Mostrando postagens com marcador community ecology. Mostrar todas as postagens
Mostrando postagens com marcador community ecology. Mostrar todas as postagens

sábado, 15 de agosto de 2015

Journals: Community Ecology

Community Ecology

- Abreviatura: Community Ecol.
- Qualis CAPES: B1 (Biodiversidade), B2 (Ciências Biológicas I).
- Taxa de Publicação: Sim.
- Idiomas: Inglês.
- Disponibilidade: Restrito. Apenas as edições mais recentes ficam disponíveis no site.
- Submissão: Online, pelo sistema Editorial Manager, com acesso na home page.


Community Ecology, estabelecida pela união de dois periódicos de ecologia, o Coenoses e a Abstracta Botanica foi gerado em um esforço de criar um fórum global comum para ecólogos de comunidade que trabalhem com comunidades de plantas, animais e/ou microbiais dos sistemas terrestres, marinhos ou de água doce. As principais áreas abordadas são: (i) teoria ecológica baseada em comunidade; (ii) modelagem de comunidades ecológicas; (iii) ecofisiologia baseada em comunidades; (iv) dinâmicas temporais, incluindo sucessão; (v) interações tróficas, incluindo cadeias alimentares e competição; (vi) análise de padrões espaciais, incluindo questões de escala; (vii) padrões de riqueza de espécies e diversidade em comunidades; (viii) amostragem de comunidades ecológicas/ (ix) métodos de análise de dados. Também publica Revisões de livros publicados, anúncios e avisos.

sábado, 2 de maio de 2015

Nota sobre convergência e divergência alimentar de canídeos e felídeos (Mammalia: Carnivora) simpátricos no Cerrado brasileiro

TROVATI, R.G.; CAMPOS, C.B.; BRITO, B.A. 2008. Nota sobre convergência e divergência alimentar de canídeos e felídeos (Mammalia: Carnivora) simpátricos no Cerrado brasileiro. Neotropical Biology and Conservation 3(2):95-100.

Abstract. Feed convergence and divergence of some sympatric canids and felids in Tocantins, Brazil were analyzed. Thirty-six fecal samples were collected. The results showed that 37.3% of the canids’ diet was made up of fruit and fibers (grasses e peel fruits) and 44% of the felids’ diet was made up of mammals. There were differences in the measurement and in the overlap of trophic niche, indicating canids as generalists and felids as specialists. Feeding of Phantera onca was more divergent and feeding of Puma yagouaroundi converged with the canids. Thus, the data collected shows that small felids have a similar diet to canids and only large and medium felids present divergence, but further studies are needed to better elucidate the degree of sympatric of these animals.

sábado, 21 de março de 2015

Abundance and community composition of small mammals in different habitats in Hugumburda forest, northern Ethiopia

ADAM, M.; WELEGERIMA, K.; MEHERETU, Y. 2015. Abundance and community composition of small mammals in different habitats in Hugumburda forest, northern Ethiopia. International Journal fo Biodiversity and Conservation 7(2):119-125. doi: 10.5897/IJBC2014.0787

Abstract. Tropical forest ecosystems harbor several species of small mammals. Diversity and abundance of small mammals in these forests reflect the quality and diversity of the ecosystems. The corrent study was carried out to assess abundance and species composition of small mammals (rodents and shrews) in three habitat types (Pterolobium, Juniperus and Cadia habitats) in Hugumburda forest, a dry afromontane forest in the Tigray region of North Ethiopia. The habitat types were selected based on the floristic compositions (plant species diversity) and level of human disturbance. All together, 179 individual small mammals belonging to seven rodent and one insectivore species were captured in 4,320 trap nights. The rodent species, with their relative abundance, were Stenocephalemys albipes, 55 (30.7%); Mastomys awashensis, 53 (29.6%); Arvicanthis dembeensis, 26 (14.5%); Lophuromys flavopunctatus, 22 (12.3%); Mus (Nannomys) setulosus, 14 (7.8%); Arvicanthis abysinicus 4 (2.2%); Dendromus mystacalis, 3 (1.7%) and the insectivore Crocidura olivieri, 2 (1.1%). There was significant variation in the small mammal abundance among the habitat types (X²= 29.45, P= 0.009), with more individuals caught in Pterolobium habitat, which has relatively highest plant species composition and lowest human disturbance than the other two habitats. The highest small mammal species diversity was also recorded in this habitat (H'= 1.76). Vegetation diversity and level of human interference are likely the major factors affecting small mammal abundance and composition in Hugumburda forest.

