Water absorption of the fur and swimming behaviour of semiaquatic and terrestrial oryzomine rodents

SANTORI, R.T.; VIEIRA, M.V.; ROCHA-BARBOSA, O.; MAGNAN-NETO, J.A.; GOBBI, N. 2008. Water absorption of the fur and swimming behaviour of semiaquatic and terrestrial oryzomine rodents. Journal of Mammalogy 89(5):1152-1161.

Abstract. Locomotion in land and water requires different adaptations, hence semiaquatic mammals must deal with conflicting demands of the 2 environments. Semiaquatic rodents of the tribe Oryzomyini are considered semiaquatic mostly based on habitat use and morphology, but locomotory specializations were not yet determined for most species of the group. We compared water absorption of the fur and swimming behavior between 2 species of oryzomyine water rats (Nectomys) and 2 terrestrial species of Cerradomys. We used adult rodents captured in the wild but acclimated to laboratory conditions. Water absorption rate was determined by the relative increase in body mass after a 5-min swimming session. Animals were videotaped swimming in an aquarium to determine gaits, body posture, maneuverability, and speed. Water absorption rate was significantly lower in semiaquatic species, with no significant difference between sexes. Bipedal paddling was the more frequently used gait by all 4 species, but semiaquatic species were faster and maintained a more hydrodynamic body posture, with a short gliding phase during the gait cycle. Only semiaquatic species were capable of floating effortlessly, and used the swimming bound, a gait similar to the half bound of terrestrial locomotion. Submerged swimming was the fastest swimming gait, used by 1 terrestrial and 1 semiaquatic species. The better performance during bipedal swimming of semiaquatic water rats was related to the improved buoyancy provided by reduced water absorption of the fur, which seemed to represent an important adaptation to move in the water without compromising locomotion on land.

Fotos: Armadilha Fotográfica

Esta é uma das armadilhas fotográficas que tenho, da Tigrinus®, modelo Convencional 6.0C. As armadilhas fotográficas consistem em aparelhos fotográficos (digitais ou analógicos) acoplados a um sensor de movimento. Toda vez que algum animal passa em frente à armadilha, o sensor ativa e a armadilha obtêm o registro fotográfico.  Geralmente são presas em árvores, com a lente e o sensor voltados para uma trilha. Pode-se usar isca para atrair os animais ou não. Maiores informações no site da Trigrinus (http://www.tigrinus.com.br/).
Fotógrafo: Maury S.L. Abreu
Contato: maury.abreu@gmail.com

Arboreal walking performance in seven didelphid marsupials as an aspect of their fundamental niche

DELCIELLOS, A.C.; VIEIRA, M.V. 2006. Arboreal walking performance in seven didelphid marsupials as an aspect of their fundamental niche. Austral Ecology 31:449-457.

Abstract. Species of didelphid marsupials (Didelphimorphia, Didelphidae) differ in their use of the forest strata, but it is not clear whether these differences are in fundamental or realized niches. The fundamental niche of seven species of didelphids (Caluromys philander, Didelphis aurita, Gracilinanus microtarsus, Marmosops incanus, Metachirus nudicaudatus, Micoureus demerarae, and Philander frenatus) was compared using their performance in arboreal walking. The association between performance and vertical use of the forest also was tested accounting for phylogenetic and allometric effects. Tests consisted of making the animal cross five 3 m long horizontal supports of different diameters, 1 m from the ground. The cycle of maximum speed was chosen to measure stride length, frequency and velocity. Arboreal species performed better than the terrestrial ones, but a major part of the variation in stride length (70.95%) and stride frequency (88.10%) was associated with body size. Part of the variation in stride length independent of body size (14.05%) was associated with the degree of vertical use of the forest, after phylogenetic effects were accounted for. Fundamental niches of six of the seven species were discriminated with the performance tests used. Discrepancies between the realized and fundamental niches can be inferred for two of these species, D. aurita and P. frenatus.

Fotos: Myotis cf. nigricans

Não sou muito bom com morcegos, mas este parece um Myotis nigricans. Foi capturado em rede de neblina, perto das 19:00 (foi a hora em que fomos revisar a rede).
Espécie: Myotis cf. nigricans.
Fotógrafo: Paulo T. Sarti.
Contato: paulo.tomasi@gmail.com

Distribution extension and sympatric occurrence of Gracilinanus agilis and G. microtarsus (Didelphimorphia, Didelphidae), with cytogenetic notes

GEISE, L.; ASTÚA, D. 2009. Distribution extension and sympatric occurrence of Gracilinanus agilis and G. microtarsus (Didelphimorphia, Didelphidae), with cytogenetic notes. Biota Neotropica 9(4):269-276.

Abstract. Gracilinanus microtarsus, from the Atlantic Forest and G. agilis, widespread in central Brazil in the Cerrado and in the northeastern Caatinga are two small Neotropical arboreal opossum species not frequently recorded in simpatry. Here we report eight G. agilis specimens from three localities and 17 G. microtarsus, from 10 localities, all in Minas Gerais, Rio de Janeiro and Bahia states. Species proper identification followed diagnostic characters as appearance of dorsum pelage, ocular-mark, ears and tail lengths and size proportion of the posteromedial vacuities in cranium. Chromosomes in metaphases of five specimens were obtained for both species. Our records extend the previous known geographical distribution of G. microtarsus to Chapada Diamantina, in Bahia State and report the occurrence of both species in simpatry. G. microtarsus, in coastal area, was captured in dense ombrophilous and in semideciduous forests, in deciduous seasonal forest and Cerradão in Chapada Diamantina. G. agilis was recorded in gallery forests of Cerrado and very green and dense bush formation of Caatinga. Autosomal complement showed the same diploid and autosomal number already described for both species (2n = 14, NA = 24). Measurements are according to those given in literature and pelage characteristics were useful for the correct species identification. Here we report both G. agilis, described to be endemic to the Cerrado/Caatinga, in opposite to G. microtarsus, considered to be endemic to Atlantic Forest occurring in simpatry in two localities of the Cerrado. Such results indicates that long term trapping effort are necessary to a better definition of species taxonomy, distribution patterns along time and comprehensive understanding how anthropic environmental changes can be interfering in their evolutionary history.

VI Congresso Brasileiro de Mastozoologia - Quarta Circular

Já está no ar o site do VI Congresso Brasileiro de Mastozoologia: http://www.eventus.com.br/sbmz2012/index.html.

Para quem ainda não sabe o VICBMz ocorrerá em Corumbá, MS, entre 25 e 29 de junho de 2012, no Centro de Convenções do Pantanal (mapa no site). A programação já está disponível no site, mas ainda não há confirmação das mesas redondas e mini-cursos.

The question of scale in threat analysis: a case study with Brazilian mammals

GRELLE, C.E.V.; FONSECA, G.A.B.; FONSECA, M.T.; COSTA, L.P. 1999. The question of scale in threat analysis: a case study with Brazilian mammals. Animal Conservation 2:149-152.

