RESUMO
The lowland Atlantic Forest, at altitudes of below 500 m, is highly fragmented, and is home to many threatened species of birds. The Brazilian state of Rio de Janeiro has a high concentration of threatened birds in the Americas and is an important residual of the dense ombrophilous formations of the Atlantic Forest, which includes the Reserva Biológica União, a high priority area for conservation of Atlantic Forest birds. This study compiled empirical and secondary records of threatened birds in this reserve and discusses potential factors determining their local occurrence. Since 2008, regular observations, including transect surveys and mist-netting, in addiction to secondary data, have provided records of 306 bird species, of which 49 appear on red lists at some level (state, national or global), including 34 listed as endangered, of which 13 are listed globally, eight of them dependent on well-conserved lowland rainforest. Future studies should include new areas of the reserve, with the aim of confirming the presence of additional threatened species. The long-term conservation of this fauna will depend not only on the adequate management of the reserve, but also the reestablishment of its connectivity with adjacent forest fragments and upland areas in the state.
Assuntos
Aves , Conservação dos Recursos Naturais , Espécies em Perigo de Extinção , Florestas , Animais , Brasil , Aves/classificação , Aves/fisiologia , Densidade Demográfica , BiodiversidadeRESUMO
The general assumption that the survival patterns of tropical and southern temperate birds are similar lacks empirical data from higher latitudes. Regional comparisons of New World species are rare, and this assumption has been based on data from African studies. Here, we estimate the survival rates of 88 tropical and southern temperate bird populations (69 species) from eight localities in South America to evaluate the hypothesis that the survival of these populations is homogeneous at the regional scale. We estimated survival based on the Cormack-Jolly-Seber model and compared values from different environments. The survival estimates ranged from 0.30 to 0.80 (0.56 ± 0.12). Apparent survival did not differ significantly between low-latitude tropical environments (03°S) and the other sites from high-latitudes (between 22° and 34°S). Despite a predicted positive trend, body size was not significantly related to survival among passerines. On the other hand, phylogenetic relationships explained more than a third of the variation in bird survival. Based on the largest available database on South American bird species, our findings support the hypothesis that bird survival is homogeneous, at the regional scale, along the southern hemisphere. In particular, we reinforce the hypothesis that climatic variation has a limited influence on bird survival in the southern hemisphere.
Assuntos
Clima Tropical , Filogenia , América do Sul , Tamanho CorporalRESUMO
Ticks (Ixodida) are ecologically important ectoparasites that may impact human health and economic activities. Parasitoid wasps are natural enemies of ticks and a potential option for its biological control. In the present study, we recorded parasitism of the nymphs of the tick Amblyomma nodosum by the parasitoid wasp Ixodiphagus hookeri. The ticks, in turn, were parasitizing white-bearded manakins, Manacus manacus (Passeriformes: Pipridae) in the União Biological Reserve, one of the last major remnants of lowland rainforest in Rio de Janeiro state, southeastern Brazil. During the collection of ectoparasites from two manakins in this reserve, 20-30 parasitoid wasps hatched spontaneously from two of the ticks collected. The species of the tick nymphs and adult wasps were identified using morphological traits and molecular analyses. This record is the first documented case of I. hookeri parasitizing A. nodosum and the first time that parasitoid wasps have been found in ticks parasitizing birds in Brazil. This is also the first record of Ixodiphagus from southeastern Brazil in more than a century, with the only other record dating back to 1914. The record presented here provides valuable new information on the biology of this tick and its parasitoids, and new insights into this interspecific interaction. Further research on these vertebrate-tick-wasp interactions will be necessary to better understand the respective roles of the organisms involved in these processes.
