Suchergebnisse

Um levantamento da avifauna foi executado na Estação Ecológica do Rio Acre (ESEC Rio Acre), uma unidade de conservação remota situada na região sul do estado do Acre, na fronteira com o Peru, com a finalidade de subsidiar o seu plano de manejo. Os trabalhos de campo foram realizados nas épocas seca (agosto de 2005) e chuvosa (fevereiro de 2006), com a realização de levantamentos qualitativos (observações e gravações de vocalizações) e quantitativos, por meio da captura com redes de neblina (mist-nets). Após o acúmulo de 180 horas de observações qualitativas e cerca de 2.500 horas.rede de capturas distribuídos em 26 dias de amostragem, registrou-se 365 espécies de aves. Vários dos registros obtidos na ESEC Rio Acre são aqui discutidos em detalhes em função da sua relevância biogeográfica e para a conservação. Os resultados gerais obtidos, aliados ao registro de grandes populações de espécies de aves com alto valor cinegético, indicam que a ESEC Rio Acre encontra-se ainda em ótimo estado de conservação. Infelizmente, essa situação pode mudar rapidamente caso a expansão madeireira, atualmente em curso no lado Peruano da fronteira (em área limítrofe à unidade), seja direcionada ilegalmente para o território brasileiro.

We carried out seven two-week long avifaunal inventories in five newly-established conservation units spanning the entire 'Calha Norte' area, a portion of the Guiana Shield in the northern part of the state of Pará, Brazil, between January 2008 and January 2009. Prior to our study, most of this part of Amazonia was regarded as virtually unsampled from an ornithological perspective. Here, we present an annotated check-list with 446 species of birds recorded during the surveys, including 62 species for which our records represented significant range extensions, and hence are discussed in detail. The number of species recorded at each site varied between 203 and 302, and was positively correlated with the local availability of steep altitudinal and vegetational (forest/savanna and seasonally-flooded/upland forest) gradients. The number of unique species recorded at each site varied between 2 and 27, and reflected an interesting biogeographic pattern in which the Trombetas river appears to separate distinct upland and white-sand forest bird faunas on the Guiana Shield, a pattern also verified for the herpetofauna. Our results also showed that savannas represent a very important component of the local biota, with enclaves harboring a typical bird fauna also distributed in similar habitats in nearby southern Guyana, Suriname, and the state of Amapá in Brazil. Altogether, the five conservation units surveyed harbour 74 bird species of special interest for conservation (threatened, endemic, rare, range-restricted, and hunted species) and therefore play a key role in the preservation of all main subsets of the heterogeneous bird fauna of the Guiana Shield.

The role of climate as a speciation driver in the Amazon has long been discussed. Phylogeographic studies have failed to recover synchronous demographic responses across taxa, although recent evidence supports the interaction between rivers and climate in promoting speciation. Most studies, however, are biased toward upland forest organisms, while other habitats are poorly explored and could hold valuable information about major historical processes. We conducted a comparative phylogenomic analysis of floodplain forest birds to explore the effects of historical environmental changes and current connectivity on population differentiation. Our findings support a similar demographic history among species complexes, indicating that the central portion of the Amazon River basin is a suture zone for taxa isolated across the main Amazonian sub-basins. Our results also suggest that changes in the fluvial landscape induced by climate variation during the Mid- and Late Pleistocene drove population isolation, leading to diversification with subsequent secondary contact. Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).

Since 2005, the Brazilian Ornithological Records Committee (CBRO) has published updated checklists of Brazilian birds almost every year. Herein, we present a completely new and annotated version of our checklist. For the first time, we list all bird subspecies known from Brazil that are currently accepted by at least one key ornithological reference work. The inclusion of the subspecies should be seen as a synthesis, and not as a taxonomic endorsement. As such, we include in the new checklist 1919 avian species, 910 of which are treated as polytypic in reference works (2042 subspecies), totaling 3051 taxa at the species and subspecies level. We anticipate that several of the subspecies included in our list may be subject to future taxonomic upgrades to species status, while others will probably be shown to be invalid in the light of future taxonomic studies. The results highlight Brazil as a megadiverse country and reinforce the need for proper enforcement of political tools, laws and international commitments assumed by the country to preserve its biodiversity. © 2015, Sociedade Brasileira de Ornitologia. All rights reserved.