Izaias Fernandes

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• Professor at Federal University of Rondônia

As in other countries, Brazil has used standardized tests as a tool to measure the quality of education. The Ministry of Education, incorporated large-scale assessments into its educational policy in the early 1990s through the System for Basic Education Assessment. In addition to the exam used to assess elementary school, students are also assesse...

The Amazon is one of the regions with the greatest fish diversity on the planet. In this vast biodiversity, there is Serrasalmus rhombeus, a predatory species that plays a vital ecological role in aquatic ecosystems. In order to generate biological data and valuable information to management efforts, we characterized the somatic growth pattern of S...

We assessed variations in water temperature, dissolved oxygen, electrical conductivity, and pH in a seasonally inundated area of the Pantanal wetland. These variables are principal environmental factors influencing species distribution in aquatic systems. To understand how local and regional factors govern spatiotemporal variations in water conditi...

1. The African species Cloeon smaeleni is one of the three Ephemeroptera species recorded as exotic and was introduced in Brazilian port areas. The records of this exotic species do not have a pattern, making it challenging to propose control measures and impact investigations. 2. We utilized Species Distribution Models (SDMs) to address: (i) What...

Graphical abstract Highlights d Ecological metadata were compiled for 7,694 sites across the Brazilian Amazon d Accessibility and proximity to research facilities influenced research probability d Knowledge gaps are greater in uplands than in wetlands and aquatic habitats d Undersampled areas overlap predicted hotspots of climate change and defores...

Aquatic environments are among the most difficult environments to sample, and this reflects in the limited knowledge about the biology of some aquatic organisms. Adapting existing collection methods or creating new equipment is thus essential for collecting new species or increasing knowledge about habitats that have not yet been properly sampled....

Measurement of the recovery of wood stocks in logging areas in the Amazon helps to understand the efficiency of policies for the use and conservation of native forests. This work evaluated the effects of logging on the dynamics and production of commercial species in the short and medium term in a conservation unit in the state of Rondônia. Structu...

Studies on the diet of fish allow assessing the role of these species in the community, in addition to providing important information on the functioning of the ecosystems in which they are inserted. Thus, this study aims to analyze the diet of Cichla pleiozona (Kullander & Ferreira 2006) and Serrasalmus rhombeus (Linnaeus 1766) in artificial reser...

Rhinoclemmys punctularia punctularia is the only turtle of the family Geoemydidae with part of its range in Brazil. The species is semi-aquatic and widely distributed across the Amazon basin but is still poorly studied. We evaluated aspects of the population structure, habitat use, seasonal activity, and diet of the species during one year, from th...

Desertification is defined as land degradation in arid, semiarid, and dry sub-humid regions, and it is caused primarily by human activities and climate change. The semiarid region of Northeast (NE) Brazil is a very large, populous region, and thus, it is hard to monitor the dynamics of its desertified areas; therefore, the present study aimed to de...

Although environmental filtering and spatial structuring are commonly regarded as two key factors shaping community dynamics, their relative contribution remains unknown for numerous aquatic ecosystems, particularly highly dynamic floodplain lakes. This issue is here addressed by examining the seasonal metacommunity dynamics of freshwater fishes in...

Understand the role of the drivers in vegetation pattern is essential in ecology since diversity plays a major role in the stability and maintenance of plant communities. The murundus are small and scattered earthmounds with a differentiated flora of its surrounding. In our study site (Campo Maior, Piauí, Northeastern Brazil), we classified them in...

As características hidrogeomorfométricas associadas às informações sobre dinâmica da cobertura do solo são cruciais para o planejamento e a gestão dos recursos naturais. Neste contexto, o trabalho teve como objetivo obter informações sobre as características da paisagem na microbacia do rio Cachara, por meio de geotecnologias e equações. A microbac...

É necessário conhecer as características da paisagem para se identificar as potencialidades e vulnerabilidade do ecossistema, e com base nessas informações, fazer o planejamento e a gestão ambiental, a fim de conservar os recursos naturais e favorecer o desenvolvimento sustentável. Assim, objetivou-se com este trabalho analisar as características h...

