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 sampli ng 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 throug h MNKA estimator, survivorship and recruitment rates through Jolly-Seber es timator. Nectomys squamipes and Didelphis aurita were the most abundant spe cies, followed by Akodon cursor, Philander frenata and Oligoryzomys nigripe s. Marsupials reproduced from July/August to March, with the highest popula tion sizes and recruitment rates in the end of the rainy periods and beginn ing of the dry period. Rodents were able to reproduce throughout the year. N. squamipes' population size was correlated with survivorship; peaks and t he bulk of reproduction occurred during and after the rainy periods. A. cur sor's population size increased in dry periods. These species displayed sea sonal patterns of population dynamics related to reproduction, with some va riations among years chiefly for the rodents.