1,720,972 research outputs found
Impacto de depredación y selección de presa del lince ibérico y el zorro sobre el conejo
Get PDF[ES] Durante los años 1995-96 y 97 en el parque Nacional de Doñana, en la finca concodia como "Coto del Rey" (Huelva) se ha censado las poblaciones de lince ibérico, zorro y conejo, a la par que realizado un estudio sobre la importancia del conejo en la dieta de ambos carnívoros. Con todo ello se determinó el impacto de depredación, medido como porcentaje de presas consumidas del total presente, así como la selección de tamaño de conejos que estos carnívoros efectuaron a lo largo del tiempo
Reassessment of the conservation status of the Iberian lynx Lynx pardinus for the IUCN Red List of Threatened Species
No full textDuring the last 70 years, the Iberian lynx Lynx pardinus has experienced dramatic changes in its environment, range size, and population size. In a context of widespread support for Iberian lynx conservation, its recent downgrading from Critically Endangered to Endangered in the IUCN Red List has drawn some public concern. Here we expand the summarized account published in the IUCN Red List website to illustrate how assessments are performed in well studied species. Assessment requires assignment to the highest threat category for which the species qualifies according to any of five criteria. Using 2012 as the reference year, no decline was observed during the last three lynx generations, and criteria regarding Population size reduction (A1, A2 and A4) were not met. Under criterion B (Geographic range) the species should be listed as Vulnerable. Considering Criterion D (Very small or restricted population), the Iberian lynx should be assigned to the Endangered category because in 2012 the estimated number of mature individuals (168) was under the established threshold of 250. A complex population model incorporating the combined effects of climate change, prey availability and conservation strategies reveals the critical need of maintaining current reintroduction efforts to avoid lynx extinction. If this condition is fulfilled, the species should be downgraded to Endangered under criterion E (Quantitative analysis). If reintroductions are discontinued, the category Endangered would be assigned under criteria A3 (Projected population reduction) and C (Small population and decline). We discuss the objectivity, transparency and conservation implications of the Iberian lynx downlisting.Durante los últimos 70 años, las condiciones ambientales, el área de distribución y el tamaño poblacional del lince ibérico Lynx pardinus han experimentado cambios sustanciales. Vivimos un periodo en el que la conservación del lince recibe un fuerte apoyo social y, en este contexto, la reciente catalogación de la especie como En Peligro en la Lista Roja de la UICN, rebajando su anterior estatus de En Peligro Crítico, ha despertado cierta preocupación. Usando el caso del lince ibérico, ilustramos con detalle cómo se evalúa el grado de amenaza y se catalogan en la Lista Roja de la IUCN las especies para las que existe mucha información biológica. Las especies deben catalogarse en la categoría de amenaza más alta resultante de la valoración independiente de cinco criterios. Tomando 2012 como el año de
referencia, no encontramos indicios de declive desde hace tres generaciones y, por tanto, los criterios de reducción de tamaño poblacional A1, A2 y A4 no se cumplen. Considerando el criterio B, relativo a atributos del área de distribución, la especie debe clasificarse como Vulnerable. Según el criterio D, relativo a poblaciones pequeñas y de distribución restringida, el lince entra en la categoría En Peligro porque el número estimado de individuos maduros en el año de referencia (168) es inferior al umbral establecido por este criterio (250). La dinámica poblacional predicha por un modelo que considera el efecto combinado del cambio climático, la disponibilidad de presas y las estrategias de conservación señala la necesidad de mantener los actuales esfuerzos de reintroducción para evitar la extinción del lince en las décadas venideras. Si estos esfuerzos se mantienen, el nivel de amenaza puede rebajarse a
En Peligro, según el criterio E, relativo al resultado de análisis cuantitativos. Si, por el contrario, las reintroducciones se suspenden, el lince no solo se mantendría como En Peligro Crítico según el criterio E, sino que también se asignaría a En Peligro según los criterios A3 (reducción poblacional esperada) y C (combinación de poblaciones pequeñas y declive poblacional). Discutimos brevemente la objetividad, la transparencia y las implicaciones de conservación del cambio de categoría de amenaza del lince ibérico
Ontogenia del comportamiento del lince ibérico ("Lynx pardinus") en cautividad
Get PDFEl lince ibérico es una de las especies de mamífero más amenazada del mundo. Su cría en cautividad es una de las medidas puestas en marcha para la conservación de esta especie. Esta Tesis Doctoral tiene como objetivo describir la ontogenia física y del comportamiento de los cachorros de lince ibérico nacidos en cautividad, y conocer los factores que van a influir en su desarrollo, para mejorar el manejo de la especie en cautividad. Se realizó el seguimiento del comportamiento de los cachorros de lince ibérico nacidos en los centros de cría "El Acebuche" (Huelva, España) y "La Olivilla" (Jaén, España) entre los años 2005 y 2013, mediante un sistema de video vigilancia remota que permitía obtener los registros del comportamiento evitando las alteraciones derivadas de la presencia del observador cerca de los animales.