Assuntos
Ixodidae , Passeriformes , Infestações por Carrapato , Carrapatos , Vespas , Animais , Humanos , Amblyomma , Brasil , Ninfa/parasitologia , Infestações por Carrapato/veterináriaRESUMO
The common bottlenose dolphin, Tursiops truncatus, is widely distributed. However, information about its ecology and behavior in Brazilian waters is scarce especially about the 'offshore' ecotype, an Evolutionarily Significant Unit in the Southwest Atlantic. We report for the first time the occurrence, behavior and habitat use of bottlenose dolphins Tursiops truncatus truncatus, in two Marine Protected Areas (MPA) in Cabo Frio coast, Brazil. There were fifteen sightings of different groups throughout the year. An overall of 429 individuals were photo-identified. 90.7% dolphins did not present a degree of residence, 1.4% dolphins were considered with high residency to the area, 5.8% medium and 2.1% low. Our habitat use map indicated dolphins were more common off ~10km from Cabo Frio municipality and between depths around 20-70m. Bottlenose dolphins on Cabo Frio coast were more frequently observed performing travelling, followed by foraging and socio-sexual behavior. Group sizes varied from three to 120 individuals. Larger groups were observed when travelling and foraging. Despite the existence of two local Marine Protected Areas, the fast human development in Cabo Frio may threaten this important area for bottlenose dolphins in terms of food resources and shelter from predators.
Assuntos
Golfinho Nariz-de-Garrafa , Migração Animal , Animais , Brasil , EcossistemaRESUMO
Hummingbirds are the most important and specialized group of pollinating birds in the Neotropics and their interactions with plants are key components to many communities. In the present study we identified the assemblage of plants visited by hummingbirds and investigated the temporal availability of floral resources in an area of restinga, sandy plain coastal vegetation associated with the Atlantic forest, in Southeastern Brazil. We recorded flower and nectar features, flowering phenology and interactions between plants and hummingbirds and estimated the amount of calories produced per hectare from June 2005 to August 2006. Ten plant species were visited by two hummingbirds, Amazilia fimbriata and Eupetomena macroura. Resource availability was highly variable among plant species and over time. Nectar volume and concentration per flower were similar to other Neotropical hummingbird-visited plant assemblages. The estimated nectar resource availability between months varied from 0.85 to 5.97 Kcal per hectare/day, demanding an area between one and 6.8 ha to support a single hummingbird. Our study reports an unusual tropical setting where almost all interactions between hummingbirds and plants were performed by a single hummingbird species, A. fimbriata. Hence, the variable nectar availability is probably influencing hummingbird movements, its foraging area, and consequently plant pollination.
Assuntos
Aves/classificação , Aves/fisiologia , Comportamento Alimentar/fisiologia , Flores/classificação , Néctar de Plantas/classificação , Animais , Brasil , Estações do AnoRESUMO
The purpose of this study was to investigate the reproductive phenology and sharing of floral resource (nectar) of Dahlstedtia pinnata (Benth.) Malme. (Fabaceae), endemic of Atlantic forest, among hummingbirds. For the phenology, we looked at the presence of reproductive structures in the plants, and for floral resource sharing, the frequency of potential pollinators and foraging behaviors were examined. This study was conducted in Pedra Branca State Park, in state of Rio de Janeiro, in a dense ombrophilous forest, between August 2010 and August 2011. Flowering occurred between December 2010 and March 2011, and fruiting between April and June 2011. Hummingbirds' foraging schedules differed significantly, with legitimate visits to the flowers occurring in the morning and illegitimate visits occurring during late morning and the afternoon. Five species visited flowers, three of which were legitimate visitors: Phaethornis ruber, P. pretrei, and Ramphodon naevius. Amazilia fimbriata and Thalurania glaucopis females only visited illegitimately. Phaethornis ruber robbed nectar (78% of illegitimate visits, n=337). Ramphodon naevius, with a territorial foraging behavior and a body size bigger than that of other observed hummingbird species, dominated the floral visits, which suggests that D. pinnata is an important nourishing resource for this endemic bird of the Atlantic forest, currently globally categorized as Near Threatened.
