<i>Identification of hydrologically homogeneous regions in the Solimões river basin in the Amazon region</i>

2018 ◽  
Author(s):  
Clívia Dias Coelho ◽  
Demetrius David da Silva ◽  
Naziano Pantoja Filizola ◽  
Silvio Bueno Pereira ◽  
Michel Castro Moreira
Keyword(s):  
River Basin ◽  
Amazon Region ◽  
Homogeneous Regions ◽  
Solimões River

scholarly journals A snapshot on prokaryotic diversity of the Solimões River basin (Amazon, Brazil)

2017 ◽  
Vol 16 (2) ◽  
Author(s):  
D. Toyama ◽  
C.D. Santos-Júnior ◽  
L.T. Kishi ◽  
T.C.S. Oliveira ◽  
J.W. Garcia ◽  
...  
Keyword(s):  
River Basin ◽  
Prokaryotic Diversity ◽  
Solimões River

scholarly journals Anthropic transformation in the Gurupi river basin, eastern Amazon

2019 ◽  
Vol 10 (3) ◽  
pp. 212-235
Author(s):  
Fabiana da Silva Pereira ◽  
Ima Célia Guimarães Vieira
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Land Cover Change ◽  
River Basin ◽  
Forest Cover ◽  
Temporal Changes ◽  
Amazon Region ◽  
Digital Data ◽  
Forest Protection ◽  
Spatial And Temporal Changes

The objective of this paper was to evaluate the degree of anthropic transformation of a river basin in the Amazon region. We used the digital data of the TerraClass Project to calculate the Anthropic Transformation Index - ATI. In order to verify spatial and temporal changes along a decade in the Gurupi river basin, we used the database of the years 2004 and 2014. The results showed an increase of anthropic changes in the basin over a decade, as a result of forest cover conversion into agricultural and pastures areas. Although the Gurupi river basin remains at a regular level of degradation after a decade, the intensification of land use and land cover change is a threat to the few rainforest remnants of the river basin, which can lead the region to the next level of degradation, if effective forest protection, conservation and restoration actions are not implemented in the region.  

A new species of Loricaria (Siluriformes: Loricariidae) from the Turiaçu River basin, Eastern Amazon region, Brazil

Zootaxa ◽  
2021 ◽  
Vol 4915 (3) ◽  
pp. 424-434
Author(s):  
ANANDA CAROLINA S. SARAIVA ◽  
JOÃO MARCELO S. ABREU ◽  
FELIPE POLIVANOV OTTONI ◽  
NIVALDO MAGALHÃES PIORSKI
Keyword(s):  
New Species ◽  
Freshwater Fish ◽  
River Basin ◽  
Standard Length ◽  
Freshwater Fishes ◽  
Amazon Region ◽  
Fish Diversity ◽  
Pectoral Girdle ◽  
Median Region ◽  
A New Species

A new species of Loricaria is herein described from the Turiaçu River basin, Eastern Amazon region, Maranhão state, Brazil, within the Maranhão Hydrological Unit (MHU). Loricaria turi differs from its congeners mainly by the following combination of characters: abdominal plate development confined to the posterior median region, pectoral girdle mostly naked, with cluster of plates near pectoral fin bases; large eyes (minimum orbital diameter 16.2–20.7% of HL and maximum orbital diameter 19.8–24.0% of HL), 214.4 mm of maximum standard length, and large basicaudal plate (16.6–29.2% of HL). The description of this new species strengthens the hypothesis that the Maranhão Hydrological Unit (MHU) is a possible area of endemism for freshwater fishes and contributes to the knowledge of the freshwater fish diversity and composition of the region. 

