Rarity in neotropical forest mammals and its ecological correlates

ARITA, H.T.; ROBINSON, J.G.; REDFORD, K.H. 1990. Rarity in neotropical forest mammals and its ecological correlates. Conservation Biology 4(2):181-192.

 Abstract. Local density and size of distributional range have been used to characterize rarity, but conclusions are weakened by their possible lack of independence. The usefulness and validity of using these two variables were tested with data on distribution, local density, body size, and feeding habits for a set of 100 Neotropical forest mammals.
In a bivariate plot of distributional range against local density, species clustered according to their trophic or taxonomic groups. This indicates that diet and phylogenetic history have an influence on rarity. A negative correlation was found between distribution and abundance. However, this correlation was weaker within trophic or taxonomic groups, and vanished when body size was held constant. These results show that both distribution and abundance are valid and independent estimators of rarity when comparing species with similar sizes and ecological traits. Regression analysis showed that larger animals tend to have lower densities and wider distributional ranges. Rarity is clearly associated with body size.
A dichotomous classification of rarity based on area of distribution and local density is suitable for Neotropical forest mammals. Species in each of four categories created by such a scheme require different conservation and management policies that are determined by the ecological characteristics of the spcies. Final conservation strategies must also be shaped by political and economic constraints.

Identificação de marsupiais do Rio Grande do Sul através da microestrutura dos pelos-guarda

ABREU, M.S.L.; CHRISTOFF, A.U.; VIEIRA, E.M. 2011. Identificação de marsupiais do Rio Grande do Sul através da microestrutura dos pelos-guarda. Biota Neotropica 11(3):377-386.

Abstract: The analysis of mammalian hairs is a non-invasive technique that may help in the identification of Brazilian marsupials. Our objective was to identify microscopic patterns of marsupial guard-hairs (cuticle and medulla) from species with occurrence in the state of Rio Grande do Sul, southern Brazil. We also present a hair-based identification key for this group. Specifically for Monodelphis, a still taxonomically obscure genus that needs revision, we present detailed description of observed hair patterns. We obtained the analyzed material by collecting hair samples of marsupials captured in field or else deposited in different zoological collections. We identified hair patterns of ten marsupial species: Caluromys　lanatus, Chironectes　minimus, Didelphis　aurita, Didelphis　albiventris, Cryptonanus　guahybae, Gracilinanusagilis, Gracilinanusmicrotarsus, Lutreolinacrassicaudata, Micoureusparaguayanus and Philander　frenatus. Individuals of the Monodelphis genus were analyzed together, considered as part of the dimidiata group. We found three distinct patterns for this group, suggesting the possible occurrence of a third species besides the two already recognized (M. brevicaudis and M. 　dimidiata). These morphs show distinct distribution in the state, with some degree of distribution overlap. The analysis of microscopic patterns of mammal hairs allowed the successful identification of the great majority of marsupials that occur in the Rio Grande do Sul state. Our results suggest that the two Monodelphis species of the dimidiata group might occur with a distinct distribution in the state, one of them occupying mainly the northern part and the other one the eastern region, with some overlap in the central part of the state.

VII Congresso Brasileiro de Unidades de Conservação

Mais um evento esta programado para ocorrer em 2012. É o VII Congresso Brasileiro de Unidades de Conservação, que ocorrerá entre os dias 24 e 27 de setembro de 2012, em Natal/RN. As inscrições e as submissões de trabalhos~já estão abertas.

Maiores informações no site do evento.