149 research outputs found

    Efectos de radio-emisores de cola en cernícalos primilla adultos

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    [ENG]The behavior,b reeding successa nd survivalo f radio-taggeda nd non-radio-tagged (control) Lesser Kestrels (Falco naumanni) in southern Spain in 1989-1990 were compared. The copulation period, copulation rates and prey delivery rates to both mates and nestlings did not differ significantlyb etween radio-taggeda nd control individuals.I n addition, there were no differences in annual survival rates or breeding success between radio-tagged and control birds.[ESP]-Sec ompararon aspectosd e comportamiento,6 xito reproductor y supervivencia entre cernlcalosp rimillas (Falco naumanni) portadores de radiotransmisorese n la cola y otros marcados finicamente con anillas (controles) en el sur de Espafia en 1989-1990. E1 periodo de c6pulas, la frecuencia de las mismas, asi como las tasas de cebas de pareja y a los pollos no se diferenci6 significativamentee ntre los individuosp ortadoresd e radiotransmisoresy los controles.T ampoco se detectaron diferenciase n las tasasd e supervivenciaa nual y 6xito reproductivo entre los dos grupos comparados.Peer reviewe

    Contradiction in conservation of island ecosystems: Plants, introduced herbivores and avian scavengers in the Canary Islands

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    Introduction of alien herbivores in sensitive island systems has resulted in massive effects on vegetation cover, floristic richness and composition of communities; some species can be even totally extirpated by grazing pressure. Goats Capra hircus and wild rabbits Oryctolagus cuniculus were introduced in the Canary Islands around 500 B.C. Barbary ground squirrels Atlantoxerus getulus were introduced in 1967. Traditional extensive livestock exploitations have been maintained to the present but in the last decades the number of goats has sharply increased up to densities of 53 heads/km2. Overgrazing and trampling have heavily affected eleven island endemic plant species. Some populations have been reduced to less than 10 viable individuals. On the other hand, goat carcasses and wild rabbit and squirrel populations help to maintain populations of three endangered endemic subspecies of birds. This conflict presents important economic and social ramifications: whereas public funds (mainly through European LIFE projects) are devoted to conservation of plant and avian endemic taxa, the number of goats increases rapidly thanks to subventions derived from the European Common Agricultural Policy (CAP). Similar conflicts are apparent in other Mediterranean Basin insular systems. It is urgently necessary to harmonize farming and conservation objectives in the Canary Islands. The impact of goats on the vegetation should be minimized through limitation of grazing in sensitive areas with high degree of endemism. Creation of 'vulture restaurants' may reduce the dependence of scavengers on extensive livestock exploitations. We recommend a careful study of ecological relationships within island communities where non-native species are susceptible of playing a keystonrole as occurs in the Mediterranean Basin archipelagos. © Springer 2006.Peer Reviewe

    Large scale risk-assessment of wind-farms on population viability of a globally endangered long-lived raptor

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    Wind-farms receive public and governmental support as an alternative energy source mitigating air pollution. However, they can have adverse effects on wildlife, particularly through collision with turbines. Research on wind-farm effects has focused on estimating mortality rates, behavioural changes or interspecific differences in vulnerability. Studies dealing with their effects on endangered or rare species populations are notably scarce. We tested the hypothesis that wind-farms increase extinction probability of long-lived species through increments in mortality rates. For this purpose, we evaluate potential consequences of wind-farms on the population dynamics of a globally endangered long-lived raptor in an area where the species maintains its greatest stronghold and wind-farms are rapidly increasing. Nearly one-third of all breeding territories of our model species are in wind-farm risk zones. Our intensive survey shows that wind-farms decrease survival rates of this species differently depending on individual breeding status. Consistent with population monitoring, population projections showed that all subpopulations and the meta-population are decreasing. However, population sizes and, therefore, time to extinction significantly decreased when wind-farm mortality was included in models. Our results represent a qualitative warning exercise showing how very low reductions in survival of territorial and non-territorial birds associated with wind-farms can strongly impact population viability of long-lived species. This highlights the need for examining long-term impacts of wind-farms rather than focusing on short-term mortality, as is often promoted by power companies and some wildlife agencies. Unlike other non-natural causes of mortality difficult to eradicate or control, wind-farm fatalities can be lowered by powering down or removing risky turbines and/or farms, and by placing them outside areas critical for endangered birds. © 2009 Elsevier Ltd. All rights reserved.Peer Reviewe