sábado, 5 de julho de 2014

Use of arboreal and terrestrial space by a small mammal community in a tropical rain forest in Borneo, Malaysia

WELLS, K. PFEIFFER, M.; LAKIM, M.B.; LINSENMAIR, K.E. 2004. Use of arboreal and terrestrial space by a small mammal community in a tropical rain forest in Borneo, Malaysia. Journal of Biogeography 31:641-652.

Abstract:
Aim: Small mammals were live-trapped in a primary rain forest to evaluate the relative distribution of species to each other and to microhabitat properties on the ground and in the canopy.
Location: Kinabalu National Park in Borneo, Sabah, Malaysia.
Methods: Seven trapping sessions were conducted along two grids with 31 trap points at distances of 20 m on the ground and in the lower canopy at an average height of 13.5 m.
Results: Species diversity and abundance of small mammals proved to be high: 20 species of the families Muridae, Sciuridae, Tupaiidae, Hystricidae, Viverridae and Lorisidae were trapped, with murids being dominant in both habitat layers. The terrestrial community was significantly more diverse with 16 captured species (Shannon–Wiener’s diversity index H'terr = 2.47), while 11 species were trapped in the canopy (H'arb = 1.59). The Whitehead’s rat, Maxomys whiteheadi, and the red spiny rat, Maxomys surifer, dominated the terrestrial community whereas the large pencil-tailed tree mouse, Chiropodomys major, was by far the most abundant species in the canopy. Other abundant species of the canopy community, the dark-tailed tree rat, Niviventer cremoriventer, and the lesser treeshrew, Tupaia minor, were also abundant on the ground, and there was no clear boundary between arboreal and terrestrial species occurrences.
Main Conclusions: As most species were not confined to specific microhabitats or habitat layers, species seemed to rely on resources not necessarily restricted to certain microhabitats or habitat layers, and separation of species probably resulted mainly from a species’ concentrated activity in a preferred microhabitat rather than from principal adaptations to certain habitats. Ecological segregation was stronger in the more diverse terrestrial community, though microhabitat selection was generally not sufficient to explain the co-occurrences of species and the variability between local species assemblages. Constraints on small mammal foraging efficiency in the three-dimensional more complex canopy may be responsible for the similarity of microhabitat use of all common arboreal species. Community composition was characterized by mobile species with low persistence rates, resulting in a high degree of variability in local species assemblages with similar turnover rates in both habitats.

sábado, 22 de fevereiro de 2014

Effects of fragmentation of the Atlantic forest on mammal communities in south-eastern Brazil

CHIARELLO, A.G. 1999. Effects of fragmentation of the Atlantic forest on mammal communities in south-eastern Brazil. Biological Conservation 89:71-82.

Abstract. Six Atlantic forest reserves, two large (c. 20,000 ha each), two medium-sized (c. 2,000 ha each) and two small (c. 200 ha each), located in northern Espírito Santo, south-eastern Brazil were censured for mammals from October 1994 to April 1996. Diurnal and nocturnal line-transect sampling was used for censusing mammals > 1 kg body weight, and the relative abundance of species in the six fragments was compared. The number of mammal species recorded in the reserves was strongly related to the forest area, the richest community being recorded in the two large reserves and the poorest in the two small reserves. The large reserves had a structurally more complex community, with top predators, large, terrestrial frugivores and large myrmecophages. The mammal community of the small and the medium-sized reserves was impoverished and less complex. Frugivores were numerically predominant in both large and medium-sized reserves, whereas herbivores dominated the mammal community of the small reserves, mainly through the absence of agoutis Dasyprocta leporina and the high density of maned sloth Bradypus torquatus in the two small reserves. The lack of predators and the proliferation of secondary vegetation and lianas throughout the small reserves are probably the main causes for the success of arboreal folivores there. Illegal hunting was found to reduce the encounter rates of mostly large, terrestrial frugivores such as agoutis, pacas Agouti paca, peccaries Pecari tajacu and Tayassu pecari and deer Mazama spp., and is contributing to keep the population of the surviving species low.

