Population dynamics and reproduction of marsupials and rodents in a Brazilian rural area: a five-year study

A five-year mark-recapture study of small mammals was conducted with sampling every two months in a rural area of Sumidouro, State of Rio de Janeiro, Brazil, from June 1991 to July 1996. Population sizes were estimated through MNKA estimator, survivorship and recruitment rates through Jolly-Seber estimator. Nectomys squamipes and Didelphis aurita were the most abundant species, followed by Akodon cursor, Philander frenata and Oligoryzomys nigripes. Marsupials reproduced from July/August to March, with the highest population sizes and recruitment rates in the end of the rainy periods and beginning of the dry period. Rodents were able to reproduce throughout the year. N. squamipes' population size was correlated with survivorship; peaks and the bulk of reproduction occurred during and after the rainy periods. A. cursor's population size increased in dry periods. These species displayed seasonal patterns of population dynamics related to reproduction, with some variations among years chiefly for the rodents.