Fire and Power on the River Basin: Irregular Warfare and Socio-Environmental Consequences of the Guerrilla in Araguaia, Brazil

2021 ◽  
Vol 14 (1) ◽  
pp. 58-85
Author(s):  
Claudio De Majo
Keyword(s):  
Small Group ◽  
River Basin ◽  
Communist Party ◽  
Local Population ◽  
Amazon Region ◽  
Irregular Warfare ◽  
Military Dictatorship ◽  
Environmental Consequences ◽  
The Military ◽  
Geographical Characteristics

The aim of this article is to retrace a guerrilla episode that occurred in the Amazon region of Araguaia during the military dictatorship in Brazil (1972?1975), opposing a group of militants from the Communist Party of Brazil (PCdoB) and the National Brazilian Army. Taking advantage of the geographical characteristics of the region, a small group of guerrilla fighters was able to confront a large military contingent for almost three years. As this article demonstrates, appealing to the powerful symbolic potential of the Amazon jungle, the guerrilla created a solid environmental narrative of force and shrewdness supported by the local population. However, as military forces began to better explore the region and to resort to irregular warfare strategies, they managed to curb the guerrilla, exterminating almost every member involved in the fight. Finally, this article looks at the marked socio-environmental scars that the conflict left in the region, and how these influenced social, political and ecological equilibriums during the following decades.

Community and infracommunities of metazoan parasites in Hemiodus unimaculatus (Hemiodontidae) from Jari River basin, a tributary of Amazon River (Brazil)

2021 ◽  
Vol 30 (4) ◽  
Author(s):  
Odonei Moia Almeida ◽  
Marcos Sidney Brito Oliveira ◽  
Marcos Tavares-Dias
Keyword(s):  
Species Richness ◽  
River Basin ◽  
Parasite Community ◽  
Amazon Region ◽  
Amazon River ◽  
Metazoan Parasites ◽  
Random Dispersion ◽  
Northern Brazil ◽  
Species Richness And Abundance ◽  
Over Time

Abstract Parasites are an important part of biodiversity, and knowledge of species and their relationship with their hosts helps in monitoring an ecosystem over time. The aim of this study was to investigate the fauna of metazoan parasites in Hemiodus unimaculatus from the Jari River, in the eastern Amazon region, northern Brazil. Of the fish examined, 96.7% were parasitized by one or more species, and a total of 336 parasites such as Dactylogyridae gen. sp.1, Dactylogyridae gen. sp.2, Dactylogyridae gen. sp.3, Dactylogyridae gen. sp.4, Gyrodactilydae gen. sp., Urocleidoides sp.1, Urocleidoides sp.2, Urocleidoides sp.3, metacercariae of Digenea gen. sp., Procamallanus (Spirocamallanus) inopinatus, Contracaecum sp., Neoechinorhynchus sp. and Acarina gen. sp. The parasite community showed low Brillouin diversity (0.58 ± 0.29), low evenness (0.44 ± 0.21) and low species richness (7.40 ± 3.83). There was a predominance of ectoparasites, mainly monogeneans and digeneans. The parasites showed an aggregate dispersion, except for P. (S.) inopinatus, which had a random dispersion. The size of the hosts had no effect on diversity, species richness and abundance of parasites, but other factors structured the parasite community. This is the first study on the parasite community and infracommunities in H. unimaculatus.

scholarly journals Multivariate statistical analysis to support the minimum streamflow regionalization

2015 ◽  
Vol 35 (5) ◽  
pp. 838-851 ◽  
Author(s):  
Abrahão A. A. Elesbon ◽  
Demetrius D. da Silva ◽  
Gilberto C. Sediyama ◽  
Hugo A. S Guedes ◽  
Carlos A. A. S. Ribeiro ◽  
...  
Keyword(s):  
Cluster Analysis ◽  
Statistical Analysis ◽  
River Basin ◽  
Multivariate Statistical Analysis ◽  
Annual Rainfall ◽  
Morphometric Characteristics ◽  
Multivariate Statistical ◽  
Independent Variables ◽  
Homogeneous Regions ◽  
Doce River