sábado, 5 de outubro de 2013

Support diameter, incline, and vertical movements of four didelphid marsupials in the Atlantic forest of Brazil

CUNHA, A.A.; VIEIRA, M.V. 2002. Support diameter, incline, and vertical movements of four didelphid marsupials in the Atlantic forest of Brazil. Journal of Zoology, London 258:419-426.

Abstract. Didelphids use vertical strata in different ways, suggesting the existence of a wider variety of niches than simply arboreal or terrestrial. This variety could be related to the differential ability to deal with support diameters and inclines, and might be important for the coexistence of species in local assemblages. From data obtained with the spool-and-line technique, the use of the vertical space and above-ground supports is described in four species of an assemblage of didelphid marsupials in south-east Brazil. The stratification in this and other assemblages in the Atlantic forest and in the Amazon is also compared. Animals were trapped in Serra dos Órgãos, state of Rio de Janeiro, and equipped with a spool-and-line device before release. The paths were tracked by measuring variables related to support diameter, incline, distance and height moved above ground. The diameter of supports used was positively related to body size, and the incline to the dominant direction of movement (horizontal vs vertical). The more cursorial species, Metachirus nudicaudatus, only once moved above ground in > 3200 m of paths followed. Didelphis aurita moved mostly on the ground, but was the only species that occasionally reached the canopy. Philander frenata also moved mostly on the ground, occasionally used the understorey, but never reached the canopy. The more arboreal species, Marmosops incanus, moved mostly in the understorey, but never in the canopy. This pattern of stratification is similar to that observed in other sites in the Atlantic forest and in the Amazon.

sábado, 7 de setembro de 2013

Short-term fire effects on small mammal populations and vegetation of the Northern Chihuahuan Desert

MONASMITH, T.J.; DEMARAIS, S.; ROOT, J.J.; BRITTON, C.M. 2010. Short-term fire effects on small mammal populations and vegetation of the Northern Chihuahuan Desert. International Journal of Ecology, v. 2010, Article ID 189271, 9 pages. doi: 10.1155/2010/189271.

Abstract. Fire is an important ecological factor in semidesert grass-shrub community dynamics, but there is a lack of designed field experiments documenting effects on vegetation and small mammals.We document effects of June prescribed fire on vegetation and small mammals on 20, 25-ha study areas in the Northern Chihuahuan Desert of Southern New Mexico, USA one month and one year posttreatment. Canopy cover of shrubs and grasses recovered to 68 and 27% of the preburn canopy cover, respectively, after one year. Prescribed burns during June enhanced short-term forb production by reducing competition from grasses and shrubs. Thirty thousand trap-nights yielded 1744 captures of 766 individuals of 15 small mammal species. Burns did not affect small mammal species richness and species diversity. Relative abundance of Merriam’s kangaroo rats (Dipodomys merriami) was 91% greater on burned sites than on control sites one year postburn. Silky pocket mouse (Perognathus flavus) relative abundance was 221% greater on burned sites one year postburn. Chihuahuan Desert pocket mice (Chaetodipus eremicus) responded negatively to the fire, with relative abundance 170% greater on control sites (P = .080). Burning produced short-term benefits for two heteromyids, Merriam’s kangaroo rats and silky pocket mice.

sábado, 24 de agosto de 2013

Activity patterns of the culpeo fox (Lycalopex culpaeus megellanica) in a non-hunting area of northwestern Patagonia, Argentina

MONTEVERDE, M.J.; PIUDO, L. 2011. Activity patterns of the culpeo fox (Lycalopex culpaeus megellanica) in a non-hunting area of northwestern Patagonia, Argentina. Mammal Study 36:119-125.