Assuntos
Aves/fisiologia , Fabaceae/fisiologia , Comportamento Alimentar/fisiologia , Inflorescência/fisiologia , Polinização/fisiologia , Animais , Fabaceae/classificação , Feminino , Florestas , Estações do AnoRESUMO
We describe the nest, eggs, and nestlings of the Restinga Antwren (Formicivora littoralis), an endangered bird of Restinga ecosystem (sandy coastal plain vegetation) that is endemic to Rio de Janeiro state. Twelve nests were found at the edges of trails or natural gaps at Massambaba Restinga region, in different supporting plants and heights from the ground (X ± SD 1.27 ± 0.97 m, range 0.27 to 3.45 m). Nests were cup-shaped and were in horizontal forks attached to branches at three to five points with whitish, soft, and thin cotton-like vegetable fiber. The nests' cup shape and measurements were similar to congeneric species, but nest material was different. Eggs were white with brown spots concentrated on the large end or around the middle, giving the appearance of a rough brown ring. Their mean (± SD) minimum diameter was 13.1 ± 0.34 mm, with maximum diameter of 18.0 ± 0.38 mm, and mass of 1.7 ± 0.18 g (n = 8). We found two nestlings completely naked on their first day after hatching.
Assuntos
Comportamento de Nidação/fisiologia , Óvulo , Passeriformes/classificação , Passeriformes/fisiologia , Animais , Animais Recém-Nascidos , Espécies em Perigo de ExtinçãoRESUMO
Some types of plant accumulate liquid in their inflorescences creating phytotelmata. These environments protect the flowers against florivory, although they may be colonized by aquatic or semi-aquatic florivorous insect larvae, whose effects on the fitness of the plants remain unclear. We tested the hypothesis of floral antagonism by the occupants of phytotelmata, which predicts that florivory by the occupants of the phytotelmata represents a cost to the female fitness of the plant, reducing its fecundity. We manipulated experimentally the infestation by 3 florivores larvae species occupants of phytotelmata in inflorescences of Heliconia spathocircinata (Heliconiaceae) to test for negative direct trophic effects on the fecundity of the flowering and fruiting bracts. We found that the foraging of the hoverfly (Syrphidae) and moth (Lepidoptera) larvae in the inflorescences contributed to a decline in the fecundity of the plant. While the lepidopteran impacted fecundity when foraging in both flowering and fruiting bracts, the syrphid only affected the fruiting bracts, which indicates that the nectar and floral tissue are the principal resource exploited by the hoverfly. By contrast, soldier fly (Stratiomyidae) had a neutral effect on fecundity, while foraging in flowering or fruiting bracts. These findings corroborate our hypothesis, that herbivory by the larval occupants represents cost to the host plant having phytotelmata. The negative influence of this foraging on plant fecundity will nevertheless depend on the consequences of the exploitation of resources, which vary considerably in ephemeral habitats such as the phytotalmanta of flower parts.
RESUMO
Flowering plant species and their nectar-feeding vertebrates exemplify some of the most remarkable biotic interactions in the Neotropics. In the Brazilian Atlantic Forest, several species of birds (especially hummingbirds), bats, and non-flying mammals, as well as one lizard feed on nectar, often act as pollinators and contribute to seed output of flowering plants. We present a dataset containing information on flowering plants visited by nectar-feeding vertebrates and sampled at 166 localities in the Brazilian Atlantic Forest. This dataset provides information on 1902 unique interactions among 515 species of flowering plants and 129 species of potential vertebrate pollinators and the patterns of species diversity across latitudes. All plant-vertebrate interactions compiled were recorded through direct observations of visits, and no inferences of pollinators based on floral syndromes were included. We also provide information on the most common plant traits used to understand the interactions between flowers and nectar-feeding vertebrates: plant growth form, corolla length, rate of nectar production per hour in bagged flowers, nectar concentration, flower color and shape, time of anthesis, presence or absence of perceptible fragrance by human, and flowering phenology as well as the plant's threat status by International Union for Conservation of Nature (IUCN) classification. For the vertebrates, status of threat by IUCN classification, body mass, bill or rostrum size are provided. Information on the frequency of visits and pollen deposition on the vertebrate's body is provided from the original source when available. The highest number of unique interactions is recorded for birds (1771) followed by bats (110). For plants, Bromeliaceae contains the highest number of unique interactions (606), followed by Fabaceae (242) and Gesneriaceae (104). It is evident that there was geographical bias of the studies throughout the southeast of the Brazilian Atlantic Forest and that most effort was directed to flower-hummingbird interactions. However, it reflects a worldwide tendency of more plants interacting with birds compared with other vertebrate species. The lack of similar protocols among studies to collect basic data limits the comparisons among areas and generalizations. Nevertheless, this dataset represents a notable effort to organize and highlight the importance of vertebrate pollinators in this hotspot of biodiversity on Earth and represents the data currently available. No copyright or proprietary restrictions are associated with the use of this data set. Please cite this data paper when the data are used in publications or scientific events.
