Sidnei de Melo Dantas

Two hundred years of local avian extinctions in Eastern Amazonia

Local, regional, and global extinctions caused by habitat loss, degradation, and fragmentation have been widely reported for the tropics. The patterns and drivers of this loss of species are now increasingly well known in Amazonia, but there remains a significant gap in understanding of long-term trends in species persistence and extinction in anthropogenic landscapes. Such a historical perspective is critical for understanding the status and trends of extant biodiversity as well as for identifying priorities to halt further losses. Using extensive historical data sets of specimen records and results of contemporary surveys, we searched for evidence of local extinctions of a terra firma rainforest avifauna over 200 years in a 2500 km(2) eastern Amazonian region around the Brazilian city of Belém. This region has the longest history of ornithological fieldwork in the entire Amazon basin and lies in the highly threatened Belém Centre of Endemism. We also compared our historically inferred extinction events with extensive data on species occurrences in a sample of catchments in a nearby municipality (Paragominas) that encompass a gradient of past forest loss. We found evidence for the possible extinction of 47 species (14% of the regional species pool) that were unreported from 1980 to 2013 (80% last recorded between 1900 and 1980). Seventeen species appear on the International Union for Conservation of Nature Red List, and many of these are large-bodied. The species lost from the region immediately around Belém are similar to those which are currently restricted to well-forested catchments in Paragominas. Although we anticipate the future rediscovery or recolonization of some species inferred to be extinct by our calculations, we also expect that there are likely to be additional local extinctions, not reported here, given the ongoing loss and degradation of remaining areas of native vegetation across eastern Amazonia.

Molecular systematics of the new world screech-owls (Megascops: Aves, Strigidae): biogeographic and taxonomic implications ☆

Megascops screech-owls are endemic to the New World and range from southern Canada to the southern cone of South America. The 22 currently recognized Megascops species occupy a wide range of habitats and elevations, from desert to humid montane forest, and from sea level to the Andean tree line. Species and subspecies diagnoses of Megascops are notoriously difficult due to subtle plumage differences among taxa with frequent plumage polymorphism. Using three mitochondrial and three nuclear genes we estimated a phylogeny for all but one Megascops species. Phylogenies were estimated with Maximum Likelihood and Bayesian Inference, and a Bayesian chronogram was reconstructed to assess the spatio-temporal context of Megascops diversification. Megascops was paraphyletic in the recovered tree topologies if the Puerto Rican endemic M. nudipes is included in the genus. However, the remaining taxa are monophyletic and form three major clades: (1) M. choliba, M. koepckeae, M. albogularis, M. clarkii, and M. trichopsis; (2) M. petersoni, M. marshalli, M. hoyi, M. ingens, and M. colombianus; and (3) M. asio, M. kennicottii, M. cooperi, M. barbarus, M. sanctaecatarinae, M. roboratus, M. watsonii, M. atricapilla, M. guatemalae, and M. vermiculatus. Megascops watsonii is paraphyletic with some individuals more closely related to M. atricapilla than to other members in that polytypic species. Also, allopatric populations of some other Megascops species were highly divergent, with levels of genetic differentiation greater than between some recognized species-pairs. Diversification within the genus is hypothesized to have taken place during the last 8 million years, with a likely origin in Central America. The genus later expanded over much of the Americas and then diversified via multiple dispersal events from the Andes into the Neotropical lowlands.

Status of the globally threatened forest birds of northeast Brazil

A Floresta Atlântica do Nordeste do Brasil abriga uma biota unica que esta entre as mais ameacadas na regiao Neotropical. A quase total conversao dos habitats florestais em areas de plantacao de cana-de-acucar deixou a avifauna florestal endemica da regiao isolada em poucos remanescentes florestais altamente fragmentados e degradados. Aqui, resumimos o status atual de 16 especies globalmente ameacadas baseado em pesquisas conduzidas nos ultimos 11 anos. Encontramos uma situacao desanimadora para a maioria dessas especies e consideramos que tres especies endemicas: Glaucidium mooreorum (cabure-de-pernambuco), Cichlocolaptes mazarbarnetti (gritador-do-nordeste) e Philydor novaesi (limpa-folha-do-nordeste) estejam provavelmente extintas. Algumas noticias positivas podem, no entanto, ser reportadas para Leptodon forbesi (gaviao-de-pescoco-branco) e Synallaxis infuscata (tatac), do qual necessitam de uma reavaliacao de seus respectivos status na lista vermelha. Descrevemos em linhas gerais um planejamento para priorizar as intervencoes conservacionistas na regiao direcionadas na prevencao da extincao do conjunto das especies de aves ameacadas e sua biota associada.

What is the avifauna of Amazonian white-sand vegetation?

White-sand vegetation (WSV) is a rare vegetation type in the Amazon basin that grows in nutrient impoverished sandy soils that occur as patches of variable size. Associated with this vegetation is bird assemblage that has not yet been fully characterized. Based on published species inventories and our own field data we compile a checklist of bird species recorded in WSV. In addition, we compared the avifauna of WSV with that found in savanna patches, another type of Amazonian open vegetation. WSV hosted a distinctive avifauna including endemic and threatened species. The number of bird species was lower in WSV compared to nearby terra firme forests, seasonally flooded forests and Amazonian savannas. Despite its low diversity, the avifauna of WSV has a distinctive species composition and makes a significant contribution to Amazonian beta diversity. At least 35 bird species can be considered as indicator species for this environment. Previously identified areas of endemism within the Amazon basin house at least one WSV indicator bird including cases of congeneric species with allopatric distributions. Seven of the WSV indicator species (20% of this avifauna) are in an IUCN threatened category, with one species Polioptila clementsi considered Critically Endangered. Their isolated distribution, small area occupied, and fragility to human-driven disturbances makes WSV one of the most threatened vegetation types in the Amazon basin. The study of WSV avifauna contributes to a better understanding of mechanisms that generate and maintain species diversity as well as of the environmental history of the most biologically diverse biome of the planet.

Range extension and conservation of Psophia interjecta Griscom & Greenway, 1937 (Aves: Psophidae) in the Tocantins–Araguaia interfluve, state of Tocantins, Brazil

The genus Psophia includes terrestrial birds endemic to the Amazon. The number of species in this genus is still controversial, with alternative taxonomic treatments currently available. We present new and historical records of P. interjecta for the state of Tocantins, which extend this species’ range to the Tocantins–Araguaia interfluve, in southeasternmost Amazonia. Psophia interjecta is considered Vulnerable in Brazil, but we discuss that the species is likely more Critically Endangered in Tocantins due to drastic deforestation and hunting.