A simple graphical model of small mammal succession after fire in the Brazilian cerrado

We studied the succession of small mammal species after fire in the cerrado (Neotropical savanna) of Central Brazil. Populations of small mammals were sampled with live-trapping techniques in a series of nine sites of different successional age, ranging from 1 to 26 years after fire. Ten species of small mammals were captured through all the seral stages of succession. Species richness ranged from two to seven species by seral stage. The species were arranged in different groups with respect to abundance along the succession: the first was composed of early successional species that peaked <2 years after fire (Calomys callosus, C. tener, Thalpomys cerradensis, Mus musculus, Thylamys velutinus); the second occurred or peaked 2-3 years after fire (Necromys lasiurus, Gracilinanus sp., Oryzomys scoth). Gracilinanus agilis peaked in the last seral stage. Species richness of small mammals showed an abrupt decrease from an average of four species immediately after fire to two species 5-26 years after the last fire. We propose a simple graphical model to explain the pattern of species richness of small mammals after fire in the cerrado. This model assumes that the occurrence of species of small mammals is determined by habitat selection behavior by each species along a habitat gradient. The habitat gradient is defined as the ratio of cover of herbaceous to woody vegetation. The replacement of species results from a trade-off in habitat requirements for the two habitat variables.

Phenotypic changes and small mammal impoverishment on a Brazilian Atlantic Forest Island

Faunal impoverishment and distorted species compositions are common phenomena in oceanic islands; however, many land-bridge islands are poorly inventoried, especially in the Neotropics. We sampled a small mammal community on a land-bridge island (Anchieta Island) along the Brazilian coast. We found only one marsupial Didelphis aurita (Wied-Neuwied, 1826) and two rodent species Oligoryzomys nigripes (Olfers, 1818) and Trinomys iheringi (Thomas, 1911) during 12 months of live trapping and 9195 trap-nights. The diversity of rodents and marsupials was not explained by species-area relations, indicating possible past extinctions. The abundance of D. aurita and O. nigripes was approximately three times higher, while the abundance of T. iheringi was approximately four times lower than abundances reported from other Brazilian Atlantic Forest sites. The population of D. aurita exhibited many phenotypic changes; males were on average 8 % smaller and females produced 30 % less litters than those from the mainland and other land-bridge islands. The long history of forest disturbance, habitat loss, reduction in forest productivity, and the recent introduction of mesopredators may be the major drivers that explain the small mammal community composition on this island. © 2013 Walter de Gruyter GmbH, Berlin/Boston.

Toward reliable estimates of seed removal by small mammals and birds in the Neotropics

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Habitat associations of small mammals in southern Brazil and use of regurgitated pellets of birds of prey for inventorying a local fauna

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Post-fire succession of small mammals in the Cerrado of central Brazil

In the Cerrado savannas from Brazil fire events are common and strongly influence the vegetation structure and, consequently, the associated small mammals. In this paper, we investigate changes in the structure of small mammal communities related to sites of different post-fire ages. Mammals were captured in similar Cerrado sites that differed in time since the last burn ( 1 to 26 yr). We sampled six sites in the wet season of 1997 ( phase 1) and, three years later, six sites in the wet and dry seasons ( phase 2). Six rodent species and four marsupials were captured. Community composition changed drastically as a function of time since fire. The diversity and abundance of small mammals reached maximum values in the early successional stages. The rodent Calomys tener was present only in early seral stages. The rodent Bolomys lasiurus was more frequent in mid-successional stages and decreased in later seral stages, and the rodent Oryzomys subflavus occupied all successional stages. The marsupial Gracilinanus agilis was dominant in the area that did not burn for at least 23 yr. Changes in composition of the community of small mammals were more accelerated in early successional stages, when there are more drastic vegetational changes. The ability of small mammals to cope with Cerrado fires and the great dissimilarity among post-burning seral stages suggest that a mosaic of areas representing different post-fire seral stages could increase the regional diversity of this group.

