amazon basin
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2024 ◽  
Vol 84 ◽  
Author(s):  
F. M. Dutra-Vieira ◽  
M. S. Silva ◽  
G. S. Vieira ◽  
A. S. Carvalho ◽  
B. C. Schimming

Abstract The present study aimed to evaluate the diet of the free-living crab-eating fox by identifying the stomach contents of the 17 crab-eating foxes (Cerdocyon thous) roadkilled in two conservation units, both located in the Amazon rainforest. The food items were quantified by frequency of occurrence (FO) and percentage of occurrence (PO). The stomach contents were analysed for dry matter (DM), crude protein (CP), crude fibre (CF), ether extract (EE), and mineral matter (MM). Nitrogen-free extractives (NFE), metabolisable energy (ME) values, as well as the energy need for maintenance were estimated. The composition of the diet for the crab-eating fox presented 29 food items from the different taxonomic groups, with a greater diversity of items of animal origin (n=22), although the highest frequency of occurrence was gramineae (Poaceae) (41.18%). Among the items of animal origin, 21% were mammals, 18% reptiles, 10% amphibians, 9% invertebrates and 3% birds. A high content of CF (62.76%) were determined. Nitrogen-free extractive and dry matter averages were 5.91% and 141.82 kcal/100g, respectively. The average maintenance energy was 447.01 kcal/day. These findings suggesting that the crab-eating foxes have a generalist diet with an omnivorous diet in the Amazon basin, feeding on gramineae, fruits, insects, snakes, amphibians, birds and small mammals and have the same feeding habit that present in other Brazilian biomes.


2022 ◽  
Vol 92 (1) ◽  
pp. 32-49
Author(s):  
Jonathan Ledesma ◽  
Cecilia E. Del Papa ◽  
Patricio Payrola

Abstract The Puna–Altiplano Plateau of the Central Andes is the second-highest plateau in the world (after Tibet), with a mean elevation of 4000 m.a.s.l. and an arid to hyperarid climate. Uplift of the Puna–Altiplano Plateau has affected lower-level atmospheric circulation, acting as a barrier to humid easterly winds from the Amazon basin and favoring an across-strike precipitation gradient resulting in a humid climate towards the east of the plateau and an arid to hyperarid climate in the orogen's interior. In the modern climate, the Bolivian High anticyclone regulates upper troposphere circulation, but little is known about the high-altitude tropospheric circulation of the past. This work focuses on the eolian record of the San Antonio de los Cobres basin along the eastern border of the Puna Plateau, NW Argentina, with the aim of analyzing its origin and thus elucidating the late Miocene winds. The eolian deposits are constrained by 7.8 Ma (K/Ar and U/Pb) and 6.4 Ma (U/Pb) ignimbrites at the nearly basal and upper contacts, respectively. Based on stratigraphic, sedimentological, and provenance analysis of the eolian units, we have identified three main facies associations (FAs): FA1) cross-stratified sandstones with large- to small-scale tabular, planar cross-bedding and with trough cross-stratification; FA2) sandstones with planar to low-angle stratification associated with thinly laminated ripple sandstone strata; FA3) medium- to coarse-grained massive sandstones associated with pebbly to bouldery, matrix-supported conglomerates and clast-supported conglomerates. The lateral and vertical facies assemblages indicate a dune field confined to topographic depressions dominated by transverse dunes with straight and sinuous crestlines that laterally grade into sandsheets associated with ephemeral streams. Paleoflows, lithotypes, and grain-size determinations indicate a persistent north-northwest provenance and wind velocities of 24–38 km/h (with maximum velocities of 55–75 km/h). The results of our analysis coupled with data from previous studies indicates that, for at least the last ca. 8 Myr, the winds have been blowing constantly from the north-northwest with an intensity similar to the present. This implies that the paleo-atmospheric circulation had a similar pattern to the present-day one. Therefore, we conclude that the upper-troposphere circulation in the Puna Plateau of NW Argentina was already regulated by the Bolivian High anticyclone during the Miocene, generating constant north-northwesterly winds.