Assuntos
Néctar de Plantas , Polinização , Animais , Aves , Flores , Florestas , Humanos , MamíferosRESUMO
Sex determination is important for conservation and population studies, particularly for reproduction programs of threatened species and behavioural ecology. Turdus amaurochalinus, Creamy-bellied Thrush, only exhibits sexual dimorphism during the breeding season, when males are considered to show intense yellow bills, and females and immature males show dark brown bills. The objectives of this study were: 1) to determine the sex of individuals using genetic techniques, and 2) to test the hypothesis that sex dimorphism can be detected by morphometry. This study was carried out at Parque Nacional da Restinga de Jurubatiba, a preserved area located on the North coast of Rio de Janeiro State. The birds were captured using ornithological nets, singly marked with metal rings, weighed, measured and had blood samples collected before being released. The sex of 42 T. amaurochalinus individuals was determined using the CHD gene marker. A total of 20 males and 22 females were identified from June to August, with peak capture frequency in June. Turdus amaurochalinus females and males differed significantly in morphometrical measures. The most important traits to distinguish males from females were wing length (Student t-test = 4.34, df = 40, p = 0.0001) and weight (Student t-test = 2.08, d f = 40, p = 0.044): females were heavier and had significantly shorter wing length than males. Females and males were correctly classified in 86% and 75% of cases, respectively, using Discriminant Analysis. The molecular analysis was the most secure method for sex determination in the studied species.
Assuntos
Proteínas Aviárias/genética , Proteínas de Ligação a DNA/genética , Passeriformes/genética , Análise para Determinação do Sexo/métodos , Animais , Feminino , Marcadores Genéticos/genética , Masculino , Passeriformes/anatomia & histologia , Passeriformes/classificaçãoRESUMO
Scientists have long been trying to understand why the Neotropical region holds the highest diversity of birds on Earth. Recently, there has been increased interest in morphological variation between and within species, and in how climate, topography, and anthropogenic pressures may explain and affect phenotypic variation. Because morphological data are not always available for many species at the local or regional scale, we are limited in our understanding of intra- and interspecies spatial morphological variation. Here, we present the ATLANTIC BIRD TRAITS, a data set that includes measurements of up to 44 morphological traits in 67,197 bird records from 2,790 populations distributed throughout the Atlantic forests of South America. This data set comprises information, compiled over two centuries (1820-2018), for 711 bird species, which represent 80% of all known bird diversity in the Atlantic Forest. Among the most commonly reported traits are sex (n = 65,717), age (n = 63,852), body mass (n = 58,768), flight molt presence (n = 44,941), molt presence (n = 44,847), body molt presence (n = 44,606), tail length (n = 43,005), reproductive stage (n = 42,588), bill length (n = 37,409), body length (n = 28,394), right wing length (n = 21,950), tarsus length (n = 20,342), and wing length (n = 18,071). The most frequently recorded species are Chiroxiphia caudata (n = 1,837), Turdus albicollis (n = 1,658), Trichothraupis melanops (n = 1,468), Turdus leucomelas (n = 1,436), and Basileuterus culicivorus (n = 1,384). The species recorded in the greatest number of sampling localities are Basileuterus culicivorus (n = 243), Trichothraupis melanops (n = 242), Chiroxiphia caudata (n = 210), Platyrinchus mystaceus (n = 208), and Turdus rufiventris (n = 191). ATLANTIC BIRD TRAITS (ABT) is the most comprehensive data set on measurements of bird morphological traits found in a biodiversity hotspot; it provides data for basic and applied research at multiple scales, from individual to community, and from the local to the macroecological perspectives. No copyright or proprietary restrictions are associated with the use of this data set. Please cite this data paper when the data are used in publications or teaching and educational activities.
