GALETTI, M. DONATTI, C.I.; PIRES, A.S.; GUIMARÃES JR., P.R.; JORDANO, P. 2006. Seed survival and dispersal of an endemic Atlantic forest palm: the combined effects of defaunation and forest fragmentation. Botanical Journal of the Linnean Society 151:141-149.
Abstract. About 45 palm species occur in the Atlantic forest of Brazil, and most of them are affected by loss of seed dispersers resulting from forest fragmentation and hunting. Here we report the effects of habitat loss and defaunation on the seed dispersal system of an endemic palm, Astrocaryum aculeatissimum. We evaluated seed removal, insect and rodent seed predation, and scatter-hoarding in nine sites, ranging from 19 ha to 79 000 ha. We report the seedling, juvenile and adult palm densities in this range of sites. Endocarps remaining beneath the parent palm had a higher probability of being preyed upon by insects in small, mostly fragmented and more defaunated sites. The frequency of successful seed removal, scatter-hoarding and consumption by rodents increased in the larger, less defaunated sites. Successful removal and dispersal collapsed in small (< 1000 ha), highly defaunated sites and frequently resulted in low densities of both seedlings and juveniles. Our results indicate that a large fraction of Atlantic forest palms that rely on scatter-hoarding rodents may become regionally extinct due to forest fragmentation and defaunation. Current management practices including palm extraction and hunting pressure have a lasting effect on Atlantic forest palm regeneration by severely limiting successful recruitment of prereproductive individuals.
Mostrando postagens com marcador interactions. Mostrar todas as postagens
Mostrando postagens com marcador interactions. Mostrar todas as postagens
sábado, 3 de outubro de 2015
sábado, 26 de setembro de 2015
Seed predation by rodents and safe sites for large-seeded trees in a fragment of the Brazilian Atlantic forest
PINTO, S.R.R.; SANTOS, A.M.M.; TABARELLI, M. 2009. Seed predation by rodents and safe sites for large-seeded trees in a fragment of the Brazilian Atlantic forest. Brazilian Journal of Biology 69(3):763-771.
Abstract. Seed predation by small rodents is an emerging theme in the ecology of modified landscapes. Here we investigate the role played by the small rodent Oryzomys oniscus as a seed predator of large-seeded trees in a large remnant of the Atlantic forest - the Coimbra forest (3,500 ha), Alagoas state, northeastern Brazil. O. oniscus was captured and identified by setting twenty 500 m long transects, each one composed of 25 traps 20 m apart. This procedure resulted in 483 trap-nights set during a 20-mo period. We used 692 seeds (>15 mm length) from ten local large-seeded tree species for the seed predation trials that basically consisted of three treatments: one seed on the ground freely accessed by vertebrates (unprotected seed), one seed totally protected by an exclosure, and one partially-protected seed (exclosure just for medium-sized and large vertebrates). O. oniscus was captured throughout the Coimbra forest including forest edges (76 captures) and interior areas (67), and this small rodent was responsible for all seed predation visually documented inside exclosures. A 24 hours period of seed exposition permitted elevated rates of seed removal and predation. Seeds were much more removed/predated beneath fruiting trees, but rates varied according to the level of seed protection — 26.3% of predation among partially-protected versus 19.2% among unprotected seeds. Seeds suffered higher levels of seed predation/removal at the forest edge as well (up to 90%). In both habitats, most seeds (>84%) remained intact beneath trees without fruits, regardless of the level of seed protection. Our results suggest that O. oniscus may operate as an effective large-seed predator in forest fragments, in which adult trees without fruits constitute low resource spots and thereby provide, at least temporarily, safe sites for large seeds.
Abstract. Seed predation by small rodents is an emerging theme in the ecology of modified landscapes. Here we investigate the role played by the small rodent Oryzomys oniscus as a seed predator of large-seeded trees in a large remnant of the Atlantic forest - the Coimbra forest (3,500 ha), Alagoas state, northeastern Brazil. O. oniscus was captured and identified by setting twenty 500 m long transects, each one composed of 25 traps 20 m apart. This procedure resulted in 483 trap-nights set during a 20-mo period. We used 692 seeds (>15 mm length) from ten local large-seeded tree species for the seed predation trials that basically consisted of three treatments: one seed on the ground freely accessed by vertebrates (unprotected seed), one seed totally protected by an exclosure, and one partially-protected seed (exclosure just for medium-sized and large vertebrates). O. oniscus was captured throughout the Coimbra forest including forest edges (76 captures) and interior areas (67), and this small rodent was responsible for all seed predation visually documented inside exclosures. A 24 hours period of seed exposition permitted elevated rates of seed removal and predation. Seeds were much more removed/predated beneath fruiting trees, but rates varied according to the level of seed protection — 26.3% of predation among partially-protected versus 19.2% among unprotected seeds. Seeds suffered higher levels of seed predation/removal at the forest edge as well (up to 90%). In both habitats, most seeds (>84%) remained intact beneath trees without fruits, regardless of the level of seed protection. Our results suggest that O. oniscus may operate as an effective large-seed predator in forest fragments, in which adult trees without fruits constitute low resource spots and thereby provide, at least temporarily, safe sites for large seeds.
