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 CorporalRESUMO
Migratory birds are implicated in dispersing haemosporidian parasites over great geographic distances. However, their role in sharing these vector-transmitted blood parasites with resident avian host species along their migration flyway is not well understood. We studied avian haemosporidian parasites in 10 localities where Chilean Elaenia, a long-distance Neotropical austral migrant species, spends part of its annual cycle to determine local parasite transmission among resident sympatric host species in the elaenia's distributional range across South America. We sampled 371 Chilean Elaenias and 1,818 birds representing 243 additional sympatric species from Brazilian wintering grounds to Argentinian breeding grounds. The 23 haemosporidian lineages found in Chilean Elaenias exhibited considerable variation in distribution, specialization, and turnover across the 10 avian communities in South America. Parasite lineage dissimilarity increased with geographic distance, and infection probability by Parahaemoproteus decreased in localities harbouring a more diverse haemosporidian fauna. Furthermore, blood smears from migrating Chilean Elaenias and local resident avian host species did not contain infective stages of Leucocytozoon, suggesting that transmission did not take place in the Brazilian stopover site. Our analyses confirm that this Neotropical austral migrant connects avian host communities and transports haemosporidian parasites along its distributional range in South America. However, the lack of transmissive stages at stopover site and the infrequent parasite lineage sharing between migratory host populations and residents at breeding and wintering grounds suggest that Chilean Elaenias do not play a significant role in dispersing haemosporidian parasites, nor do they influence local transmission across South America.
Assuntos
Doenças das Aves , Haemosporida , Parasitos , Passeriformes , Plasmodium , Animais , Prevalência , Chile/epidemiologia , Doenças das Aves/epidemiologia , Doenças das Aves/parasitologia , Haemosporida/genética , FilogeniaRESUMO
South American dry forests have a complex and poorly understood biogeographic history. Based on the fragmented distribution of many Neotropical dry forest species, it has been suggested that this biome was more widely distributed and contiguous under drier climate conditions in the Pleistocene. To test this scenario, known as the Pleistocene Arc Hypothesis, we studied the phylogeography of the Rufous-fronted Thornbird (Phacellodomus rufifrons), a widespread dry forest bird with a disjunct distribution closely matching that of the biome itself. We sequenced mtDNA and used ddRADseq to sample 7,167 genome-wide single-nucleotide polymorphisms from 74 P. rufifrons individuals across its range. We found low genetic differentiation over two prominent geographic breaks - particularly across a 1,000 km gap between populations in Bolivia and Northern Peru. Using demographic analyses of the joint site frequency spectrum, we found evidence of recent divergence without subsequent gene flow across those breaks. By contrast, parapatric morphologically distinct populations in northeastern Brazil show high genetic divergence with evidence of recent gene flow. These results, in combination with our paleoclimate species distribution modelling, support the idea that currently disjunct patches of dry forest were more connected in the recent past, probably during the Middle and Late Pleistocene. This notion fits the major predictions of the Pleistocene Arc Hypothesis and illustrates the importance of comprehensive genomic and geographic sampling for examining biogeographic and evolutionary questions in complex ecosystems like Neotropical dry forests.
Assuntos
Aves , Ecossistema , Polimorfismo de Nucleotídeo Único , Animais , Aves/genética , Bolívia , Brasil , Florestas , Variação Genética , Peru , Filogenia , Filogeografia , Polimorfismo de Nucleotídeo Único/genéticaRESUMO
Secondary contact between species often results in the formation of a hybrid zone, with the eventual fates of the hybridizing species dependent on evolutionary and ecological forces. We examine this process in the Amazon Basin by conducting the first genomic and phenotypic characterization of the hybrid zone formed after secondary contact between two obligate army-ant-followers: the White-breasted Antbird (Rhegmatorhina hoffmannsi) and the Harlequin Antbird (Rhegmatorhina berlepschi). We found a major geographic displacement (â¼120 km) between the mitochondrial and nuclear clines, and we explore potential hypotheses for the displacement, including sampling error, genetic drift, and asymmetric cytonuclear incompatibilities. We cannot exclude roles for sampling error and genetic drift in contributing to the discordance; however, the data suggest expansion and unidirectional introgression of hoffmannsi into the distribution of berlepschi.
Assuntos
Hibridização Genética , Passeriformes , Animais , Evolução Biológica , DNA Mitocondrial/genética , Deriva Genética , Passeriformes/genéticaRESUMO
Determining the prevalence and local transmission dynamics of parasitic organisms are necessary to understand the ability of parasites to persist in host populations and disperse across regions, yet local transmission dynamics, diversity, and distribution of haemosporidian parasites remain poorly understood. We studied the prevalence, diversity, and distributions of avian haemosporidian parasites of the genera Plasmodium, Haemoproteus, and Leucocytozoon among resident and migratory birds in Serra do Mar, Brazil. Using 399 blood samples from 66 Atlantic Forest bird species, we determined the prevalence and molecular diversity of these pathogens across avian host species and described a new species of Haemoproteus. Our molecular and morphological study also revealed that migratory species were infected more than residents. However, vector infective stages (gametocytes) of Leucocytozoon spp., the most prevalent parasites found in the most abundant migrating host species in Serra do Mar (Elaenia albiceps), were not seen in blood films of local birds suggesting that this long-distance Austral migrant can disperse Leucocytozoon parasite lineages from Patagonia to the Atlantic Forest, but lineage sharing among resident species and local transmission cannot occur in this part of Brazil. Our study demonstrates that migratory species may harbor a higher diversity and prevalence of parasites than resident species, but transportation of some parasites by migratory hosts may not always affect local transmission.