RESUMO
The Brazilian tanager, Ramphocelus bresilius is an endemic species from Brazil that is sexually dimorphic in adult plumage. Young males are similar to adult and young females until their second year. Adults and young females are not distinguishable in plumage. We tested whether iris colour can be used to separate adult females from immature females. We used for the first time the molecular sexing technique based on CHD-genes to confirm the sex of the individuals classified as "female plumage with red iris", and to identify the sex of individuals classified as "female plumage and brown iris". The adult males were used as a positive control. DNA samples from 190 individuals were analysed. The sizes of the PCR products were identified as 350 base pairs (bp) for CHD-Z and 388 bp for CHD-W. We confirmed that adult females have a red iris and the young females a brown iris. We could also separate young males and females which present the same iris colour and plumage. Although there are indications that the iris colour can be used by birds to identify the adults in co-operative breeding species such as the Brazilian tanager, more behavioural data are required to understand the role of iris coloration in this species.
Assuntos
Iris/anatomia & histologia , Passeriformes/anatomia & histologia , Pigmentação/fisiologia , Fatores Etários , Animais , DNA/análise , Feminino , Masculino , Passeriformes/genética , Passeriformes/crescimento & desenvolvimento , Reação em Cadeia da Polimerase , Caracteres Sexuais , Análise para Determinação do Sexo/métodos , Análise para Determinação do Sexo/veterináriaRESUMO
Restingas are considered stressful habitats associated with the Brazilian Atlantic forest, and their ecological interactions are poorly known. The goal of the present study was to determine the potential role of frugivorous birds as seed dispersers in a restinga habitat. Data were collected in Parque Nacional da Restinga de Jurubatiba, southeastern Brazil, where the main physiognomy (Open Clusia Formation) is characterized by the presence of patches of vegetation covering 20 to 48 % of the sandy soil and reaching a height of 5 m. Birds were captured with mist nets (12 x 2.5 m; 36 mm mesh; 1,680 net-hrs) and had their fecal and regurgitate samples inspected for seeds. Six plant species found in these bird samples were studied. The germination of seeds obtained from plants was compared to those from the birds. Both groups of seeds were set on Petri dishes at room temperature and washed when infected with fungi. In general, there was no effect on germination rate, and the effect on germination speed was negative. Germination of seeds from Pilosocereus arrabidae treated by the birds seemed to be influenced by storage of defecated seeds, while few Miconia cinnamomifolia seeds both from plants and from birds germinated. Ocotea notata presented a great variation in time to the onset of germination, perhaps an advantage against dissecation. Aechmea nudicaulis, Clusia hilariana and Erythroxylum subsessile probably take advantage of the arrival to favorable microhabitats, not by the gut effect on the seeds. All plant species studied are numerically important for the community and some of them are main actors in the succession of vegetation patches. Among the birds, Mimus gilvus is an important resident species, endemic to restingas in Brazil, while Turdus amaurochalinus is a visitor and may be important for plants that fructify during its passage by the study site. Although the effect of pulp removal was only tested for one species (Achmea nudicaulis) in the present study, we confirmed that the tested effect of restinga frugivorous birds on seed germination was generally null. Although there is a need for more detailed studies on specific animal-plant interactions on this habitat, the overall effect of the birds on seed dispersal in restinga is probably positive.
