Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Oecologia ; 202(2): 239-250, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37253787

RESUMO

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 Corporal
2.
Sci Total Environ ; 861: 160534, 2023 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-36574545

RESUMO

The escape behaviour, measured as flight initiation distance (FID; the distance at which individuals take flight when approached by a potential predator, usually a human in the study systems), is a measure widely used to study fearfulness and risk-taking in animals. Previous studies have shown significant differences in the escape behaviour of birds inhabiting cemeteries and urban parks in European cities, where birds seem to be shyer in the latter. We collected a regional dataset of the FID of birds inhabiting cemeteries and parks across Latin America in peri-urban, suburban and urban parks and cemeteries. FIDs were recorded for eighty-one bird species. Mean species-specific FIDs ranged from 1.9 to 19.7 m for species with at least two observations (fifty-seven species). Using Bayesian regression modelling and controlling for the phylogenetic relatedness of the FID among bird species and city and country, we found that, in contrast to a recent publication from Europe, birds escape earlier in cemeteries than parks in the studied Latin American cities. FIDs were also significantly shorter in urban areas than in peri-urban areas and in areas with higher human density. Our results indicate that some idiosyncratic patterns in animal fearfulness towards humans may emerge among different geographic regions, highlighting difficulties with scaling up and application of regional findings to other ecosystems and world regions. Such differences could be associated with intrinsic differences between the pool of bird species from temperate European and mostly tropical Latin American cities, characterized by different evolutionary histories, but also with differences in the historical process of urbanization.


Assuntos
Cemitérios , Ecossistema , Animais , Humanos , América Latina , Filogenia , Parques Recreativos , Teorema de Bayes , Aves , Cidades , Europa (Continente)
3.
Parasitol Res ; 121(11): 3203-3215, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36056960

RESUMO

Espinilho savanna ("seasonal steppe savanna") is a unique vegetation formation of the Pampas biome that is found near the tri-border of Brazil, Uruguay, and Argentina. The Yellow Cardinal (Gubernatrix cristata) is a flagship species of this ecosystem, but it is classified as "critically endangered" in Brazil due to habitat loss and poaching for the illegal trade. Population supplementation through the release of individuals that were captive-bred or apprehended by authorities from the illegal trade has been considered as a conservation strategy for this species; however, the risk of pathogen introduction is a critical concern. We used microscopy and molecular methods to investigate the occurrence of blood parasites in wild passerines (n = 64, including three Yellow Cardinals) at Espinilho State Park, Rio Grande do Sul, Brazil, and in captive Yellow Cardinals (n = 30) at three facilities in Brazil. Haemosporidian parasites were detected in the blood smears of 10.9% of the wild passerines, comprising the morphospecies Haemoproteus erythrogravidus in Rufous-collared Sparrow (Zonotrichia capensis), H. quiscalus in Grayish Baywing (Agelaioides badius), and H. tyranni in Great Kiskadee (Pitangus sulphuratus); these are the southernmost records for these morphospecies and their first record for the Pampas biome. No haemosporidian parasites were detected in the blood smears of the Yellow Cardinals, wild or captive. Microfilariae were detected in the blood smears of 14.1% of the wild passerines, including all wild Yellow Cardinals, and in 43.3% of captive Yellow Cardinals. Trypanosoma sp. was detected in the blood smear of one captive Yellow Cardinal. Nested PCR and gene sequencing of the cyt-b gene of Haemoproteus/Plasmodium was used to test a subset of wild passerines and captive Yellow Cardinals, allowing for the molecular barcoding of H. quiscalus lineage AGEBAD04 and H. tyranni lineage PITSUL01; additionally, DNA identical to that of lineage PITSUL01 was detected in the blood of one captive Yellow Cardinal. This study provides valuable data to support the conservation management of the Yellow Cardinal and other threatened passerines from the Pampas and highlights the need for further studies on the epidemiology and pathology of filarioid worms and trypanosomes in passerines from this biome.


Assuntos
Doenças das Aves , Haemosporida , Lepidópteros , Parasitos , Infecções Protozoárias em Animais , Pardais , Animais , Doenças das Aves/parasitologia , Brasil , Suplementos Nutricionais , Ecossistema , Haemosporida/genética , Parasitos/genética , Filogenia , Infecções Protozoárias em Animais/epidemiologia , Infecções Protozoárias em Animais/parasitologia
4.
PLoS One ; 15(12): e0243070, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33264348

RESUMO

Despite the importance and ubiquity of grasslands, the degradation and the loss of these habitats have negatively affected bird populations throughout the world. The use of fire to manage grassland areas in some regions of southern Brazil can help to maintain these areas but can also influence the bird community in different ways. We assessed temporal changes in richness, abundance, and composition of bird communities in areas with different histories of fire disturbance in highland grasslands of southern Brazil, the most extensive remnant of grassland of the Atlantic Forest domain. We censused birds during four breeding seasons (2015-2018), through point counts in areas burned only once in the last ten years (OF, n = 3), areas burned annually (AF, n = 2), and areas without fire in the last ten years (WF, n = 2). In OF the richness, abundance, and species composition changed in the year of the fire, compared to the previous year, and returned to the initial values two years later. In AF and WF we found some differences among the years, but not with an equally clear pattern. Three of the six grassland associated species assessed individually for density responded significantly to temporal habitat modification since the fire. Our results show that two years without fire were enough time for the bird community to recover after a fire, but some responses are species-specific. Therefore, fire can be used as a management tool for grasslands and may help in the conservation of birds of southern Brazil, as long as with a minimum interval between fires in an area is guaranteed.


