5 research outputs found
Habitat determinants of goldenâheaded lion tamarin (Leontopithecus chrysomelas) occupancy of cacao agroforests: Gloomy conservation prospects for management intensification
Organismal distributions in humanâmodified landscapes largely depend on the capacity of any given species to adapt to changes in habitat structure and quality. The goldenâheaded lion tamarin (GHLT; Leontopithecus chrysomelas) is an Endangered primate from the Brazilian Atlantic Forest whose remaining populations occupy heterogeneous landscapes consisting primarily of shade cacao (Theobroma cacao) agroforestry, locally known as cabrucas. This cash crop can coexist with high densities of native tree species and holds a significant proportion of the native fauna, but its widely extolled wildlifeâfriendly status is increasingly threatened by management intensification. Although this potentially threatens to reduce the distribution of GHLTs, the main determinants of tamarin's occupancy of cabrucas remain unknown, thereby limiting our ability to design and implement appropriate conservation practices. We surveyed 16 cabruca patches in southern Bahia, Brazil, and used occupancy modeling to identify the best predictors of GHLT patch occupancy. Key explanatory variables included vegetation structure, critical resources, landscape context, human disturbance, and predation pressure. We found a negative relationship between GHLT occupancy and the prevalence of jackfruit trees (Artocarpus heterophylus), which is likely associated with the low representation of other key food species for GHLTs. Conversely, cabrucas retaining largeâdiameter canopy trees have a higher probability of GHLT occupancy, likely because these trees provide preferred sleeping sites. Thus, key large tree resources (food and shelter) are currently the main drivers of GHLT occupancy within cabruca agroecosystems. Since both factors can be directly affected by crop management practices, intensification of cabrucas may induce significant habitat impacts on GHLT populations over much of their remaining rangeâwide distribution
Consumption of a ringed kingfisher (Megaceryle torquata) by a White-tailed Hawk (Buteo albicaudatus) in southeastern Brazil
Volume: 38Start Page: 191End Page: 19
Ecology and natural history of Akodon lindberghi (Rodentia, Sigmodontinae) in southeastern Brazil
We studied the ecology and natural history of the globally threatened and poorly known Akodon lindberghi Hershkovitz, 1990 in Parque Nacional da Serra da Canastra (PNSC) and Juiz de Fora (JF), southeastern Brazil. From November 1998 to September 2001 a total of 131 individuals were captured in wire-cage live-traps and 52 by pitfalls traps. They were all marked and released at the site. The largest abundances were registered during the dry season, and most of the captures occurred in open habitats. The mean body mass of the two populations was significantly different (18.1 g at PNSC versus 13.1 g at JF; H = 46.2678, g.l.=2, p<0.001). In PNSC, individuals were reproductively active from August to February, and juveniles were present from May to August. The results suggest that the changes in vegetation structure caused by deforestation and intensive agricultural activities could increase the predation rate, affecting the mean body mass of the population
Barn owl (Tyto alba) predation on small mammals and its role in the control of hantavirus natural reservoirs in a periurban area in southeastern Brazil
The aim of this study was to inventory the species of small mammals in UberlĂąndia, Minas Gerais, Brazil, based on regurgitated pellets of the barn owl and to compare the frequency of rodent species in the diet and in the environment. Since in the region there is a high incidence of hantavirus infection, we also evaluate the importance of the barn owl in the control of rodents that transmit the hantavirus. Data on richness and relative abundance of rodents in the municipality were provided by the Centro de Controle de Zoonoses, from three half-yearly samplings with live traps. In total, 736 food items were found from the analysis of 214 pellets and fragments. Mammals corresponded to 86.0% of food items and were represented by one species of marsupial (Gracilinanus agilis) and seven species of rodents, with Calomys tener (70.9%) and Necromys lasiurus (6.7%) being the most frequent. The proportion of rodent species in barn owl pellets differed from that observed in trap samplings, with Calomys expulsus, C. tener and Oligoryzomys nigripes being consumed more frequently than expected. Although restricted to a single place and based on few individuals, the present study allowed the inventory of eight species of small mammals in UberlĂąndia. The comparison of the relative frequencies of rodent species in the diet and in the environment indicated selectivity. The second most preyed upon species was N. lasiurus, the main hantavirus reservoir in the Cerrado biome. In this way, the barn owl might play an important role in the control of this rodent in the region, contributing to the avoidance of a higher number of cases of hantavirus infection