Abstract. Rates of biodiversity loss are clearly associated with a reduction in the extent of original habitat. The most frequently used method to derive such estimates comes from the well-known species–area relationship. We explored the relationship between habitat loss and area for the Brazilian mammal fauna on a biome level (Atlantic Forest, Cerrado and the Brazilian portion of the Amazon basin), as well as on a smaller regional scale (the Rio Doce Valley of the Atlantic Forest). Habitat loss overestimates the number of threatened species when the entire species pool is considered (endemics and wideranging species). Restricting the analyses to the endemic species, the predicted extinction as a function of habitat loss in the Atlantic Forest and in the Cerrado is found to be greater than the number of taxa actually listed as threatened. This relation is reversed in the Amazon. When considering only the localized species pool for the Rio Doce Valley region of the Atlantic Forest, the function accurately predicts the number of extinctions resulting from habitat loss. We suggest that there is both theoretical and empirical evidence to suggest that threat analysis will generate more accurate estimates of species loss when conducted on a more local scale, particularly for the fauna of non-insular, continental regions. Furthermore, other phenomena affecting the likelihood of extinction of certain groups of species, such as hunting, need to be taken into account in order to better understand the dynamics of biodiversity loss.

Spatial scale, species diversity, and habitat structure: small mammals in Australian Tropical Rain Forest

WILLIAMS, S.E.; MARSH, H.; WINTER, J. 2002. Spatial scale, species diversity, and habitat structure: small mammals in Australian Tropical Rain Forest. Ecology 83(5):1317-1329.

Abstract. We investigated patterns of mammal assemblage structure on the Atherton Tableland in the Wet Tropics biogeographic region of northeastern Australia. We used live trapping and quantitative estimates of stratified vegetation density to examine the relationships between the structure of the mammal assemblage and habitat structure over three nested spatial scales across a natural vegetation gradient from rain forest to dry, open forest. The narrow transition zone enabled us to examine the relationships between mammal assemblage structure and habitat structure while minimizing the confounding effects of distance, climate, and biogeographic history. The structure of the mammal assemblages was closely related to vegetation structure across and within habitats, and over all spatial scales examined. Vegetation complexity and heterogeneity both influenced assemblage structure, but the relationships varied with spatial scale. Species richness was highest in the open forest and decreased across the gradient into the rain forest. Point diversity was only weakly explained by vegetation structure, whereas .80% of the variation in species richness at the local scale could be explained by vegetation structure. Local-scale species richness of ground-dwelling mammals was mostly a product of the spatial variability in assemblage structure (b diversity), which was associated with the spatial variability in vegetation structure. Local-scale habitat heterogeneity thus promoted local-scale species richness via the close ecological interaction between mammals and habitat structure. The multiscale approach used here, and the nesting of spatial variability in within-habitat vegetation structure, enabled us to demonstrate the scale-dependent effects of spatial habitat heterogeneity and complexity on the structure and diversity of the small-mammal assemblage.

Fotos: Juliomys sp.

Juliomys é um gênero de roedor arborícola neotropical com três espécies reconhecidas (J. pictipes, J. rimmofrons e J. ossitenuis). O gênero foi descrito recentemente, sendo que antigamente as espécies conhecidas eram parte do gênero Wilfredomys (hoje este gênero inclui apenas a espécie W. oenax). É um roedor muito pouco conhecido e pouco abundante nas áreas onde ocorre. O nome comum de cada espécie utiliza o termo "juliomys", portanto o nome comum do gênero seria pronunciado de maneira idêntica ao gênero.
Espécie: Juliomys sp.
Fotógrafo: Maury S.L. Abreu
Contato: maury.abreu@gmail.com

Differences in population density and energy use between birds and mammals: a macroecological perspective

SILVA, M.; BROWN, J.H.; DOWNING, J.A. 1997. Differences in population density and energy use between birds and mammals: a macroecological perspective. Journal of Animal Ecology 66(3):327-340.

Abstract.
1. Data from 364 mammal and 564 bird species were used to compare these two taxa in the patterns of variation in population density and energy use as a function of body mass.
2. This study demonstrates previously unappreciated quantitative differences between mammals and birds. Over a wide range of sizes, population densities and rates of energy use are at least one order of magnitude higher in mammals than in birds of similar size. The highest population densities are found in species that weigh about 100 g in mammals and 30 g in birds.
3. Comparisons between mammals and birds from the same dietary category indicate that mammals maintain higher densities and use more energy than birds. Insectivorous mammals and birds maintain the lowest densities.
4. Flying mammals and birds reach lower densities and use more energy than nonflying forms.

5. These findings reveal relationships between the morphology, physiology and behaviour of individual organisms and the ecological performance of these endothermic vertebrates in populations, communities and ecosystems: relationships that have not previously been appreciated.

Fotos: Gracilinanus microtarsus

O nome gracilinanus vem do latim gracilis (delgado, fino) e do grego nanos (anão), enquanto o epíteto microtarsus vem do prefixo grego micro (pequeno) e o substantivo grego tarsos (tornozelo, sola do pé) (PIRES et al., 2010 - Mammalian Species 42(851):33-40).
Espécie: Gracilinanus microtarsus (cuíca graciosa, guaiquica, Brazilian gracile mouse opossum).
Fotógrafo: Maury S.L. Abreu
Contato: maury.abreu@gmail.com

The Brazilian Caatinga in South American zoogeography: tropical mammals in a dry region

MARES, M.A.; WILLIG, M.R.; LACHER JR., T.E. 1985. The Brazilian Caatinga in South American zoogeography: tropical mammals in a dry region. Journal of Biogeography 12:57-69.

Abstract. Recent research in South American biogeography on groups other than mammals suggests that the semi-arid Caatinga of northeastern Brazil provided xeric refugia during mesic phases of the Pleistocene climatic cycles. If this supposition is correct, the Caatinga mammal fauna might be expected to contain numerous species showing a pronounced level of adaptation to aridity and the origins of a substantial segment of the fauna slr~ould be traceable to the diversification and eventual speciation that would be expected to have resulted from extended isolation in a xeric environment. An analysis of the extant mammal fauna fails to corroborate these predictions; only one endemic mammal species is found in the Caatinga, and the fauna lacks the expected physiological and morphological adaptations. Other vertebrate groups also exhibit low levels of endemism. The high degree of climatic unpredictability that is characteristic of the Caatinga may preclude the development of a unique fauna adapted to xeric conditions. It appears that the present inhabitants of the region avoid the environmental effects of aridity and climatic unpredictability during harsh periods by utilizing the numerous mesic enclaves scattered throughout the Northeast. Indeed, even during periods of elevated precipitation, most mammal species reach their highest density in these relatively restricted areas. Although the Caatinga contains a xeric-adapted flora, it harbours an anomalous mammal fauna that is more characteristic of a mesic tropical biome in terms of both species composition and overall adaptation. The development of an assemblage of vertebrates whose adaptations do not parallel those of the dominant flora in a region is an unusual situation which should be of particular interest to palaeontologists attempting to reconstruct ancient environments.

The looming crisis: interactions between marine mammals and fisheries

READ, A.J. 2008. The looming crisis: interactions between marine mammals and fisheries. Journal of Mammalogy 89(3):541-548.

Abstract. Direct fisheries interactions pose a serious threat to the conservation of many populations and some species of marine mammals. The most acute problem is bycatch, unintended mortality in fishing gear, although this can transition into unregulated harvest under some circumstances. A growing issue in some fisheries is depredation, in which marine mammals remove captured fish from nets or lines. Depredation reduces the value of catch and may lead to a greater risk of entanglement and the potential for retaliatory measures taken by fishermen. The conservation threat caused by direct fisheries interactions is most dire for small populations of cetaceans and dugongs. Immediate action is needed to assess the magnitude of bycatch, particularly in many areas of Africa and Asia where little work has been conducted. New and innovative solutions to this problem are required that take account of the socioeconomic conditions experienced by fishermen and allow for efficient transfer of mitigation technology to fisheries of the developing world.

