Explorando o nicho de peixes de água doce: Uma abordagem evolutiva e conservacionista em igarapés de terra firme Amazônicos

The main threats to freshwater ecosystems and organisms are habitat alteration by anthropic impact. The vulnerability of these ecosystems has been discussed over the last decade; however, little attention has been given to protect these ecosystems. The most threatened vertebrates are the freshwater fishes, whose highest richness is in the Amazon basin, as the widest gap of information, especially for stream species. Species distribution modeling (SDM) has become an important tool in ecology, biogeography, evolution and conservation studies. SDM is based on a set of macroscale variables that determine the distribution of organisms. Thus, a set of environmental variables are used as an input for these models. However, insufficient attention is given to discussing the use of these environmental data for the modeling of aquatic organisms. Freshwater ecosystems are dependent on the surrounding landscape, and some models built with macroscale variables yielded similar results as models based on local variables for distribution of aquatic organisms. The knowledge of species ecological requirements could help understanding the local and/or regional biodiversity. Some authors attribute the high diversity of species in the tropics to conservation niche. They state that the diversity is due to the climatic stability of these regions, and that clades have more time to diversify. This tendency for close related species to have similar fundamental or realized niches is known as Phylogenetic Niche Conservatism. The conservatism of ecological niches could determine environmental conditions in which a taxon of a particular clade can be occupied by dispersing. Conversely, species that retain their niche for long periods of time could have difficulty adapting to environmental changes, and this characteristic could lead them to extinction. Thus, we tested whether the Amazon stream fishes are formally protected by the Amazon Protected Areas (PAs), the Megareserves.As principais ameaças aos sistemas e os organismos de água doce são as alterações direta do habitat pelo impacto antrópico. A vulnerabilidade desses ecossistemas tem sido discutida nas últimas décadas, entretanto, pouco se tem feito para a conservação desses sistemas. Hoje em dia o grupo de vertebrados mais ameaçados são os peixes de água doce, a maior riqueza desse grupo está na bacia Amazônica, juntamente com as maiores lacunas de informação, principalmente sobre espécies de peixes de igarapés. A modelagem de distribuição de espécies (MDE) tem se tornado uma importante ferramenta em estudos de ecologia, biogeografia, evolução e conservação, especialmente em áreas com lacunas de informação. Isso é devido ao fato da MDE ser baseada em variáveis climáticas de macroescala que determinam a distribuição dos organismos. Entretanto, pouco se discute sobre o uso dessas variáveis ambientais de macroescala para a modelagem de organismos aquáticos. Sabe-se que os ecossistemas aquáticos são dependentes das paisagens que os cercam, assim, alguns modelos construídos com variáveis de macroescala obtiveram resultados semelhantes aos modelos baseados em variáveis locais para a distribuição de espécies aquáticas. Isso possibilita compreender as exigências ecológicas das espécies podendo auxiliar no entendimento sobre a biodiversidade local e/ou regional, especialmente em áreas pouco conhecidas como os trópicos. Alguns autores argumentam que a diversidade nos trópicos é devida à estabilidade climática dessas regiões, fazendo com que os clados tivessem mais tempo para se diversificar, e atribuem essa diversidade de espécies à conservação de nicho. Essa tendência de espécies filogeneticamente próximas terem o nicho fundamental ou realizado similares é conhecida como Conservação Filogenética do Nicho. Essa característica, de manter o nicho conservado ao longo do tempo, pode determinar em que condições ambientais um táxon de um determinado clado pode ocupar ou tolerar. Por outro lado, espécies que retêm seu nicho similar por longos períodos podem ter dificuldade em se adaptarem a mudanças no nicho, podendo levá-las a extinção, tornando-as mais vulneráveis em relação aos impactos antrópicos. Uma das formas de tentar barrar esse impacto é através das Áreas Protegidas (APs). A região Amazônica possui as maiores APs do Brasil, entretanto, elas não foram idealizadas para proteger organismos aquáticos. Assim, esse estudo teve como um dos objetivos relacionar o nicho Grinneliano dessas espécies com variáveis locais, para obter melhores modelos para essas espécies. Dentro dessa abordagem do Nicho Grinneliano ter uma boa correlação com as características limnológicas, também exploramos a evolução desse nicho ao longo do tempo evolutivo. Por fim, verificamos se as espécies de peixes de igarapés Amazônicos são protegidas formalmente pelas Áreas Protegidas da Amazônia legal Brasileira, as Megareservas. Uma vez que para a criação e implementação dessas áreas foram somente considerando ecossistemas e organismos terrestres, e áreas de alta pressão antrópica. Assim, as diferentes formas em que o nicho dessas espécies foi explorado mostrou que, apesar de se conhecer pouco sobre esses organismos, eles são altamente vulneráveis aos impactos antrópicos, e precisam ser incluídos nos planejamentos sistemáticos a para conservação da Amazônia