sábado, 8 de agosto de 2015
Barn Owl pellets (Aves: Tyto furcata) reveal a higher mammalian richness in the Restinga de Jurubatiba National Park, Southeastern Brazil
LEMOS, H.M.; SILVA, C.A.O.; PATIU, F.M.; GONÇALVES, P.R. 2015. Barn Owl pellets (Aves: Tyto furcata) reveal a higher mammalian richness in the Restinga de Jurubatiba National Park, Southeastern Brazil. Biota Neotropica 15(2):1-9. http://dx.doi.org/10.1590/1676-06032015012114
Abstract. The northern coast of the state of Rio de Janeiro harbors the largest coastal sandy plains (restingas) of southeastern Brazil, severely threatened due to recent human occupation. In this context, mammal inventories becomes urgent to support biodiversity conservation and management policies. This paper aims to update the knowledge on the mammalian species richness of Restinga de Jurubatiba National Park by analyzing pellets of the Barn owl Tyto furcata. The analyses of 4745 mammalian bone fragments (1739 individuals) revealed the occurrence of 17 species belonging to the orders Rodentia (9 spp.), Didelphimorphia (2 spp.) and Chiroptera (6 spp.). The rodents Mus musculus and Cerradomys goytaca accounted for 77.2% of the total individuals preyed, suggesting that the Barn owl hunts in both disturbed and natural open shrub formations. A compilation of previous records, together with those provided in the present study, indicates the occurrence of 44 species of mammals in the Restinga de Jurubatiba National Park, of which six (13.6%) were exclusively detected in pellets. These new records include species adapted to open formations of the interior of Brazil that were not previously reported in restingas on the basis of voucher-specimens, such as the rodents Necromys lasiurus and Calomys tener, the latter being recorded for the first time in the littoral of Rio de Janeiro state. This study underscores the importance of owl pellet analysis as a complementary and indispensable method for inventorying mammals. The results highlight the Restinga de Jurubatiba National Park as one of the restingas in Southeastern Brazil with the highest number of mammal species.
Abstract. The northern coast of the state of Rio de Janeiro harbors the largest coastal sandy plains (restingas) of southeastern Brazil, severely threatened due to recent human occupation. In this context, mammal inventories becomes urgent to support biodiversity conservation and management policies. This paper aims to update the knowledge on the mammalian species richness of Restinga de Jurubatiba National Park by analyzing pellets of the Barn owl Tyto furcata. The analyses of 4745 mammalian bone fragments (1739 individuals) revealed the occurrence of 17 species belonging to the orders Rodentia (9 spp.), Didelphimorphia (2 spp.) and Chiroptera (6 spp.). The rodents Mus musculus and Cerradomys goytaca accounted for 77.2% of the total individuals preyed, suggesting that the Barn owl hunts in both disturbed and natural open shrub formations. A compilation of previous records, together with those provided in the present study, indicates the occurrence of 44 species of mammals in the Restinga de Jurubatiba National Park, of which six (13.6%) were exclusively detected in pellets. These new records include species adapted to open formations of the interior of Brazil that were not previously reported in restingas on the basis of voucher-specimens, such as the rodents Necromys lasiurus and Calomys tener, the latter being recorded for the first time in the littoral of Rio de Janeiro state. This study underscores the importance of owl pellet analysis as a complementary and indispensable method for inventorying mammals. The results highlight the Restinga de Jurubatiba National Park as one of the restingas in Southeastern Brazil with the highest number of mammal species.
sábado, 1 de agosto de 2015
Are otters generalists or do they prefer large, slower prey? Feeding flexibility of the Neotropical otter Lontra longicaudis in the Atlantic Forest
RHEINGANTZ, M.L.; OLIVEIRA-SANTOS, L.G.; WALDEMARIN, H.F.; CARAMASCHI, E.P. 2012. Are otters generalists or do they prefer large, slower prey? Feeding flexibility of the Neotropical otter Lontra longicaudis in the Atlantic Forest. IUCN Otter Specialist Group Bulletin 29(2):80-94.
Abstract. Despite there being several studies focusing on feeding habits of Lontra longicaudis, few studies aimed to evaluate its prey selectivity and none of them considered prey mobility. In this study, we report both its feeding flexibility and specialist feeding behaviour between two parts of Mambucaba River, Southeastern Brazil. We observed that they fed mainly on fish, crabs and crayfish. We did not observe seasonality either in diet or prey community availability. However, using ANOVA, we found differences between stretches for diet composition and in the availability of prey. Monotonic Multi-Dimensional Scaling ordination showed that the otter diet in mangroves was dominated by Brachyura and the prey availability by Brachyura, Caridea, Ariidae, Mugilidae, Gerreidae, Centropomidae and Cichlidae, while the diet in the river stretch was dominated by Cichlidae, Caridea and Heptapteridae, and the prey availability by Characidae, Erythrinidae and Heptapteridae. According to Ivlev Electivity Index, along the river few preys were consumed according to their abundance, the majority being selected. Otters preferred slower prey, no matter their size. We observed variation in the level of preference of the same prey in different stretches, with flexibility in otter diet. Otter ate few preys according to their abundance, but showed specialist feeding behaviour, eating the slowest prey of the stretch.
Abstract. Despite there being several studies focusing on feeding habits of Lontra longicaudis, few studies aimed to evaluate its prey selectivity and none of them considered prey mobility. In this study, we report both its feeding flexibility and specialist feeding behaviour between two parts of Mambucaba River, Southeastern Brazil. We observed that they fed mainly on fish, crabs and crayfish. We did not observe seasonality either in diet or prey community availability. However, using ANOVA, we found differences between stretches for diet composition and in the availability of prey. Monotonic Multi-Dimensional Scaling ordination showed that the otter diet in mangroves was dominated by Brachyura and the prey availability by Brachyura, Caridea, Ariidae, Mugilidae, Gerreidae, Centropomidae and Cichlidae, while the diet in the river stretch was dominated by Cichlidae, Caridea and Heptapteridae, and the prey availability by Characidae, Erythrinidae and Heptapteridae. According to Ivlev Electivity Index, along the river few preys were consumed according to their abundance, the majority being selected. Otters preferred slower prey, no matter their size. We observed variation in the level of preference of the same prey in different stretches, with flexibility in otter diet. Otter ate few preys according to their abundance, but showed specialist feeding behaviour, eating the slowest prey of the stretch.
