Assemblages of bird and mammal communities in two major Ecological Units of the andean highland plateau of southern Peru

Ecología Aplicada, 6(1,2), 2007 ISSN 1726-2216 Depósito legal 2002-5474 © Departamento Académico de Biología, Universidad Nacional Agraria La Molina, Lima – Perú. Presentado: 05/07/2007 Aceptado: 08/12/2007 ASSEMBLAGES OF BIRD AND MAMMAL COMMUNITIES IN TWO MAJOR ECOLOGICAL UNITS OF THE ANDEAN HIGHLAND PLATEAU OF SOUTHERN PERU ESTRUCTURA DE LAS COMUNIDADES DE AVES Y MAMÍFEROS EN DOS UNIDADES ECOLÓGICAS DE LOS ANDES DEL SUR DEL PERÚ Oswaldo Ramirez1, Margarita Arana1, Enrique Bazán1, Angel Ramirez2 y Asunción Cano2 Abstract Grasslands in the Andean highlands plateau of southern Peru have been considered as a single and homogeneous dry habitat also known as Puna. However, in some regions, a highest rainfall regimen is found, and the name of wet puna has begun to be used by some authors. Since no studies have been carrying out specifically to test if dry and wet puna are different ecological units, we chose two representative localities of each one of these habitat to evaluate assemblages of bird and mammal communities and their continuity or independence between these apparently similar habitats. Our results suggest that wet puna has different mammal diversity than dry puna, and a heterogeneous bird community with species that have been previously reported exclusively in paramo or exclusively in puna. In spite of the apparent uniform flora in the Andean highlands of South Peru, data suggest that rainfall regimens produce a mosaic of habitats that will be determining ecological barriers for terrestrial mammals, in particular for small mammals. Key words: Andean grasslands, Andean plateau, Cuzco, Oriental Cordillera, paramo, puna, Puno. Resumen Los Pajonales de los Andes del sur del Perú, también conocidos como Puna, son considerados como hábitats homogéneos y secos. Sin embargo, en algunas regiones se encuentra un alto régimen de precipitaciones y algunos autores han empezado a usar el nombre de Puna Húmeda. Hasta la actualidad no se vienen realizando estudios específicos para probar si la Puna Húmeda y Seca son dos unidades ecológicas diferentes. Se escogieron dos localidades representativas de cada uno de estos hábitat para evaluar la estructura de las comunidades de aves y mamíferos y su continuidad o independencia entre estos hábitat aparentemente similares. Los resultados sugieren que la Puna Húmeda tiene una diversidad de mamíferos diferente a la de la Puna Seca, y una comunidad de aves heterogénea con especies que vienen siendo previamente reportadas como exclusivas de Páramo o de Puna. A pesar de la aparente uniformidad de la flora en los Andes del sur del Perú, la información sugiere que los regimenes de precipitaciones producen un mosaico de hábitat que estaría determinando barreras ecológicas para mamíferos terrestres, en particular para pequeños mamíferos. Palabras claves: Pajonal, Andes, Cuzco, Cordillera Oriental, Páramo, Puna, Puno Introduction Two major ecological units have been distinguished in the Andean Highlands above 3 300 m. In most of Peru and southward this altitudinal zone is known as “Puna” (Reig, 1986; Young et al., 1997), whereas from Colombia and western Venezuela through most of Colombia and Ecuador up to northern Peru as “paramo” (Cuatrecasas, 1957; Vuilleumier, 1979). However, floristic boundaries have not been rigorously established to delimit unambiguously these ecological units. In general the Peruvian puna is relatively dry (Young et al., 1997), but wetter areas in northern Peru are distinguished by the term “jalca” (Weberbauer, 1945), and in southern Peru as wet Puna (Tossi, 1960; Troll, 1968). Grassland, also known as Puna by some authors, is the predominant vegetation type in the Andean highlands, although woodland patches, scrub and wetlands are also frequently found. Only relatively small areas of Puna are included within protected areas in southern Peru. For example, only 1.4 percent of the Manu National Park (Departments of Madre de Dios and Cuzco, Peru), one of the largest protected areas in the world, is representative of the Andean highlands (Plan Maestro del Parque Nacional del Manu, 2004). Two other protected areas that include highlands in the Southern Peru are Salinas y Aguada Blanca National Reserve, and Aymara-Lupaca Reserved Zone. In this work, we carried out a diversity evaluation of birds and mammals in two Andean highland localities of South Peru. One of them, a wet Puna site ASSEMBLAGES OF ANDEAN BIRD AND MAMMAL COMMUNITIES Diciembre 2007 __________________________________________________________________________________________ in Acjanaco, Eastern Andes, is located within Manu National Park, while the other locality is a dry Puna site in Tupala, located in the highland plateau of the Aymara-Lupaca Reserved Zone. Our principal aim for this study was not to obtain complete biological inventories, but to study the assemblage of bird and mammal communities in representative areas of the grasslands, scrub and upper montane forest of the Andean highlands of southern Peru. Data on species assemblage and biodiversity in these selected habitats will provide a better insight into the biotic and biogeographical relationships between these regions. Methods STUDY AREA.- Tupala is a very small town of pastoralists in the highland plateau of the Department of Puno, Peru (17°00’42’’S, 69°37’52’’W, 4 000 m elevation). This locality is a typical dry Puna with less than 400 mm of annual precipitation, falling usually between December and April. Nearby Tupala, two habitat were studied: the scrub locally known as tola and the alpine grassland or “pajonal”. Tola is the Andean equivalent of sagebrush and consists of flat expanses of bushes of one or more species of Lepidophyllum or Bacharis (Asteraceae) (Pearson & Ralph, 1978). In the tola habitat of Tupala the dominant shrubs were Parastrephia lucida, Baccharis incarum, Senecio spinosus and Adesmia espinosa. Meanwhile, in the grassland habitat of Tupala, two families were dominant: Poaceae (species of genus Stipa, Calamagrostis, and Muhlenbergia) and Rosaceae (Alchemilla pinnata). Acjanaco is a locality on the eastern flanks of the Eastern Cordillera of South Peru, in the Department of Cuzco (13°11’47’’S, 71°37’10’’W, 3 450 m). The mean annual precipitation is between 1 000 and 2 000 mm, and the mean annual temperatures are around 610°C (Cano et al., 1995). This locality is a wet Puna where two absolutely different habitats converge, the upper montane rain forest and the tropical alpine grassland. The upper montane forest has a high diversity of flowering plants in comparison to the grassland habitat of Acjanaco (Cano, 1994). The flora of the upper montane forest in Acjanaco is dominated by trees of Polylepis and Clethra, and shrubs of Oreopanax and Gynoxis. In the grassland habitat, the most abundant genus are Calamagrostis, Cortaderia, Stipa (Poaceae), Gaultheria and Pernettya (Ericaceae) (Young & Cano, 1994). A total of four habitats were studied: tola and grassland in Tupala, (...truncated)