ECOLOGY OF TROPICAL FOREST SMALL MAMMAL POPULATIONS: PATTERNS AND PROCESS REVEALED BY THE LONGEST LONG-TERM MONITORING STUDY IN BRAZIL

Abstract

: Long-term monitoring studies have spearheaded the development of population ecology as a discipline. Today, the vast amount of information obtained from these studies is concentrated at higher-latitude ecosystems. Here we present the advances achieved by the largest long-term monitoring study of small mammals carried out in a tropical forest in Brazil. Along 22 years, since 1997, the Garrafão project was developed in one of the largest Atlantic Forest remnants, in the southern limit of the Serra dos Órgãos National Park, state of Rio de Janeiro. Most studies developed with this valuable dataset have focused on the most abundant species of marsupials and rodents. In general, this long-term study brought important advances in the understanding of the ecology of mammals in tropical forests, such as: (1) the predominance of population self-regulation in one of the most species-rich environments; (2) the importance of survival for population growth and regulation; (3) seasonal and continuous reproduction in marsupial and rodents, respectively; (4) the positive relationship between body size and space use in marsupials weighing up to 100 g (opposite relationship in species weighing less than 100 g); (5) differences in space use between species, sexes and age classes, and positive (and negative) effects of density; and (6) differences in habitat selection in species living in different forest strata. Several other questions remain to be answered with this dataset and this review aims to stimulate new questions and new long-term monitoring studies in different ecosystems in the tropical region.