Phylogeography and conservation genetics of the Amazonian freshwater stingray Paratrygon aiereba Müller & Henle, 1841 (Chondrichthyes: Potamotrygonidae)

The family Potamotrygonidae is monophyletic comprising three genera: Paratrygon Duméril, Potamotrygon Garman and Plesiotrygon Rosa, Castello & Thorson. The distribution of most species in this family is restricted to a single basin or fluvial system. Only Potamotrygon motoro, Potamotrygon orbignyi and Paratrygon aiereba are found in more than one river basin. In this study we investigate genetic structuring of Paratrygon aiereba, from five rivers of the Amazon region: Negro, Solimões- Amazon-Estuary system, Tapajós, Xingu and Araguaia. Sixty-three individuals were sequenced for ATPase 6, and a representative subsample of 27 individuals was sequenced for COI. The COI dataset analysis indicated that Paratrygon is sister to all other potamotrygonid genera and species. Population parameters inferred from the analysis of ATPase 6 sequences revealed that the populations of this species are structured within each river, with no or nearly non-existent gene flow occurring between rivers and a positive correlation between geographic and genetic distances. Paratrygon aiereba is comprised of three geographically restricted clades with K2P interclade distances of at least 2%. Intraspecific divergence within P. aiereba is similar to the interspecific divergence observed in Potamotrygon spp. sampled throughout the same geographic area. Using the premises of COI barcoding and the allopatric distribution of the three P. aiereba clades, the taxon P. aiereba most likely comprises three distinct biological species. Since freshwater stingrays of the family Potamotrygonidae are highly exploited for the aquarium trade, management and conservation strategies need to be implemented at the level of each river basin, rather than at the level of the Amazon basin. © 2012 Sociedade Brasileira de Ictiologia

Trends in studies of Brazilian stream fish assemblages

Studies about fish assemblages in Brazilian streams have grown in recent years, however, it remains unclear whether this increase is followed by increments in the diversity of addressed topics and theoretical frameworks adopted by researchers. We performed a systematic search for Brazilian studies on stream fish assemblages recording study region, publication year, objectives, and spatial and temporal scales adopted. The number of studies is unevenly distributed among regions. Most papers describe the general structure of local fish assemblages and their scientific objectives have not varied through time. Studies have been conducted mainly at small temporal and spatial scales, though the latter is increasing over time. We argue for the need of focusing on recently developed ecological theories and frameworks, and expanding the temporal and spatial scales of studies. These changes will improve regional and local conservation policies, and the visibility of aquatic Brazilian research in the global scientific community. © 2016 Associação Brasileira de Ciência Ecológica e Conservaçã

EFFECT OF A SHORT PERIOD WHOLE BODY VIBRATION WITH 10 HZ ON BLOOD BIOMARKERS IN WISTAR RATS

Background: Exposure to whole body vibration exercises (WBVE), besides some biological effects, causes alterations in the concentration of some blood biomarkers. The aim of this study is to evaluate the action of vibration (10 Hz) of WBVE on the concentration of blood biomarkers in Wistar rats. Materials and Methods: Wistar rats were divided in 2 groups. The experimental group (EG) was subjected to vibrations of 10Hz (one min per day, one week, total time of seven min), while the control group (CG) has not experienced vibration. Samples of whole blood were drawn for biochemical analysis of the concentration of total cholesterol, triglycerides, HDL, LDL, VLDL, glucose, CPK, albumin, alkaline phosphates, TGP, TGO, γGT, lipase, amylase, urea and creatinine. Results: White blood cell count and a platelet-hemogram were also performed. Significant (