Abstract. The culpeo fox is the largest native canid in Patagonia. The majority of past studies on culpeo foxes have focused on trophic ecology, population dynamics, natural history, competitive interactions, management, and habitat use. Little work has been done on determining activity patterns of the fox and thus, conclusions regarding culpeo fox activity patterns have been based on limited data. The objective of our study was to determine culpeo fox activity patterns in a protected area (Lanín National Park, Argentina) using “camera-traps” to test the hypothesis that the culpeo fox is still nocturnal in non-hunting areas. Data were collected from October 2008 through May 2009 at 29 infrared triggered camera stations. We obtained 1,261 culpeo fox photos of which 234 were used for analyses. Diet was studied from 34 culpeo fox scats. Culpeo foxes were most active during nighttime (>70% of the records) confirming the general patterns obtained in other studies. Additionally, examination of culpeo fox scats revealed that they mostly preyed on nocturnal small mammals. The present study offers evidence against the widespread assumption that nocturnal activity of this species is a behavioral response to human harassment, as it was conducted in a protected area where culpeo foxes are not hunted. Instead, their nocturnal behavior may be related to prey activity patterns.

sábado, 11 de maio de 2013

Factors affecting the use of space by two rodent species in Brazilian Atlantic forest

BERGALLO, H.G.; MAGNUSSON, W.E. 2004. Factors affecting the use of space by two rodent species in Brazilian Atlantic forest. Mammalia 68(2-3):121-132.

Abstract. The main purpose of this study was to determine whether the maximum distance traveled and home range are of Nectomys squamipes and Oryzomys russatus differ between sexes, breeding seasons and species. We also evaluated whether rainfall and food availability influenced the maximum distance traveled. Rats were trapped monthly from February 1993 to January 1995 in an area of Atlantic forest, Brazil. Maximum distance traveled by N. squamipes was not related to mass and was longer during the breeding season for males. There were not differences between seasons in the distances traveled by O. russatus, but larger males traveled further. Food availability and rainfall had no effect on the distance traveled by each species. Home ranges of male N. squamipes were larger than those of females during the breeding season, but home ranges did not differ between the sexes in O. russatus. Differences between the two species in movement may be related to differences in mating systems, which are probably promiscuous in N. squamipes and monogamous in O. russatus.

sábado, 23 de março de 2013

Rodent handling of Araucaria araucana seeds

SHEPHERD, J.D.; DITGEN, R.S. 2013. Rodent handling of Araucaria araucana seeds. Austral Ecology 38:23-32. doi: 10.1111/j.1442-9993.2012.02366.x.

Abstract. In an intermast year of very low seed production, we studied seed handling in an Araucaria araucana (Araucariaceae) forest in Neuquén Province, Argentina. Rodents identified in 844 photographs from automatic cameras removed 589 seeds marked with small embedded magnets.Within 12 days of removal, 460 were recovered using a magnetic field locator; 79% of recoveries were from burrows and caches in litter or soil. Rodents exhibited a diversity of seed-handling strategies and differed in their potential as dispersal agents. Seed removal was most likely between 15.00 hours and 21.00 hours, but diurnal and nocturnal visits were recorded for all species. Oligoryzomys longicaudatus (Cricetidae) was a seed predator that took 8% of marked seeds and left none whole. Chelemys macronyx (Cricetidae) and Rattus norvegicus (Muridae) removed 25% and 19% of marked seeds respectively.These two species deposited the majority of seeds in groups of 10 or more in burrow larders that were unfavourable seedling establishment sites far from daylight. Abrothrix longipilis (Cricetidae) removed 43% of seeds, scatter-hoarded the largest percentage of whole seeds (37%), moved some seeds farther than 40 m, and left them in favourable seedling establishment sites near daylight. For all species, the number and proportion of seeds cached whole increased as more seeds were removed. Rodents, especially A. longipilis, may play an important role in regeneration of A. araucana. Seed-handling strategies and potentially effective dispersal are discussed in terms of masting seed production.

sábado, 2 de março de 2013

Contemporary neotropical defaunation and forest structure, function, and diversity - a sequel to John Terborgh

DIRZO, R.; MIRANDA, A. 1990. Contemporary neotropical defaunation and forest structure, function, and diversity - a sequel to John Terborgh. Conservation Biology 4(4):444-447.

