The Effect of Seed Availability on Population Density of Oryzomys in Southern Chile

González, Luz Angélica Muñoz; Murúa, Roberto; Jofre, C

doi:10.2307/1381527

Cited by 20 publications

(12 citation statements)

References 7 publications

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“…Proponemos que en todas las áreas silvestres protegidas con presencia de reservorios de hantavirus, con flujos relevantes de turistas y administrativos residentes, se elaboren cartas de riesgos, como las propuestas, y que éstas sean incorporadas en los respectivos planes de manejos de esas unidades. (González et al 1989, Engelthaler et al 1999, Gallardo & Mercado 1999, González & Donoso 1999, Lima et al 1999, Jaksic & Lima 2003, Murúa et al 2003. Por este motivo el mapa de riesgo debe estar claramente referido a la estación y año en que fue realizado.…”

Section: Carta De Riesgounclassified

Mapas de riesgo para Hantavirus en el Parque Nacional Conguillío, sur de Chile

Muñoz‐Pedreros

Rutherford

Gil

2007

Rev. chil. hist. nat.

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RESUMENEl riesgo de infección con Hantavirus depende de factores, que determinan una probabilidad de contagio con los reservorios, tales como: (a) la estructura vegetacional y el uso del suelo como un escenario primario, donde los factores específicos de composición, estructura y densidad de la vegetación detallan elementos relacionados con el hábitat de los reservorios. (b) La existencia de poblaciones de roedores reservorio. (c) Establecimientos humanos, como disponibilidad y densidad de caminos, áreas habitadas o de presencia humana (e.g., casas, bodegas). Estos tres factores, hábitat (probabilidad de ocurrencia del reservorio), roedores seropositivos (peligro de contagio) y humanos (población expuesta), conjugados, proporcionan los elementos de juicio necesarios para establecer el riesgo. Es importante considerar que estos factores tienen una dinámica de cambio estacional durante el año y modificaciones ambientales naturales y antrópicas. Así, buscamos comprender el riesgo a que está sometido el ser humano en el espacio rural. Los modelos espaciales corresponden a representaciones de la realidad observada en un área determinada y condicionada a diversos factores geográficos, topográficos, biológicos, climáticos, etc. El objetivo de este estudio fue establecer sectores potenciales de riesgo al hantavirus en un parque nacional de la IX Región de Chile empleando cartas temáticas de variables ambientales en un Sistema de Información Geográfica para analizar fotografías aéreas mediante fotointerpretación, transferencia, digitalización y manejo de base de datos gráfica y alfanumérica, validada en terreno. La capa vectorial fue "rasterizada" con un tamaño de píxel de 50 m. El mapa de riesgo se construyó utilizando un modelo aditivo de capas mediante el uso del software Model Builder 1.0, extensión de ArcView 3.2. La base del procedimiento fue el proceso de "overlay" aritmético, que sobrepone las capas adicionando los términos de valor de cada variable utilizando la misma de ponderación en cada una de ellas (e.g., uso del suelo, hábitat del reservorio, seropositividad del reservorio, casos y asentamientos humanos). Presentamos un mapa de riesgo que señala como principales áreas de riesgo, precisamente donde se emplaza la infraestructura turística principal de este visitado parque.Palabras clave: Hantavirus, mapas de riesgo, sur de Chile. ABSTRACTThe risk of infection with Hantavirus depends on factors that determine a probability of contagion with the reservoirs: (a) the vegetation structure and the land use as a primary scene, where specific factors such as composition, structure and density of the vegetation describe elements related to the habitat of the reservoirs. (b) The existence of populations of reservoir rodents. (c) Human establishments, such as availability and density of roads, inhabited areas or human presence (e.g., houses, warehouses). These three factors, brought together, provide the necessary facts to establish the risk. It is important to consider that these factors have a dynamics of seasonal ch...

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Section: Carta De Riesgounclassified

Mapas de riesgo para Hantavirus en el Parque Nacional Conguillío, sur de Chile

Muñoz‐Pedreros

Rutherford

Gil

2007

Rev. chil. hist. nat.

