?Evaluaci?n de la dieta de Tremarctos ornatus (CUVIER 1825) ?Oso andino? y su funci?n en la dispersi?n de especies vegetales de bosque montano y p?ramo en Pacaipampa (Piura: Ayabaca)?

Abstract

Tremarctos ornatus es el ?nico ?rsido que se encuentra en Sudam?rica y su mayor ?rea de ocupaci?n est? en el Per?. Esta especie habita ecosistemas muy diversos desde los 250 hasta 4750 msnm. El estado de conservaci?n en que se encuentra el oso andino en el Per? es de Vulnerable desde el 2014. En el presente trabajo se realiz? un an?lisis de la dieta de T. ornatus, a nivel de los compuestos alimentarios de 22 excretas. El muestreo se realiz? durante los meses de Abril y Mayo del 2014, durante un periodo de 10 d?as, abarcando los ecosistemas de P?ramo, Transici?n y Bosque Montano en el distrito de Pacaipampa, departamento de Piura. Este consisti? en el registro de evidencias directas e indirectas de oso andino, mediante una b?squeda extensiva al azar, sin considerar su antig?edad. Tambi?n se realiz? una colecta de plantas potenciales para su dieta. Se analizaron las excretas colectadas, identificando los componentes alimenticios seg?n el origen animal o vegetal, de los cuales, se realiz? un an?lisis m?s detallado del contenido vegetal, identificando como ?tems a las partes vegetativas como tallos y hojas, y partes reproductivas como frutos y semillas. Los componentes vegetales fueron los m?s recurrentes en las excretas, constituyendo todo su volumen en algunas de ellas. Los ?tems Hojas y Frutos obtuvieron mayor PO con 31.34% y 22.39% respectivamente de las 22 excretas. Se identific? taxon?micamente 4 especies de plantas consumidas en la dieta del oso andino, como Puya sp, Guzmania sp, Chusquea sp y Vaccinium floribundum. Los ?tems frutos y semillas pertenec?an a V. floribundum de la familia Ericaceae, los que se encontraron ?ntegros. El valor obtenido del ?ndice de importancia relativa (%IRI) de las especies consumidas muestra que V. floribundum tuvo mayor porcentaje en los tres ecosistemas en los que se encontr? con 48.58%, 58,35% y 44.41% respectivamente, mostrando ser una especie vegetal de gran inter?s en su dieta durante la temporada de lluvias. Tremarctos ornatus is the only ursid that occur in South America and it has an extensive part of its territory in Peru. The Andean bear lives in diverse habitats from 250 to 4750 meters in elevation. The Conservation Status of T. ornatus in Peru is Vulnerable, since 2014. This study analyzed the diet of Andean bear using scats that were collected during April and May of 2014. The scats were collected in three mountain ecosystems, Paramo, Transition and Montane forest located in Pacaipampa, Department of Piura. The register of evidence considering the indirect and direct ones, that provide information of the specie in the area. Searching for the scats was an intense walk going up and down hills in the study area. It wasn?t necessary to make a selection of the old scats and new ones, all the scats were collected for this study, without distinguish. Plants were collected too to have information of possible species that are important for the diet of the Andean bear. The scats were analyzed, and the first isolation was to separate the animal content from the vegetal. The vegetal contents were a group of different structures that were identify as vegetal items, the vegetative part as trunk and leaves and the reproductive structures were fruits and seeds. All these items were found more frequently in the scats content, in some scats all the volume were vegetal content. The leaves and fruits items obtained a high percentage of occurrence (PO) with 31.34% and 22.39% for each item from 22 scats. Four species of plants were identify taxonomically as part of the Andean bear diet, as Puya sp, Guzmania sp, Chusquea sp y Vaccinium floribundum. The fruit and seed items correspond to V. floribundum from the Ericaceae family. This items were found completely undamaged. The value of the index percentage of relative importance of the species consume (%IRI) that had obtained in the analysis, show to V. floribundum as important plant species into the Andean bear diet because the values to each ecosystem were 48.58%, 58,35% and 44.41% respectively to Paramo, Transition and Montane forest, during the rainy season.