Avifauna montana do Pantepui: modelos de distribuição de espécies e estudo de caso na Serra da Mocidade, Roraima, Brasil

Located on the Guiana Shield, the Pantepui is a biogeographic region formed by tabular mountains, known as tepuis, of great scientific interest due to their endemic biota and notorious inaccessibility. Ecologically, Pantepui incorporates other types of mountain ranges, with distinct shape and geological origin, but which harbor species considered typical of this region. The majority of Pantepui is located in Venezuela, but it also expands to bordering regions of Brazil and Guyana and isolated components in Colombia and Suriname. After almost two centuries of ornithological studies, knowledge about the Pantepui avifauna is still far from complete. Ornithological expeditions have historically prioritized large tepuis, usually in Venezuela; however, recent studies have revealed the presence of a typical tepui avifauna in smaller and more isolated mountain ranges, increasing knowledge about the distribution of these species. The main objective of this work is, based on points of occurrence extracted from an extensive bibliographical survey and cietific collections, to model the distribution of montane bird species to predict which localities, within the geographical extension of Pantepui, have high environmental suitability for the occurrence of these species. Subsequently, we tested the accuracy of the models by comparing the predicted values of environmental suitability with empirically obtained field records during an expedition to Serra da Mocidade, a previously unexplored mountain range in the state of Roraima, northern Brazilian Amazonia. Besides the occurrence of tepui species, the Serra da Mocidade presents interesting biogeographic characteristics such as the longitudinally central location in Pantepui and its pronounced isolation, surrounded by lowlands, favoring the occurrence of endemic species that, since it is a place never studied before, would necessarily represent taxa new to science. We used the MaxEnt algorithm to model the distribution of 94 species considered characteristic of Pantepui, those absent from the adjacent lowlands or endemics of one or more of the mountains. To generate environmental suitability, we used a package of bioclimatic variables and altitude. In order to compare the predicted results with the records obtained in Serra da Mocidade, we extracted from the models the maximum suitabilityix value in the area sampled during the expedition. We defined a threshold of suitability to determine the species expected to occur in the Serra da Mocidade. Of the 121 typical Pantepui bird species, it was possible to model 94, of which 41 were recorded on Mocidade; all but three of these were predicted to occur. Of the other 53 Pantepui species not found on Serra da Mocidade, many were predicted to occur. We believe that most of these absences are related to the lack of appropriate habitat on Serra da Mocidade, and therefore, to the lack of adequate variables in the model, or to the intrinsic dispersion capacity of the species, which becomes unable to colonize Serra da Mocidade due to its high degree of isolation. This study adds knowledge about the montane bird species of Pantepui, a region that is very little studied relative to the lowlands that surround it, mainly due to the great difficulty of access. The results highlight the importance of empirical validation on spatial projections of species distribution models. It also emphasizes the relevance of an island biogeography perspective and the importance of studies in smaller or more isolated mountains of this biogeographic region, since these mountain ranges affords important tests of dispersal and colonization capacity, provide information on habitat preferences, and potentially enlarge the distribution of species, thus increasing knowledge of the natural history of the entire Pantepui.Localizado