ABSTRACT This study aimed to develop a methodology based on multivariate statistical analysis of principal components and cluster analysis, in order to identify the most representative variables in studies of minimum streamflow regionalization, and to optimize the identification of the hydrologically homogeneous regions for the Doce river basin. Ten variables were used, referring to the river basin climatic and morphometric characteristics. These variables were individualized for each of the 61 gauging stations. Three dependent variables that are indicative of minimum streamflow (Q7,10, Q90 and Q95). And seven independent variables that concern to climatic and morphometric characteristics of the basin (total annual rainfall – Pa; total semiannual rainfall of the dry and of the rainy season – Pss and Psc; watershed drainage area – Ad; length of the main river – Lp; total length of the rivers – Lt; and average watershed slope – SL). The results of the principal component analysis pointed out that the variable SL was the least representative for the study, and so it was discarded. The most representative independent variables were Ad and Psc. The best divisions of hydrologically homogeneous regions for the three studied flow characteristics were obtained using the Mahalanobis similarity matrix and the complete linkage clustering method. The cluster analysis enabled the identification of four hydrologically homogeneous regions in the Doce river basin.

scholarly journals Myxobolus sp. (Myxozoa; Myxosporea) causing asymptomatic parasitic gill disease in Astyanax aff. bimaculatus (Characiformes; Characidae) in the Tocantins river basin, amazon region, Brazil

2019 ◽  
Vol 28 (4) ◽  
pp. 739-743
Author(s):  
Marcelo Francisco da Silva ◽  
Dalila de Deus Sousa-Henrique ◽  
Nirvana Messias-Luz ◽  
Larissa dos Santos Borralho ◽  
Jorge Diniz de Oliveira ◽  
...  
Keyword(s):  
River Basin ◽  
High Mortality ◽  
Mortality Rates ◽  
Amazon Region ◽  
Zoonotic Potential ◽  
Aquatic Biota ◽  
Number Of Species ◽  
Gill Filaments ◽  
Tocantins River ◽  
Gill Disease

Abstract The middle course of the Tocantins river is located in the eastern portion of the “Legal Amazon” region of Brazil and the Dantas river is one of its tributaries. Among the components of the aquatic biota, eukaryote microparasites establish direct relationships with several species of fish and have zoonotic potential that is still little known. Myxozoans stand out among these parasites: they cause myxosporidiosis, a disease that gives rise to high mortality rates worldwide. The genus Myxobolus accounts for the largest number of species that have been described. Thirty specimens of Astyanax aff. bimaculatus that had been caught in the Dantas river were examined. The prevalence of cysts with spores morphologically compatible with myxozoans of the genus Myxobolus in the arcuate and gill filaments of these specimens was 20%.

Delineation of homogeneous regions for streamflow via fuzzy c-means in the Amazon

2018 ◽  
Vol 13 (1) ◽  
pp. 210-218 ◽  
Author(s):  
Francisco Carlos Lira Pessoa ◽  
Claudio José Cavalcante Blanco ◽  
Evanice Pinheiro Gomes
Keyword(s):  
Cluster Analysis ◽  
Optimal Number ◽  
Amazon Region ◽  
Number Of Clusters ◽  
Fuzzy C Means ◽  
Important Stage ◽  
Streamflow Data ◽  
Homogeneous Regions ◽  
Climatic Characteristics ◽  
Optimal Number Of Clusters

Abstract Lack of streamflow data is one of the main limitations in hydrologic studies. One method of solving this problem is by streamflow regionalization. The identification of hydrologically homogeneous regions is the main and most important stage of regionalization. In this study homogeneous flow regions are identified by fuzzy c-means (FCM) cluster analysis based on morpho-climatic characteristics from streamflow at 208 stream gauges in the Amazon region. The optimal number of clusters in the dataset was identified by applying the PBM validation index, maximized for ten clusters, with a fuzzing parameter of 1.6. The application dataset is best divided into 10 groups. These were well defined and demonstrated the Amazon's hydrologic similarity.

scholarly journals Annotated list of freshwater fishes of the Limoncocha Lagoon, Napo river basin, northern Amazon region of Ecuador

Check List ◽  
2018 ◽  
Vol 14 (1) ◽  
pp. 55-75 ◽  
Author(s):  
Jonathan Valdiviezo-Rivera ◽  
Carolina Carrillo-Moreno ◽  
Enrique Gea-Izquierdo
Keyword(s):  
River Basin ◽  
Freshwater Fishes ◽  
Amazon Region ◽  
Annotated List
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