    Post-fledging dependence period and onset of natal dispersal in Bearded Vultures (Gypaetus barbatus): new insights from GPS satellite telemetry.

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    Utilizamos telemetría satelital para estudiar el periodo de dependencia post emplumamiento de tres individuos silvestres y seis individuos cautivos de Gypaetus barbatus. El primer vuelo tuvo lugar cuando los pollos tenían 126 ± 7 días de edad (rango  =  111-134 días) y el inicio de la dispersión ocurrió a los 193 ± 40 días desde el primer vuelo (rango  =  143-231 días). Los jóvenes permanecieron en sus áreas natales (o de liberación, en el caso de aves criadas en cautiverio) durante los primeros dos meses desde la fecha de emplumamiento. Luego, comenzaron a incrementar progresivamente la distancia a sus áreas natales; durante este tiempo, la mayoría de los desplazamientos de larga distancia (>15 km) tuvieron lugar antes del mediodía. Los tamaños de las áreas de acción registrados en este estudio fueron superiores a los descritos con anterioridad para la especie, principalmente debido a la diferencia en los métodos de rastreo empleados: la telemetría satelital permitió la detección de movimientos de larga distancia más allá del rango de medición del rastreo por radio convencional. Finalmente, la adquisición de la independencia (i.e., emancipación) se solapó con la siguiente temporada de cría de los adultos

    Apex scavengers from different European populations converge at threatened savannah landscapes

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    Over millennia, human intervention has transformed European habitats mainly through extensive livestock grazing. “Dehesas/Montados” are an Iberian savannah-like ecosystem dominated by oak-trees, bushes and grass species that are subject to agricultural and extensive livestock uses. They are a good example of how large-scale, low intensive transformations can maintain high biodiversity levels as well as socio-economic and cultural values. However, the role that these human-modified habitats can play for individuals or species living beyond their borders is unknown. Here, using a dataset of 106 adult GPS-tagged Eurasian griffon vultures (Gyps fulvus) monitored over seven years, we show how individuals breeding in western European populations from Northern, Central, and Southern Spain, and Southern France made long-range forays (LRFs) of up to 800 km to converge in the threatened Iberian “dehesas” to forage. There, extensive livestock and wild ungulates provide large amounts of carcasses, which are available to scavengers from traditional exploitations and rewilding processes. Our results highlight that maintaining Iberian “dehesas” is critical not only for local biodiversity but also for long-term conservation and the ecosystem services provided by avian scavengers across the continent