Abstract. From a series of long-term studies at the Los Tuxtlas Tropical Research Station, Mexico, it is argued that a number of features of this forest's understorey support Terborgh's contention [see Conservation Biology (1988) 2 402-403] that big animals of the tropical forest play an important though largely unappreciated role in the diversity and structure of these natural ecosystems.

sábado, 23 de fevereiro de 2013

rich: an R package to analyse species richness

ROSSI, J-P. 2011. rich: an R package to analyse species richness. Diversity 3(1):112-120. doi: 10.3390/d3010112.

Abstract. The paper describes rich, a new R package to perform species richness estimation and comparison. Species richness is the simplest surrogate for the more complex concept of species biodiversity. It is relatively easy to assess although estimations strongly depend on sampling intensity with the consequence that richness estimations should be standardized to perform valid comparisons. The R package rich allows such corrections as well as the computation of various statistics and implements different randomization tests to compare cumulative and average species richness of two communities. These tests are useful for ranking sites or communities which is a classical goal in restoration ecology and conservation biology.

sábado, 29 de setembro de 2012

Toward an ecological synthesis: a case for habitat selection

MORRIS, D.W. 2003. Toward an ecological synthesis: a case for habitat selection. Oecologia 136:1-13.

Abstract. Habitat selection, and its associated density and frequency-dependent evolution, has a profound influence on such vital phenomena as population regulation, species interactions, the assembly of ecological communities, and the origin and maintenance of biodiversity. Different strategies of habitat selection, and their importance in ecology and evolution, can often be revealed simply by plots of density in adjacent habitats. For individual species, the strategies are closely intertwined with mechanisms of population regulation, and with the persistence of populations through time. For interacting species, strategies of habitat selection are not only responsible for species coexistence, but provide one of the most convenient mechanisms for measuring competition, and the various community structures caused by competitive interactions. Other kinds of interactions, such as those between predators and prey, demonstrate that an understanding of the coevolution of habitat-selection strategies among strongly interacting species is essential to properly interpret their spatial and temporal dynamics. At the evolutionary scale, the frequency dependence associated with habitat selection may often allow populations to diverge and diversify into separate species. Habitat selection thereby demonstrates how we can map microevolutionary strategies in behavior onto their population and community consequences, and from there, onto macroevolutionary patterns of speciation and adaptive radiation. We can anticipate that future studies of habitat selection will not only help us complete those maps, but that they will also continue to enrich the panoply of ideas that shape evolutionary ecology.

sábado, 15 de setembro de 2012

Disponibilidade de frutos e a dieta de Lycalopex vetulus (Carnivora - Canidae) em um cerrado de Mato Grosso, Brasil

DALPONTE, J.C.; LIMA, E.S. 1999. Disponibilidade de frutos e a dieta de Lycalopex vetulus (Carnivora - Canidae) em um cerrado de Mato Grosso, Brasil. Revista Brasileira de Botânica 22(2):325-332.

Abstract. (Fruit availability and the diet of Lycalopex vetulus (Carnivora - Canidae) in a cerrado vegetation of Mato Grosso, Brazil). The fruiting phenology of 41 species known as potential food for mammals was monitored monthly during the period of 1985 and 1986, and compared with the frugivorous diet of the hoary fox (Lycalopex vetulus) in a cerrado area near Chapada dos Guimarães National Park, Mato Grosso, Brazil. The fruiting pattern was seasonal, with peaks of greater availability in the beginning of dry and wet seasons. Hancornia speciosa, Rauwolfia sp. and Solanum lycocarpum showed a long (nine to 12 months) fruiting pattern, while Guettarda viburnioides and Mouriri elliptica a short pattern (five to eight months). Seventy percent of the fruit species were eaten by the hoary fox. Despite the large number of fruit species consumed, a small percentage (26%) of these species reaches 10% of the occurrence frequency in the fox scats. The consumption of fruits by the hoary fox was opportunistic, generally consistent with the seasonal fruiting pattern in the study area. H. speciosa and S. lycocarpum were considered the most important fruit species in the diet of the hoary fox, since they give sources of alternative food year round, including periods of low availability of other fruits, like the peak os dry season. Changes in the intensity of fruit used by the hoary fox, like the replacement of some species by others, seem to show states of satiation and interest for new atractive fruits. Apparently, accessibility, strong smell and energetic content are features of the fruits that determine primary preferences for some species. The role of the hoary fox as an important agent to diesperse fruits in the cerrado may be suggested by the large number of fruit species eaten, and by the presence of undamaged seeds in the scats.