Assuntos
Aves , Incêndios , Pradaria , Animais , Biodiversidade , Brasil , Fatores de Tempo
5.
Sci Rep ; 10(1): 19708, 2020 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-33184441

RESUMO

Grassland ecosystems are evolutionarily linked to disturbances such as grazing and fire. These disturbances define grassland plant communities and habitat heterogeneity, which influence animal communities. We evaluated the influence of fire disturbance on plant and bird communities and on habitat structure by sampling grassland fragments with different time elapsed since the last fire event. Habitat structure was sampled using plant life forms and abiotic variables and birds were sampled through point counts. We recorded 862 bird individuals from 70 species. Intermediately-burnt sites harbor higher habitat heterogeneity and plant species richness in comparison with recently or long-burnt sites. Bird abundance and taxonomic diversity decreased linearly as time since fire increased. Finally, time since fire influenced the relative distribution of plant life forms and bird food guilds. Our results indicate that fire management should be included in the framework for conservation and sustainable use of grasslands, because it promotes habitat heterogeneity and diversity. To maintain habitat heterogeneity and the related habitat-specific bird species and functional groups, conservation efforts should maintain grassland patches under different management intensities and frequencies on a landscape level. However, studies focused on determining the periodicity with which fire management should be used are still lacking.


Assuntos
Aves/classificação , Herbivoria/fisiologia , Animais , Aves/fisiologia , Brasil , Conservação dos Recursos Naturais , Ecossistema , Incêndios , Pradaria , Filogenia , Dinâmica Populacional
6.
Ecology ; 100(6): e02647, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30845354

RESUMO

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.

7.
Sci Adv ; 3(5): e1602404, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28560331

RESUMO

Instances of recent and rapid speciation are suitable for associating phenotypes with their causal genotypes, especially if gene flow homogenizes areas of the genome that are not under divergent selection. We study a rapid radiation of nine sympatric bird species known as capuchino seedeaters, which are differentiated in sexually selected characters of male plumage and song. We sequenced the genomes of a phenotypically diverse set of species to search for differentiated genomic regions. Capuchinos show differences in a small proportion of their genomes, yet selection has acted independently on the same targets in different members of this radiation. Many divergent regions contain genes involved in the melanogenesis pathway, with the strongest signal originating from putative regulatory regions. Selection has acted on these same genomic regions in different lineages, likely shaping the evolution of cis-regulatory elements, which control how more conserved genes are expressed and thereby generate diversity in classically sexually selected traits.


Assuntos
Tentilhões/genética , Genoma , Pigmentação/genética , Característica Quantitativa Herdável , Seleção Genética , Animais , Feminino , Masculino
8.
Mitochondrial DNA A DNA Mapp Seq Anal ; 28(2): 231-232, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-26679427

RESUMO

Among known bird species, oscines are one of the few groups that produce complex vocalizations due to vocal learning. One of the most conspicuous oscine passerines in southeastern South America is the Rufous-bellied Thrush, Turdus rufiventris. The complete mitochondrial genome of this species was sequenced with the Illumina HiSeq platform (Illumina Inc., San Diego, CA), assembled using MITObim software and annotated by MITOS web server and Artemis software. This mitogenome contained 16 669 bases, organized as 13 protein-coding genes, 22 transfer RNAs, two ribosomal RNAs, and a control region (d-loop). The sequencing of the Rufous-bellied Thrush mitochondrial genome is of particular interest for better understanding of population genetics and phylogeography of the Turdidae family.


Assuntos
Genoma Mitocondrial , Passeriformes/genética , Animais , Proteínas Aviárias/genética , Sequenciamento de Nucleotídeos em Larga Escala , Proteínas Mitocondriais/genética , Anotação de Sequência Molecular , Filogenia , Filogeografia , RNA Ribossômico/genética , RNA de Transferência/genética , América do Sul
9.
Mol Phylogenet Evol ; 53(2): 450-62, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19632344

RESUMO

Scytalopus and the recently erected Eleoscytalopus are among the Neotropical groups of birds whose taxonomy is most difficult to resolve given their very conservative morphology. We investigated the phylogeny and species limits of Eleoscytalopus and the eastern Scytalopus using two mitochondrial genes and two nuclear introns of multiple individuals from all species of these groups. The eastern Scytalopus are separated in three well defined clades also supported by morphological or vocal characteristics, although the relationships between these clades could not be resolved. We found several allopatric and very divergent lineages in these genera whose characteristics are consistent with species-level divergence, especially in S.speluncae. The great divergence between E. psychopompus and its sister species supports the former as a valid species. Our results corroborate the importance of the Bahia refuge as an avian center of endemism.


Assuntos
Especiação Genética , Passeriformes/genética , Filogenia , Animais , Brasil , Núcleo Celular/genética , DNA Mitocondrial/genética , Evolução Molecular , Genética Populacional , Geografia , Íntrons , Passeriformes/classificação , Análise de Sequência de DNA , Especificidade da Espécie
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...