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.
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, 25 de abril de 2015
Incidental catch of South American sea lion in a pair trawl off southern Brazil
MACHADO, R.; OLIVEIRA, L.R.; MONTEALEGRE-QUIJANO, S. 2015. Incidental catch of South American sea lion in a pair trawl off southern Brazil. Neotropical Biology and Conservation 10(1):43-47. doi: 10.4013/nbc.2015.101.06
Abstract. The population of the South American sea lion, Otaria flavescens (Shaw, 1800), in Uruguay is declining at an annual rate of 1.6 to 2.0%. Although the reasons are still unknown, interactions with fishing activities have been identified as a major cause. The individuals that arrive along the coast of Brazil come from the breeding colonies off Uruguay after their breeding period. We report here the first record of incidental catch of South American sea lions in Brazilian waters by a pair trawl. On July 17th, 2008 a young male of South American sea lion was incidentally caught during a commercial pair trawl fishing trip along the southern Brazilian coast (32º57’S, 52º31’W), in a depth ranging from 15 to 20 m. Despite being punctual, this record is an evidence of a potential major threat to South American sea lions in southern Brazil and Uruguay, since trawl industrial fishing is a very important economic activity in South Brazil.
Abstract. The population of the South American sea lion, Otaria flavescens (Shaw, 1800), in Uruguay is declining at an annual rate of 1.6 to 2.0%. Although the reasons are still unknown, interactions with fishing activities have been identified as a major cause. The individuals that arrive along the coast of Brazil come from the breeding colonies off Uruguay after their breeding period. We report here the first record of incidental catch of South American sea lions in Brazilian waters by a pair trawl. On July 17th, 2008 a young male of South American sea lion was incidentally caught during a commercial pair trawl fishing trip along the southern Brazilian coast (32º57’S, 52º31’W), in a depth ranging from 15 to 20 m. Despite being punctual, this record is an evidence of a potential major threat to South American sea lions in southern Brazil and Uruguay, since trawl industrial fishing is a very important economic activity in South Brazil.
quarta-feira, 15 de abril de 2015
Journals: Plant Ecology
Plant Ecology
-
Abreviatura: Plant Ecol.
- Qualis
CAPES: A2 (Biodiversidade), B2 (Ciências Biológicas I).
- Taxa
de Publicação: Nenhuma.
-
Idiomas: Inglês.
-
Disponibilidade: Restrito. A maioria dos artigos é de acesso
restrito e pago.
- Submissão:
Online, pelo sistema Editorial Manager, com acesso na home page.
Plant
Ecology publica artigos científicos originais que reportam e
interpretam os achados de pesquisas puras e aplicadas na ecologia de plantas
vasculares nos ecossistemas terrestres e pântanos. Artigos empíricos,
experimentais, teóricos e de revisão reportando ecologia ecofisiologia,
população, comunidade, ecossistema, paisagem, molecular e histórica estão no
escopo do periódico.
O periódico publica Artigos de Pesquisa (Research Papers) e Cartas de Pesquisa (Research Letters), revisões e fascículos
especiais por submissão e por convite. Longas monografias podem ser aceitas
pelo Editor-Chefe se um caso é feito pelos autores em relação a trabalhos de
alta qualidade. Comunicações de Pesquisa (Research
Communications) podem reportar sobre qualquer área no escopo do periódico,
mas são particularmente procurados em relação a questões tópicas em ecologia
vegetal, especialmente no que concerne à teoria e metodologia. O periódico não
publica revisões de livros.
Embora Plant
Ecology seja um periódico de ecologia vegetal, ele também aceita artigos de
interação animal-planta, e por isso algumas vezes pode ser procurado por
mastozoólogos.
sábado, 4 de abril de 2015
Niche separation between the maned wolf (Chrysocyon brachyurus), the crab-eating fox (Dusicyon thous) and the hoary fox (Dusicyon vetulus) in central Brazil
JÁCOMO, A.T.A.; SILVEIRA, L.; DINIZ-FILHO, J.A.F. 2004. Niche separation between the maned wolf (Chrysocyon brachyurus), the crab-eating fox (Dusicyon thous) and the hoary fox (Dusicyon vetulus) in central Brazil. Journal of Zoology, London 262:99-106. DOI:10.1017/S0952836903004473
Abstract. Four species of canids occur in the Cerrado of central Brazil. Three of them, the maned wolf Chrysocyon brachyurus, the crab-eating fox Dusicyon thous and the hoary fox Dusicyon vetulus, were studied in Emas National Park between 1996 and 1999 to investigate niche separation. The diet of the three species was studied to understand niche breadth and degree of overlap. Habitat and activity patterns were used as second and third ecological parameters to define niche dimensions, and were estimated using camera-trap data. The maned wolf is the largest species, weighing c. 21 kg, and is about three times larger than the crab-eating fox and six times larger than the hoary fox. The major ecological differences between the three species were found in their food niche and habitat use, where crab-eating fox presented higher differences from the hoary fox (Pianka’s index of niche overlap (O) = 0.405). Despite differences in niche breadth, habitat use between the hoary fox and the maned wolf were more similar, explaining their larger overlap, in comparison with habitat use by the crab-eating fox. Activity patterns among the species showed less divergence. The three species presented two activity peaks, one in the dusk–night period and another in the morning period. These data permit a better understanding of the ecological separation of the three Cerrado canids that enables their coexistence.