no Escudo da Guianas, o Pantepui é uma região biogeográfica formada por montanhas tabulares, conhecidas como tepuis, de grande interesse científico devido sua biota endêmica e notória dificuldade de acesso. Ecologicamente, o Pantepui abrange outras formações serranas, com formato e origem geológica distintos, mas que aportam espécies consideradas típicas desta região. A maioria do Pantepui se encontra na Venezuela mas também se expande para regiões limítrofes de Brasil e Guiana e componentes isolados na Colômbia e Suriname. Após quase dois séculos de estudos ornitológicos, o conhecimento sobre a avifauna do Pantepui ainda permanece longe de estar completo. Expedições ornitológicas historicamente priorizaram tepuis de grande porte, geralmente na Venezuela, porém estudos recentes revelaram a presença de uma avifauna típica de tepuis em formações serranas menores e mais isoladas, aumentando o conhecimento sobre a distribuição das espécies. O objetivo principal deste trabalho é, com base em pontos de ocorrência extraídos de extenso levantamento bibliográfico e coleções científicas, fazer a modelagem da distribuição de espécies de aves montanas para assim prever quais localidades, dentro da extensão geográfica do Pantepui, têm alta adequabilidade ambiental para ocorrência destas. Subsequentemente, testamos a acurácia dos modelos através da comparação dos valores de adequabilidade ambiental previstos com registros obtidos empiricamente em campo durante expedição à Serra da Mocidade, uma formação serrana previamente inexplorada, no estado de Roraima, norte da Amazônia brasileira. Além de ocorrência de espécie dos tepuis, a Serra da Mocidade apresenta características biogeográficas interessantes como sua localização longitudinalmente central no Pantepui e o pronunciado isolamento, rodeada por terras baixas, favorecendo a possibilidade da ocorrência de espécies endêmicas que, por ser uma localidade nunca antes estudada, necessariamente representariam novos táxons para a ciência. Utilizamos o algoritmo MaxEnt para modelar a distribuição de 94 espécies consideradas características do Pantepui, aquelas ausentes das terras baixas adjacentes ou endêmicas de uma ou mais montanhas. Para gerar a adequabilidade ambiental, utilizamos variáveis bioclimáticas e altitude. Para comparar os resultados previstos com os registros obtidos na Serra da Mocidade, extraímos dos modelos o valor máximo de adequabilidade na áreavii amostrada durante a expedição. Definimos um limiar de adequabilidade para determinar as espécies esperadas que ocorressem na Serra da Mocidade. Das 121 espécies de pássaros típicas do Pantepui, foi possível modelar 94, das quais 41 foram registradas na Serra da Mocidade; todas, exceto três, tiveram ocorrência prevista. Das outras 52 espécies do Pantepui não encontradas na Serra da Mocidade, muitas tiveram ocorrência prevista. Acreditamos que a maior parte destas ausências estão relacionadas à falta de habitat adequado na Mocidade, e portanto, à falta de variáveis adequadas no modelo, ou à capacidade de dispersão intrínsecas às espécies, incapazes de colonizar a Serra da Mocidade devido ao seu alto grau de isolamento. Este estudo agrega conhecimento sobre as espécies de aves montanas do Pantepui, região pouco estudada em relação às terras baixas que a circundam, principalmente devido à grande dificuldade de acesso. Os resultados salientam a importância da validação empírica sobre projeções espaciais de modelos de distribuição de espécies. Eles também enfatizam a relevância da perspectiva biogeográfica insular e a importância dos estudos em montanhas menores ou mais isoladas desta região biogeográfica, uma vez que estas formações serranas proporcionam testes importantes da capacidade de dispersão e colonização, fornecem informações sobre preferências de hábitat e potencialmente ampliam a distribuição de espécies, aumentando assim o conhecimento da história natural de todo o Pantepui