Feeding habits of the crab-eating fox, Cerdocyon thous (Carnivoria: Canidae), in a mosaic area with native and exotic vegetation in Southern Brazil

ROCHA, V.J.; AGUIAR, L.M.; SILVA-PEREIRA, J.E.; MORO-RIOS, R.F.; PASSOS, F.C. 2008. Feeding habits of the crab-eating fox, Cerdocyon thous (Carnivoria: Canidae), in a mosaic area with native and exotic vegetation in Southern Brazil. Revista Brasileira de Zoologia 25(4):594-600.

Abstract. Cerdocyon thous (Linnaeus, 1766) is the most widespread neotropical canid, most commonly inhabiting forested areas. This animal is a generalist omnivore that is able to use environments disturbed by human activities. The aim of this study was to describe its diet through the stomach content analysis of 30 samples obtained from specimens that were run over in a mosaic composed by Araucaria Pine Forest, Smidecidual Seasonal Forest, natural grasslands, and exotic vegetation. The items were quantified by frequency of occurrence (F.O.) and percentage of occurrence (P.O.). A total of 64 food items were found among 171 occurrences. According to F.O. method, plant items corresponded to 93.3% of the occurrences, followed by animal items (86.7%) and human rejects (16.6%) Among plants, fruits accounted for 92.9% of the occurrences, followed by leaves (53.6%) and flowers (10.7%). Syagrus romanzoffianum (Cham.) Glassman, 1968 and the exotic Hovenia dulcis Thunberg were the most consumed fruits (30% each), and the most consumed leaves were Poaceae. Among preyed animals, the F.O. was 73.3% for invertebrates (mostly Orthoptera and Coleoptera, 36.7% each) and 63.3% for vertebrates (mostly mammals, 33.3%). Regarding the P.O. method, there was an overestimation of invertebrates (98.1%) due to the preference of ants and termites in the stomach of a single individual. In general, C. thous presented its usual diet. Its generalistic feeding habits can positively influence its survival in altered environments. This study also compares different methods for dietary analysis and discusses some opportunistic behaviours of C. thous, such as the consumption of exotic species and the use of silviculture areas as hunting sites.

Scale-dependent habitat selection in three didelphid marsupials using the spool-and-line technique in the Atlantic forest of Brazil

MOURA, M.C.; CAPARELLI, A.C.; FREITAS, S.R.; VIEIRA, M.V. 2005. Scale-dependent habitat selection in three didelphid marsupials using the spool-and-line technique in the Atlantic forest of Brazil. Journal of Tropical Ecology 21:337-342.

Abstract. Habitat selection can be detected at different scales. For small mammals, habitat studies normally evaluate micro- or meso-habitat selection, but rarely are multiple scales analysed simultaneously. These studies use quantitative data of structural characteristics around the trap stations to evaluate selection. We test an alternative method to evaluate habitat selection in three didelphid marsupials (Didelphis aurita, Philander frenatus and Metachirus nudicaudatus), using a spool-and-line device, and measure habitat selection at two spatial scales. Habitat was characterized by seven habitat variables measured at ten points of direction change along the path traversed by each individual, and at 25 trap stations distributed in a 1-ha area. Micro-habitat selection was estimated at each point by comparing habitat measures between the direction selected against other directions. Meso-habitat selection was estimated by comparing habitat measurements on the whole path of an individual against habitat measures on the 25 trap stations. Patterns of selection for each species could only be detected at the meso-habitat scale, although a few individuals in each species were selective at the micro-habitat scale. Studies of habitat selection need to address the scale of study quantitatively, if possible comparing two or more scales to determine the scale of selection.

Coexistence of temporal partitioned spiny mice: roles of habitat structure and foraging behaviour

JONES, M.; MANDELIK, Y.; DAYAN, T. 2001. Coexistence of temporal partitioned spiny mice: roles of habitat structure and foraging behaviour. Ecology 82(8):2164-2176.

Abstract. Two coexisting species of spiny mice in rocky deserts in Israel temporally partition activity in opposite parts of the diel cycle. Acomys cahirinus is nocturnal and A. russatus is diurnal, although it becomes nocturnal if its congener is experimentally removed, suggesting that the temporal partitioning is driven by interspecific competition. Such extreme temporal partitioning within the diel cycle has not previously been recorded elsewhere among mammals. Using artificial food patches, we studied microhabitat use and foraging efficiencies under seasonally variable predator regimes and physiological pressures to assess the roles that habitat structure and foraging behavior might play in coexistence. The two species showed trade-offs in foraging efficiency leading to different strategies of microhabitat use that may help promote coexistence. A. cahirinus is a "cream skimmer," a relatively inefficient forager that gives up at relatively high giving-up densities, and a habitat generalist; whereas A. russatus is a habitat specialist, perhaps compensating for this restricted niche by foraging very efficiently to low giving-up densities. Seasonal shifts in foraging microhabitat suggest that the response to predation risk from snakes in summer overrides and opposes the effects of physiological costs and risk from owls and diurnal raptors, leading to increased predatory risk and foraging microhabitat overlap in summer. Temporal partitioning of the food resource may compensate for decreased partitioning of the habitat resource in summer. Provision of cover was more important than escape distance in determining habitat and microhabitat use. Boulder fields in rocky deserts provide a physical structure that is more complex and provides more continuous cover than is available in open deserts, where most research on community structure of desert rodents has been carried out. We propose that this physical structure of rocky deserts, in conjunction with the desert adaptations of A. russatus, may enable the extreme temporal partitioning to opposite parts of the diel cycle and, therefore, contributes to coexistence in this community.

PPG em Ecologia e Conservação pela UNEMAT - Edital

Esta aberto o edital de processo seletivo para ingresso no curso de Mestrado em Ecologia e Conservação para 2012 da Universidade do Estado de Mato Grosso. São ofertadas 12 vagas nas seguintes linhas de pesquisa: Ecologia de Sistemas e Comunidades Terrestres e Ecologia de Sistemas e Comunidades de Áreas Úmidas.
Maiores informações no edital.

Diet of crab-eating fox, Cerdocyon thous (Linnaeus) (Carnivora, Canidae), in a suburban area of southern Brazil

PEDÓ, E.; TOMAZZONI, A.C.; HARTZ, S.M.; CHRISTOFF, A.U. 2006. Diet of crab-eating fox, Cerdocyon thous (Linnaeus) (Carnivora, Canidae), in a suburban area of southern Brazil. Revista Brasileira de Zoologia 23(3):637-641.

Abstract. The crab-eating fox, Cerdocyon thous (Linnaeus, 1766), is a small canid with twilight and nocturnal habits from savanna and forests of South America. In this study, we seasonally determined and quantified the diet of C. thous in Lami Biological Reserve, a conservation unit with 179.78 ha situated in a suburban area in the municipality of Porto Alegre, southern Brazil. During the year 2000, we colected 80 fecal samples - 20 for each season - in two or three week sampling intervals, along trails inside the Reserve. Samples were dried in an oven for 24h at 60ºC, immersed in 70% alcohol, and prey items were identified using a stereomicroscope. The diet of the crab-eating fox was essentially carnivorous (87.62% composed by vertebrates), with seasonal variation (p = 0.0009) and absence of fruits. Small non-flying mammals and birds were the most frequent prey, being proportionally more preyed in autumn and summer, respectively. Arthropods were more preyed in winter and spring and bird/respile eggs only in summer and spring, in the reproduction period of these groups.