Assuntos
Ecossistema , Comportamento Alimentar/fisiologia , Germinação/fisiologia , Magnoliopsida/crescimento & desenvolvimento , Passeriformes/fisiologia , Sementes/fisiologia , Animais , BrasilRESUMO
Individual responses, particularly based on personality, can have important consequences for individual fitness, based upon success in exploring new habitats, feeding on novel foods, and aggressiveness in competitive interactions. We conducted laboratory experiments to analyze individual responses to different artificial conditions that could suit specific male and female personalities in the endangered seahorse, Hippocampus reidi. Our experiments with H. reidi evaluated individual responses to a new habitat, novel objects, level of inactivity and social interactions. We demonstrate that approximately half of the seahorses have a bold personality, readily inspecting new habitats and objects and sporadically presenting social approaches. The remaining shy individuals had high levels of inactivity and did not check novelties in their habitats. Although we expected that males would have shyer personalities when compared with females, due to their ecological role in the provision of parental care, we found no statistical difference between the sexes in terms of these aspects of personality. The similar frequency of both types of personality in males and females suggests that these features may be balanced and evolutionarily stable in the sampled population.
Assuntos
Caracteres Sexuais , Timidez , Smegmamorpha , Animais , Ecossistema , Comportamento Exploratório , Feminino , Relações Interpessoais , Masculino , Atividade Motora , PersonalidadeRESUMO
BACKGROUND: A key strategy in biodiversity conservation is the establishment of protected areas. In the future, however, the redistribution of species in response to ongoing climate change is likely to affect species' representativeness in those areas. Here we quantify the effectiveness of planning protected areas network to represent 151 birds endemic to the Brazilian Atlantic Forest hotspot, under current and future climate change conditions for 2050. METHODS: We combined environmental niche modeling and systematic conservation planning using both a county and a regional level planning strategy. We recognized the conflict between biodiversity conservation and economic development, including socio-economic targets (as opposed to biological only) and using planning units that are meaningful for policy-makers. RESULTS: We estimated an average contraction of 29,500 km2 in environmentally suitable areas for birds, representing 52% of currently suitable areas. Still, the most cost-effective solution represented almost all target species, requiring only ca. 10% of the Atlantic Forest counties to achieve that representativeness, independent of strategy. More than 50% of these counties were selected both in the current and future planned networks, representing >83% of the species. DISCUSSION: Our results indicate that: (i) planning protected areas network currently can be useful to represent species under climate change; (ii) the overlapped planning units in the best solution for both current and future conditions can be considered as "no regret" areas; (iii) priority counties are spread throughout the biome, providing specific guidance wherever the possibility of creating protected area arises; and (iv) decisions can occur at different administrative spheres (Federal, State or County) as we found quite similar numerical solutions using either county or regional level strategies.
RESUMO
Most conservation decisions take place at national or finer spatial scales. Providing useful information at such decision-making scales is essential for guiding the practice of conservation. Brazil is one of the world's megadiverse countries, and consequently decisions about conservation in the country have a disproportionate impact on the survival of global biodiversity. For three groups of terrestrial vertebrates (birds, mammals, and amphibians), we examined geographic patterns of diversity and protection in Brazil, including that of endemic, small-ranged, and threatened species. To understand potential limitations of the data, we also explored how spatial bias in collection localities may influence the perceived patterns of diversity. The highest overall species richness is in the Amazon and Atlantic Forests, while the Atlantic Forest dominates in terms of country endemics and small-ranged species. Globally threatened species do not present a consistent pattern. Patterns for birds were similar to overall species richness, with higher concentrations of threatened species in the Atlantic Forest, while mammals show a more generalized pattern across the country and a high concentration in the Amazon. Few amphibians are listed as threatened, mostly in the Atlantic Forest. Data deficient mammals occur across the country, concentrating in the Amazon and southeast Atlantic Forest, and there are no data deficient birds in Brazil. In contrast, nearly a third of amphibians are data deficient, widespread across the country, but with a high concentration in the far southeast. Spatial biases in species locality data, however, possibly influence the perceived patterns of biodiversity. Regions with low sampling density need more biological studies, as do the many data deficient species. All biomes except the Amazon have less than 3% of their area under full protection. Reassuringly though, rates of protection do correlate with higher biodiversity, including higher levels of threatened and small-ranged species. Our results indicate a need for expanded formal protection in Brazil, especially in the Atlantic forest, and with an emphasis on fully protected areas.