RESUMO
Host phylogenetic relatedness and ecological similarity are thought to contribute to parasite community assembly and infection rates. However, recent landscape level anthropogenic changes may disrupt host-parasite systems by impacting functional and phylogenetic diversity of host communities. We examined whether changes in host functional and phylogenetic diversity, forest cover, and minimum temperature influence the prevalence, diversity, and distributions of avian haemosporidian parasites (genera Haemoproteus and Plasmodium) across 18 avian communities in the Atlantic Forest. To explore spatial patterns in avian haemosporidian prevalence and taxonomic and phylogenetic diversity, we surveyed 2241 individuals belonging to 233 avian species across a deforestation gradient. Mean prevalence and parasite diversity varied considerably across avian communities and parasites responded differently to host attributes and anthropogenic changes. Avian malaria prevalence (termed herein as an infection caused by Plasmodium parasites) was higher in deforested sites, and both Plasmodium prevalence and taxonomic diversity were negatively related to host functional diversity. Increased diversity of avian hosts increased local taxonomic diversity of Plasmodium lineages but decreased phylogenetic diversity of this parasite genus. Temperature and host phylogenetic diversity did not influence prevalence and diversity of haemosporidian parasites. Variation in the diversity of avian host traits that promote parasite encounter and vector exposure (host functional diversity) partially explained the variation in avian malaria prevalence and diversity. Recent anthropogenic landscape transformation (reduced proportion of native forest cover) had a major influence on avian malaria occurrence across the Atlantic Forest. This suggests that, for Plasmodium, host phylogenetic diversity was not a biotic filter to parasite transmission as prevalence was largely explained by host ecological attributes and recent anthropogenic factors. Our results demonstrate that, similar to human malaria and other vector-transmitted pathogens, prevalence of avian malaria parasites will likely increase with deforestation.
Assuntos
Doenças das Aves , Haemosporida , Malária Aviária , Parasitos , Plasmodium , Animais , Doenças das Aves/epidemiologia , Florestas , Haemosporida/genética , Humanos , Malária Aviária/epidemiologia , Filogenia , Plasmodium/genética , PrevalênciaRESUMO
A saracura-carijó Pardirallus maculatus possui uma distribuição ampla e disjunta na América Central e na América do Sul, ocorrendo em todas as regiões do Brasil. No estado de São Paulo, Sudeste do País, os registros são escassos, e estão espalhados entre interior e litoral. Com isso, apresentamos aqui o primeiro registro documentado desta espécie para o município de Bertioga, litoral de São Paulo. Uma ave adulta foi encontrada no dia 9 de outubro de 2020, em uma área urbana, sendo resgatada e solta no mesmo dia em uma área natural no Serviço Social do Comércio (Sesc) em Bertioga. Essa ave apareceu após uma forte tempestade, e sua ocorrência pode ter relação com isso, ou poderia estar fazendo algum deslocamento regional, comportamento já observado em outros ralídeos. Devido ao baixo número de registros desta espécie para o litoral paulista, este relato pode ajudar a entender melhor sua ocorrência nesta região do estado de São Paulo, contribuindo com sua conservação.
The Spotted Rail Pardirallus maculatus has a wide and disjunct distribution in Central and South America, occurring in all regions of Brazil. In the state of São Paulo, southeast of the country, records are scarce, and are scattered between the interior and the coast. Thus, we present here the first documented record of this species for the municipality of Bertioga, on the coast of São Paulo. An adult bird was found on October 9, 2020, in an urban area, being rescued and released on the same day in a natural area at Serviço Social do Comércio (Sesc) in Bertioga. This bird appeared after a strong storm, and its occurrence may be related to this, or it could be making some regional movement, a behavior already observed in other rails. Due to the low number of records of this species for the São Paulo coast, this report can help to better understand its occurrence in this region of the state of São Paulo, contributing to its conservation.
Assuntos
Animais , Comportamento , Aves , Registros , Relatório de PesquisaRESUMO
A Estação Ecológica Serra Geral do Tocantins (EESGT) é uma das maiores Unidades de Conservação dentro do Bioma Cerrado. A avifauna desta UC foi inventariada entre os dias 25 de janeiro e 15 de fevereiro de 2008. Durante esse trabalho buscou-se amostrar os diferentes hábitats encontrados na EESGT, bem como algumas localidades no entorno. Além de registros auditivos e visuais foram utilizadas redes-de-neblina e armas de fogo para coletas de material testemunho, que se encontra depositado na coleção ornitológica do Museu de Zoologia da Universidade de São Paulo (MZUSP). Os resultados obtidos foram comparados com os dados disponíveis para outras unidades de conservação presentes na região. Foram registradas 254 espécies de aves, incluindo 11 endêmicas do Cerrado e outras três ameaçadas de extinção (Taoniscus nanus, Anodorhynchus hyacinthinus e Procnias averano). Três indivíduos pertencentes ao gênero Picumnus foram coletados; estes apresentam um distinto padrão de plumagem e de vocalização, podendo representar um táxon ainda não descrito.
The Estação Ecológica Serra Geral do Tocantins is one of the largest conservation units in Cerrado Biome. The avifauna of this locality was studied from January 25 to 15 February, 2008. We attempted to sample the different habitats found both within the EESGT as in its surroundings. In addition to audio and visual records, mist nets and shotguns were used to collect testimony material, which was deposited in the ornithological collection of the Museu de Zoologia da Universidade de São Paulo (MZUSP). The results were compared with data available from other conservation units nearby the EESGT. We recorded 254 bird species; among these 11 were considered endemic to the Cerrado region and other three considered threatened (Taoniscus nanus, Anodorhynchus hyacinthinus and Procnias averano). Three individuals belonging to the Picumnus genus also were collected; they presented unusual plumage and vocalization patterns, which suggests an undescribed taxon.