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The efficiency of different methods to extract environmental DNA from freshwater samples of Solimões and Negro rivers
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Neogene paleoecology and biogeography of a Malvoid pollen in northwestern South America
No full textWestern Amazonian landscapes evolved dynamically during the Neogene. Large wetlands developed responding to Andean uplift what promoted the rise and diversification of many plant groups. One such group is the well-documented Malvoid pollen Malvacipolloides maristellae from the Miocene of northwestern South America. In the present contribution, we compared the botanical affinity among fossil and extant Malvoid, reconstructed past distributions of the taxa and their relative abundance throughout the Neogene-Quaternary, and interpreted the biogeographical and paleoecology of the group. We found similar pollen morphologies among the fossil and 14 extant Malvoids, mainly Allosidastrum, Sphaeralcea, Monteiroa, Malvella, and Wissadula. These belong to the Malveae tribe (subtribes Abutilinae and Malvinae), which are extra-Amazonian, mostly found in drier-colder settings, in full light environments (savannahs, forest edges), and tolerating varied oligotrophic and hydric stress soils. We recorded widespread Miocene populations of the fossil, from western Amazonia to coastal Venezuela, with high abundances in the early Miocene, when the group first appeared, then dropped significantly from the late Miocene onwards. The gradual demise of M. maristellae is attributed to the negative effects of brackish water inundations and the gradual increase of humidity and forest cover following the decline of wetlands that narrowed the open, light-demanding ecological niche exploited by M. maristellae. In the Pliocene-Quaternary, no records were found in western Amazonia, attesting to its final displacement outside the forest structure. In its northern extension (Venezuela and Colombia), the fossil survived for longer due to available open-dry environments that developed in the latest Neogene. © 2019 Elsevier B.V
Using Acoustic and Physiological Characteristics for Ecological Approaches of Birds in a Fragmented Landscape in Central Amazonia
No full textIn Amazon, the construction of hydroelectric dams is a growing factor in the biodiversity loss. In such environments, fragments acts as true islands, presenting low species richness on small islands. Consequently, tools that can monitor changes in communities are becoming increasingly important. In the first chapter, we evaluated the performance of seven acoustic indices (biodiversity indices based on the soundscapes analysis) in forest islands within an anthropogenic archipelago of central Amazonia, to address the following questions: (1) is there a relationship between bird richness and acoustic indices? (2) what is the relationship between soundscape patterns and landscape features such as island size? (3) how do soundscapes change throughout the day in islands of different sizes? and finally; (4) how do birds and cicadas use their acoustic space on islands of different sizes? In fragmented environments it is also necessary uncover the physiological mechanisms underlying the success of organisms living in disturbed habitats. In the second chapter, we use the corticosterone levels present in bird feathers as a measure of physiological stress, assessing whether corticosterone levels reflect the effects of landscape fragmentation related to the island size. For the first chapter, 12 islands and two areas of continuous forest were sampled. Using two autonomous recorders per area, one-minute recordings were made at five-minute intervals, for 24 hours, for three consecutive days. The acoustic indices exhibited different patterns, with marked changes between day and night. Our results show that five indices (acoustic complexity, acoustic diversity, acoustic entropy, median of the amplitude envelope and spectral flatness) reflect the species richness in each area. When we correlate the acoustic indices with island size, only the acoustic entropy index had significant results, presenting higher values with increasing area size. For the second chapter, we captured birds in 13 islands of varying size and in two continuous forests and analysed feather corticosterone levels of 265 individuals from eight different species. Our findings did not support the hypothesis that corticosterone varies in relation to island size, except for Hypocnemis cantator, which presented the predicted pattern: decreasing feather corticosterone levels with increasing island size. Overall, we conclude that even in a highly diverse environment, such as tropical forests, acoustic indices provide an excellent complementary tool for biodiversity assessment when provided with a ground-truthed database. Further studies are necessary to assess the reliability of corticosterone levels as a physiological measurement of stress and to determine which parameters are useful to understand how insularization caused by human activities may influence the resistance of avian populations to habitat disturbances.Na Amazônia, a construção de usinas hidrelétricas é uma ação que amplia a perda de biodiversidade. Nesses ambientes, fragmentos