Navegando por Autor "Claudino, Ricardo Marcelino"
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Item Como a fragmentação da Mata Atlântica no sudoeste de Minas Gerais afeta aspectos da ecologia de população e assembleia de corujas (Aves: Strigiformes).(2013) Claudino, Ricardo Marcelino; Antonini, YasmineO estudo da ecologia populacional, seleção e/ou uso de habitas e influências das variáveis climáticas têm como foco compreender os mecanismos que causam flutuações na densidade populacional das espécies. Este estudo teve como objetivos responder ás seguintes questões: 1) Espécies de corujas de maior massa corpórea apresentam uma menor densidade populacional quando comparadas com espécies de menor massa corpórea? 2) Corujas de espécies distintas usam os mesmos habitats de Floresta Atlântica? 3) Variáveis ambientais influenciam o comportamento das corujas dificultando seus registros? O estudo foi desenvolvido de outubro de 2011 a setembro de 2012 em remanescentes de Floresta Atlântica, localizado no Parque Estadual do Itacolomi, Floresta Estadual do Uaimii, Estação Ecológica do Tripui, Serra do Ouro Branco, Serra da Brígida e Condomínio Paragem do Tripui no estado de Minas Gerais, Brasil. Os resultados demonstram que Megascops choliba apresentou uma menor densidade populacional quando comparado com Strix hylophila uma espécie de coruja de grande porte e não foi possível fazer comparação entre o numero populacional de Aegolius harrisii com as outras duas espécies de corujas pelo fato do baixo número de registro da espécie. Também verificou que as espécies de corujas (Aegolius harrisii, Megascops choliba e Strix hylophila) apresentam densidades populacionais diferentes, usam habitats diferentes, e que as variáveis ambientais não influenciam a detecção das espécies estudadas, com exceção da umidade relativa do ar para Strix hylophila. Necessitando desta maneira de mais estudos para uma maior compreensão dos reais efeitos das variáveis no comportamento desses animais.Item Feeding behavior by hummingbirds (Aves: Trochilidae) in artificial food patches in an Atlantic Forest remnant in southeastern Brazil.(2017) Lanna, Lucas L.; Azevedo, Cristiano Schetini de; Claudino, Ricardo Marcelino; Oliveira, Reisla Silva de; Itabaiana, Yasmine AntoniniDuring flight, hummingbirds achieve the maximum aerobic metabolism rates within vertebrates. To meet such demands, these birds have to take in as much energy as possible, using strategies such as selecting the best food resources and adopting behaviors that allow the greatest energy gains. We tested whether hummingbirds choose sources that have higher sugar concentrations, and investigated their behaviors near and at food resources. The study was conducted at Atlantic forest remnant in Brazil, between June and December 2012. Four patches were provided with artificial feeders, containing sucrose solutions at concentrations of 5%, 15%, 25% and 35% weight/volume. Hummingbird behaviors were recorded using the ad libitum method with continuous recording of behaviors. The following species were observed: the Brazilian ruby Clytolaema rubricauda (Boddaert, 1783), Violet-capped woodnymph Thalurania glaucopis (Gmelin, 1788), Scale-throated hermit Phaethornis eurynome (Lesson, 1832), White-throated hummingbird Leucochloris albicollis (Vieillot, 1818), Versicoloured emerald Amazilia versicolor (Vieillot, 1818), Glittering-bellied emerald Chlorostilbon lucidus (Shaw, 1812) and other Phaethornis spp. C. rubricauda, P. eurynome and Phaethornis spp. visited the 35%-sucrose feeders more often, while the T. glaucopis visited the 25%-sucrose feeders more often. L. albicollis and A. versicolor visited more often solutions with sugar concentration of 15%. C. lucidus visited all patches equally. Three behavioral strategies were observed: 1) C. rubricauda and T. glaucopis exhibited interspecific and intraspecific dominance; 2) the remaining species exhibited subordinance to the dominant hummingbirds, and 3) P. eurynome and Phaethornis spp. adopted a hide-and-wait strategy to the dominant hummingbird species. The frequency of aggressive behaviors was correlated with the time the hummingbird spent feeding, and bird size. Our results showed that hummingbirds can adopt different strategies to enhance food acquisition; that more aggressive species feeding more than less aggressive species; and that the birds, especially if they were dominant species, visited high quality food resources more often.Item Is bigger always better? : neither body size nor aggressive behavior predicts specialization of hummingbirds in a rocky outcrop.