Abstract. Four species of canids occur in the Cerrado of central Brazil. Three of them, the maned wolf Chrysocyon brachyurus, the crab-eating fox Dusicyon thous and the hoary fox Dusicyon vetulus, were studied in Emas National Park between 1996 and 1999 to investigate niche separation. The diet of the three species was studied to understand niche breadth and degree of overlap. Habitat and activity patterns were used as second and third ecological parameters to define niche dimensions, and were estimated using camera-trap data. The maned wolf is the largest species, weighing c. 21 kg, and is about three times larger than the crab-eating fox and six times larger than the hoary fox. The major ecological differences between the three species were found in their food niche and habitat use, where crab-eating fox presented higher differences from the hoary fox (Pianka’s index of niche overlap (O) = 0.405). Despite differences in niche breadth, habitat use between the hoary fox and the maned wolf were more similar, explaining their larger overlap, in comparison with habitat use by the crab-eating fox. Activity patterns among the species showed less divergence. The three species presented two activity peaks, one in the dusk–night period and another in the morning period. These data permit a better understanding of the ecological separation of the three Cerrado canids that enables their coexistence.
sábado, 7 de fevereiro de 2015
An opportunity for testing multiple paternity in a wild Jaguar (Panthera onca)
PINHO, G.M.; FONSECA, R.; FARIAS, I.P. 2014. An opportunity for testing multiple paternity in a wild Jaguar (Panthera onca). Biota Neotropica 14(3):1-5.
Abstract. We performed a paternity test for three cubs from one wild female jaguar (Panthera onca). The opportunity for this study was generated by an accident involving a vehicle collision with a pregnant jaguar in the central Amazon. The cubs are polyzygotic triplets and were found to have been sired by the same male. Here, we also provide an overview and discuss several aspects of jaguar reproduction.
Abstract. We performed a paternity test for three cubs from one wild female jaguar (Panthera onca). The opportunity for this study was generated by an accident involving a vehicle collision with a pregnant jaguar in the central Amazon. The cubs are polyzygotic triplets and were found to have been sired by the same male. Here, we also provide an overview and discuss several aspects of jaguar reproduction.
sábado, 17 de janeiro de 2015
Echinococcus vogelu Rausch and Bernstein, 1972, from the paca, Cuniculus paca L. (Rodentia: Dasyproctidae), in the Departamento de Santa Cruz, Bolivia
GARDNER, S.L.; RAUSCH, R.L.; CAMACHO, O.C.J. 1988. Echinococcus vogelu Rausch and Bernstein, 1972, from the paca, Cuniculus paca L. (Rodentia: Dasyproctidae), in the Departamento de Santa Cruz, Bolivia. Journal of Parasitology 74 (3):399-402.
Abstract. Among approximately 2,000 mammals examined for helminths in various regions of Bolivia during 1983-1987, cysts of Echinococcus vogeli Rausch and Bernstein, 1972, were found in a single paca, Cuniculus paca L., collected at La Laguna, Departamento de Santa Cruz (lat. 16'36''W; long. 62'42''S). This record, the first from Bolivia, represents a considerable extension of the known geographic range of this species in South America. Upon analysis of the morphologic characteristics of the protoscoleces derived from the cysts, the sizes of rostellar hooks from the material from the paca were found to be well within the ranges reported in previous studies. Statistical analysis of frequency distributions of hook characteristics revealed some deviations from normality. These results indicate that parametric statistics should be applied with caution in analyses of interand intraspecific variation of morphologic characteristics of hooks of metacestodes of the genus Echinococcus.
Abstract. Among approximately 2,000 mammals examined for helminths in various regions of Bolivia during 1983-1987, cysts of Echinococcus vogeli Rausch and Bernstein, 1972, were found in a single paca, Cuniculus paca L., collected at La Laguna, Departamento de Santa Cruz (lat. 16'36''W; long. 62'42''S). This record, the first from Bolivia, represents a considerable extension of the known geographic range of this species in South America. Upon analysis of the morphologic characteristics of the protoscoleces derived from the cysts, the sizes of rostellar hooks from the material from the paca were found to be well within the ranges reported in previous studies. Statistical analysis of frequency distributions of hook characteristics revealed some deviations from normality. These results indicate that parametric statistics should be applied with caution in analyses of interand intraspecific variation of morphologic characteristics of hooks of metacestodes of the genus Echinococcus.
sábado, 10 de janeiro de 2015
Niche partitioning among white-lipped peccaries (Tayassu pecari), collared peccaries (Pecari tajacu), and feral pigs (Sus scrofa)
DESBIEZ, A.L.J.; SANTOS, S.A.; KEUROGHLIAN, A.; BODMER, R.E. 2009. Niche partitioning among white-lipped peccaries (Tayassu pecari), collared peccaries (Pecari tajacu), and feral pigs (Sus scrofa). Journal of Mammlogy 90(1):119-128.
Abstract. The introduction of a species into an ecosystem with species already occupying a similar trophic level is predicted to lead to a high degree of niche overlap. The feral pig (Sus scrofa), one of the world’s worst invasive species, was introduced to the Pantanal about 200 years ago and is thought to compete with the native whitelipped peccary (Tayassu pecari) and collared peccary (Pecari tajacu). Resource partitioning between the 3 species was examined, including analysis of fruit items and plants in fecal samples as well as encounter rates in different habitats, to help generate hypotheses about competitive interactions among the species. Overlaps in food resources and habitat use between feral pigs and peccaries were found to be lower than expected. In fact, niche overlap as highest between the native species. Results indicate that currently, feral pigs are not a direct threat to the native peccaries in the study area. Differences in morphology and behavior indicate possible mechanisms of niche partitioning between the species. Feral pigs may, nevertheless, impact the wildlife community in other ways as predators of eggs, by destruction of vegetation through rooting, or by functioning as disease reservoirs. Cattle-ranching activities may favor feral pigs and the current anthropogenic changes in the landscape could lead to changes in competitive dynamics between feral pigs and native species.