funcionam como ilhas verdadeiras, apresentando uma baixa riqueza de espécies em ilhas pequenas. Dessa maneira, ferramentas que possam monitorar mudanças nas comunidades estão se tornando cada vez mais importantes. No primeiro capítulo, avaliamos o desempenho de sete índices acústicos (índices de biodiversidade baseados na análise da paisagem acústica) em um ambiente fragmentado na Amazônia central, para acessar: (1) a relação entre riqueza de aves e índices acústicos; (2) os padrões da paisagem acústica associadas ao tamanho da ilha e (3) para caracterizar os padrões das paisagens acústicas nas ilhas ao longo de 24h. Em ambientes fragmentados também é necessário entender os mecanismos fisiológicos fundamentais ao sucesso dos organismos que vivem nesses ambientes. No segundo capítulo, usamos os níveis de corticosterona presentes nas penas das aves como uma medida dos indicadores fisiológicos de estresse, avaliando se os níveis de corticosterona refletem os efeitos da fragmentação do ambiente relacionados ao tamanho da ilha. No primeiro capítulo, foram amostradas 12 ilhas e duas áreas de floresta contínua. Utilizando dois gravadores autônomos por área, foram feitas gravações de um minuto com intervalos de cinco minutos, durante 24 horas, por três dias consecutivos. Os índices acústicos exibiram diferentes padrões, com mudanças marcantes entre dia e noite. Nossos resultados mostram que cinco índices (complexidade acústica, diversidade acústica, entropia acústica, mediana do envelope de amplitude e achatamento espectral) refletem a riqueza de espécies em cada área. Quando relacionamos os índices acústicos com o tamanho da ilha, apenas o índice de entropia acústica teve resultados significativos, apresentando valores mais altos com o aumento do tamanho da área. Para o segundo capítulo, capturamos aves em 13 ilhas de tamanho variável e duas áreas de floresta contínua e analisamos os níveis de corticosterona nas penas de 265 indivíduos de oito espécies diferentes. Nossos resultados não suportam a hipótese de que os níveis de corticosterona variam em relação ao tamanho da ilha, exceto para Hypocnemis cantator, que apresentou diminuição dos níveis de corticosterona com aumento do tamanho da ilha. No geral, concluímos que mesmo em um ambiente altamente diverso, como florestas tropicais, os índices acústicos fornecem uma excelente ferramenta complementar para a avaliação da biodiversidade quando fornecidos com um banco de dados fundamentado. Estudos adicionais são necessários para avaliar a eficiência do uso dos níveis de corticosterona como uma medida fisiológica do estresse e determinar quais parâmetros são úteis para entender como a insularização causada pelas atividades humanas pode influenciar a resistência das populações de aves a distúrbios no habitat
Five new species of Dolichomitus smith from the tropical andes, with a key for the south american species (Hymenoptera, ichneumonidae, pimplinae)
Get PDFDolichomitus Smith is a widely distributed pimpline genus with more than seventy known species. There are eight species previously reported from South America: D. annulicornis (Cameron), D. bivittatus Townes, D. hypermeces Townes, D. jatai Loffredo & Penteado-Dias, D. longicauda Smith, D. megalourus (Morley), D. moacyri Loffredo & Penteado-Dias and D. zonatus (Cresson). In this paper, we describe five new species: D. mariajosae Araujo & Pádua, sp. nov., D. menai Araujo & Pádua, sp. nov., D. orejuelai Araujo & Pádua, sp. nov., D. pimmi Araujo & Pádua, sp. nov., and D. rendoni Araujo & Pádua, sp. nov. All have been collected in cloud forests in the Colombian tropical Andes. An illustrated key to the South American species of the genus is also provided. © Rodrigo O. Araujo et al
An unusual new species of Pentaneura Philippi (Diptera: Chironomidae) from northeastern Brazil, with an emended diagnosis to the genus
No full textAbove-ground biomass estimation for a shrubby mistletoe in an Amazonian savanna
No full textMistletoes are considered keystone species on woodlands and savannas worldwide, providing a food resource for a diversified fauna, as well as a nutrient-enriched litter. Infections can be large (∼1-3 m) and, in some parts of the Amazonian savannas, parasitize up to 70% of hosts locally. Despite these facts, biomass of mistletoes is rarely investigated. Here we constructed allometric models to predict the biomass stock of the shrubby mistletoe Psittacanthus plagiophyllus in an Amazonian savanna. In addition, we determined whether host size could be used as a proxy for mistletoe biomass. Finally, we compared the biomass of mistletoes with that of trees, to evaluate their relative importance. We have shown that: (1) biomass of leaves (46.1% ± 13.5%) are as important as of stems (47.8% ± 13.5%), and relative contribution of stems increases as plant grows; (2) the model including width, breadth and vertical depth was the best (SE = 0.39, R2 = 0.9) for predicting individual mistletoe biomass; (3) mistletoe load and biomass per host had a positive, but weak (R2 = 0.11 and 0.09, respectively), relationship with host size, and thus such host information is a poor predictor of mistletoe biomass; and (4) in comparison with trees, mistletoes constituted less than 0.15% (0.5-22 kg ha-1) of the total above-ground biomass, suggesting that this life-form is irrelevant to the local biomass stock despite its unequivocal biological importance. © Cambridge University Press 2019