    Revista de Vertebrados de la Estación Biológica de Doñaña

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    Alimentación de la boga del Guadiana (Chondrostoma polylepis wi/lkommi, Stein. 1866) en la interfase río-embalse de Sierra Boyera (Córdoba. España)Predación del búho real (Bubo bubo) sobre la perdiz roja (Alectoris rufa): selección de edad y sexoAlimentación de la nutria (Lutra lufra L, 1758)en el Nordeste de la Península IbéricaDatos sobre la distribución espacialde micromamíferos en el Parque Nacionalde DoñanaGuía para el reconocimiento microscópico de los pelos de los mamíferos de la Patagonia.Sobre la distribución geográfica de Anaecypris hispanica (STEINDACHNER, 1866) (OSTEICHTHYES, CYPRINIDAE)Cronología del periodo reproductor de Rana temporaria L. en La Coruña (NW de España).Un nuevo caso de melanismo en Natrix natrix (LINNAEUS 1758) procedente de Fuente Dé (Santander)Nuevas citas de anfibios y reptiles para el SE de la Península Ibérica.Datos sobre la dieta invernal del Búho chico (Asia atus) en la provinvia de LeónLa Distribucióndel Mara (Dolichotis patagonum) según criterios ecológicos e históricosSolapamiento entre la dieta de la cabra montés (Capra pyrenaica) y la del muflón (Ovis musimon)Nota sobre dietas de carnívoros e índices de abundancia en una Reserva de caza del norte de España.Discriminación osteométrica en el géneroTalpa (LINNEO, 1758), en el norte IbéricoObservaciones sobre el comportamiento depredativo de algunos colúbridos Ibéricos en estado salvajePeer reviewe

    Revista de Vertebrados de la Estación Biológica de Doñana

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    Clave preliminar de las escamas de los peces de agua dulce de España, a nivel de familiaExito reproductor del Buitre leonado (Gyps fulvus) en NavarraAlimentación del Gavilán (Accipiter nisus) en la Isla de TenerifeEl Verdecillo (Serinus serinus): Tendencias en la estación de nidificación, en el tamaño del huevo y en la supervivencia.las batidas como método de censo en especiesde caza mayor: aplicación al caso del Jabalí (Sus scrofa L.) en la provincia de Burgos (Norte de España)La adquisición de madurez sexual en el camaleón común (Chamaeleo chamaeleon)Nuevas citas de Hemidactylus turcicus en la provincia de CáceresLa focha común (Fulica atra) en la isla de Gran Canaria: nueva especie nidificante en el archipiélago CanarioTraslado de huevos en incubación por la urraca (Pica pica)Predación de Falco peregrinus sobre Oryctolagus cuniculusCuatro nuevas especies de aves para Bolivia.Sobre la utilización de nidos de golondrina común abandonados.Parasitismo múltiple del críalo (Clamator glandarius)Predación del topo de rio (Galemys pyrenaicus, Geoffroy 1811) por parte de la lechuza común (Tyto alba, Scopoli 1769)Predación del zorro (Vulpes vulpes) sobre un pollo de buitre leonado (Gyps fulvus).Vulpes vulpes L. criando en una colonia de marmota (Marmota marmota L.) en el pirineo de LéridaObservaciones sobre la incidencia de Rattus (Fischer, 1803) en los cultivos ibéricos de caña de azúcaSituación actual de la jutiita de la tierra Capromys sanfelipensis (Rodentia, Mammalia)Notas sobre la intraducción y expansión de la ardilla común en Sierra Nevada, sureste de EspañaPeer reviewe

    Doñana, diversidad y ciencia

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    144 páginasLa biodiversidad es más que la suma de los elementos que componen el mundo vivo; también son biodiversidad las relaciones entre esos elementos, los procesos ecológicos que hacen posible su existencia y los procesos evolutivos que los han originado. […] Los seres humanos necesitamos a la biodiversidad más que ella a nosotros, ya que es la responsable de que la Tierra funcione de una manera satisfactoria. […] El entramado de la vida se ocupa de regular la composición de la atmósfera (y con ella, el clima), de depurar el aire y el agua, de hacer fértil al suelo, de evitar riadas y avalanchas, de polinizar las cosechas, de reducir las plagas, etc. Por todo ello es indispensable conservar la biodiversidad, hoy amenazada.” (Miguel Delibes) Doñana, diversidad y ciencia es un paseo conceptual por el espacio natural más emblemático de Europa. La esencia de un mito a través de decenas de fotografías… Un acercamiento respetuoso a la diversidad de sus conceptos, un paseo por la esencia de su historia y una curiosa aproximación a la ciencia que genera hoy en día. En este recorrido descubriremos el carácter distintivo de algunos de los parajes de la reserva, sus matices más interesantes, las texturas y las formas más sorprendentes de la naturaleza, sus colores y conjuntos, sus transformaciones en las últimas décadas y la influencia de la presencia humana en el privilegiado ecosistema de la Reserva Biológica de Doñana