As informações das características hidrogeomorfométricas e da dinâmica de cobertura do solo de microbacias são fundamentais para o planejamento adequado do uso da terra. Portanto, objetivou-se com este trabalho analisar as características geométricas, topográficas, hidrográficas e a dinâmica de cobertura do solo da microbacia e zona ripária do rio...

As commonly observed in turtles, sexual size dimorphism (SSD) is pronounced in the Neotropical freshwater turtle Mesoclemmys vanderhaegei (Bour, 1973), a species in which females are usually larger than males. We studied SSD in two populations of M. vanderhaegei from the Brazilian Cerrado savannah, based on 245 specimens captured between November 2...

A sub-bacia do rio Branco contém duas Terras Indígenas, duas Unidades de Conservação, oito Pequenas Centrais Hidrelétricas e 3.939 propriedades rurais, além de ser legalmente um berçário para proteção da fauna ictiológica e flora aquática. Diante da importância socioeconômica e ambiental da sub-bacia, objetivou-se avaliar a dinâmica temporal na cob...

Este estudo investiga o desempenho de escolas públicas estaduais brasileiras na área de Ciências da Natureza, no ENEM 2017. O desempenho dos alunos foi comparado entre os diferentes tipos de escolas públicas estaduais brasileiras e as taxas de seleção que podem causar diferenças. Foi avaliada a infraestrutura escolar, proporção de professores forma...

Characidium xavante was described from two tributaries of the Culuene River drainage, in the upper Xingu River basin. New samplings recorded the species for streams from the Kaaiapó River drainage (Teles Pires River drainage, upper Tapajós River basin) with additional specimens also recorded in the Xingu River basin, Paranatinga municipality, Mato...

Non-native fish (NNF) can threaten megadiverse aquatic ecosystems throughout the planet, but limited information is available for the Amazon Region. In this study we review NNF data in the Amazonian macroregion using spatiotemporal records on the occurrence and the richness of NNF from a collaborative network of 35 regional experts, establishing th...

The river continuum concept predicts that gradual changes in river geomorphology and hydrology can drive longitudinal changes in aquatic community structure. Accordingly, we evaluated how environmental variables (electrical conductivity, pH, water transparency and water velocity), spatial factors (distance from headwaters and Moran’s eigen vector m...

Nota técnica: A crescente expansão das hidrelétricas na Amazônia representa uma das principais ameaças à rica biodiversidade e aos modos de vida de populações humanas na região, tanto em áreas urbanas como rurais. Grandes obras, como por exemplo as usinas de Santo Antônio e Jirau, em Rondônia, ou Belo Monte, no Pará, já se impuseram na paisagem dos...

The structure of freshwater assemblages may be driven directly by urbanization or indirectly by a reduction in environmental heterogeneity (EH). Disentangling the effects of urbanization and EH requires uncorrelated proxies of each of these factors. We assessed the effects of the degree of urbanization and EH on the structure of fish assemblages. W...

Although dung beetles are important members of ecological communities and indicators of ecosystem quality, species diversity, and how it varies over space and habitat types, remains poorly understood in the Brazilian Cerrado. We compared dung beetle communities among plant formations in the Serra Azul State Park (SASP) in the state of Mato Grosso,...

Desertification is a phenomenon that takes place in the arid, semi‐arid and dry sub‐humid areas of the planet. Although its causes and consequences are well known, data and robust information are often insufficient to provide indicators that allow desertification effects to be measured precisely and efficiently. Accordingly, the objective of this s...

Length-weight relationships and condition factor of the predatory fish, Cichla pleiozona and Serrasalmus rhombeus, from two tropical reservoirs, Amazon basin, Brazil Abstract The aim of this study was to estimate the parameters of the weight-length relationship and the relative condition factor for Cichla pleiozona and Serrasalmus rhombeus in Branc...

The length–weight relationships (LWRs) were estimated of seven fish species from 22 localities in the Pantanal wetland between Mach 2006 and April 2011. Fish were sampled using seven gill nets (20 × 1.5 m; mesh size: 12, 15, 18, 20, 25, 30 and 50 mm between opposing knots) and throw traps (made of 1 m³ metal cubes, covered by a 1.5 mm nylon mesh)....

