Diversidad de micromamíferos en tres ambientes de la Reserva Nacional Lago Peñuelas, Región de Valparaíso, Chile/Diversity of small mammals in three environments of the National Reserve Lago Peñuelas, Región de Valparaíso, Chile

RESUMEN. Los ecosistemas mediterraneos de Chile, los unicos en Sudamerica de los cuatro presentes en el mundo, son considerados areas prioritarias para la conservacion, por su alta concentracion de especies endemicas y las aceleradas tasas de destruccion del habitat. Estos contienen mas del 39% de las especies de mamiferos, 47% de las especies endemicas y el 65% de las especies amenazadas del pais. Aun asi, estos ecosistemas estan inadecuadamente representados en el sistema de areas silvestres protegidas, siendo una de ellas la Reserva Nacional Lago Peñuelas (RNLP) parte de la Reserva de Biosfera La Campana-Peñuelas. La mastofauna de la RNLP esta pobremente documentada. Estudiamos la diversidad α y β en el ensamble de micromamiferos presentes en los tres ambientes de la RNLP (bosque esclerofilo, matorral mixto y sabana de Acacia caven). Instalamos grillas de trampas Sherman, recolectamos y analizamos egagropilas de dos especies de aves rapaces (Tyto alba y Bubo magellanicus) y registramos huellas, signos y observacion directa en las cuatro estaciones del ano 2001. Determinamos la riqueza de especies (S), abundancia relativa, diversidad ¿ considerando su riqueza y estructura (indices de Shannon y Wiener y de Pielou), diversidad À (indice de Bray-Curtis) y comparamos la diversidad encontrada con lo documentado en la misma latitud de este a oeste. Registramos un total de 16 especies: Thylamys elegans, Oligoryzomys longicaudatus, Abrothrix longipilis, A. olivaceus, Chelemys megalonyx, Phyllotis darwini, Myocastor coypus, Octodon degus, O. lunatus, Spalacopus cyanus, Abrocoma bennetti, Rattus norvegicus, R. rattus, Mus musculus, Lepus capensis y Oryctolagus cuniculus. El bosque esclerofilo costero fue el mas diverso con distribucion homogenea de sus especies, seguido del matorral mixto y finalmente la sabana de A. caven. Por otro lado el bosque esclerofilo es similar al matorral mixto y ambos a su vez muy disimiles de la sabana de A. caven. La diversidad registrada en el area de estudio es concordante con la correspondiente a otras areas mediterraneas de Chile. Se discute la situacion de estos ecosistemas y se contrasta la diversidad documentada para seis localidades a la misma latitud. Palabras clave: Biodiversidad, mamíferos, roedores, Chile central. ABSTRACT. Chilean Mediterranean ecosystems, the only of this type present in South America of the four present in the world, are considered priority areas for conservation due to their high concentration of endemic species that have experienced accelerated rates of habitat destruction. They contain more than 39% of the mammal species, 47% of its endemic species, and 65% of the threatened species of Chile. Yet, these ecosystems are poorly represented in the system of protected areas, one of which is the Reserva Nacional Lago Peñuelas (RNLP) that is part of the Biosphere Reserve La Campana-Peñuelas, but whose mammal fauna is poorly documented. We studied both α and β diversity of the mammal assemblage in all three environments present at the RNLP (sclerophyllous forest, mixed shrub, and savanna of Acacia caven). Sherman traps grids were installed, pellets of two raptors (Tyto alba and Bubo magellanicus) were analyzed, tracks and signs were recorded, and direct observations were performed in the four seasons of the year 2001. We determined species richness (S), relative abundance, α diversity - considering its richness and structure (Shannon-Wiener and Pielou indexes)-, β diversity (Bray-Curtis index), and compared the diversity found with that documented for the same latitude from east to west. We recorded a total of 16 species: Thylamys elegans, Oligoryzomys longicaudatus, Abrothrix longipilis, A. olivaceus, Chelemys megalonyx, Phyllotis darwini, Myocastor coypus, Octodon degus, O. lunatus, Spalacopus cyanus, Abrocoma bennetti, Rattus norvegicus, R. rattus, Mus musculus, Lepus capensis, and Oryctolagus cuniculus. The coastal sclerophyllous forest was the most diverse with a species homogeneous distribution, followed by the mixed shrub, and finally the A. caven savanna. Also, the sclerophyllous forest is similar to the mixed scrub; in turn, both are very dissimilar to the savanna of A. caven. The diversity recorded in the study area is consistent with that of other areas of the Mediterranean areas. We discuss the status of these ecosystems and the diversity is compared to six documented locations at the same latitude. Keywords: Biodiversity, mammals, rodents, Central Chile.

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