Abstract. The introduction of a species into an ecosystem with species already occupying a similar trophic level is predicted to lead to a high degree of niche overlap. The feral pig (Sus scrofa), one of the world’s worst invasive species, was introduced to the Pantanal about 200 years ago and is thought to compete with the native whitelipped peccary (Tayassu pecari) and collared peccary (Pecari tajacu). Resource partitioning between the 3 species was examined, including analysis of fruit items and plants in fecal samples as well as encounter rates in different habitats, to help generate hypotheses about competitive interactions among the species. Overlaps in food resources and habitat use between feral pigs and peccaries were found to be lower than expected. In fact, niche overlap as highest between the native species. Results indicate that currently, feral pigs are not a direct threat to the native peccaries in the study area. Differences in morphology and behavior indicate possible mechanisms of niche partitioning between the species. Feral pigs may, nevertheless, impact the wildlife community in other ways as predators of eggs, by destruction of vegetation through rooting, or by functioning as disease reservoirs. Cattle-ranching activities may favor feral pigs and the current anthropogenic changes in the landscape could lead to changes in competitive dynamics between feral pigs and native species.
sábado, 20 de dezembro de 2014
Coexistence of jaguar (Panthera onca) and puma (Puma concolor) in a mosaic landscape in the Venezuelan llanos
SCOGNAMILLO, D.; MAXIT, I.E.; SUNQUIST, M.; POLISAR, J. 2003. Coexistence of jaguar (Panthera onca) and puma (Puma concolor) in a mosaic landscape in the Venezuelan llanos. Journal of Zoology, London 259:269-279.
Abstract. Jaguar Panthera onca and puma Puma concolor are sympatric throughout the jaguar’s distribution. Although several studies have focused on the interactions between these two predators, the ecological and behavioural factors that promote their coexistence remain unclear. The goal of this study was to identify those factors that facilitate the coexistence of these cats in a mosaic landscape in the Venezuelan llanos. The study was conducted from January 1996 until November 1998. Five jaguars and six pumas were captured and radio-collared. A high degree of spatial overlap was observed between jaguars and pumas, which may be related to the abundance and distribution of prey species. At a fine scale, there was little overlap of puma locations with jaguar locations. Both species were more active at night than during daytime, but seasonal differences were detected in the activity levels of these predators. Major segregation was found in food habits. Jaguars selected for large prey and pumas for medium-sized prey. Jaguars selected for capybara Hydrochaeris hydrochaeris and collared peccary Tayassu tajacu and consumed caiman Caiman crocodilus and white-tailed deer Odocoileus virginianus less than expected. Pumas selected just for collared peccary and also killed caiman less than expected. It is suggested that the abundance of medium-sized prey is an ecological factor that is facilitating the coexistence of jaguar and puma in the study area. Habitat heterogeneity may be another influential factor leading to the coexistence. Seasonal differences in activity levels probably reflect differences in the size and species of prey taken by these cats.
Abstract. Jaguar Panthera onca and puma Puma concolor are sympatric throughout the jaguar’s distribution. Although several studies have focused on the interactions between these two predators, the ecological and behavioural factors that promote their coexistence remain unclear. The goal of this study was to identify those factors that facilitate the coexistence of these cats in a mosaic landscape in the Venezuelan llanos. The study was conducted from January 1996 until November 1998. Five jaguars and six pumas were captured and radio-collared. A high degree of spatial overlap was observed between jaguars and pumas, which may be related to the abundance and distribution of prey species. At a fine scale, there was little overlap of puma locations with jaguar locations. Both species were more active at night than during daytime, but seasonal differences were detected in the activity levels of these predators. Major segregation was found in food habits. Jaguars selected for large prey and pumas for medium-sized prey. Jaguars selected for capybara Hydrochaeris hydrochaeris and collared peccary Tayassu tajacu and consumed caiman Caiman crocodilus and white-tailed deer Odocoileus virginianus less than expected. Pumas selected just for collared peccary and also killed caiman less than expected. It is suggested that the abundance of medium-sized prey is an ecological factor that is facilitating the coexistence of jaguar and puma in the study area. Habitat heterogeneity may be another influential factor leading to the coexistence. Seasonal differences in activity levels probably reflect differences in the size and species of prey taken by these cats.
sábado, 11 de outubro de 2014
Diet of two sympatric carnivores, Cerdocyon thous and Procyon cancrivorus, in a restinga area of Espirito Santo State, Brazil
GATTI, A.; BIANCHI, R.; ROSA, C.R.X.; MENDES, S.L. 2006. Diet of two sympatric carnivores, Cerdocyon thous and Procyon cancrivorus, in a restinga area of Espirito Santo State, Brazil. Journal of Tropical Ecology 22:227-230.
Abstract. The description of resource sharing between sympatric species can be used to determine the factors that allow species to coexist. The feeding habits of the crab-eating fox and of the raccoon were determined on the basis of scats collected. The importance of each prey type was analysed based on the frequency of its occurrence in the scats. The data suggest that the crab-eating fox and the raccoon have basically frugivorous diets, complemented by arthropods, mainly insects, and small vertebrates.