Wild dogs at stake: deforestation threatens the only Amazon endemic canid, the short-eared dog (Atelocynus microtis)

The persistent high deforestation rate and fragmentation of the Amazon forests are the main threats to their biodiversity. To anticipate and mitigate these threats, it is important to understand and predict how species respond to the rapidly changing landscape. The short-eared dog Atelocynus microtis is the only Amazon-endemic canid and one of the most understudied wild dogs worldwide. We investigated short-eared dog habitat associations on two spatial scales. First, we used the largest record database ever compiled for short-eared dogs in combination with species distribution models to map species habitat suitability, estimate its distribution range and predict shifts in species distribution in response to predicted deforestation across the entire Amazon (regional scale). Second, we used systematic camera trap surveys and occupancy models to investigate how forest cover and forest fragmentation affect the space use of this species in the Southern Brazilian Amazon (local scale). Species distribution models suggested that the short-eared dog potentially occurs over an extensive and continuous area, through most of the Amazon region south of the Amazon River. However, approximately 30% of the short-eared dog's current distribution is expected to be lost or suffer sharp declines in habitat suitability by 2027 (within three generations) due to forest loss. This proportion might reach 40% of the species distribution in unprotected areas and exceed 60% in some interfluves (i.e. portions of land separated by large rivers) of the Amazon basin. Our local-scale analysis indicated that the presence of forest positively affected short-eared dog space use, while the density of forest edges had a negative effect. Beyond shedding light on the ecology of the short-eared dog and refining its distribution range, our results stress that forest loss poses a serious threat to the conservation of the species in a short time frame. Hence, we propose a re-assessment of the short-eared dog's current IUCN Red List status (Near Threatened) based on findings presented here. Our study exemplifies how data can be integrated across sources and modelling procedures to improve our knowledge of relatively understudied species

FIRST REPORT ON OTOTOXICITY OF MEGLUMINE ANTIMONIATE

Pentavalent antimonials are the first drug of choice in the treatment of tegumentary leishmaniasis. Data on ototoxicity related with such drugs is scarcely available in literature, leading us to develop a study on cochleovestibular functions. Case Report: A case of a tegumentary leishmaniasis patient, a 78-year-old man who presented a substantial increase in auditory threshold with tinnitus and severe rotatory dizziness during the treatment with meglumine antimoniate, is reported. These symptoms worsened in two weeks after treatment was interrupted. Conclusion: Dizziness and tinnitus had already been related to meglumine antimoniate. However, this is the first well documented case of cochlear-vestibular toxicity related to meglumine antimoniate

Unexpected species diversity in electric eels with a description of the strongest living bioelectricity generator

Is there only one electric eel species? For two and a half centuries since its description by Linnaeus, Electrophorus electricus has captivated humankind by its capacity to generate strong electric discharges. Despite the importance of Electrophorus in multiple fields of science, the possibility of additional species-level diversity in the genus, which could also reveal a hidden variety of substances and bioelectrogenic functions, has hitherto not been explored. Here, based on overwhelming patterns of genetic, morphological, and ecological data, we reject the hypothesis of a single species broadly distributed throughout Greater Amazonia. Our analyses readily identify three major lineages that diverged during the Miocene and Pliocene—two of which warrant recognition as new species. For one of the new species, we recorded a discharge of 860 V, well above 650 V previously cited for Electrophorus, making it the strongest living bioelectricity generator. © 2019, The Author(s)

Protected areas: A focus on Brazilian freshwater biodiversity

Brazil has a variety of aquatic ecosystems and rich freshwater biodiversity, but these components have been constantly damaged by the expansion of unsustainable activities. An array of different conservation strategies is needed, especially the creation of protected areas (PAs, hereafter). However, Brazil's PAs are biased towards terrestrial ecosystems and we argue that current PAs have limited efficacy in the protection of freshwater biodiversity. New PAs should better consider aquatic environments, covering entire basins, rivers and other freshwater habitats. We recommend ways to implement these PAs and provide guidance to avoid social impacts. Freshwater systems in Brazil provide essential goods and services but these ecosystems are being rapidly degraded and will be lost if not adequately protected. © 2018 The Authors. Diversity and Distributions Published by John Wiley & Sons Lt