(2022) Claudino, Ricardo Marcelino; Itabaiana, Yasmine Antonini; Martins, Cristiane; Beirão, Marina do Vale; Braga, Érika Martins; Azevedo, Cristiano Schetini deInterspecific competition can strongly influence community structure and shape niche breadth and overlap. One of the main factors that determines hummingbird community structure is competition for food. Hummingbirds’ functional attributes, such as beak length and body mass, influence nectar acquisition in flowers. This study evaluates how functional and behavioral attributes of hummingbirds influence their specialization, as measured by pollen transportation. We tested the following hypothesis: H1) smaller and short-billed hummingbirds will carry higher pollen richness and relatively more pollen grains than long-billed hummingbirds; H2) dominant and territorial hummingbirds carry a lower richness of pollen types and fewer pollen grains when compared to subordinate hummingbirds, and H3) the similarity in the composition of pollen morphotypes, between the hummingbirds species, will be low because we expect to find high specialization in the use of plant species. We conducted the study between September 2018 and March 2019 in a Campo Rupestre (rocky outcrops) in Southeastern Brazil. Hummingbirds were captured with a trap. The pollen adhered to the body parts was collected, counted, and identified in the laboratory. We recorded hummingbirds’ beak sizes and body masses. Behavioral responses of hummingbirds to artificial feeders were collected regarding the time and duration of each visit and the outcome of aggressive inter- actions. An interaction network was built based on the pollen grains found on each hummingbird. Our results showed that neither body size nor aggressive behaviors influenced pollen richness on hummingbirds’ bodies. Beak length was the most important hummingbird attribute that influenced pollen richness, but not pollen relative abundance. Short-billed hummingbirds carried the greatest richness of pollen grains. The hummingbird pollen-grain interaction network was generalized in the pollen grains transported. We conclude that hummingbirds’ beak length is the cen- tral morphological variable related to pollen grain transport in rocky outcrops.Item Owl assemblages in fragments of atlantic forest in Brazil.(2018) Claudino, Ricardo Marcelino; Motta Junior, José Carlos; Antonini, YasmineHabitat loss and fragmentation is recognized as one of the main causes of global biodiversity declines. Birds of prey are considered good environmental bioindicators because they are sensitive to changes in the environment and can suffer local extinctions due to habitat fragmentation. In this study, we aimed to determine whether forest fragment area is correlated with the richness and abundance of owl species, and whether owl species recorded exhibit preferences for fragment edge or interior. The study was undertaken in six remnants of southeastern Atlantic Forest located in Minas Gerais State, Brazil. Six species of owls were recorded: Buff-fronted Owl (Aegolius harrisii), Tropical Screech-Owl (Megascops choliba), Tawny-browed Owl (Pulsatrix koeniswaldiana), Striped Owl (Asio clamator), Mottled Owl (Strix virgata), and Rusty-barred Owl (Strix hylophila). Megascops choliba was the most abundant species. The richness and abundance of species were higher at the edge when compared to the interior of the fragments. The owl species recorded did not seem to prefer the forest interior, while M. choliba had a preference for forest edges. This study adds new empirical knowledge on the effects of fragmentation on Neotropical owl communities.Item Perch usage by hummingbirds in a fragment of Atlantic Forest in Brazil.(2016) Lanna, Lucas L.; Azevedo, Cristiano Schetini de; Claudino, Ricardo Marcelino; Oliveira, Reisla Silva de; Itabaiana, Yasmine AntoniniWe investigated if there are aspects of perches that are more attractive for hummingbirds, such as perch height, diameter, and distance from a food patch. The study was conducted in a fragment of Atlantic Forest of the Itacolomi State Park, in Minas Gerais, Brazil, with artificial feeders simulating a rich food patch. Characteristics of perches used by the recorded hummingbirds, such as height, diameter and distance from the food patch, were measured. From the six hummingbird species recorded visiting the artificial feeders, two preferentially used perches with certain characteristics: Thalurania glaucopis used more perches at a height of 0.51–1.0 m (intermediary high), and Leucochloris albicollis used more perches located 1.1–2.0 m distance from the food patch. T. glaucopis was territorial and defended the food patch; L. albicollis was subordinate and did not defend the food patch. The other species seemed to use perches randomly. Our results suggest that hummingbirds used perches according to their social status. Territorial species use perches primarily as platforms for defense and observation of the territory, as well as places of rest between feeding events; subordinate species use perches mainly as resting places during feeding bouts in the absence of the dominant species.