The Aripuanã River basin is part of one of the most biodiverse hydrographic basins on the planet; however, the lack of information on fish diversity in the basin is notable, particularly upstream to the Dardanelos and Andorinhas waterfalls complex. For this study, we sampled 50 m stretches of 71 streams in the Aripuanã River basin, upstream and dow...

Intra and interspecific competition may influence the strength of individual specialization in resource use. We evaluated how intra and interspecific competition affects the degree of individual specialization in food resource use within sub-populations of Hoplerythrinus unitaeniatus. To do so, we identified food items from fishes collected in the...

Surrogate groups have been used as a useful tool for biodiversity conservation. The occurrence and distribution of a taxon can be predicted based on the occurrence of other biological species or groups. Consequently, the current study sought to determine the presence of one or more surrogate groups in a seasonally flooded region in the South Americ...

A new species of Astyanax is described from the upper Rio Paraguai basin, Mato Grosso State, Brazil. The new species can be distinguished from congeners by having the body intensely yellowish in life (v. silvery, reddish or lightly yellow) and by morphometric and meristics traits. Astyanax dolinae n. sp. cannot be assigned to any of the Astyanax sp...

Clove oil is used as a fish anesthetic because it is a natural and inexpensive product with low toxicity risks. The goal of the present study was to determine the appropriate concentration of clove oil for small-sized tropical fish to be used in mark-recapture studies or when individuals are to be sacrificed. We applied three different clove oil co...

Context The replacement of native vegetation by exotic grasses for livestock production is driving landscape homogenization, habitat fragmentation and reducing connectivity between habitat patches in floodplains ecosystems. Objective In this context we examined how changes in native and exotic vegetation cover, connectivity and water depth affect t...

Each species has a reproductive strategy that is adapted to the intensity and predictability of spatial and temporal variations in local environmental conditions. This study sets out to evaluate the temporal and spatial variations in some life history traits, including maturation time and length at first maturity, of three small fish species from s...

Freshwater habitats are among the most impacted ecosystem on Earth. Consequently, reserves have been implemented in an attempt to reduce the threat to freshwater biodiversity. However, few studies have evaluated how effective these protected areas (PA) are for the conservation of freshwater organisms. In the present study, we compared species richn...

The metacommunity framework has greatly advanced our understanding about the importance of local and regional processes structuring ecological communities. However, information on how metacommunity structure and the relative strengths of their underlying mechanisms change through time is largely lacking. Dynamic systems that undergo environmental t...

The aim of this study was to evaluate the effects of local, regional and temporal factors structuring fish assemblages in Meridional Amazonian streams during the months of May (rainy season) and August (dry season) of 2008. To accomplish this task, 14 streams located in Serra do Expedito (Aripuanã River basin) were sampled along 30-m stretches. A t...

The present study has assessed spatial and temporal variations in the length structure of Hemigrammus marginatus Ellis, 1911 and estimated growth parameters for the species. Sampling was carried out in five streams in the Vitoria and Piravevě sub-basins of the Ivinhema River from January to December 2002. A total of 933 specimens of H. marginatus w...

The present study has assessed spatial and temporal variations in the length structure of Hemigrammus marginatus Ellis, 1911 and estimated growth parameters for the species. Sampling was carried out in five streams in the Vitoria and Piraveve sub-basins of the Ivinhema River from January to December 2002. A total of 933 specimens of H. marginatus w...

In this study, we evaluated how cichlid assemblages are affected by seasonal and interannual variations in water volume in the floodplain lagoons of the Cuiabá River in the Pantanal wetland. Eleven lagoons were sampled in the early dry season and the early rainy season over a three-year period. Analysis of similarity (ANOSIM) showed that the specie...

The influence of habitat, biomass of herbaceous vegetation, depth and distance from permanent water bodies on the structure of fish assemblages of a seasonal floodplain was evaluated using data collected along 22 transects in an area of 25 km² in the floodplain of Cuiabá River, Pantanal, Brazil. Each transect was sampled for fish using throw traps...

O presente trabalho avaliou a distribuição espacial e temporal da riqueza de espécies de peixes da zona litoral vegetada de 15 lagoas marginais da planície de inundação do Rio Cuiabá, Pantanal. As lagoas foram amostradas em três períodos ao longo da sessão seca (junho, setembro e dezembro de 2005), por meio de nove lances de peneira, distribuídos s...