Janaina Casella

Mammal occurrence and roadkill in two adjacent ecoregions (Atlantic Forest and Cerrado) in south-western Brazil

This paper examines the frequencies of mammal roadkill in two adjacent biogeographic ecoregions (Atlantic Forest and Cerrado) of Brazil. Mammals were recorded during a seven-year period and over 3,900 km of roads, in order to obtain data for frequencies of species in habitats (sites) and frequencies of species killed by cars on roads. Sites (n = 80) within ecoregions (Cerrado, n = 57; Atlantic Forest, n = 23) were searched for records of mammals. Species surveyed in the entire region totaled 33, belonging to nine orders and 16 families. In the Cerrado, 31 species were recorded in habitats; of these, 25 were found dead on roads. In the Atlantic Forest ecoregions, however, we found 21 species in habitats, 16 of which were also found dead on roads. There was no overall significant difference between ecoregions for frequencies of occurrence in habitats or for roadkills, but there were differences between individual species. Hence, anteaters were mostly recorded in the Cerrado ecoregion, whereas caviomorph rodents tended to be more frequent in the Atlantic Forest ecoregion (seen mainly by roadkills). The greater number of species (overall and threatened) and the greater abundance of species records in the Cerrado suggest that this ecoregion has a greater biodiversity and is better conserved than the Atlantic Forest ecoregion, in the state of Mato Grosso do Sul, south-western Brazil.

Mammals in a fragmented savannah landscape in south-western Brazil

Mammal abundance, richness, and community structure were examined in fragments of savannah and in gallery forests of south-western Brazil in order to assess the influence of fragment size and habitat on the communities. Five savannah fragments and two gallery forests were sampled. Within the savannah fragments, environmental parameters such as tree and shrub densities were measured. Live-traps and pitfalls were used for trapping small mammals; larger mammals were recorded from footprints and sightings. Seventeen species of small mammal and 15 species of large mammal were recorded. Small mammals were affected by fragment size and isolation, whereas larger mammals were not. Communities of small mammals were better structured in the largest fragments, and those in smaller fragments were subsets of the communities in larger fragments. Gallery forests revealed a rather different assemblage of mammals, but also contained species common to both gallery and large savannah remnants. Data are discussed relating mammal community structure to area size and vegetation structure, in an attempt to understand the present conservation status of this fragmented landscape.

Diet of four small mammal species from Atlantic forest patches in South Brazil

In this study we analyse the diet composition of small mammals of western Parana state, southern Brazil. Species studied were mostly unknown on feeding habits. Animals were sampled during the faunal survey carried out in October 1998 when implementing the Salto Caxias dam. The diet composition, based on gut contents, seems to be mostly opportunistic and generalist for the three marsupials, Micoureus paraguayanus , Caluromys lanatus , and Monodelphis sorex , and for the rodent, Akodon paranaensis , studied. Caeca of the four small mammal species had in general a small quantity of insects when compared with other digestive tract portions. However, when volume consumed was evaluated, Arthropoda was the most important item for three species of them. Inversely, fruits were important for C. lanatus . The estimated amount of plant material (seeds and other plant structures) had a higher importance for C. lanatus , mainly for caecum samples, however these items were also found in the other mammal species samples but in lower proportions. The high proportion of intact seeds on both, digestive tract and caecum, when compared with predated seeds, is noticeable, suggesting that the species are seed dispersal. Monodelphis sorex seems to have a more insectivorous diet, as it is a small cursorial mammal, although there was also evidence for frugivory or carnivory. Akodon paranaensis was insectivorous-omnivorous, although fruits and vertebrate prey were also consumed, indicating also and opportunistic diet. Caluromys lanatus is classifi ed as a more frugivorous species, besides the consumption of vertebrate prey. Insectivorous habit seems to be frequent in neotropical small mammals, with consumption of vertebrates or fruits being only opportunistic. The insectivory (except for C. lanatus ) and opportunistic habit appear to dominate among the small mammal species studied. Key words: Micoureus paraguayanus , Caluromys lanatus , Monodelphis sorex , Akodon paranaensis , food habits.

Natural history of the marsupial Thylamys macrurus (Mammalia, Didelphidae) in fragments of savannah in southwestern Brazil

The objective of this study was to furnish information on the natural history of the Neotropical marsupial Thylamys macrurus in the southern Cerrado of Brazil. A range expansion of the species was observed to the northeast of the Mato Grosso do Sul state, Brazil. Specimens were surveyed in fragments of savannah (40–600 ha) during dry and wet seasons in 2003 and 2004 with live‐trap grids and pitfall lines. With an effort of 9767 trap nights and 2200 pitfall nights, we obtained 102 captures and 49 recaptures of T. macrurus. The data analyzed (57 males and 40 females) showed that males are more abundant in the dry season and females in the wet season. Young were recorded mostly during the wet season. Thylamys macrurus was scansorial, using the floor and the understorey. Sexual dimorphism was recorded, with males being larger than females. Information on ectoparasites is supplied.

Distribuição geográfica de pequenos mamíferos não voadores nas bacias dos rios Araguaia e Paraná, região centro-sul do Brasil

Realizaram-se amostragens de pequenos mamiferos em duas bacias hidrograficas do Brasil central pertencentes aos rios Araguaia e Parana com intuito de descrever a composicao de especies de pequenos mamiferos de habito florestal e comparar suas distribuicoes geograficas. Quatorze pontos de coleta foram amostrados, subdivididos em oito na bacia do Rio Parana e seis na bacia do Rio Araguaia. Foram registradas 20 especies de pequenos mamiferos na regiao (oito de marsupiais e 12 de roedores), sendo 16 delas por meio de armadilhas metalicas (5.253 armadilhas-noite) e oito delas por meio de armadilhas de queda (224 baldes-noite), totalizando 161 capturas de 139 individuos. A bacia do Rio Parana apresentou 16 especies (armadilhas-noite: 3.115; baldes-noite: 104) e a bacia do Araguaia apresentou 11 especies (armadilhas-noite: 2.138; baldes-noite: 120), sendo que as riquezas foram similares quando aplicado o metodo da rarefacao. Das 20 especies registradas, sete (35%) ocorreram em ambas as bacias. Apesar da elevada riqueza de especies amostrada, destacou-se a elevada abundância do marsupial Didelphis albiventris Lund, 1840. As especies de marsupiais amostradas foram D. albiventris, Caluromys philander (Linnaeus, 1758), Cryptonanus cf. agricolai Voss, Lunde & Jansa, 2005, Gracilinanus agilis (Burmeister, 1854), G. microtarsus (Wagner, 1842), Lutreolina crassicaudata (Desmarest, 1804), Marmosa murina (Linnaeus, 1758), e Philander opossum (Linnaeus, 1758). As especies de roedores amostradas foram Akodon gr. cursor, Calomys tener (Winge, 1887), Nectomys rattus (Pelzen, 1883), N. squamipes (Brants, 1827), Oecomys bicolor (Tomes, 1860), Oryzomys maracajuensis Langguth & Bonvicino, 2002, Oryzomys cf. marinhus, O. megacephalus (Fischer, 1814), Oligoryzomys fornesi (Massoia, 1973), Oligoryzomys sp., Proechimys longicaudatus (Rengger, 1830) e P. roberti (Thomas, 1901). A ampliacao da distribuicao de algumas especies e discutida, assim como aspectos biogeograficos. A Serra dos Caiapos pode ter sido uma barreira geografica para algumas especies de pequenos mamiferos em face da retracao e expansao das florestas ocorridas no passado.