2022 ◽  
Vol 23 (1) ◽  
Author(s):  
Rogério Ribeiro Marinho ◽  
Naziano Pantoja Filziola ◽  
Jean-Michel Martinez ◽  
Tristan Harmel

2022 ◽  
Vol 14 (2) ◽  
pp. 338
Author(s):  
Carlos Antonio da Silva Junior ◽  
Mendelson Lima ◽  
Paulo Eduardo Teodoro ◽  
José Francisco de Oliveira-Júnior ◽  
Fernando Saragosa Rossi ◽  
...  

The Amazon Basin is undergoing extensive environmental degradation as a result of deforestation and the rising occurrence of fires. The degradation caused by fires is exacerbated by the occurrence of anomalously dry periods in the Amazon Basin. The objectives of this study were: (i) to quantify the extent of areas that burned between 2001 and 2019 and relate them to extreme drought events in a 20-year time series; (ii) to identify the proportion of countries comprising the Amazon Basin in which environmental degradation was strongly observed, relating the spatial patterns of fires; and (iii) examine the Amazon Basin carbon balance following the occurrence of fires. To this end, the following variables were evaluated by remote sensing between 2001 and 2019: gross primary production, standardized precipitation index, burned areas, fire foci, and carbon emissions. During the examined period, fires affected 23.78% of the total Amazon Basin. Brazil had the largest affected area (220,087 fire foci, 773,360 km2 burned area, 54.7% of the total burned in the Amazon Basin), followed by Bolivia (102,499 fire foci, 571,250 km2 burned area, 40.4%). Overall, these fires have not only affected forests in agricultural frontier areas (76.91%), but also those in indigenous lands (17.16%) and conservation units (5.93%), which are recognized as biodiversity conservation areas. During the study period, the forest absorbed 1,092,037 Mg of C, but emitted 2908 Tg of C, which is 2.66-fold greater than the C absorbed, thereby compromising the role of the forest in acting as a C sink. Our findings show that environmental degradation caused by fires is related to the occurrence of dry periods in the Amazon Basin.


Genes ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 113
Author(s):  
Carla L. Saldaña ◽  
Pedro Rodriguez-Grados ◽  
Julio C. Chávez-Galarza ◽  
Shefferson Feijoo ◽  
Juan Carlos Guerrero-Abad ◽  
...  

Capirona (Calycophyllum spruceanum Benth.) belongs to subfamily Ixoroideae, one of the major lineages in the Rubiaceae family, and is an important timber tree. It originated in the Amazon Basin and has widespread distribution in Bolivia, Peru, Colombia, and Brazil. In this study, we obtained the first complete chloroplast (cp) genome of capirona from the department of Madre de Dios located in the Peruvian Amazon. High-quality genomic DNA was used to construct libraries. Pair-end clean reads were obtained by PE 150 library and the Illumina HiSeq 2500 platform. The complete cp genome of C. spruceanum has a 154,480 bp in length with typical quadripartite structure, containing a large single copy (LSC) region (84,813 bp) and a small single-copy (SSC) region (18,101 bp), separated by two inverted repeat (IR) regions (25,783 bp). The annotation of C. spruceanum cp genome predicted 87 protein-coding genes (CDS), 8 ribosomal RNA (rRNA) genes, 37 transfer RNA (tRNA) genes, and one pseudogene. A total of 41 simple sequence repeats (SSR) of this cp genome were divided into mononucleotides (29), dinucleotides (5), trinucleotides (3), and tetranucleotides (4). Most of these repeats were distributed in the noncoding regions. Whole chloroplast genome comparison with the other six Ixoroideae species revealed that the small single copy and large single copy regions showed more divergence than inverted regions. Finally, phylogenetic analyses resolved that C. spruceanum is a sister species to Emmenopterys henryi and confirms its position within the subfamily Ixoroideae. This study reports for the first time the genome organization, gene content, and structural features of the chloroplast genome of C. spruceanum, providing valuable information for genetic and evolutionary studies in the genus Calycophyllum and beyond.