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“…Information about the eating habits of small herbivorous mammals, mainly rodents, is scarce due to their efficient food mastication, which results in small fragments, which are difficult to identify (Hansson 1970). In the Neotropics, some work has been done on food availability as correlated with habitat (Borchert and Hansen 1983;Martinez et al 1990;Bergallo and Magnusson 1999), demographic population (Fleming 1971;Gonza´lez et al 1989;Adler and Beatty 1997;Adler 1998;Bergallo and Magnusson 1999) and the reproductive cycle of those animals (Martino and Aguilera 1989;Bilenca et al 1992;Suarez 1994). In Brazil, the details of the diet of small mammals is limited to some studies (Leite et al 1996;Santori et al 1996Santori et al , 1997Talamoni et al 1999).…”

Section: Introductionmentioning

confidence: 99%

Diet of some species of Neotropical small mammals

et al. 2008

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Dietary analysis was performed to determine the variations in diet of some small neotropical species of mammals collected in seasonal areas of the cerrado (a savannah-like grassland) and semi-deciduous forest. Food items were determined based on the analysis of stomach contents of 126 animals (one didelphid and five sigmodontine rodent species). Most species presented herbivorous-omnivorous habits, with a preference for the vegetative parts of plants. Akodon montensis Thomas (1913) was the most abundant species in the forest area and demonstrated a uniform consumption of animal and vegetal items through the year, and contained 65.7% plant material in its diet. Necromys lasiurus (Lund, 1841) was the most abundant in the cerrado with 72.6% of vegetation in its diet, but showed a high consumption of animal items during the rainy season. Oligoryzomys nigripes (Olfers, 1818) contained 95.1% of plant material, while Oxymycterus delator (Thomas, 1903) consumed 61.6% invertebrates, mainly insects. The didelphid Philander frenatus (Olfers, 1818) consumed invertebrates (47.7%), small vertebrates (7.3%) and plant material (44.9%).

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“…longicaudatus have biennial cycles of high abundance; years with high offspring production promote high density populations the following year. The population dynamics of this rodent has been well studied in longterm investigations (e.g., >4 years), describing its seasonal and biannual variations (e.g., Murúa et al 1986;González et al 1989;Meserve et al 2003;Murúa et al 2003;Murúa and Briones 2005), as well as its fluctuations during the phenomenon of ENSO (Lima and Jaksic 1998a, b;Lima et al 1999a, b;Jaksic 2001;Lima et al 2002;Jaksic and Lima 2003), in southern and central Chile. Since the variations of the population of O. longicaudatus in this study are not attributable to climate variations (e.g., ENSO) or the biannual cycle, they might be attributable to the impact of predation by T. alba since in central Chile, small rodents respond with an increase in their populations within months of El Niño arrival which occurred in [2001][2002][2003], and the biannual variations described occur in southern Chile due to the biannual variations of the seed production, a characteristic of many tree species in those temperate forests.…”

Section: Small Mammal Populations and Predation Impactmentioning

confidence: 99%

“…In the Lago Peñuelas, the O. longicaudatus population starts with low numbers in the summer, increases in March and April, peaks in May and June, and then begins to decline drastically (González et al 1989). In the sclerophyllous shrub of Santiago, an annual density of 12 ind/ha has been documented, constituting the second most abundant mammal species, but with strong fluctuations (coefficient of variation (CV)=90.0).…”

Section: Small Mammal Populations and Predation Impactmentioning

confidence: 99%

“…In Concepción, it reached 9.4 ind/ha/year (1984)(1985) with strong monthly fluctuations (CV= 103.4). In San Martin (Valdivia), at the time of blossoming of Chusquea quila, it peaked at 172 ind/ha (see González et al 1989;Muñoz-Pedreros 1992;Meserve et al 1999;Gallardo and Mercado, 1999;Murúa et al 2003).…”

Section: Small Mammal Populations and Predation Impactmentioning

confidence: 99%

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Raptor habitat management and its implication on the biological control of the Hantavirus

et al. 2010

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Rodents have a high impact on human activities, producing economical losses and diseases. One of these diseases is Hantavirus syndrome, whose reservoir is Oligoryzomys longicaudatus. Raptors are the natural biological controllers of rodents, being, therefore, our efficient and effective allies. Despite the existing legal dispositions for protection, 11 of the 33 species of raptors in Chile have conservation problems. We evaluated the effectiveness of nest boxes for Tyto alba, as a way to increase its population and propose a procedure for the biological control of O. longicaudatus. The study area was the National Reserve Lago Peñuelas, Valparaíso, Chile. The variation of population density before and after the installation of the nest boxes was established both for T. alba and rodents. The results show that the nest boxes installed dramatically increased the population and the total density of T. alba, and a significant reduction of the abundance of small mammals was stated. We propose a methodological diagram for the biological control of the reservoir of the Hantavirus, which we have been implementing since 2001.

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The Effect of Seed Availability on Population Density of Oryzomys in Southern Chile

Cited by 20 publications

References 7 publications

Mapas de riesgo para Hantavirus en el Parque Nacional Conguillío, sur de Chile

Mapas de riesgo para Hantavirus en el Parque Nacional Conguillío, sur de Chile

Diet of some species of Neotropical small mammals

Raptor habitat management and its implication on the biological control of the Hantavirus

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