El lince ibérico es una especie semi-altricial. Los cachorros nacieron en el interior de las parideras y no eran capaces de caminar, su desarrollo sensorial era relativamente atrasado y dependían de la madre para alimentarse. Durante el primer mes de vida, se produjo la maduración sensorial y motora, lo que permitió a los cachorros abandonar la paridera, propiciando los principales cambios en el comportamiento. El crecimiento de los cachorros se ajustó a la función de von Bertalanffy. Los machos crecieron más rápido que las hembras, de forma que eran un 8% más grandes de adultos; mientras que el método de crianza (criados con sus madres/crianza artificial) modificó la tasa de crecimiento, pero no el tamaño de adulto. La lactancia ocupó gran parte del tiempo de los cachorros durante las primeras semanas de vida, pero decreció rápidamente conforme crecieron. El destete, periodo en el que se alimentan tanto de comida sólida como de leche materna, ocurrió durante el último tercio del total del periodo lactante, por lo que el papel principal de la lactancia en el lince ibérico parece ser la nutrición de los cachorros. Una vez fuera de la paridera, la actividad diaria se incrementó hasta el tercer mes de vida, a partir del cual permaneció constante en torno al 50%. El patrón circadiano bimodal con máximos en los crepúsculos surgió en el segundo mes de vida y quedó completamente establecido a partir del tercer mes.
El incremento en la actividad diaria vino acompañado de la aparición de nuevos comportamientos como el juego y la depredación. Se pudieron observar cuatro categorías de juego en los cachorros de lince ibérico. El juego social fue el primero en aparecer al mes de vida y ocupó la mayor parte del tiempo de juego de las crías. Los juegos de tipo locomotor se vieron por primera vez a los 55 días, los juegos con objetos a los 59 días y los juegos con la presa a los 61 días. El juego alcanzó su máxima prevalencia entre las semanas 11 y 14, descendiendo posteriormente, aunque sin desaparecer por completo al final del estudio. Por su parte, el proceso de aprendizaje de la caza comenzó al mes de vida, cuando la madre les llevó una presa a sus cachorros por primera vez. Las primeras etapas del aprendizaje dependieron de la iniciativa materna, que les facilitó la tarea de ingestión y captura de la presa, hasta que las crías eran capaces de cazar sin ayuda a las 15 semanas. La secuencia básica del etograma de la depredación estuvo constituida por la búsqueda, el ataque, la captura, el mordisco, el traslado de la presa y la ingesta; viéndose alterada en ocasiones por juegos o peleas. Durante el ataque, los cachorros emplearon cuatro técnicas de caza, en orden de prevalencia: acoso, rececho, acecho y persecución. El éxito total de captura fue del 53%.
A partir de los resultados obtenidos se estima que la duración de las cuatro etapas del desarrollo en especies altriciales para el lince ibérico es: periodo neonatal (semanas 0 a 3); periodo de transición (semanas 4 y 5), periodo de socialización (semanas 6 a 15) y periodo juvenil (semana 16 hasta la maduración sexual).The Iberian lynx is one of the most endangered mammal species in the world. The captive breeding is one of the main measures implemented for the conservation of this species. This thesis aims to describe the physical and behavioral ontogeny of Iberian lynx cubs born in captivity and to know the factors that may influence its development, in order to improve the husbandry of the species in captivity. It was tracked the behavior of the Iberian lynx cubs born in the Iberian Lynx Breeding Centers of "El Acebuche" (Huelva, Spain) and "La Olivilla" (Jaen, Spain) between 2005 and 2013, by a video surveillance system, that allowed the remote data collection, avoiding the disturbances arising from the presence of the observer close to the animals.
The Iberian lynx is a semi-altricial species. The cubs were born inside a den and were not able to walk, its sensory development was relatively backward and they were dependent on the mother for feeding. During the first month of life, there was the sensory and motor maturation, allowing the cubs to leave the den, leading to the major changes in behavior. The growth of the cubs fitted to von Bertalanffy function. Males grew faster than females, so they were an 8% larger in adulthood; whereas the rearing method (mother vs hand-reared) modified the growth rate, but not the adult body mass. The lactation occupied much of the time of the cubs during the first weeks of life, but it decreased rapidly as grew. The weaning period, in which the cubs feed both on solid food and on milk, occurred during the last third of lactation period, so the main role of lactation in the Iberian lynx seems to be the nutrition of the cubs. Once out of the den, daily activity increased until the third month of life, after which it remained constant at around 50%. The bimodal circadian pattern with peaks in the twilights emerged in the second month of life and was fully established after the third month.
The increase in daily activity was accompanied by the emergence of new behaviors like play and predation. It was observed four categories of play in the Iberian lynx cubs. The social play was the first in appear at one month old and occupied most of the playtime of the cubs. The locomotor play was observed for the first time at 55 days, the object play at 59 days and the predatory play at 61 days. The play behavior reached its highest prevalence between weeks 11 and 14. Then decreased, but it did not disappear completely at seven months old. Meanwhile, the process of learning to hunt began when the cubs were one month old and the mother took them a prey for the first time. The early stages of learning depended on maternal initiative, which facilitated the tasks of ingestion and capture the prey, until the cubs were able to hunt without help at 15 weeks. The basic sequence of predatory ethogram consisted on search, attack, capture, bite, move the prey and eat; and sometimes was disrupted by play bouts or fights. During the attack, the cubs used four hunting techniques, in order of prevalence: harassment, ambushing, stalking and persecution. The hunting success was 53%.
According to the results of the thesis, it is estimated that the duration of the four periods of development in altricial species for the Iberian lynx is: neonatal period (weeks 1-3 ); transition period (weeks 4 and 5), socialization period (weeks 6-15) and juvenile period (week 16 to sexual maturation).Departamento de Biología Ambiental y Salud Públic
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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