Abstract

POLOP, Francisco J; POLOP, Jaime  and  PROVENSAL, M. Cecilia. Parámetros poblacionales de Oligoryzomys longicaudatus en Cholila (Chubut, Argentina). Mastozool. neotrop. [online]. 2016, vol.23, n.1, pp.117-126. ISSN 0327-9383.

The objective of this study was to describe and quantify population parameters of O. longicaudatus in Cholila (Chubut, Argentina). Individuals were sampled seasonally over 5 years by removal trapping in forest and shru­bland habitats, and bimonthly over 3 years with capture-mark-recapture trapping in 3 grids located in shrubland habitats. Abundance was estimated for each habitat and season. Animals were classified as reproductively active or inactive, the number of embryos in females captured dead was tallied, and the frequency of pregnancy was recorded for both habitats. Ages of individuals were estimated from body mass. Survival rate and residency status (resident vs. transient) were determined for individuals from live-trap grids. O. longicaudatus showed seasonal fluctuations and inter-annual differences in abundances between habitats; abundances were greatest in autumn-winter in shrubland and in summer-autumn in forest. Adults dominated the population throughout the study period, followed by sub-adults and juveniles in low percentages. Reproductive activity exhibited sea­sonal and inter-annual differences as well as differences between habitats. The number of transients was higher than residents, especially for males. Survival was higher in autumn and winter than in spring and summer. Differences in abundance among years can be explained by reproductive parameters and population structure.

Keywords : Abundance; Colilargo mouse; Population variation; Reproductive activity.