Abstract. The description of resource sharing between sympatric species can be used to determine the factors that allow species to coexist. The feeding habits of the crab-eating fox and of the raccoon were determined on the basis of scats collected. The importance of each prey type was analysed based on the frequency of its occurrence in the scats. The data suggest that the crab-eating fox and the raccoon have basically frugivorous diets, complemented by arthropods, mainly insects, and small vertebrates.
sábado, 6 de setembro de 2014
Small mammals in the diet of Barn owls, Tyto alba (Aves: Strigiformes) along the mid-Araguaia River in central Brazil
ROCHA, R.G.; FERREIRA, E.; LEITE, Y.L.R.; FONSECA, C.; COSTA, L.P. 2011. Small mammals in the diet of Barn owls, Tyto alba (Aves: Strigiformes) along the mid-Araguaia River in central Brazil. Zoologia 282(6):709-716. doi: 10.1590/S1984-46702011000600003
Abstract. We collected and analyzed 286 Barn owl, Tyto alba (Scopoli, 1769), pellets from two nests in different environments along the mid-Araguaia River in central Brazil. Our analyses revealed that these owls feed mainly on small mammals, especially rodents. Owls from the riverbanks at Fazenda Santa Fé had a more diverse diet, preying mainly on rodents that typically inhabit riparian grasslands – Holochilus sciureus Wagner, 1842 – and forests – Hylaeamys megacephalus (Fischer, 1814) and Oecomys spp., which probably also occur in forest borders or clearings. On the other hand, owls from an agroecosystem at Fazenda Lago Verde preyed mostly on rodent species common in these agrarian fields, Calomys tocantinsi Bonvicino, Lima & Almeida, 2003. Additionally, we compared small mammal richness estimates based on the analysis of owl pellets with estimates from live-trapping in the same areas. Owl pellets revealed two rodent species undetected by live traps – Euryoryzomys sp. and Rattus rattus (Linnaeus, 1758) – and four rodent species were trapped, but not found in owl pellets – Oecomys roberti Thomas, 1904, Pseudoryzomys simplex (Winge, 1887), Rhipidomys ipukensis Rocha, B.M.A. Costa & L.P. Costa, 2011, and Makalata didelphoides (Desmarest, 1817). Traps yielded higher species richness, but these two methods complement each other for surveying small rodents
Abstract. We collected and analyzed 286 Barn owl, Tyto alba (Scopoli, 1769), pellets from two nests in different environments along the mid-Araguaia River in central Brazil. Our analyses revealed that these owls feed mainly on small mammals, especially rodents. Owls from the riverbanks at Fazenda Santa Fé had a more diverse diet, preying mainly on rodents that typically inhabit riparian grasslands – Holochilus sciureus Wagner, 1842 – and forests – Hylaeamys megacephalus (Fischer, 1814) and Oecomys spp., which probably also occur in forest borders or clearings. On the other hand, owls from an agroecosystem at Fazenda Lago Verde preyed mostly on rodent species common in these agrarian fields, Calomys tocantinsi Bonvicino, Lima & Almeida, 2003. Additionally, we compared small mammal richness estimates based on the analysis of owl pellets with estimates from live-trapping in the same areas. Owl pellets revealed two rodent species undetected by live traps – Euryoryzomys sp. and Rattus rattus (Linnaeus, 1758) – and four rodent species were trapped, but not found in owl pellets – Oecomys roberti Thomas, 1904, Pseudoryzomys simplex (Winge, 1887), Rhipidomys ipukensis Rocha, B.M.A. Costa & L.P. Costa, 2011, and Makalata didelphoides (Desmarest, 1817). Traps yielded higher species richness, but these two methods complement each other for surveying small rodents
sábado, 2 de agosto de 2014
Morphometric variations of laelapine mite (Acari: Mesostigmata) populations infesting small mammals (Mammalia) in Brazil
MARTINS-HATANO, F.; GETTINGER, D.; MANHÃES, M.L.; BERGALLO, H.G. 2012. Morphometric variations of laelapine mite (Acari: Mesostigmata) populations infesting small mammals (Mammalia) in Brazil. Brazilian Journal of Biology 72(3):595-603.
Abstract. The goal of this study was to evaluate the morphometric variation of laelapine populations (Acari, Mesostigmata) associated with neotropical oryzomyine rodents at different geographic localities in Brazil. Three nominal mite species were selected for study, all infesting the pelage of small mammals at different localities in Rio de Janeiro, Espírito Santo, Bahia, and the Federal District, Brazil. To analyse morphometric characteristics, thirty-seven morphological characters distributed across the whole body of each specimen were measured. We use the Analysis of Principal Components, extracting the three first axes and projecting each mite in these axes. Major species level changes in the taxonomy of the host mammals allows an independent examination of morphometric variation of mites infesting a set of distinctly different host species at different geographic localities. Gigantolaelaps vitzthumi and Laelaps differens are associated with oryzomyine rodents of the genus Cerradomys, and consistently showed a tendency to cluster by host phylogeny. Laelaps manguinhosi associated with Nectomys rattus in central Brazil is morphometrically distinct from mites infesting N. squamipes in the coastal restingas of Rio de Janeiro and Espírito Santo. The results obtained here indicate that laelapine mite populations can vary among geographic areas and among phylogenetically related host species. Clearly, the study of these mites at the population level can be an important tool for clarifying the taxonomy of both mites and hosts.