sábado, 1 de setembro de 2012

Small mammal community structure and composition in the Cerrado Province of central Brazil

MARES, M.A.; ERNEST, K.A.; GETTINGER, D.D. 1986. Small mammal community structure and composition in the Cerrado Province of central Brazil. Journal of Tropical Ecology 2:289-300.

Abstract. Community structure, microhabitat selection, and patterns of species co-occurrence were examined during a 14-month study of small mammals in the Cerrado Province of central Brazil. Data were collected from mark-recapture grids in brejo and gallery forest, and from live-trapping and specimen collection in all habitat types withing cerrado (campo limpo, campo sujo, cerrado [s.s.], cerradão, brejo, valley-side wet campo, and gallery forest). Gallery forest supported the highest species richness, most complex vertical distribution of species, highest level of trophic diversity, and highest macroniche diversity. Degree of habitat selection varied widely. All habitat types supported both rodents and marsupials, althought marsupials tended to be much less common in the grasslands (campos) than in woodlands (cerrado) and forest (cerradão, gallery forest). Some species, such as Didelphis albiventris, occurred in all habitat types, while others were much more restricted. Oryzomys bicolor, for example, ocurred only in gallery forest. No habitat type has a completely distinct fauna: overlap in species composition always occurred with at least one other habitat type. Because of the great variability of habitats, and the fact that subsets of the mammal fauna were frequently habitat specific, the overall species richness of any portion of mixed cerrado vegetation is remarkably high.

sábado, 18 de agosto de 2012

Ecology of a small mammal community in an Atlantic forest area in southeastern Brazil

BERGALLO, H.G. 1994. Ecology of a small mammal community in an Atlantic forest area in southeastern Brazil. Studies on Neotropical Fauna and Environment 29(4):197-217.


Abstract. During a 14 month mark-and-release project in a Atlantic forest area (Jurélia Ecological Station), I studied the population ecology of 8 species of small mammals (3 marsupials and 5 rodents). In a 4,307 trap nights, 182 individuals were captured 650 times. The rodents were caught 73% of the total capture and the marsupials 27%. Oryzomys nitidus was the commonest species in the grid followed by Proechimys iheringi and Metachirus nudicaudatus. The marsupials showed a seasonal pattern of reproduction. As a consequence, the population densities has a peak during the wet months with the antrance of the youngs . The rodents, P. iheringi and O. nitidus bred throughtout the year, althought the former one has a peak in the dry months. Density of O. nitidus was fairly constant, whereas that of P. ihenrigi was higher during the recruitment time. Rodents and marsupials contributed with the same biomass in Juréia small mammal community.

sábado, 11 de agosto de 2012

Elevational gradients in diversity of small mammals

MCCAIN, C.M. 2005. Elevational gradients in diversity of small mammals. Ecology 86(2):366-372.

Abstract. A global analysis of elevational diversity trends for nonvolant small mammals revealed a clear pattern of mid-elevational peaks in species richness. Fifty-six data sets were used to test the predictions of a null model (the mid-domain effect) and climatic hypotheses. Very few data sets fit entirely within the predictions of the null model, and the average predictive power of the null model was low. Regional (gamma) diversity fit the null model better than did local (alpha) diversity. Diversity peaked at higher elevations on taller mountains, consistent with climatic factors producing elevationally correlated habitat bands (Massenerhebung effect). This positive, linear relationship was documented for all data sets but was particularly pronounced for alpha diversity. Gamma diversity, which is generally highly influenced by area, exhibited a trend of highest diversity shifting toward lower elevations, and higher elevational peaks in species diversity at higher latitudes. The elevation of temperate diversity peaks exhibited a negative association with latitude. These results are evidence for the importance of a suite of interacting climatic, area, and geometric factors on elevational diversity patterns, apparent in spite of noise associated with different sampling techniques, localities, and historical pressures.