Area de acción, actividad y uso de hábitat del zorro patas negras, Cerdocyon thous, en un bosque seco

MAFFEI, L.; TABER, A.B. 2003. Area de acción, actividad y uso de hábitat del zorro patas negras, Cerdocyon thous, en un bosque seco. Mastozoologia Neotropical 10(1):154-160.

Abstract. Home range, activity, and habitat use of the crab-eating fox (Cerdocyon thous) in a dry forest. The ranging behaviour of three crab-eating foxes in a dry forest in Santa Cruz, Bolivia was studied using radiotracking. Animals occupied an area between 110 and 280 ha estimated with Minimum Convex Polygon and has a small overlap (27 ha) between ranges. The foxes were principally active at night between 17:00 and 08:00 hours. They preferred riparian forest over chacoan and montane forest habitats, althought the former was less available than the others.

Fotos: Dasypus novemcinctus

Esse é o Zeca. Na verdade era pra ser "Jeca Tatu", mas eu me confundi na hora e acabou ficando Zeca mesmo. Esse tatu ciu em uma pitfall para roedores e estava quase morto quando encontramos. Ficamos o dia inteiro cuidando dela, aquecendo e tentando dar comida, e no fim do dia conseguimos fazer ele ir embora e seguir seu rumo sozinho.
Espécie: Dasypus novemcinctus (tatu-galinha, armadillo de nueve bandas, nine-banded armadillo).
Fotógrafo: Maury S.L. Abreu
Contato: maury.abreu@gmail.com

Evolution of nakedness in Homo sapiens

RANTALA, M.J. 2007. Evolution of nakedness in Homo sapiens. Journal of Zoology 273:1-7.

Abstract. Homo sapiens L. is the only existing primate species lacking in functionally effective thermally insulating fur. As all other primates have considerable hair covering, it has always been accepted that our ancestors must once have had a respectable amount of body hair. Unfortunately, fossils cannot help us when it comes to differences in skin and hair. Recent DNA analysis, however, has given us some idea of when and where the great denudation took place. A number of hypotheses have been proposed to account for this feature, but none of these has gained general acceptance. In this paper, I present these hypotheses in the light of current empirical evidence and discussion.

Fotos: Armadilha de queda (pitfall trap)

Mais uma foto sobre técnicas para estudos com mamíferos. Armadilhas de queda (pitfall traps) são especialmente úteis para capturar animais terrestres sem o uso de iscas. Também tem a vantagem de serem permanentes, por isso não é preciso carregar equipamento. Contudo, a instalação é trabalhosa (precisa cavar buracos profundos), e não é efetiva para animais essencialmente arborícolas. Alguns dizem que as recapturas são menores, pois os animais tendem a evitar as armadilhas, mas no único estudo com essas armadilhas que acompanhei havia um bom número de recapturas.
A foto mostra uma pitfall de 60 livros, ideal para pequenos mamíferos (roedores e marsupiais). Modelos menores (como copos de 300ml) são usados para invertebrados e modelos maiores (verdadeiras trincheiras) para grandes vertebrados.
Fotógrafo: Maury S.L. Abreu
Contato: maury.abreu@gmail.com

Holocene vegetation chance and the mammal faunas of South America and Africa

VIVO, M.; CARMIGNOTTO, A.P. 2004. Holocene vegetation chance and the mammal faunas of South America and Africa. Journal of Biogeography 31:943-957.

Abstract
Aim. Although sharing many similarities in their vegetation types, South America and Africa harbour very dissimilar recent mammal faunas, not only taxonomically but also in terms of several faunistic patterns. However late Pleistocene and mid-Holocene faunas, albeit taxonomically distinct, presented many convergent attributes. Here we propose that the effects of the Holocene climatic change on vegetation physiognomy has played a crucial role in shaping the extant mammalian faunistic patterns.
Location. South America and Africa from the late Pleistocene to the present.
Methods. Data presented here have been compiled from many distinct sources, including palaeontological and neontological mammalian studies, palaeoclimatology, palynology, and publications on vegetation ecology. Data on Pleistocene, Holocene and extant mammal faunas of South America and Africa allowed us to establish a number of similar and dissimilar faunistic patterns between the two continents across time. We then considered what changes in vegetation physiognomy would have occurred under the late Pleistocene last

glacial maximum (LGM) and the Holocene climatic optimum (HCO) climatic regimes. We have ordained these proposed vegetation changes along rough physiognomic seral stages according to assumptions based on current botanical research. Finally, we have associated our hypothesized vegetation changes in South America and Africa with mammalian faunistic patterns, establishing a putative causal relationship between them.

Results. The extant mammal faunas of South America and Africa differ widely in taxonomical composition; the number of medium and large species they possess; behavioural and ecological characteristics related to herbivore herding, migration and predation; and biogeographical patterns. All such distinctions are mostly

related to the open formation faunas, and have been completely established around the mid-Holocene. Considering that the mid-Holocene was a time of greater humidity than the late Pleistocene, vegetation cover in South America and Africa would have been dominated by forest or closed vegetation landscapes, at

least for most of their lower altitude tropical regions. We attribute the loss of larger-sized mammal lineages in South America to the decrease of open vegetation area, and their survival in Africa to the existence of vast savannas in formerly steppic or desertic areas in subtropical Africa, north and south of the equator. Alternative explanations, mostly dealing with the disappearance of South American megamammals, are then reviewed and criticized.

Main conclusions. The reduction of open formation areas during the HCO in South America and Africa explains most of the present distinct faunistic patterns between the two continents. While South America would have lost most of its open formations within the 30 latitudinal belt, Africa would have kept large areas suitable to the open formation mammalian fauna in areas presently occupied by desert and semi-arid vegetation. Thus, the same general climatic events that affected South America in the late Pleistocene and Holocene also affected Africa, leading to our present day faunistic dissimilarities by maintaining the African mammalian communities almost unchanged while dramatically altering those of South America.

Fotos: Hydrochoerus hydrochaeris

A capivara é o maior roedor vivo em todo o planeta. Tem habito semi-aquático e se distribui por todo o Brasil, sempre associada aos corpos d'água.
Espécie: Hydrochoerus hydrochaeris (capivara, carpincho, puerco de agua, capybara).
Fotógrafo: Nathalia dos Santos Freitas.
Contato: sfreitas.nathalia@gmail.com

Where have all the cavies gone? Causes and consequences of predation by minor grison on a wild cavy population

KRAUS, C.; RÖDEL, H.G. 2004. Where have all the cavies gone? Causes and consequences of predation by minor grison on a wild cavy population. Oikos 105:489-500.

