Selección de hábitat de Lontra longicaudis (Carnivora, Mustelidae) en zonas con influencia de la represa hidroeléctrica del río Peñas Blancas y algunos de sus tributarios, San Ramón de Alajuela, Costa Rica
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Fecha
2015
Autores
Navarro Picado, Jonathan
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Universidad Nacional (Costa Rica)
Resumen
Los cambios producidos por actividades humanas sobre los ecosistemas acuáticos reducen y reconfiguran los hábitats disponibles, además de alterar las relaciones intra- e interespecíficas de los organismos que los habitan. Por ello, el objetivo de este estudio file evaluar la selección de hábitat de la nutria neotropical (Lontra longicaudis), en zonas con influencia de la represa hidroeléctrica del río Peñas Blancas y algunos de sus tributarios, con el fin de recomendar acciones para la conservación de la nutria. En la zona de estudio, se muestrearon cinco sectores, distribuidos en dos del río Peñas Blancas y tres de sus tributarios en busca de indicios de la nutria, para lo cual se recorrieron 45 segmentos de río en total, en cada uno de ellos se midieron siete variables ambientales con el fin determinar la probabilidad de ocurrencia y detectabilidad. Por último, se colectaron y analizaron excretas para encontrar el uso de presas por parte de la nutria neotropical. Se observó que el ancho del río y la proporción de bosque fueron las variables más influyentes positivamente en la 0Currencia de la especie. Además, la probabilidad de ocurrencia fue más alta en el caudal de compensación del río Peñas Blancas. En cuanto a la dieta de la nutria, los peces fueron la categoría de presa más frecuente en los últimos años, con los cíclidos y poecílidos como las familias predominantes. El ancho del río y la Cobertura boscosa proporcionan zonas de refugio y alimentación idóneas para la supervivencia de la nutria. Por Otra parte, las nutrias poseen amplios rangos de hogar por lo cual se obtuvo una idea de la selección de requerimientos de hábitat aunque, las relaciones con la ocurrencia no fueran muy fuertes. El uso de peces encontrado en el presente estudio es apoyado por otros estudios, principalmente la frecuencia en peces de movimientos lentos. por lo contrario, en los poecílidos, su alta frecuencia posiblemente se deba a la abundancia de ésta familia en la zona de estudio. Cabe resaltar que los peces continúan siendo un
C0mP0nente importante en la dieta de la nutria, a pesar de las actividades generadas por la represa a través de los años. Por último, es necesario implementar un programa de monitoreo de la nutria neotropical en la Cuenca del río San Juan o parte de la misma, como medida de conservación de la especie y de la cadena trófica presente en ríos, analizar cambios temporales, mostrar tendencias e influencia de la represa a largo plazo.
The changes produced by human activities on aquatic ecosystems reduce and reconfigure the available habitats, in addition to altering the intra- and interspecific relationships of the organisms that inhabit them. Therefore, the objective of this study was to evaluate the habitat selection of the Neotropical otter (Lontra longicaudis), in areas influenced by the Peñas Blancas river hydroelectric dam and some of its tributaries, in order to recommend actions for conservation. of the otter In the study area, five sectors were sampled, distributed in two of the Peñas Blancas river and three of its tributaries in search of signs of the otter, for which a total of 45 river segments were covered, in each of them they were measured. seven environmental variables in order to determine the probability of occurrence and detectability. Finally, excreta were collected and analyzed to find the use of prey by the Neotropical otter. It was observed that the width of the river and the proportion of forest were the most positively influential variables in the 0Currency of the species. In addition, the probability of occurrence was higher in the compensation flow of the Peñas Blancas river. Regarding the otter's diet, fish were the most frequent prey category in recent years, with cichlids and poeciliids as the predominant families. The width of the river and the forest cover provide shelter and feeding areas suitable for the survival of the otter. On the other hand, otters have wide home ranges, so an idea of the selection of habitat requirements was obtained, although the relationships with occurrence were not very strong. The use of fish found in the present study is supported by other studies, mainly the frequency in slow-moving fish. on the contrary, in poecilids, its high frequency is possibly due to the abundance of this family in the study area. It should be noted that fish continue to be a An important component in the otter's diet, despite the activities generated by the dam over the years. Finally, it is necessary to implement a monitoring program for the neotropical otter in the San Juan River Basin or part of it, as a conservation measure for the species and the trophic chain present in rivers, analyze temporal changes, show trends and influence of the dam in the long term.
The changes produced by human activities on aquatic ecosystems reduce and reconfigure the available habitats, in addition to altering the intra- and interspecific relationships of the organisms that inhabit them. Therefore, the objective of this study was to evaluate the habitat selection of the Neotropical otter (Lontra longicaudis), in areas influenced by the Peñas Blancas river hydroelectric dam and some of its tributaries, in order to recommend actions for conservation. of the otter In the study area, five sectors were sampled, distributed in two of the Peñas Blancas river and three of its tributaries in search of signs of the otter, for which a total of 45 river segments were covered, in each of them they were measured. seven environmental variables in order to determine the probability of occurrence and detectability. Finally, excreta were collected and analyzed to find the use of prey by the Neotropical otter. It was observed that the width of the river and the proportion of forest were the most positively influential variables in the 0Currency of the species. In addition, the probability of occurrence was higher in the compensation flow of the Peñas Blancas river. Regarding the otter's diet, fish were the most frequent prey category in recent years, with cichlids and poeciliids as the predominant families. The width of the river and the forest cover provide shelter and feeding areas suitable for the survival of the otter. On the other hand, otters have wide home ranges, so an idea of the selection of habitat requirements was obtained, although the relationships with occurrence were not very strong. The use of fish found in the present study is supported by other studies, mainly the frequency in slow-moving fish. on the contrary, in poecilids, its high frequency is possibly due to the abundance of this family in the study area. It should be noted that fish continue to be a An important component in the otter's diet, despite the activities generated by the dam over the years. Finally, it is necessary to implement a monitoring program for the neotropical otter in the San Juan River Basin or part of it, as a conservation measure for the species and the trophic chain present in rivers, analyze temporal changes, show trends and influence of the dam in the long term.
Descripción
Navarro Picado, J. (2015). Selección de hábitat de Lontra longicaudis (Carnivora, Mustelidae) en zonas con influencia de la represa hidroeléctrica del río Peñas Blancas y algunos de sus tributarios, San Ramón de Alajuela, Costa Rica. [Tesis de Licenciatura]. Universidad Nacional, Heredia, C.R.
Palabras clave
REPRESAS, DAMS, LONTRA LONGICAUDIS, HABITAT, POECILIIDAE, RIOS, RIVERS, ECOSISTEMAS, BOSQUES, ESPECIES