Display above courts of White-throated manakins: A new view about its display behavior
No full textIn order to breed successfully, organisms exhibit multiple strategies to enhance mate attraction, such as elaborate physical ornamentation, behavioral courtship displays, and social interactions, leading to competition or cooperation among potential mates. Within lek mating systems, species evolve under strong sexual selection, which promotes the evolution of exaggerated sexual traits such as male courtship displays. The White-throated manakin, Corapipo gutturalis, is a small Neotropical bird mating in leks where males display courtships to attract females. Their displays commonly take place on fallen logs on the forest floor, but there are descriptions of displays on higher forest stratum above the typical logs. In this study, we aimed at adding new behavioral information on the above-log displays and to compare them to log displays in their potential to attract females. For this, we conducted focal observations on seven display courts in two reproductive seasons for 193 hr and recorded above-log displays in four of the seven observed courts. Above-log displays were always performed in groups of up to four males from multiple ages and, on only two occasions, these displays ended on the display log. We recorded the same elements previously described during above-log displays for the species, besides the side-to-side slide that had not yet been registered for the species. Above-log displays included more males than log displays. However, there was no significant difference in the frequency of females visits to above-log displays or log displays and, likewise, the number of males engaging in the above-log displays did not determine female visits either. Thus, we found no evidence that above-log displays are more effective at attracting females than those on the log display. Since above-log displays are always in the presence of multiple males, we suggest that it may represent male–male competition to define male individuals accessing the display logs. © 2020 Blackwell Verlag Gmb
Different responses of dung beetle diversity and feeding guilds from natural and disturbed habitats across a subtropical elevational gradient
No full textUnderstanding the effects of natural and anthropogenic processes that drives biodiversity is urgently needed to improve conservation strategies at the landscape scale. Although natural drivers on altitudinal gradients have been well studied, the concatenated effect of habitat disturbance across different altitudes over biodiversity is still poorly known. We aimed to test the effect of habitat transformation on assemblage metrics of dung beetles across an altitudinal gradient (between 0 and 3400 m.a.s.l.; 18 elevational bands). Our results highlighted four main findings: (i) dung beetle forests or pastures specialized species changed their habitat specificity depending on the elevation range; (ii) a hump-shaped pattern of dung beetle diversity at intermediate elevations was found both in forests and pastures; (iii) species turnover was the main component of β diversity in both forest and pastures; (iv) presence of crops and human settlements across elevational gradient influenced changes the taxonomical and feeding guild composition of dung beetle assemblages, but these effects were elevation-site-dependent. These results suggest that the impacts of habitat disturbance on beetle assemblages caused by humans’ activities on mountains are spatial site dependents. We highlight the importance of understanding the effect of environmental disturbance in mountain ecosystems using a wide range of assemblage metrics. This research serves as basis for the development of efficient conservation strategies to protect species and ecosystem functions in these fragile environments. © 2020 Elsevier Masson SA
Biometrics and germination of Macrolobium acaciifolium (Benth.) Benth. seeds from floodplain and igapó in Central Amazonia [Biometria e germinação de sementes de Macrolobium acaciifolium (Benth.) Benth. de várzea e igapó da Amazônia Central]
No full textThis study focuses on the morphometric analysis of seeds of Macrolobium acaciifolium from environments of Amazonian floodplains and igapó, as well as the effect of the substrates of these areas on the germination and seedling formation of the species. A biometric analysis of 200 M. acaciifolium seeds from populations of both Central Amazon environments was performed. In greenhouse, germination of seeds under their soil of origin and under vermiculite was analyzed. The seeds from igapó presented higher mean weight and thickness compared to the floodplain seeds, which, on occasion, presented higher averages of length and width. The seed germination percentage of both environments was similar, but the speed was higher for the igapó seeds, regardless of the substrate. The igapó seeds are larger than the floodplain seeds and, because they have more reserves, they are able to produce more vigorous seedlings, regardless the physical conditions of the substrate. © 2020 Fundacao Zoobotanica do Rio Grande do Sul. All rights reserved