, Aves, Mammalia) were of little importance. At Messolonghi, crabs (Carcinus sp.) were the prey most often consumed ; insects (mainly Orthoptera and Coleoptera) were less common in the diet and other prey types (Arachnida, Amphibia, Osteichthyes) were of minor importance. Trophic diversity indices differed between years in the Evros Delta. A brief review of the literature shows that, in contrast to what has been previously suggested, trophic diversity of Gull-billed Terns is independent of latitude. Methodological aspects are discussed in order to improve our knowledge of the feeding ecology of Gull-billed Terns.Le régime de la Sterne hansel Gelochelidon nilotica a été étudié par analyse des pelotes de régurgitation dans trois zones humides de Grèce, le delta de l’Evros (1985-87), Alyki Kitrous (1989) et Messolonghi (1989). Dans la première localité, les insectes, et en particulier les Coléoptères, constituent les proies principales, les autres taxons (Mollusques bivalves, Crustacés, Poissons téléostéens, Reptiles, Mammifères) n’ayant qu’une importance secondaire. À Alyki, ce sont les Orthoptères qui prédominent. À Messolonghi, les crabes arrivent en tête, suivis par les insectes (Orthoptères et Coléoptères principalement), puis les proies de moindre importance (Arachnides, Amphibiens, Poissons téléostéens). Les indices de diversité trophique varient d’une année à l’autre dans le delta de l’Evros. Contrairement à ce qui a été suggéré antérieurement, la diversité du régime de la Sterne hansel est indépendante de la latitude.Goutner Vassilis. Food and feeding ecology of Gull-billed Terns (Gelochelidon nilotica) in Greece. In: Revue d'Écologie (La Terre et La Vie), tome 46, n°4, 1991. pp. 373-384