Abstract. We investigated whether predation by the minor grison (Galictis cuja , a small mustelid) played a key role in limiting a wild cavy population (Cavia magna), ultimately leading to its local extinction. Radio-telemetry and capture-mark-recapture techniques were used to estimate grison predation rates (kill rates), time-specific probabilities of apparent mortality (population loss rate), overall mortality and grison predation for the cavy population. Additionally, we present data on alternative prey species, grison diet and reproduction to show potential proximate mechanisms of grison predation on wild cavies. The predictions specified were mostly confirmed: (1) grison predation was responsible for almost 80% of the cavies killed by known predators; (2) grison predation probabilities paralleled those of overall mortality of cavies over time; and (3) also those of the apparent mortality of the population. Thus, the population dynamics and the local extinction of the cavy population were not due to emigration processes. (4) Grison predation rates were not density-dependent, but showed pronounced peaks during the austral summer. The grison mainly preyed on small mammals: two water-rat species and the wild cavies. When the availability of alternative prey decreased in summer, the grison appeared to specialise on cavies. The onset of grison reproduction was somewhat delayed in relation to the onset of cavy reproduction. The lack of alternative prey coincided with high grison food demands due to reproduction, leading to a very high predation pressure ultimately resulting in the local extinction of the cavy population. We conclude that grison predation was indeed the main factor driving changes of the cavy population studied and speculate why caviomorph rodents might be especially susceptible to local extinction processes.

III Simpósito de Biodiversidade

O Simpósio de Biodiversidade é um evento nacional, realizado a cada dois anos, que busca esclarecer ao biólogo, ao estudante de ciências biológicas e à sociedade, conceitos relacionados à biodiversidade bem como ressaltar a importância da aplicação desses conceitos para amenizar o processo de degradação ambiental, melhorando a qualidade de vida de todas as espécies. O evento é promovido pelo Programa de Pós Graduação em Biodiversidade Animal e pelo Curso de Ciências Biológicas da Universidade Federal de Santa Maria.

Nesta edição, o tema gerador do evento é "Filosofia da Ciência e a Prática Científica". Pensamos que a abordagem deste tema é fundamental para formação dos profissionais que trabalham (ou irão trabalhar) com as questões relacionadas à biodiversidade. Faz-se necessário para a ciência moderna a recuperação de seus valores questionadores, afinal, foram esses valores que a colocaram em sua posição atual. Nesse sentido, a filosofia é uma aliada mais que desejada para entendermos os efeitos da atividade humana nas espécies, comunidades e ecossistemas, e para desenvolver abordagens práticas com o intuito de prevenir a extinção de espécies e, se possível, reintegrar as espécies ameaçadas de extinção.

Está aberta a chama para resumos para serem divulgados no evento. A data limite é 5 de novembro de 2011.

As inscrições ao 3º Simpósio de Biodiversidade já estão abertas pelo site www.ufms.br/isbio.

Maiores informações veja o 1º Informativo do Evento.

Road Ecology Brazil 2011

O Road Ecology Brazil 2011 é um evento científico que ocorrerá em Lavras, MG, entre os dias 17 e 19 de outubro deste ano focado temas de ecologia e sua relação com estradas e rodovias. A Comissão Organizadora lembra que as inscrições com valores reduzidos se encerram no dia 16 de setembro, e que as inscrições pela internet encerram dia 30 de setembro. Então se estiver interessado entre em contato pelo e-mail oficial do evento - roadecology2011@gmail.com - ou visite o site oficial: http://www.dbi.ufla.br/reb2011/index.php.

Fotos: Dasyprocta azarae

Espécie: Dasyprocta azarae (cutia).
Fotógrafo: Nathalia dos Santos Freitas.

Contato: nfreitas.nathalia@gmail.com

Otter (Lutra lutra) predation on stocked brown trout (Salmo trutta) in two Danish lowland rivers

JACOBSEN, L. 2005. Otter (Lutra lutra) predation on stocked brown trout (Salmo trutta) in two Danish lowland rivers. Ecology of Freshwater Fish 14:59-68.

Abstract. This study aimed to evaluate otter predation on stocked trout. Large hatchery-reared trout (16–30 cm) were stocked into two Danish rivers with different fish populations. Otter diet before and after trout stocking was determined by analysing 685 spraints, collected regularly during the 35-day study period. Fish composition in the rivers before stocking was assessed by electrofishing. In River Trend, a typical trout river, the proportion of trout in the otter diet increased from 8% before stocking to 33% a few days after stocking. Moreover, trout lengths in the diet changed significantly towards the lengths of stocked trout, indicating that newly stocked trout were preferred to wild trout. In River Skals, dominated by cyprinids, there was no change in otter diet after stocking of hatchery trout, i.e., these were ignored by otter. Otter predation should be taken into account together with fish and bird predation, when stocking is used as a measure for conserving endangered salmonid populations.

Fotos: Myocastor coypus

O ratão-do-banhado é um roedor semi-aquático de grande porte nativo do Rio Grande do Sul e parte de Santa Catarina. Também pode ser visto em São Paulo, onde foi introduzido por criadores. Filogeneticamente esse roedor permanece mal resolvido: já esteve incluído nas famílias Capromyidae e Echimyidae. Atualmente encontra-se classificado como único representante da família Myocastoridae.
Espécie: Myocastor coypus (ratão-do-banhado).
Fotógrafo: Nathália dos Santos Freitas.
Contato: sfreitas.nathalia@gmail.com

Unisinos - Seleção de Docente

A Universidade do Vale do Rio dos Sinos (UNISINOS), localizada em São Leopoldo, Rio Grande do Sul, abriu processo de seleção para docentes. Os interessados devem ter título de Doutor. Maiores informações no edital de seleção.

Impact of hunting on large vertebrates in the Mbaracayu Reserve, Paraguay

HILL, K.; PADWE, J.; BEJYVAGI, C.; BEPURAGI, A.; JUKAGI, F.; TYKUARANGI, R.; TYKUARANGI, T. 1997. "Impact of hunting on large vertebrates in the Mbaracayu Reserve, Paraguay. Conservation Biology 11(6):1339-1353.

Abstract. Over 1,400,000 m of line transect data were collected in collaboration with Ache Indians to determine encounter rates with all large vertebrates in the Mbaracayu Reserve Paraguay. The data were analyzed using logistic regression in order to determine the impact of human hunting on animal encounter rates in the reserve. The method controlled for effects of season, weather, time of day, and habitat in order to statistically isolate the human predation effect. Encounters with the animals themselves as well as fresh signs of their activity allowed us to determine whether lower encounter rates in hunted zones are simply due to increased wariness by target species. Our results show that areas near hunters are hunted more frequently, and that Dasypus novemcinctus, Cebus apella, Tapirus terrestris, and Mazama spp. are all encountered at lower rates in those areas than in unhunted zones. We were unable to show that encounter rates with other important game species have been affected by human hunting. Demonstration of local depletion by central place foragers is expected, However, and cannot be used to conclude that prey species are in danger of regional extirpation. 

Landscape ecology: what is the state of the science?

TURNER, M.G. 2005. Landscape ecology: what is the state of the science? Annual Review of Ecology, Evolution and Systematics 36:319-344.