Abstract. The goal of this study was to evaluate the morphometric variation of laelapine populations (Acari, Mesostigmata) associated with neotropical oryzomyine rodents at different geographic localities in Brazil. Three nominal mite species were selected for study, all infesting the pelage of small mammals at different localities in Rio de Janeiro, Espírito Santo, Bahia, and the Federal District, Brazil. To analyse morphometric characteristics, thirty-seven morphological characters distributed across the whole body of each specimen were measured. We use the Analysis of Principal Components, extracting the three first axes and projecting each mite in these axes. Major species level changes in the taxonomy of the host mammals allows an independent examination of morphometric variation of mites infesting a set of distinctly different host species at different geographic localities. Gigantolaelaps vitzthumi and Laelaps differens are associated with oryzomyine rodents of the genus Cerradomys, and consistently showed a tendency to cluster by host phylogeny. Laelaps manguinhosi associated with Nectomys rattus in central Brazil is morphometrically distinct from mites infesting N. squamipes in the coastal restingas of Rio de Janeiro and Espírito Santo. The results obtained here indicate that laelapine mite populations can vary among geographic areas and among phylogenetically related host species. Clearly, the study of these mites at the population level can be an important tool for clarifying the taxonomy of both mites and hosts.
sábado, 3 de maio de 2014
Interactions between Atlantic spotted (Stenella frontalis) and bottlenose (Tursiops truncatus) dolphins off Bimini, The Bahamas, 2003-2007
MELILLO, K.E.; DUDZINSKI, K.M.; CORNICK, L.A. 2009. Interactions between Atlantic spotted (Stenella frontalis) and bottlenose (Tursiops truncatus) dolphins off Bimini, The Bahamas, 2003-2007. Aquatic Mammals 35(2):281-291. DOI: 10.1578/AM.35.2.2009.281
Abstract. Interspecific interactions have been observed in a variety of social animal. Functional explanations include foraging, anti-predatory, and social advantages. These behaviours are poorly understood in marine mammals but are increasingly studied phenomena in sympatric populations. Resident Atlantic spotted dolphins (Stenella frontalis) off Bimini, The Bahamas, have been the subject of ongoing photo-identification and behavioural studies since 2001. A lesser-known population of bottlenose dolphins (Tursiops truncatus) has been observed interacting with these S. frontalis since 2003. To examine the functional significance of these interactions, interspecific behaviours were documented with underwater video using focal animal sampling. Mating or sexual play were the primary activities observed in nearly 50% of interactions, with male T. truncatus as the initiators. Therefore, the most likely functional explanation for these interactions is social. We hypothesize that male T. truncatus which lack acess to T. truncatus females because of sexual immaturity or low social status seek copulations with S. frontalis females as an alternative.
Abstract. Interspecific interactions have been observed in a variety of social animal. Functional explanations include foraging, anti-predatory, and social advantages. These behaviours are poorly understood in marine mammals but are increasingly studied phenomena in sympatric populations. Resident Atlantic spotted dolphins (Stenella frontalis) off Bimini, The Bahamas, have been the subject of ongoing photo-identification and behavioural studies since 2001. A lesser-known population of bottlenose dolphins (Tursiops truncatus) has been observed interacting with these S. frontalis since 2003. To examine the functional significance of these interactions, interspecific behaviours were documented with underwater video using focal animal sampling. Mating or sexual play were the primary activities observed in nearly 50% of interactions, with male T. truncatus as the initiators. Therefore, the most likely functional explanation for these interactions is social. We hypothesize that male T. truncatus which lack acess to T. truncatus females because of sexual immaturity or low social status seek copulations with S. frontalis females as an alternative.
sábado, 26 de abril de 2014
Artibeus lituratus (Chiroptera, Phyllostomidae): biologia e dispersão de sementes no Parque do Museu de Biologia Prof. Mello Leitão, Santa Teresa (ES)
PASSOS, J.G.; PASSAMANI, M. 2003. Artibeus lituratus (Chiroptera, Phyllostomidae): biologia e dispersão de sementes no Parque do Museu de Biologia Prof. Mello Leitão, Santa Teresa (ES). Natureza on line 1(1):1-6.
Abstract. Artibeus lituratus (Chiroptera, Phyllostomidae): biology and seed dispersion in the park of Museu de Biologia Prof. Mello leitão, Santa Teresa, ES. Aspects of biology and seed dispersion by Artibeus lituradus were studied in the Museu de Biologia Prof. Mello Leitão (MBML) from August 2000 to March 2002. Pregnant females were collected from October to February. Fruits were the main food consumed, including native and exotic species. Fruits of Cecropiaceae were largely dispersed by A. lituratus. There was no significant difference in the forearm size between sexes, neither correlation between forearm size and number of seeds dispersed.
Abstract. Artibeus lituratus (Chiroptera, Phyllostomidae): biology and seed dispersion in the park of Museu de Biologia Prof. Mello leitão, Santa Teresa, ES. Aspects of biology and seed dispersion by Artibeus lituradus were studied in the Museu de Biologia Prof. Mello Leitão (MBML) from August 2000 to March 2002. Pregnant females were collected from October to February. Fruits were the main food consumed, including native and exotic species. Fruits of Cecropiaceae were largely dispersed by A. lituratus. There was no significant difference in the forearm size between sexes, neither correlation between forearm size and number of seeds dispersed.
sábado, 12 de abril de 2014
Ocelot (Leopardus pardalis) predation on primates in Caatinga Biological Station, southeast Brazil
BIANCHI, R.C.; MENDES, S.L. 2007. Ocelot (Leopardus pardalis) predation on primates in Caatinga Biological Station, southeast Brazil. American Journal Primatology 69:1173-1178. doi: 10.1002/ajp.20415
This study demonstrates that ocelots (Leopardus pardalis) extensively use primates as a food resource at the Caratinga Biological Station (CBS) in Southeast Brazil. Analysis of 60 fecal samples collected over 4 years revealed predation upon the brown howler monkey (Alouatta guariba), the muriqui (Brachyteles hypoxanthus), and the brown capuchin monkey (Cebus apella). The most frequent items found in the fecal samples analyzed were Calomys (n= 16) and non-identified Aves (n=15), followed by A. guariba (n=12). Although Rodentia was the most common group consumed (n=52) Primates were found in 27% of total fecal samples and were the third most consumed group in relation to the total items. Particularly, predation of A. guariba by ocelots (20% of the total fecal samples) was not an isolated event; our results showed that this species was preyed on across several months. Predation on primates was far higher at CBS than at other sites where comparable studies have been carried out.