Small mammals in the diet of barn owls (Tyto alba) in agroecosystems of southern Brazil

We studied the diet of the Barn Owl (Tyto alba) in an agricultural area of southern Brazil (29degrees36'S, 52degrees11'W), based on analysis of regurgitated remains. The results clearly showed that the diet of the Barn Owl reflects the human impact on its habitat. The cosmopolitan house mouse (Mus musculus) was the most preyed upon small mammal (81.9%) and the most important in terms of the Barn Owl ingested biomass (69%). This rodent, due to its small size, is also responsible for the relatively low me-an weight off small mammal prey in the owl diet (19.6 g). In southern Brazilian agroecosystems, the Barn Owl probably feeds mainly on mice due to their great abundance in crop fields and grain storage areas of the region.

New karyologycal data and cytotaxonomic considerations on small mammals from Santa Virginia (Parque Estadual da Serra do Mar, Atlantic Forest, Brazil)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Geographic variation in the size of mammalian prey taken by White-tailed Kites in the Americas

I examined the size of small mammal prey taken by White-tailed Kites (Elanus leucurus) in the Americas from data obtained in the literature and unpublished material from southern Brazil. Mean weight of adult small mammal prey in the kite's diet ranged between 19.5 and 64.2 g. Mammalian prey taken weighed between 2 and 53% of the kite's body weight. Although the White-tailed Kite is a small mammal specialist, in relation to the size of prey taken, this raptor can be considered a generalist hunter.

Food partitioning between breeding White-tailed Kites (Elanus leucurus; Aves; Accipitridae) and Barn Owls (Tyto alba; Aves; Tytonidae) in southern Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos da defaunação na comunidades de pequenos mamíferos na Mata Atlântica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ecologia trófica de pequenos mamíferos não voadores em uma área contínua de Mata Atlântica

Pós-graduação em Ciências Biológicas (Zoologia) - IBRC

Sazonalidade da dieta e hábitos alimentares do gavião-peneira (Elanus leucurus) em habitats agrícolas no sul do Brasil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Paracellular Absorption: A Bat Breaks the Mammal Paradigm

Bats tend to have less intestinal tissue than comparably sized nonflying mammals. The corresponding reduction in intestinal volume and hence mass of digesta carried is advantageous because the costs of flight increase with load carried and because take-off and maneuverability are diminished at heavier masses. Water soluble compounds, such as glucose and amino acids, are absorbed in the small intestine mainly via two pathways, the transporter-mediated transcellular and the passive, paracellular pathways. Using the microchiropteran bat Artibeus literatus (mean mass 80.6 +/- 3.7 g), we tested the predictions that absorption of water-soluble compounds that are not actively transported would be extensive as a compensatory mechanism for relatively less intestinal tissue, and would decline with increasing molecular mass in accord with sieve-like paracellular absorption. Using a standard pharmacokinetic technique, we fed, or injected intraperitonealy the metabolically inert carbohydrates L-rhamnose (molecular mass = 164 Da) and cellobiose (molecular mass = 342 Da) which are absorbed only by paracellular transport, and 3-O-methyl-D-glucose (3OMD-glucose) which is absorbed via both mediated (active) and paracellular transport. As predicted, the bioavailability of paracellular probes declined with increasing molecular mass (rhamnose, 90 +/- 11%; cellobiose, 10 +/- 3%, n = 8) and was significantly higher in bats than has been reported for laboratory rats and other mammals. In addition, absorption of 3OMD-glucose was high (96 +/- 11%). We estimated that the bats rely on passive, paracellular absorption for more than 70% of their total glucose absorption, much more than in non-flying mammals. Although possibly compensating for less intestinal tissue, a high intestinal permeability that permits passive absorption might be less selective than a carrier-mediated system for nutrient absorption and might permit toxins to be absorbed from plant and animal material in the intestinal lumen.

Habitat patch size modulates terrestrial mammal activity patterns in Amazonian forest fragments

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)