Abstract. Landscape ecology focuses on the reciprocal interactions between spatial pattern and ecological processes, and it is well integrated with ecology. The field has grown rapidly over the past 15 years. The persistent influence of land-use history and natural disturbance on contemporary ecosystems has become apparent. Development of pattern metrics has largely stabilized, and they are widely used to relate landscape pattern to ecological responses. Analyses conducted at multiple scales have demonstrated the importance of landscape pattern for many taxa, and spatially mediated interspecific interactions are receiving increased attention. Disturbance remains prominent in landscape studies, and current research is addressing disturbance interactions. Integration of ecosystem and landscape ecology remains challenging but should enhance understanding of landscape function. Landscape ecology should continue to refine knowledge of when spatial heterogeneity is fundamentally important, rigorously test the generality of its concepts, and develop a more mechanistic understanding of the relationships between pattern and process.

A complete phylogeny of the whales, dolphins and even-toed hoofed mammals (Cetartiodactyla)

PRICE, S.A.; BININDA-EMONDS, O.R.P.; GITTLEMAN, J.L. 2005. A complete phylogeny of the whales, dolphins and even-toed hoofed mammals (Cetartiodactyla). Biology Review 80:445-473.

Abstract. Despite the biological and economic importance of the Cetartiodactyla, the phylogeny of this clade remains controversial. Using the supertree approach of matrix representation with parsimony, we present the first phylogeny to include all 290 extant species of the Cetacea (whales and dolphins) and Artiodactyla (even-toed hoofed mammals). At the family-level, the supertree is fully resolved. For example, the relationships among the Ruminantia appear as (((Cervidae, Moschidae) Bovidae) (Giraffidae, Antilocapridae) Tragulidae). However, due to either lack of phylogenetic study or contradictory information, polytomies occur within the clades Sus, Muntiacus, Cervus, Delphinidae, Ziphiidae and Bovidae. Complete species-level phylogenies are necessary for both illustrating and analysing biological, geographical and ecological patterns in an evolutionary framework. The present species-level tree of the Cetartiodactyla provides the first opportunity to examine comparative hypotheses across entirely aquatic and terrestrial species within a single mammalian order.

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Fotos: Thaptomys nigrita

Capturado durante levantamento de mamíferos em Guaporé, este roedor Akodontini caracteriza-se por apresentar porte bem pequeno (este indivíduo tinha 28 gramas, mas outro indivíduo de 16 gramas já havia sido capturado), cauda pequena (menor do que o corpo), orelhas pequenas e coloração escura, sem diferença marcante entre ventre e dorso. As orelhas são tão pequenas que nem sequer é possível colocar anilha.
Espécie: Thaptomys nigrita (rato-pitoco).
Fotógrafo: Paulo T. Sarti.
Contato: paulo.tomasi@gmail.com.

Capturando pequenos mamíferos arborícolas

GRAIPEL, M.E.; MORAES, D.A. 2004. Capturando pequenos mamíferos arborícolas. Boletim da Sociedade Brasileira de Mastozoologia 39:1-2.

Este pdf é um texto curto, publicado no Boletim da Sociedade Brasileira de Mastzoologia em 2004 por Maurício Graipel e Diego Astúa. Interessante para quem trabalha ou pretende trabalhar com animais arborícolas.

VI Congresso Brasileiro de Mastozoologia - Terceira Circular

Saiu a terceira circular do VI Congresso Brasileiro de Mastozoologia, que ocorrerá em Corumbá. O prazo para submissão de propostas de conferências, mesas-redonda e mini-cursos foi prorrogado até 30 de agosto de 2011. As instruções estão no arquivo pdf da circular.

Download da Terceira Circular do VI CBMz.

Fotos: Kannabateomys amblyonyx

Dois indivíduos de rato-da-taquara, um roedor equimídeo (família Echimyidae) que ocorrem associados a taquarais. Estes roedores se alimentam essencialmente de brotos de bambu e são conhecidos por apresentarem comportamento social: vivem em casais e criam dos filhotes juntos. Procurei algum artigo sobre cuidado parental da espécie, mas não encontrei nada que estivesse disponível on-line.
Espécie: Kannabateomys amblyonyx (rato-da-taquara).
Fotógrafo: Maury S.L. Abreu.
Contato: maury.abreu@gmail.com.

Comparação de métodos para captura da cuíca-d'água, Chironectes minimus (Zimmerman, 1780) (Mammalia, Didelphidae) no sul do Brasil

BRESSIANI, V.B.; GRAIPEL, M.E. 2008. Comparação de métodos para captura da cuíca-d'água, Chironectes minimus (Zimmerman, 1780) (Mammalia, Didelphidae) no sul do Brasil. Mastozoologia Neotropical 15(1):33-39.

Resumo. A falta de conhecimento acerca da biologia de Chironectes minimus provavelmente está relacionada com as dificuldades de captura. Assim, dois métodos usando armadilhas do tipo Young, com dois tipos de iscas, foram comparados com o método usual de captura (controle). O estudo foi desenvolvido de fevereiro a junho de 2003 em dois córregos do Parque Municipal da Lagoa do Peri, na Ilha de Santa Catarina, sul do Brasil. Quatro indivíduos foram capturados duas vezes e aspectos da biologia da espécie foram registrados. Todas as capturas ocorreram através do método controle. Armadilhas instaladas em passagens estreitas dos rios, em locais com maior quantidade de rochas e raízes, foram mais efetivas para a captura de C. minimus. O sucesso de captura, considerando apenas o método controle, foi de 4%. Aspectos positivos e negativos de todos os métodos foram apresentados e discutidos.

Fotos: Armadilha de arame de dupla passagem

Existem armadilhas de arame (similar ao modelo Tomahawk) que funcionam de maneira diferente - elas possuem duas portas, uma de cada lado, e se fecham quando o animal tenta atravessar a armadilha. Estas armadilhas tem a vantagem de que não precisam de isca. Devem ser instaladas de maneira que os animais sejam capazes de passar por elas. Criar túneis e canais que obriguem o animal a entrar é uma boa estratégia.
Há um estudo sobre uso dessas armadilhas para captura de cuíca d'água (Chironectes minimus), instalando em córregos (Bressiani et al. 2008; acompanhem a próxima postagem).
Fotógrafo: Maury S.L. Abreu.
Contato: maury.abreu@gmail.com.

Marsupial relationships and a timeline for marsupial radiation in South Gondwana

NILSSON, M.A.; ARNASON, U.; SPENCER, P.B.S.; JANKE, A. 2004. Marsupial relationships and a timeline for marsupial radiation in South Gondwana. Gene 340:189-196.

Abstract. Recent marsupials include about 280 species divided into 18 families and seven orders. Approximately 200 species live in Australia/New Guinea. The remaining species inhabit South American with some of these secondarily ranging into North America. In this study, we examine marsupial relationships and estimate their divergences times using complete mitochondrial (mt) genomes. The sampling, which includes nine new mtDNAs and a total number of 19 marsupial genomes, encompasses all extant orders and 14 families. The analysis identified a basal split between Didelphimorphia and remaining orders about 69 million years before present (MYBP), while other ordinal divergences were placed in Tertiary times. The monotypic South American order Microbiotheria (Dromiciops gliroides, Monito del Monte) was solidly nested among its Australian counterparts. The results suggest that marsupials colonized Australia twice from Antarctica/South America and that the divergence between Microbiotheria and its Australian relatives coincided with the geological separation of Antarctica and Australia. Within Australia itself, several of the deepest divergences were estimated to have taken place close to the Eocene/Oligocene transition.