sábado, 28 de julho de 2012

Ecological scale and habitat use

MORRIS, D.M. 1987. Ecological scale and habitat use. Ecology 68(2):362-369

Abstract. Population density can respond to habitat at different scales. If habitat selection occurs as a consequence of resource exploitation, the density of fine-grained consumers should reflect microhabitat variation. But if habitat use is controlled by a variety of selective pressured, it is no longer apparent whether density should respond to micro- or macrohabitat. These two alternatives can be tested simultaneously by multiple regression models where macrohabitat are represented by dummy variables. When the local densities of two Temperate Zone rodents were analyzed in this way, macrohabitat and temporal effects were consistent significant predictors of rodent density; microhabitat was not. This analysis suggests species whose patterns of resource and habitat use probably depart from classical interpretations of species coexistence. It is probably premature to assess the role of habitat selection in the structure of ecological systems until the results of further tests of habitat scaling are reported.

sábado, 14 de julho de 2012

Habitat fragmentation and movements of three small mammals (Sigmodon, Microtus, and Peromyscus)

DIFFENDORFER, J.E.; GAINES, M.S.; HOLT, R.D. 1995. Habitat fragmentation and movements of three small mammals (Sigmodon, Microtus, and Peromyscus). Ecology 76(3):827-839.

Abstract. We studied the effects of habitat fragmentation on the movements of cotton rats (Sigmodon hispidus), deer mice (Peromyscus maniculatus), and prairie voles (Microtus ochrogaster) living in a fragmented landscape using 7.7 yr (1984-1992) of mark-recapture data. The study area included three kinds of 0.5-ha blocks: single large patches (5000 m²), clusters of medium patches (288 m²), and clusters of small patches (32 m²). We tested three predictions regarding animal movements. First, animal should move longer distances as fragmentation increases. Second, the proportion of animals moving will decrease as fragmentation increases. Third, species will show more movement from putative sources to putative sinks. In support of our first two predictions, all species (except male cotton rats) moved farther, and lower proportions of animals moved, as fragmentation increased. In testing our third prediction, we found no trends, for all species, between patch size and the net number of animals a block either imported or exported, indicating source-sink dynamics were probably not occurring on our study site. Furthermore, animals of all species (except female deer mice) switched more frequently to blocks of larger patches. For prairie voles in the spring and deer mice in the summer, relative abundance among blocks predicted from a Markov matrix model of switching probabilities showed high congruence with the actual abundances, indicating movement and abundance were related. In both cotton rats and prairie voles but not in deer mice, more juveniles and nonreproductive animals switched between blocks than did adults or reproductive animals. Deer mice switched more frequently than did either cotton rats or prairie voles; the latter species switched in similar frequencies. We discuss the implications of our data for modeling and conservation.

sábado, 26 de maio de 2012

Morcegos (Chiroptera) capturados em lagoas do Parque Nacional da Restinga de Jurubatiba, Rio de Janeiro, Brasil

LUZ, J.L.; MANGOLIN, R.; ESBÉRARD, C.E.L.; BERGALLO, H.G. 2011. Morcegos (Chiroptera) capturados em lagoas do Parque Nacional da Restinga de Jurubatiba, Rio de Janeiro, Brasil. Biota Neotropica 11(4):000-000.

Abstract. The aim of this study was to perform a list of bat species captured in six lagoons in the Parque Nacional da Restinga de Jurubatiba, Rio de Janeiro State, Brazil. The park is located about 180 km eastward of Rio de Janeiro city and covers the municipalities of Macaé, Carapebus and Quissamã. The region is dominated by sand dunes and sand ridges formed in the Quaternary. We captured 149 bats belonging to three families and 14 species. Most species caught in restinga de Jurubatiba were frugivores, partly due to technique employed, mist-net, that favors the capture of individuals of the Phyllostomidae family. Five species are uncommonly captured in bats inventories (Uroderma magnirostrum, Lasiurus cinereus, Lophostoma brasiliense, Chiroderma villosum and Diaemus youngi). Species caught varied among lagoons, showing the importance of these habitats for maintaining the diversity of bats.