Assuntos
Biodiversidade , Espécies em Perigo de Extinção/estatística & dados numéricos , Vertebrados/fisiologia , Animais , Brasil , Parques Recreativos/estatística & dados numéricosRESUMO
Sex determination is important for conservation and population studies, particularly for reproduction programs of threatened species and behavioural ecology. Turdus amaurochalinus, Creamy-bellied Thrush, only exhibits sexual dimorphism during the breeding season, when males are considered to show intense yellow bills, and females and immature males show dark brown bills. The objectives of this study were: 1) to determine the sex of individuals using genetic techniques, and 2) to test the hypothesis that sex dimorphism can be detected by morphometry. This study was carried out at Parque Nacional da Restinga de Jurubatiba, a preserved area located on the North coast of Rio de Janeiro State. The birds were captured using ornithological nets, singly marked with metal rings, weighed, measured and had blood samples collected before being released. The sex of 42 T. amaurochalinus individuals was determined using the CHD gene marker. A total of 20 males and 22 females were identified from June to August, with peak capture frequency in June. Turdus amaurochalinus females and males differed significantly in morphometrical measures. The most important traits to distinguish males from females were wing length (Student t-test=4.34, df=40, p=0.0001) and weight (Student t-test=2.08,df=40, p=0.044): females were heavier and had significantly shorter wing length than males. Females and males were correctly classified in 86% and 75% of cases, respectively, using Discriminant Analysis. The molecular analysis was the most secure method for sex determination in the studied species. Rev. Biol. Trop. 59 (2): 789- 794. Epub 2011 June 01.
La determinación del sexo es importante para la conservación y los estudios poblacionales. Turdus amaurochalinus no presenta aparente dimorfismo sexual. El objetivo de este estudio fue determinar el sexo a través de una técnica genética, mediante el uso del marcador del gen CHD y se puso a prueba la hipótesis de que el dimorfismo sexual puede ser detectado por morfometría. Este estudio se llevó a cabo en el Parque Nacional da Restinga de Jurubatiba, una zona protegida situada en la costa norte de Río de Janeiro. Las aves fueron capturadas con redes de niebla, los individuos se marcaron con anillos de metal, se pesaron, medieron y se les tomó una muestra de sangre antes de ser liberados. Un total de 20 machos y 22 hembras fueron identificados en el área de estudio desde junio hasta agosto, con la frecuencia máxima de captura en junio. La prueba de t-student fue usada para evaluar si hembras y machos se diferencian considerablemente en relación a medidas morfométricas. Los rasgos más importantes para distinguir machos de hembras fueron la longitud del ala y el peso: las hembras eran más pesadas y tenían longitud de ala considerablemente más corta que los machos. Hembras y machos fueron correctamente clasificados en un 86% y 75% de casos respectivamente, donde se usó un análisis discriminante. El análisis molecular es el método más seguro para la determinación sexual en la especie estudiada.
Assuntos
Animais , Feminino , Masculino , Proteínas Aviárias/genética , Proteínas de Ligação a DNA/genética , Passeriformes/genética , Análise para Determinação do Sexo/métodos , Marcadores Genéticos/genética , Passeriformes/anatomia & histologia , Passeriformes/classificaçãoRESUMO
Understanding how birds use vegetation to obtain food resources has implications for habitat conservation and management. Restinga is a poorly known and threatened tropical habitat, associated to the Atlantic forest, that could benefit from this kind of information to know which plants can be used and dispersed by birds that can help on the maintenance of this habitat. Frugivorous and insectivorous birds are important components of tropical ecosystems, such as restinga. To provide more information regarding the ecology of restinga, we studied the feeding behavior and spatial use of this vegetation by birds at Restinga de Jurubatiba National Park, southeastern Brazil. We found that feeding behavior was similar to that recorded for the same species in other vegetation types. In addition, spatial use of the restinga vegetation by the most abundant species did not overlap greatly, except for two insectivorous species that used different foraging maneuvers and two frugivorous birds that foraged in flocks. The two most abundant species were generalists in their diet and were capable of feeding at the ground level on sand substrate.