Fotos: Armadilha Tomahawk

Outro modelo de armadilha de captura viva tipicamente utilizado em levantamentos de pequenos mamíferos, o modelo Tomahawk consiste em uma gaiola. O animal fica menos protegido, mas há quem afirme que as tomahawks capturam animais que não são capturados nas Sherman. Também precisa de isca.
Nesta foto, a armadilha esta instalada em um suporte de madeira, preso por cordas para içar a armadilha até o dossel da floresta, permitindo assim captura de animais essencialmente arborícolas. É uma boa técnica em estudos de estratificação vertical. As armadilhas modelo Sherman também podem ser instaladas nesses suportes, assim como as de modelo Tomahawk também podem ser instaladas no solo e no sub-bosque (galhos e vegetação suspensa).
Fotógrafo: Maury S.L. Abreu.
Contato: maury.abreu@gmail.com.

Effects of fire on the abundance of xenarthrans in Mato Grosso, Brazil

PRADA, M.; MARINHO-FILHO, J. 2004. Effects of fire on the abundance of xenarthrans in Mato Grosso, Brazil. Austral Ecology 29:568-593.

Abstract. Fire is an important ecological factor in Cerrado vegetation of central Brazil, and in other savanna

ecosystems. The effect of fire on the abundance of some Xenarthran mammal species Priodontes maximus

Kerr, 1792 (giant armadillo), Euphractus sexcinctus Linnaeus, 1758 (yellow armadillo) and Myrmecophaga tridactyla Linnaeus, 1758 (giant anteater)) was studied at Reserva Xavante do Rio das Mortes, a 329 000 ha Xavante Indian reserve in the Cerrado of Mato Grosso, Brazil. Track counts were used to compare the abundance of these mammals along seven burned and seven unburned transects, on seven occasions between August 1995 and August 1996. The number of tracks in burned and unburned areas did not differ. Xenarthrans probably use burned areas to obtain food resources, basically termites and ants. Xavante traditional fire hunts may reduce fuel accumulation and function as a mechanism to prevent more destructive fires. Fire management at Reserva Xavante is recommended because the burning system of Brazilian farmers is already influencing the Xavante community. Xavante traditional knowledge about fire could be an important instrument for this management.

Fotos: Armadilha Sherman

A técnica mais frequentemente utilizada para levantamentos de pequenos mamíferos é captura viva com armadilhas. Essa foto mostra uma armadilha modelo Sherman. Na foto ela esta instalada em um galho para captura de pequenos mamíferos arborícolas e escansoriais (como para estudos de uso do espaço vertical), mas o mais comum é instalar a armadilha no solo. Essas armadilhas possuem um gatilho no fundo, e quando o animal pisa, a porta se fecha, e só pode ser aberta pelo lado de fora. É necessário uso de isca.
Fotógrafo: Maury S.L. Abreu.
Contato: maury.abreu@gmail.com.

Movement distances and density estimation of small mammals using the spool-and-line technique

MENDEL, S.M.; VIEIRA, M.V. 2003. Movement distances and density estimation of small mammals using the spoll-and-line technique. Acta Theriologica 48(3):289-300.

Abstract. Edge effect is an inherent problem when using trapping grids to estimate density of small mammals, resulting in a sampling area larger than the area of the grid. Distances between captures of individuals are used to estimate A(W), the effective sampling area of a trapping grid, but grid size sets a limit for the largest detectable distance. The spool-and-line technique is proposed here as a new method to estimate A(W). Movement distances based on the spool-and-line technique were compared to similar movement distances based on capture-recapture of three spacies of marsupials of the Atlantic Forest of Brazil. Distances based on the two methos were uncorrelated, and only ln-transformed distances based on the spool-and-line were normally distributed. The maximum distance moved (MaxD) estimated by the spool-and-line was chosen as the more accurate and practical distance to estimate edge effect. Estimates of the effective sampling area and densities for the common opossum Didelphis aurita (Wied-Neuwied, 1826), were compared using MaxD based on spool-and-line (MaxDspool), capture-recapture (MaxDcap), and also the distance between traps (DT). MaxDspool reflected more accurately density variation between seasons. Movement distances of small mammals based on the spool-and-line technique permit more accurate estimates of density and its dynamics.

Fotos: Oxymycterus quaestor

Roedor de porte mais avantajado (os indivíduos que foram capturados nesta ocasião tinham entre 71 e 105 gramas), caracterizam-se por comportamento fossorial (ocorrem essencialmente no solo). Possuem unhas grandes, focinho alongado e cauda curta. Todos os indivíduos da amostragem foram capturados às margens do rio Marmeleiros, em Barracão.
Espécie: Oxymycterus quaestor (rato-focinhudo).
Fotógrafo: Maury S.L. Abreu.
Contato: maury.abreu@gmail.com.

VI Congresso Brasileiro de Mastozoologia - Segunda Circular

A Sociedade Brasileira de Mastozoologia divulgou, através da Segunda Circular do VI Congresso Brasileiro de Mastozoologia, as regras para submissão de propostas de conferências, mesas redondas e mini-cursos (até 10 de agosto de 2011). Faça download do arquivo para maiores informações.
O VI Congresso Brasileiro de Mastozoologia ocorrerá em 2012 na cidade de Corumbá, MG.

Estimating the abundance of mouse populations of known size: promises and pitfalls of new mothods

CONN, P.B.; ARTHUR, A.D.; BAILEY, L.L.; SINGLETON, G.R. 2006. Estimating the abundance of mouse populations of known size: promises and pitfalls of new mthods. Ecological Applications 16(2):829-837.

Abstract. Knowledge of animal abundance is fundamental to many ecological studies. Frequently, researchers cannot determine true abundance, and so must estimate it using a method such as mark–recapture or distance sampling. Recent advances in abundance estimation allow one to model heterogeneity with individual covariates or mixture distributions and to derive multimodel abundance estimators that explicitly address uncertainty about which model parameterization best represents truth. Further, it is possible to borrow information on detection probability across several populations when data are sparse. While promising, these methods have not been evaluated using mark–recapture data from populations of known abundance, and thus far have largely been overlooked by ecologists. In this paper, we explored the utility of newly developed mark–recapture methods for estimating the abundance of 12 captive populations of wild house mice (Mus musculus). We found that mark–recapture methods employing individual covariates yielded satisfactory abundance estimates for most populations. In contrast, model sets with heterogeneity formulations consisting solely of mixture distributions did not perform well for several of the populations. We show through simulation that a higher number of trapping occasions would have been necessary to achieve good estimator performance in this case. Finally, we show that simultaneous analysis of data from low abundance populations can yield viable abundance estimates.

Fotos: Nasua nasua

Este é o Chico, um quati domesticado que vivia aprontando em Aracuri. Uma verdadeira praga, mexia nas mochilas em busca de isca (e comia as luvas de procedimento que estavam sujas de isca), e até aprendeu a abrir as portas pra nos atazanar. Depois de um tempo, ele de repente sumiu. Mas pela foto até parece um animal silvestre...
Espécie: Nasua nasia (quati).
Fotógrafo: Maury S.L. Abreu.
Contato: maury.abreu@gmail.com

Geographic range and body size in Neotropical marsupials

OLIFIERS, N.; VIEIRA, M.V.; GRELLE, C.E.V. 2004. Geographic range and body size in Neotropical marsupials. Global Ecology and Biogeography 13:439-444.