    Laying the Foundations for a Human-Predator Conflict Solution: Assessing the Impact of Bonelli's Eagle on Rabbits and Partridges

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    BACKGROUND: Predation may potentially lead to negative effects on both prey (directly via predators) and predators (indirectly via human persecution). Predation pressure studies are, therefore, of major interest in the fields of theoretical knowledge and conservation of prey or predator species, with wide ramifications and profound implications in human-wildlife conflicts. However, detailed works on this issue in highly valuable--in conservation terms--Mediterranean ecosystems are virtually absent. This paper explores the predator-hunting conflict by examining a paradigmatic, Mediterranean-wide (endangered) predator-two prey (small game) system. METHODOLOGY/PRINCIPAL FINDINGS: We estimated the predation impact ('kill rate' and 'predation rate', i.e., number of prey and proportion of the prey population eaten, respectively) of Bonelli's eagle Aquila fasciata on rabbit Oryctolagus cuniculus and red-legged partridge Alectoris rufa populations in two seasons (the eagle's breeding and non-breeding periods, 100 days each) in SE Spain. The mean estimated kill rate by the seven eagle reproductive units in the study area was c. 304 rabbits and c. 262 partridges in the breeding season, and c. 237 rabbits and c. 121 partridges in the non-breeding period. This resulted in very low predation rates (range: 0.3-2.5%) for both prey and seasons. CONCLUSIONS/SIGNIFICANCE: The potential role of Bonelli's eagles as a limiting factor for rabbits and partridges at the population scale was very poor. The conflict between game profitability and conservation interest of either prey or predators is apparently very localised, and eagles, quarry species and game interests seem compatible in most of the study area. Currently, both the persecution and negative perception of Bonelli's eagle (the 'partridge-eating eagle' in Spanish) have a null theoretical basis in most of this area

    Network Structure of Vertebrate Scavenger Assemblages at the Global Scale: Drivers and Ecosystem Functioning Implications

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    The organization of ecological assemblages has important implications for ecosystem functioning, but little is known about how scavenger communities organize at the global scale. Here, we test four hypotheses on the factors affecting the network structure of terrestrial vertebrate scavenger assemblages and its implications on ecosystem functioning. We expect scavenger assemblages to be more nested (i.e. structured): 1) in species‐rich and productive regions, as nestedness has been linked to high competition for carrion resources, and 2) regions with low human impact, because the most efficient carrion consumers that promote nestedness are large vertebrate scavengers, which are especially sensitive to human persecution. 3) We also expect climatic conditions to affect assemblage structure, because some scavenger assemblages have been shown to be more nested in colder months. Finally, 4) we expect more organized assemblages to be more efficient in the consumption of the resource. We first analyzed the relationship between the nestedness of the scavenger assemblages and climatic variables (i.e. temperature, precipitation, temperature variability and precipitation variability), ecosystem productivity and biomass (i.e. NDVI) and degree of human impact (i.e. human footprint) using 53 study sites in 22 countries across five continents. Then, we related structure (i.e. nestedness) with its function (i.e. carrion consumption rate). We found a more nested structure for scavenger assemblages in regions with higher NDVI values and lower human footprint. Moreover, more organized assemblages were more efficient in the consumption of carrion. However, our results did not support the prediction that the structure of the scavenger assemblages is directly related to climate. Our findings suggest that the nested structure of vertebrate scavenger assemblages affects its functionality and is driven by anthropogenic disturbance and ecosystem productivity worldwide. Disarray of scavenger assemblage structure by anthropogenic disturbance may lead to decreases in functionality of the terrestrial ecosystems via loss of key species and trophic facilitation processes
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