Three bird species new to Brazil from the serra da mocidade, a remote mountain in Roraima

From 15 January to 06 February 2016, we conducted an expedition to the Serra da Mocidade, a remote and previously unexplored mountain range in extreme northern Amazonian Brazil. There we encountered three bird species never before documented in Brazilian territory: Grallaria guatimalensis (Grallariidae) was photographed, audio recorded, video recorded and a single specimen collected; Catharus aurantiirostris (Turdidae) was similarly documented and a series of specimens collected; and a single individual of Parkesia motacilla (Parulidae) was photographed. All were found in the understory of montane forest at 1000–1550 m elevation. We interpret each of these as most likely representing a regularly occurring population on Mocidade. However, each had probably been overlooked in Brazil for a different reason and represents a distinct distributional pattern. Adding these novelties to Brazil's previously published total of 1919 species clearly expresses the country's position among the most bird-rich in the world, perhaps the richest, and suggests that further exploration of Brazil's Amazonian mountains will yield more discoveries. © 2019, Sociedade Brasileira de Ornitologia. All rights reserved

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Ticks on birds caught on the campus of the Federal Rural University of Rio de Janeiro, Brazil Carrapatos em aves capturadas no campus da Universidade Federal Rural do Rio de Janeiro, Brasil

The prevalence of parasitic infections, particularly those caused by ectoparasites, may influence the biology and ecology of wild birds. The aim of this study was to investigate occurrences and identify the species of ticks collected from wild birds caught on the campus of the Federal Rural University of Rio de Janeiro. The birds were caught using mist nets between October 2009 and December 2010. In total, 223 birds were caught, represented by 53 species and 19 families in nine orders. Nineteen birds (n = 7 species) were parasitized by immature ticks (prevalence of 8.5%). Forty-four ticks were collected, of which 23 were nymphs and 21 were larvae. There were associations between parasitism by ticks and non-Passeriformes birds, and between parasitism and ground-dwelling birds, which was possibly due to the presence (or inclusion among the captured birds) of Vanellus chilensis (Charadriiformes: Charadriidae). All the nymphs collected were identified as Amblyomma cajennense. In general terms, we must emphasize that wild birds in the study area may play the role of dispersers for the immature stages of A. cajennense, albeit non-preferentially.<br>A prevalência das infecções parasitárias e em particular, aquelas causadas por ectoparasitos, pode influenciar na biologia e ecologia das aves silvestres. O objetivo do estudo foi investigar a ocorrência e identificar as espécies de carrapatos coletadas em aves silvestres capturadas no campus da Universidade Federal Rural do Rio de Janeiro. As aves foram coletadas em rede-de-neblina durante o período de outubro de 2009 a dezembro de 2010. No total foram capturadas 223 aves representadas por 53 espécies, 19 famílias em 9 ordens. Parasitismo por formas imaturas de carrapatos, foram encontradas em 19 aves (n = 7 espécies) correspondendo a uma prevalência de 8,5%. Foram coletados 44 carrapatos onde 23 estavam em estágio de ninfa e 21 em estágio de larva. Houve associação entre o parasitismo por carrapatos e aves não Passeriformes e entre o parasitismo e aves de hábitos terrestres capturadas, que se deu possivelmente pela presença (ou inclusão da captura) de Vanellus chilensis (Charadriiforme: Charadriidae). Todas as ninfas coletadas foram identificadas como Amblyomma cajennense. De modo geral, devemos ressaltar que aves silvestres da área estudada podem exercer papel de dispersoras, ainda que não preferenciais, para estágios imaturos de A. cajennense

Coccidial dispersion across trans- and cis-Andean antbirds (Passeriformes: Thamnophilidae): Isospora sagittulae (Apicomplexa: Eimeriidae) from nonsympatric hosts

Isospora sagittulae McQuistion and Capparella, 1992 (Protozoa: Apicomplexa: Eimeriidae) is reported from Whitethroated Antbirds (Gymnopithys salvini (Berlepsch, 1901)) and from Common Scale-backed Antbirds (Willisornis poecilinotus (Cabanis, 1847)), which are thamnophilid birds from the Brazilian Amazon. Its oocysts are ovoidal to ellipsoidal, 28.4 μm × 22.4 μm, with smooth, bilayered wall, 1.1 μm. Micropyle and oocyst residuum are absent, but one to three polar granules are present. Sporocysts are subspherical to ovoidal, 15.0 μm× 12.6 μm. Stieda body thin and flattened and substieda body triangular to round. Sporocyst residuum composed of scattered granules. Sporozoites with refractile body and nucleus. This coccidium was originally described from the Spotted Antbird (Hylophylax naevioides (Lafresnaye, 1847)), a trans-Andean antbird that is not sympatric with G. salvini and W. poecilinotus, which are cis-Andean antbirds from lowland Amazon forest; therefore, this current study presents some assumptions to explain the dispersion of I. sagittulae among antbird species