Abstract.
Aim. Our aim is to investigate the relationship between body size and geographical range in Neotropical marsupials, considering the possible effects of latitude and phylogeny.
Location. Neotropical region.
Methods. Phylogenetic generalized least-squares regression method (PGLS) is used to investigate the relationship between body size, geographical range, and latitude considering the phylogenetic relationship between species. Data for 22 species were compiled from the literature.
Results. The scattergram of body size vs. geographical range was triangular in shape. Body size and geographical range were positively correlated throughout the phylogeny. Latitude was not important to this relationship.
Conclusions. The polygonal relationship between geographical range and body size seems to be moulded by ecological and geographical constraints rather than by a common association with latitude.

Fotos: Cryptonanus guahybae

Originalmente pensávamos que esse animal era um Gracilinanus microtarsus, mas posteriormente um membro do Museu de Zoologia da Ulbra viu a foto e disse que se tratava de um Cryptonanus guahybae. Fui checar e vi que era mesmo. Ele foi capturado no solo, em pitfall. Este é um marsupial didelfídeo relativamente raro, único do gênero no RS (pelo que me consta). Antigamente pertencia ao gênero Gracilinanus (como G. microtarsus guahybae).
Espécie: Cryptonanus guahybae (cuíca).
Fotógrafo: Maury S.L. Abreu.
Contato: maury.abreu@gmail.com

The role of forest structure, fragment size and corridors in maintaining small mammal abundance and diversity in an Atlantic forest landscape

PARDINI, R.; SOUZA, S.M.; BRAGA-NETO, R.; METZGER, J.P. 2005. The role of forest structure, fragment size and corridors in maintaining small mammal abundance and diversity in an Atlantic forest landscape. Biological Conservation 124:253-266.

Abstract. Using the abundance and distribution of small mammals at 26 sites in an Atlantic forest landscape, we investigated how species abundance and alpha and beta diversity are affected by fragment size and the presence of corridors. To account for the variability in forest structure among fragments, we described and minimized the influence of foliage density and stratification on small mammal data. Sites were distributed among three categories of fragment size and in continuous forest. For small and medium-sized categories, we considered isolated fragments and fragments connected by corridors to larger remnants. Small mammal abundance and alpha and beta diversity were regressed against site scores from the first axis of a Principal Component Analysis on forest structure variables. Residuals were used in analyses of variance to compare fragment size and connectivity categories. Forest structure influenced total abundance and abundance of some species individually, but not the diversity of small mammal communities. Total abundance and alpha diversity were lower in small and medium-sized fragments than in large fragments and continuous forest, and in isolated compared to connected fragments. Three species were less common, but none was more abundant in smaller fragments. At least one species was more abundant in connected compared to isolated fragments. Beta diversity showed an opposite relationship to fragment size and corridors, increasing in small and isolated fragments. Results highlight the importance of secondary forest for the conservation of tropical fauna, the hyper-dynamism of small isolated fragments and the potential of corridors to buffer habitat fragmentation effects in tropical landscapes.

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Fotos: Roedor cricetídeo em armadilha fotográfica

Foto de armadilha fotográfica. O que esses roedores não fazem por comida...
Espécie: roedor cricetídeo não identificado.
Fotógrafo: Maury S.L. Abreu (em armadilha fotográfica).
Contato: maury.abreu@gmail.com.

VI Congresso Brasileiro de Mastozoologia - Primeira Circular

A Sociedade Brasileira de Mastozoologia (SBMz) em parceria com a Embrapa Pantanal, a Prefeitura Municipal de Corumbá e o Programa de Pós-graduação em Ecologia e Conservação da Universidade Federal de Mato Grosso do Sul tem o prazer de convidá-los a participar do 6° Congresso Brasileiro de Mastozoologia, que acontecerá de 25 a 29 de junho de 2012.

Nesta edição, a SBMz decidiu interiorizar o congresso, levando-o para Corumbá (MS), uma das principais portas de entrada do Pantanal brasileiro. Pesou também na escolha do local o fato de o Pantanal ser um dos poucos ambientes naturais do Brasil onde ainda é possível se ter um contato estreito com mamíferos silvestres.

A atuação humana tem provocado desequilíbrios ambientais que desencadearam a "sexta onda de extinção em massa", capaz de reduzir a biodiversidade de forma sem precedentes desde que o homem caminha sobre o planeta. Assim, apropriadamente o tema do congresso será "A mastozoologia e a crise de biodiversidade".

Os colegas que desejarem fazer sugestões sobre conferências e mesas redondas devem enviar mensagem ao endereço

O programa do congresso é sumarizado na página seguinte. Informações relativas às inscrições no evento, infra-estrutura e formas de acesso à Corumbá serão disponibilizadas na próxima circular e no sítio virtual do evento, que deverão estar disponíveis em meados de agosto de 2011.

Até breve, nos vemos no Pantanal!

Comissão Organizadora do 6° Congresso Brasileiro de Mastozoologia

Download da Primeira Circular em pdf

Niche overlap and resource partitioning between two sympatric fox species in southern Brazil

VIEIRA, E.M.; PORT, D. 2007. Niche overlap and resource partitioning between two sympatric fox species in southern Brazil. Journal of Zoology, London 272:57-63.

Abstract. Mechanisms that favour the co-occurrence of morphologically and ecologically similar species in South America are potentially relevant, because two or more species often occur in sympatry. In the present study, we investigated possible mechanisms of resource partitioning between two sympatric species of foxes, the crab-eating fox Cerdocyon thous and the pampas fox Pseudalopex gymnocercus, in the National Park of Aparados da Serra in southern Brazil (29º10'S, 50º05'W). We considered three main niche dimensions – habitat, diet and time – and evaluated the overlap between the two species in these dimensions. We conducted the study from June 2000 to October 2001 in an area composed of open grasslands and Araucaria forests. We studied the foxes by using a combination of scat analysis and direct observation. A comparison of their diet indicated that it was very similar for both species in all seasons (Pianka’s indexes ranging from 0.920 to 0.957). The most common food item for both species of foxes was rodents, followed by coleopterans, birds and plant remains (seeds and fruits). As expected by the nichecomplementarity hypothesis, we detected differences along other niche axes. Pseudalopex gymnocercus seemed to occur only in open areas, including grasslands and dirt roads, whereas C. thous was more generalist in habitat use, occurring both inside and at the edge of forests. However, both fox species were common in grassland habitats, where they might compete for resources. The differences were more marked for activity time, with the crab-eating fox being significantly more nocturnal (circular mean of time of sighting=23:39 h, SE=56 min) than the pampas fox (circular mean=19:56 h, SE=64 min; Watson’s F=6.06, P=0.02). We suggest that the larger C. thous could be limiting the activity of P. gymnocercus by interference competition.

ARCGIS aplicado à Biologia da Conservação

O CALBio (Centro Acadêmico Livre da Biologia) da Unisinos esta realizando mais um curso de extenção que deve interessar não apenas os mastozoólogos, mas qualquer profissional da área de biologia interessado em bons mapas para seus artigos. Ministrado por Msc. Rafael Gomes de Moura, o curso de ARCGis Aplicado à Biologia da Conservação será realizado na Unisinos, entre os dias 26 de junho e 8 de julho (período noturno, entre 19h e 22h, comduração de 30 horas).
Maiores informações no site: www.unisinos.br/eventos.