Population dynamics of the rat Microryzomys minutus (Rodentia: Muridae) in the Venezuelan Andes

• Main Authors: Daniel R Cabello, Guillermo Bianchi-Perez, Paolo Ramoni-Perazzi
• Format: Article
• Language: English
• Published: Vicerractoría Investigación 2006-06-01
• Series: Revista de Biología Tropical
• Subjects: roedores; neotrópico; Muridae; bosque nublado; Microryzomys minutus; Venezuela; neotropical rodents; cloud forest
• Online Access: http://www.scielo.sa.cr/scielo.php?script=sci_arttext&pid=S0034-77442006000200038
• ISSN: 0034-7744; 2215-2075

The population dynamics of the small forest rice rat Microryzomys minutus, a murid rodent that occurs in the high altitudes of the northern and central Andes, was studied in disturbed and primary environments in a cloud forest of the Venezuelan Andes (Juan Pablo Peñaloza National Park, 8º11’N, 71º49’W). We collected 121 animals (66&#9792;&#9792; and 55&#9794;&#9794; ) between 1995 and 1998, using pitfall traps with formalin. Adult males were heavier than adult females. Relative abundance was much greater in the disturbed environments (over 10 individuals in some periods) than in the primary cloud forest: 4-8 individuals. In the disturbed environments, the rats were extremely abundant in the first sampling period, and less frequent afterwards. In the cropland, abundance showed some fluctuations during the study and displayed two small abundance peaks in March-June 1997 and 1998. In the mined area, the rats had irregular fluctuations until March-June 1997 and were not recorded in July-October 1997. The occurrence of this rat in both disturbed and natural habitats confirms the wide ecological tolerance of this species. Rev. Biol. Trop. 54(2): 651-. Epub 2006 Jun 01.<br>Se analizó la dinámica poblacional de las pequeñas ratas silvestres del arroz Microryzomys minutus en ambientes alterados y primarios, en un bosque nublado de los Andes venezolanos. El estudio fue basado en 121 animales (66&#9792;&#9792; y 55&#9794;&#9794; ) recolectados entre 1995 y 1998, usando trampas que contenían formalina. Esta especie está presente en ambos hábitats lo que confirma su amplia tolerancia ecológica. La abundancia poblacional fue mayor en ambientes alterados que en los no alterados. M. minutus presenta dimorfismo sexual en el peso: los machos son más pesados que las hembras.