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COPYRIGHT 2005 Acedemia Colombiana de Ciencias Exactas, Fisicas y Naturales
Resumen
A comienzos de 2003 se obtuvieron registros de 97 especies de ranas y sapos en un parche de bosque primario y bosque inundado ubicado aproximadamente 10 kms al norte de Leticia. Sin embargo, hay buenas razones para sospechar que la fauna local consiste en no menos que 123 especies de ranas y sapos, numero que supera lo senalado en estudios anteriores realizados en la parte occidental de la cuenca Amazonica. Se sugiere que esta riqueza es mas el reflejo del empleo de nuevas metodologias que de la existencia de un "hotspot" biologico.
Palabras clave: Amazonico, Diversidad, Metodologia de inventario.
Abstract
Vouchers of 97 species of frogs and toads were obtained in a small section of primary rainforest and flooded forest approximately 10 kms north of Leticia in early 2003. In addition to the 97 species captured, there is good reason to suspect that the actual local fauna consists of no fewer than 123 species of frogs and toads. This local fauna is much larger than previous reports for the western part of the Amazon Basin but probably its size reflects the new methodologies employed rather than a biological "hotspot."
Key words: Amazonian, Diversity, Inventory methodology.
Introduction
Leticia has always been a seldom-visited site perched in the central Amazon. By 2000, only 40 species of frogs and toads (Cochran & Goin, 1970; Duellman, 1972, 1974, Flores, 1987, Goin & Layne, 1959, Heyer, 1994, Lynch, 1979, 1980, 1986, 2002, Lynch & Lescure, 1980, Rivero, 1991, Rivero & Serna, 1984, and Silverstone, 1975, 1976) had been reported from Leticia but I doubted that the fauna had been investigated adequately. Thus, in 2002, I applied for financial support from Conservacion Internacional--Colombia to carry out a definitive study of the diversity of frogs and toads in these forests. My team consisted of four undergraduates with a minimum of experience and me. I decided that if we were gong to execute this project, we needed a new methodology for an inventory. At the outset, I knew very little (having collected there only a few times in 20 years)--none-the-less, I was convinced that previous inventories had been managed badly--to allow all participants to carry out "free-searches" was inadequate. Hence, I selected my assistants with a proviso--each had to carry out a specific task and, then, if they wanted, they could join me in nocturnal forays. Long before leaving Bogota, I had decided that I needed four specialists to back-up my unrestrained nocturnal searches--thus, I assigned to each undergraduate a specific task: (1) To Andres Duarte, the monitoring of a system of pitfall traps (of 5 gallons, bordered by three drift fences two meters long)--he would need to check each trap three times a day (0600, 1200 and 1800 hrs) and record who had fallen in. This would enable me to sample the terrestrial fauna, a component I had long forgotten in my quest for centrolenids and eleutherodactylines. Years ago, I had recognized my failing of ignoring the groundfauna. (2) To Jonh Jairo Mueses, another task for which I did not have the patience, to census a single forest pond, night after night, to see who was breeding and who was merely sitting there (with this task, I hoped to show that much of the frog fauna exhibited explosive breeding). (3) To David Sanchez fell the task of collecting tadpoles whenever and wherever he could (largely, daytime work). And, (4) To Adriana Tellez fell the task of sampling the canopy fauna (initially, we planned merely to sample adults and tadpoles in arboreal bromeliads but eventually, we used also felling of primary forest and occasional visits to a canopy platform).
Initially, I had constructed an expected fauna, using all published accounts and records for the Amazon basin (Acosta, 2000, Ardila R & Ruiz C, 1997, Duellman, 1973, Lutz & Kloss, 1952, Myers & Carvalho, 1945, and Ruiz C et al., 1996) and my estimates of the distributional areas for Amazonian species. My initial construct was too ambitious--I imagined a fauna of more than 130 species of frogs and toads. Furthermore, I assigned each species to one of four habitat contingencies: (A) terrestrial, (B) aquatic, (C) canopy, and (D) inhabitant of the understory. In many cases, my assignments were based on my experiences collecting the frogs--in other cases, my failures to find them (a mixture of...
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