This study demonstrates that ocelots (Leopardus pardalis) extensively use primates as a food resource at the Caratinga Biological Station (CBS) in Southeast Brazil. Analysis of 60 fecal samples collected over 4 years revealed predation upon the brown howler monkey (Alouatta guariba), the muriqui (Brachyteles hypoxanthus), and the brown capuchin monkey (Cebus apella). The most frequent items found in the fecal samples analyzed were Calomys (n= 16) and non-identified Aves (n=15), followed by A. guariba (n=12). Although Rodentia was the most common group consumed (n=52) Primates were found in 27% of total fecal samples and were the third most consumed group in relation to the total items. Particularly, predation of A. guariba by ocelots (20% of the total fecal samples) was not an isolated event; our results showed that this species was preyed on across several months. Predation on primates was far higher at CBS than at other sites where comparable studies have been carried out.
sábado, 8 de fevereiro de 2014
An analysis and review of models of the sociobiology of the Mustelidae
JOHNSON, D.D.P.; MACDONALD, D.W.; DICKMAN, A.J. 2000. An analysis and review of models of the sociobiology of the Mustelidae. Mammal Review 30(3-4):171-196.
Abstract. Classical models of social organization in mustelids suggest that female ranging patterns are determined by the dispersion of resources, whereas those of males are determined by the dispersion of females. However, mating systems and social spacing patterns vary widely both between and withing species. For example, European Badgers exhibit a continuum from the classical mustelid model of intra-sexual territoriality and inter-sexual overlap to very large, mixed-sex, promiscuous groups. We evaluated hypotheses and existing data to explain this variation, using comparative analyses and Principal Components Analysis of life history and ecological variables. In addition, we applied a null model of allometric scaling to test for associations between group mass and residual home range size. We found that: (1) the degree of social behaviour and breeding group size increased with life history variables indicative of K-selected strategies of parental investment. (2) Absolute home range size and residual home range size (derived from allometric home range scalling) decreased, paradoxically, with breeding group size and group mass, respectively. These results provide support for ecological theories of social grouping in general and, in particular, for the importance of dispersed resource-rich patches as developed in the Resource Dispersion Hypothesis.
Abstract. Classical models of social organization in mustelids suggest that female ranging patterns are determined by the dispersion of resources, whereas those of males are determined by the dispersion of females. However, mating systems and social spacing patterns vary widely both between and withing species. For example, European Badgers exhibit a continuum from the classical mustelid model of intra-sexual territoriality and inter-sexual overlap to very large, mixed-sex, promiscuous groups. We evaluated hypotheses and existing data to explain this variation, using comparative analyses and Principal Components Analysis of life history and ecological variables. In addition, we applied a null model of allometric scaling to test for associations between group mass and residual home range size. We found that: (1) the degree of social behaviour and breeding group size increased with life history variables indicative of K-selected strategies of parental investment. (2) Absolute home range size and residual home range size (derived from allometric home range scalling) decreased, paradoxically, with breeding group size and group mass, respectively. These results provide support for ecological theories of social grouping in general and, in particular, for the importance of dispersed resource-rich patches as developed in the Resource Dispersion Hypothesis.
sábado, 4 de janeiro de 2014
Seasonal variation of consumption of the species used as fruit source by brown howler monkeys (Alouatta clamitans) in southern Brazil
SANTOS, G.A.S.D.; BIANCHINI, E.; REIS, N.R. 2013. Seasonal variation of consumption of the species used as fruit source by brown howler monkeys (Alouatta clamitans) in southern Brazil. Biota Neotropica 13(3):148-153.
Abstract. Considering the seasonal variation of fruits availability in seasonal semideciduous forests, this study analyzed whether the richness of fruit species exploited by Alouatta clamitans is higher in the rainy period rather than the dry one. Plant species consumed were investigated by visualization and feces analysis, from July 2005 to June 2006, in a seasonal semideciduous forest fragment in Paraná state, Brazil. Ten species of fruits were consumed during the rainy period and 13 during the dry period: three were consumed exclusively during the rainy period; six exclusively during the dry period; and seven in months that covered both dry and rainy periods. The number of fruit species consumed during the rainy period was considerably lower than the expected richness. Moreover, among fruit species consumed during the rainy period, only four bear fruits mainly in this period of the year, the other species bear fruits in great part of it. Therefore, the selectivity of A. clamitans was mainly directed to species capable of providing fruits along the year, prioritizing these species even when other fruit sources are available.
Abstract. Considering the seasonal variation of fruits availability in seasonal semideciduous forests, this study analyzed whether the richness of fruit species exploited by Alouatta clamitans is higher in the rainy period rather than the dry one. Plant species consumed were investigated by visualization and feces analysis, from July 2005 to June 2006, in a seasonal semideciduous forest fragment in Paraná state, Brazil. Ten species of fruits were consumed during the rainy period and 13 during the dry period: three were consumed exclusively during the rainy period; six exclusively during the dry period; and seven in months that covered both dry and rainy periods. The number of fruit species consumed during the rainy period was considerably lower than the expected richness. Moreover, among fruit species consumed during the rainy period, only four bear fruits mainly in this period of the year, the other species bear fruits in great part of it. Therefore, the selectivity of A. clamitans was mainly directed to species capable of providing fruits along the year, prioritizing these species even when other fruit sources are available.
Assinar:
Postagens (Atom)