Living and lost mammals of Rio de Janeiro's largest biological reserve: an updated species list of Tinguá / Mamíferos atuais e extintos na maior Reserva Biológica do Rio de Janeiro: uma lista atualizada de espécies do Tinguá

Abstract: The Tinguá Biological Reserve (TBR) is the largest protected area of this category in Rio de Janeiro state. Here, for the first time, we present the historical composition of terrestrial mammals' assemblage of TBR region. An inventory was conducted using transect surveys, nonstandard transects, survey of museum specimens and informal reports. Considering all the data, eighty-five species were recorded, placing TBR as the second one in the number of mammals recorded in "Serra do Mar" ecoregion of Atlantic Forest and in the Rio de Janeiro state. Among the species with historical records are the jaguar (Panthera onca) and the golden-lion-tamarin (Leontopithecus rosalia) while the current presence of the maned wolf (Chrysocyon brachyurus) was recorded for the first time. Priority studies should focus on Chiroptera, Rodentia and Didelphimorphia orders, especially in the most remote areas of the reserve, and long-term surveys of endangered species. Besides hunting, fragmentation of its interior by roads, pipelines and transmission lines and exotic species, TBR is also threatened by the urban growth around it and the pressure to reduce its area and its protection category, demanding greater attention by the high levels of governance of protected areas in Brazil.

Resumo: A Reserva Biológica Tinguá (RBT) é a maior área protegida desta categoria no estado do Rio de Janeiro. Aqui, pela primeira vez, apresentamos a composição histórica da assembleia de mamíferos terrestres da região da RBT. Um inventário foi realizado utilizando amostragem por transectos, transectos não padronizados, busca por espécimes em museu e relatos. Considerando todos os dados, foram registradas oitenta e cinco espécies, colocando a RBT como a segunda no número de mamíferos registrados na ecorregião "Serra do Mar" da Mata Atlântica e no estado do Rio de Janeiro. Entre as espécies com registros históricos estão a onça-pintada (Panthera onca) e o mico-leão-dourado (Leontopithecus rosalia), enquanto a presença atual do lobo-guará (Chrysocyon brachyurus) foi registrada pela primeira vez. Estudos prioritários devem se concentrar nas ordens de Chiroptera, Rodentia e Didelphimorphia, especialmente nas áreas mais remotas da reserva, e pesquisas de longo prazo sobre espécies ameaçadas de extinção. Além da caça, a fragmentação em seu interior por estradas, gasodutos e linhas de transmissão e a presença de espécies exóticas, a TBR é ameaçada também pelo crescimento urbano no entorno e pela pressão para reduzir sua área e categoria de proteção, exigindo maior atenção dos altos níveis de gestão de áreas protegidas no Brasil.

Dealing with extinction is forever: understanding the risks faced by small populations

Despite its importancefor ecology, extinction was often neglected by this science until the present environmental crisis brought the subject to the fore in the early eighties. Important theoretical developments, mainly island biogeography, metapopulation theory and geneticas contributed to build a set of theories on the genetic and ecological processes which threaten the persistence of small populations. Two of the greatest contributions of this paradigm were to show the propabilistic nature of extinction, and to make clear the point how a small population can be extinguished by stochastic processes even if protected from further human intervention. Four such processes can be distinguished: demographic, environmental and genetic stochasticities, and loss of adaptive flexibility. undestanding and modeling these processes resulted in the development of Population viability analysis (PVA), a family of simulation models employed to quantify the future risk of extinction of a small population. The complexity of the extinction processes poses serious problems for the reliability of the predictions; however, PVA has had considerable heuristic value in fostering improvements in understanding extinction. In addition to the scientific and technical aspects, there are also complex economic considerations involved. Nevertheless the small population paradigm and PVA have allowed great advancements in our capacity of devising scientifically sound conservation and management actions to diminish extincion.

Density dependence in within-habitat spatial distribution: contrasting patterns for a rodent and a marsupial in southeastern Brazil

We investigated the relationship between population densities of two species of small mammals and the degree of aggregation in their spatial distributions within a habitat at the Restinga de Barra de Maric , in Rio de Janeiro State. The distribution of the redent Akodon cursor was more clumped at low than at high densities. On the other hand, the aggregation of the marsupial Philander opossum was independent of its abundance. Population density must be included as a variable in quantitative analyses of habitat preferences of those species which, like A. cursor but not P. opossum, show different degrees of habitat selectivity at different population densities.