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Digital approach for measuring tree diameters in the Amazon forest
Get PDFButtresses and other natural structures modify the shape of stems in Amazonia and change the diameter at breast height (DBH) measured at 1.3 m at ground level. The lack of adequate measurement techniques affects negatively forest dynamics analyses and biomass estimating. The study evaluated an indirect method of measuring diameters in trees with DBH > 40 cm using principles of digital photogrammetry. The results obtained with two cameras (smartphone and Sony) were compared with direct measurements using diametric tape and a ladder. The technique is adequate to measure the diameters of trees with measurement point above 2 m of ground, with a confidence interval of ±1cm. The use of photogrammetry as a supplementary tool to the diametric tape (IC ± 0.24 cm) is recommended, helping to measure trees with diameter above the reach of the technician in forest inventories. © 2019 Universidade Federal Rural do Rio de Janeiro (UFRRJ)
Diet of five anuran species in a forest remnant in eastern acre state, Brazilian Amazonia
Get PDFThe diet of anuran species is based on a large variety of prey items, which may be related to the availability of prey in the environment. In Amazonia, studies on the diet of anurans have occurred mainly in primary forests. Because forest fragmentation promotes changes in the environment, it is expected that the diet of anuran species will also be affected. Here we describe the diet composition of anurans captured in a forest remnant at Fazenda Amoty, municipality of Plácido de Castro, state of Acre, Brazil. Stomach contents of 34 specimens of Allobates femoralis (Aromobatidae), Adenomera hylaedactyla, Engystomops freibergi (Leptodactylidae), Rhinella sp. (Bufonidae), and Elachistocleis muiraquitan (Microhylidae) had 877 prey items belonging to 19 prey categories. The diet of most species were arthropods. Myrmicinae ants (Hymenoptera, Formicidae) was the most abundant and frequent item in A. hylaedactyla, Rhinella sp. and A. femoralis stomachs. Termitidae (Isoptera) was the second most abundant taxon in Rhinella sp. and A. hylaedactyla, and the only taxon found eaten by E. freibergi and E. muiraquitan. Most studied species showed generalist diet, which is the habit for most anuran species. Contrarily, E. freibergi and E. muiraquitan are likely specialized in Isoptera. © 2019, Societas Europaea Herpetologica. All rights reserved
Extensive Chromosomal Reorganization in Apistogramma Fishes (Cichlidae, Cichlinae) Fits the Complex Evolutionary Diversification of the Genus
Get PDFNeotropical cichlid fishes are one of the most diversified and evolutionarily successful species assemblages. Extremely similar forms and intraspecific polychromatism present challenges for the taxonomy of some of these groups. Several species complexes have a largely unknown origin and unresolved evolutionary processes. Dwarf cichlids of the genus Apistogramma, comprising more than a hundred species, exhibit intricate taxonomic and biogeographic patterns, with both allopatric and sympatric distributions. However, karyotype evolution and the role of chromosomal changes in Apistogramma are still unknown. In the present study, nine South American Apistogramma species were analyzed using conventional cytogenetic methods and the mapping of repetitive DNA sequences [18S rDNA, 5S rDNA, and (TTAGGG)n] by fluorescence in situ hybridization (FISH). Our results showed that Apistogramma has unique cytogenetic characteristics in relation to closely related groups, such as a reduced 2n and a large number of bi-armed chromosomes. Interspecific patterns revealed a scenario of remarkable karyotypic changes, including a reduction of 2n, the occurrence of B-chromosomes and evolutionary dynamic of rDNA tandem repeats. In addition to the well-known pre-zygotic reproductive isolation, the karyotype reorganization in the genus suggests that chromosomal changes could act as postzygotic barriers in areas where Apistogramma congeners overlap
Interspecific genetic differences and historical demography in South American arowanas (Osteoglossiformes, Osteoglossidae, Osteoglossum)
Get PDFThe South American arowanas (Osteoglossiformes, Osteoglossidae, Osteoglossum) are emblematic species widely distributed in the Amazon and surrounding basins. Arowana species are under strong anthropogenic pressure as they are extensively exploited for ornamental and food purposes. Until now, limited genetic and cytogenetic information has been available, with only a few studies reporting to their genetic diversity and population structure. In the present study, cytogenetic and DArTseq-derived single nucleotide polymorphism (SNP) data were used to investigate the genetic diversity of the two Osteoglossum species, the silver arowana O. bicirrhosum, and the black arowana O. ferreirai. Both species differ in their 2n (with 2n = 54 and 56 for O. ferreirai and O. bicirrhosum, respectively) and in the composition and distribution of their repetitive DNA content, consistent with their taxonomic status as different species. Our genetic dataset was coupled with contemporary and paleogeographic niche modeling, to develop concurrent demographic models that were tested against each other with a deep learning approach in O. bicirrhosum. Our genetic results reveal that O. bicirrhosum colonized the Tocantins-Araguaia basin from the Amazon basin about one million years ago. In addition, we highlighted a higher genetic diversity of O. bicirrhosum in the Amazon populations in comparison to those from the Tocantins-Araguaia basin. © 2019 by the authors. Licensee MDPI, Basel, Switzerland
Atividade larvicida de Metarhizium anisopliae e Beauveria bassiana em Anopheles darlingi Root 1926 (Diptera: Culicidae)
No full textFrom a bat's perspective, protected riparian areas should be wider than defined by Brazilian laws
No full textRiparian areas around streams are those areas in which biological communites are directly influenced by the stream. The size of protected riparian areas and their conservation has become a controversial topic after changes implemented in the Brazilian Forest Code (BFC): a set of laws that regulates the size of Permanent Protection Areas (PPA). Here, we investigate the influence of distance from water bodies on bat-species and guild composition in a lowland Amazonian rainforest. Our hypotheses were that bat assemblages would change depending on the distance to the water body and that the abundance of herbivorous bats (frugivorous and nectarivorous) would be greater in areas close to water. Bats were captured with mist-nets in 24 riparian and 25 non-riparian plots within a trail grid in an old-growth terra-firme forest, northeast of Manaus, Amazonas, Brazil. Each plot was sampled three times in a total of 7056 net-hours. We captured 1191 bats, comprising 51 species. We used model selection based on AIC (Akaike Information Criterion) to compare linear and piecewise regressions to estimate the ecological thresholds for different bat assemblages. Piecewise models with one breakpoint were more parsimonious than linear models for abundance data, and the species and guild composition of animalivorous and frugivorous bats. Animalivorous-bat abundance increased from the stream to about 181 m, and frugivorous-bat abundance decreased within 50 m of the stream. The patterns of guild abundance suggest that frugivorous bats may need greater access to streams than animalivorous bats. The most conservative model suggests that most of the variation in bat composition occurs close to the stream and extends to up 114 m from the banks. Therefore, the 30 m wide strip of riparian forest protected by Brazilian law would maintain a relatively small fraction of bat-species assemblages in Ducke Reserve, and is insufficient to represent most of the assemblage-composition variation within the riparian zone. The suggestion to reduce the width of the protected riparian zone from 30 to 15 m for streams smaller than 10 m wide, as is under discussion, would likely be prejudicial for bat assemblages. © 2018 Elsevier Lt