O conhecimento das estratégias de uso da vegetação pela fauna para forrageio tem implicações para conservação e manejo de habitats. Restinga é um ambiente tropical, associado à Mata Atlântica, ameaçado e ainda pouco conhecido que poderia se beneficiar desse tipo de informação para conhecer quais espécies de plantas podem ser utilizadas e dispersas por aves que atuem na manutenção deste habitat. Aves frugívoras e insetívoras são importantes componentes de ecossistemas tropicais, como a restinga. Para fornecer mais informações sobre a ecologia da restinga, nós estudamos o comportamento de forrageio e o uso do espaço das aves no Parque Nacional da Restinga de Jurubatiba, sudeste do Brasil. Nós encontramos que os comportamentos de forrageio foram similares àqueles registrados para as mesmas espécies em outros ambientes. Além disso, o uso do espaço da vegetação de restinga pelas espécies mais abundantes não apresentou grande sobreposição, exceto por duas espécies insetívoras que usaram manobras de forrageio diferentes e duas aves frugívoras que forragearam em bando. As duas espécies mais abundantes foram generalistas em suas dietas e foram capazes de forragear no chão sobre areia nua.
Assuntos
Biodiversidade , Aves , Comportamento/classificação , Ecossistema , Flora , Fauna/efeitos adversos , InsetosRESUMO
Restingas are considered stressful habitats associated with the Brazilian Atlantic forest, and their ecological interactions are poorly known. The goal of the present study was to determine the potential role of frugivorous birds as seed dispersers in a restinga habitat. Data were collected in Parque Nacional da Restinga de Jurubatiba, southeastern Brazil, where the main physiognomy (Open Clusia Formation) is characterized by the presence of patches of vegetation covering 20 to 48 % of the sandy soil and reaching a height of 5 m. Birds were captured with mist nets (12 x 2.5 m; 36 mm mesh; 1,680 net-hrs) and had their fecal and regurgitate samples inspected for seeds. Six plant species found in these bird samples were studied. The germination of seeds obtained from plants was compared to those from the birds. Both groups of seeds were set on Petri dishes at room temperature and washed when infected with fungi. In general, there was no effect on germination rate, and the effect on germination speed was negative. Germination of seeds from Pilosocereus arrabidae treated by the birds seemed to be influenced by storage of defecated seeds, while few Miconia cinnamomifolia seeds both from plants and from birds germinated. Ocotea notata presented a great variation in time to the onset of germination, perhaps an advantage against dissecation. Aechmea nudicaulis, Clusia hilariana and Erythroxylum subsessile probably take advantage of the arrival to favorable microhabitats, not by the gut effect on the seeds. All plant species studied are numerically important for the community and some of them are main actors in the succession of vegetation patches. Among the birds, Mimus gilvus is an important resident species, endemic to restingas in Brazil, while Turdus amaurochalinus is a visitor and may be important for plants that fructify during its passage by the study site. Although the effect of pulp removal was only tested for one species (Achmea nudicaulis)...
Las restingas se consideran hábitats estresantes asociados al bosque del Atlántico brasileño y sus ecológicas se conocen poco. El objetivo principal del presente trabajo fue determinar el papel potencial de las aves frugívoras como dispersores de plantas en un hábitat de restinga. La información se recolectó en el Parque Nacional da Restinga de Jurubatiba, Brasil. Las aves se capturaron con redes de niebla y sus muestras fecales y de regurgitación se inspeccionaron en busca de semillas. Estudiamos seis especies de plantas de estas muestras. En general, el efecto del paso por el sistema digestivo de las aves sobre el porcentaje de germinación fue nulo (y negativo en la velocidad de germinación). Todas las especies de plantas estudiadas son numéricamente importantes a la comunidad y algunas de ellas tienen papeles principales en la sucesión de parches de vegetación. Entre las aves, Mimus gilvus es una especie residente importante, endémica de tales hábitats en Brasil, mientras que Turdus amaurochalinus es una especie visitante y puede ser importante para las plantas que fructifican durante su paso por el sitio del estudio. El efecto general de los pájaros en la dispersión de semillas en la restinga es probablemente positivo.