Insects ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 58
Author(s):  
Luiz Felipe Lima da Silveira ◽  
William Lima ◽  
Cláudio Ruy Vasconcelos da Fonseca ◽  
Joseph McHugh

Most firefly genera have poorly defined taxonomic boundaries, especially in the Neotropics, where they are more diverse and more difficult to identify. Recent advances that shed light on the diversity of fireflies in South America have focused mainly on Atlantic Rainforest taxa, whereas lampyrids in other biomes remained largely unstudied. We found three new firefly species endemic to the Amazon basin that share unique traits of the male abdomen where sternum VIII and the pygidium are modified and likely work as a copulation clamp. Here we test and confirm the hypothesis that these three species form a monophyletic lineage and propose Haplocauda gen. nov. to accommodate the three new species. Both maximum parsimony and probabilistic (Bayesian and maximum likelihood) phylogenetic analyses confirmed Haplocauda gen. nov. monophyly, and consistently recovered it as the sister group to Scissicauda, fireflies endemic to the Atlantic Rainforest that also feature a copulation clamp on abdominal segment VIII, although with a different configuration. We provide illustrations, diagnostic descriptions, and keys to species based on males and females. The three new species were sampled from different regions, and are likely allopatric, a common pattern among Amazonian taxa.


PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0262357
Author(s):  
Cédric Mariac ◽  
Fabrice Duponchelle ◽  
Guido Miranda ◽  
Camila Ramallo ◽  
Robert Wallace ◽  
...  

To date, more than 2400 valid fish species have been recorded in the Amazon basin. However, some regions remain poorly documented. This is the case in the Beni basin and in particular in one of its main sub-basins, the Tuichi, an Andean foothills rivers flowing through the Madidi National Park in the Bolivian Amazonia. The knowledge of its ichthyological diversity is, however, essential for the management and protection of aquatic ecosystems, which are threatened by the development of infrastructures (dams, factories and cities), mining and deforestation. Environmental DNA (eDNA) has been relatively little used so far in the Amazon basin. We sampled eDNA from water in 34 sites in lakes and rivers in the Beni basin including 22 sites in the Tuichi sub-basin, during the dry season. To assess the biogeographical patterns of the amazonian ichthyofauna, we implemented a metabarcoding approach using two pairs of specific primers designed and developed in our laboratory to amplify two partially overlapping CO1 fragments, one of 185bp and another of 285bp. We detected 252 fish taxa (207 at species level) among which 57 are newly identified for the Beni watershed. Species compositions are significantly different between lakes and rivers but also between rivers according to their hydrographic rank and altitude. Furthermore, the diversity patterns are related to the different hydro-ecoregions through which the Tuichi flows. The eDNA approach makes it possible to identify and complete the inventory of the ichthyofauna in this still poorly documented Amazon basin. However, taxonomic identification remains constrained by the lack of reference barcodes in public databases and does not allow the assignment of all OTUs. Our results can be taken into account in conservation and management strategies and could serve as a baseline for future studies, including on other Andean tributaries.


Author(s):  
Andrenilton Silva ◽  
Artur Barros ◽  
Alek Sousa ◽  
Daniel Jarvie ◽  
Sebastian Calderón ◽  
...  

The Barreirinha Formation-Upper Devonian, is the main petroleum source rock of the Amazon Basin, deposited during the great Devonian Transgression, contributing to significant accumulations of organic matter (OM) in anoxic conditions, which allowed its preservation. The present work had the objective of characterizing the molecular composition of biomarkers in outcrops samples of the Barreirinha Formation, aiming to evaluate the paleoenvironment, thermal evolution, and the preservation of OM total organic carbon (TOC) and Rock-Eval pyrolysis indicate considerable amounts of immature OM deposited in a low oxygenation environment. Gas chromatographymass spectrometry (GC-MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS) data corroborate that the OM was deposited in a suboxic to the oxic environment and low salinity (absence or low relative abundance of β-carotane and gammacerane). 24-N-Propyl-cholestane was detected and identified by synthetic pattern co-injection. High concentrations of tetracyclic polyprenoids (TPPs) in ascending order from base to top, high hopane/sterane ratios, to suggest that the samples had a high molecular weight n-alkanes, C29 steranes, low thermal evolution, and anoxic depositional paleoenvironment.


2022 ◽  
Vol 805 ◽  
pp. 150334
Author(s):  
Marcela Cabrera ◽  
Gabriel M. Moulatlet ◽  
Bryan G. Valencia ◽  
Luis Maisincho ◽  
Rocío Rodríguez-Barroso ◽  
...  

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