Richness and composition of the Cladocera community (Crustacea: Branchiopoda) from the Maranhão State, Northeast Brazil

The state of Maranhão, northeast Brazil, has four different biomes. The water bodies in Maranhão belongs to three hydrographic regions. Thus, the state potentially contributes to a high biodiversity. Despite that, in the state, the study of cladocerans can still be considered incipient. This work aims to summarize the list of species of cladocerans in the state of Maranhão, including the results of new fauna surveys. We report ten new species records for the state, two species represent the new record of the genus Pseudosida Herrick, 1884. The results found point to the occurrence of 82 valid taxa in the state of Maranhão.

Identification key of Ctenopoda (Cladocera, Holopedidae, Sididae) taxa from Brazil with remarks on taxonomy and geographic distribution

Using literature and field sampling data, we found that Brazilian fauna of the order Ctenopoda (Cladocera, Branchiopoda) was composed of twelve species, including the locally endemic Holopedium amazonicum and Sarsilantona behningi. In Brazil, Diapahanosoma (Neodiaphanosoma) bergamini was reported out of its type locality for the first time. Ctenopoda species were reported in all Hydrographic Regions in Brazil, however, the sampling effort was clearly distinct between many areas. These findings suggest the necessity of new faunal surveys in several parts of Brazil.

Estudos de Variabilidades Interanuais e Interdecenais da Precipitação Pluvial das Regiões Hidrográficas Tocantins-Araguaia e São Francisco no Brasil

O objetivo é investigar as fases temporais das variabilidades de precipitação pluvial das Regiões Hidrográficas do Tocantins-Araguaia e São Francisco, como, também, correlacioná-las com índices de anomalias de Temperatura da Superfície do Mar (TSM) do Pacífico, na região do Niño 3.4, utilizando a análise de transformada ondaleta. A área geográfica está localizada entre os paralelos 0,5º S a 20º S e meridianos 34,8º W a 55,4º W. Foram utilizados dados mensais de precipitação observados e de reanálise (1º x 1º), no período de 1945-2016, e de TSM de 1950-2016 provenientes de órgãos governamentais nacionais e internacionais. As Ondaletas Contínuas mostraram que as variabilidades dominantes, de precipitação total anual, nas Regiões Hidrográficas do Tocantins-Araguaia e do São Francisco são nas escalas de três a cinco anos, de 11 a 12 anos e em torno de 22 anos. Para ambas as Regiões essas frequências estão em fases, pela Transformada Ondaleta Cruzada e confirmada pela Ondaleta Coerente. Nas análises de Ondaletas Cruzada e Coerente das precipitações com os índices oceânicos se verificou que houve avanço (135º) na série do Niño 3.4 em relação as das precipitações das Regiões nas escalas de três a cinco anos, mas foram verificadas diferenças de fase nas escalas decenais da precipitação das Regiões com os índices oceânicos. Concluiu-se que as variabilidades da precipitação de ambas as Regiões estão em fase e que os eventos ENOS influenciam nas precipitações das Regiões Hidrográficas do Tocantins-Araguaia e São Francisco. Studies of Interannual and Interdecennial Variabiliteis of Rainfall in the Tocantins-Araguaia and São Francisco Hydrographic Regions in Brazil ABSTRACTThe objective is to investigate the temporal phases of the variability of rainfall in the Hydrographic Regions of Tocantins-Araguaia and São Francisco, as well as to correlate them with anomalies indexes of the Sea Surface Temperature (SST) of the Pacific, in the Niño 3.4 region, using wavelet transform analysis. The geographical area is located between the parallels 0.5º S to 20º S and meridians 34.8º W to 55.4º W. We used monthly data of observed and reanalysis precipitation (1º x 1º), in the period from 1945 to 2016, and from 1950 to 2016 for SST. The data are from national and international government agencies. The continuous wavelet showed that the dominant variability of total annual precipitation, in the Hydrographic Regions of Tocantins-Araguaia and São Francisco, are in the frequencies of three to five years, 11 to 12 years and about 22 years. These frequencies are in phases by the cross wavelet transform and confirmed by the coherent wavelet. In the cross and coherent wavelet analysis of the precipitation with the oceanic indices, there was an advance (135º) in the Niño 3.4 series in relation to the precipitation of the Regions in the frequency of three to five years, but phase differences were observed in the decadal frequencies between the precipitation of the Regions and oceanic indices. We concluded that the variability of precipitation in both regions is in phase and that the ENOS events influence the rainfall in the Hydrographic Regions of Tocantins-Araguaia and São Francisco.Keywords: El Niño, hydrographic catchment, wavelet, climate variability.

Broad and fine-scale threats on threatened Brazilian freshwater fish: variability across hydrographic regions and taxonomic groups

Anthropogenic environmental changes are the main cause of species extinction during the Holocene. Species have been exposed to major source of threats, such as habitat loss and fragmentation, pollution, introduced species, and harvesting, many of which are derived from specific anthropogenic activities, such as urbanization, agriculture, and damming (i.e. fine-scale threats). However, the importance of these threats on the species conservation status in a given region depends on the type of impacts they are exposed to and the susceptibility of species to these impacts. In this study, we used a database of threatened Brazilian freshwater fish species to test whether the major source of threats and the specific anthropogenic impacts to species vary across hydrographic regions and taxonomic groups. Our results showed that habitat loss is a ubiquitous major threat jeopardizing the conservation status of the Brazilian fish species. However, different fine-scale threats mediate this process across hydrographic regions and taxonomic groups. The combination of impacts from agriculture, deforestation, and urbanization affects most of the threatened species in the basins of the Northeast, South, and Southeast, including the species of the most threatened order, the Cyprinodontiformes. Damming is the main human activity affecting threatened species of Siluriformes, Characiformes, Gymnotiformes, and Cichliformes, especially in northern basins (Amazon and Tocantins-Araguaia). Therefore, we found that specific fine-scale threats influencing threatened species vary across hydrographic regions and taxonomic groups, probably due to geographic variability in the incidence of human activities and differential niche requirements and vulnerability of species to these activities.

Zooplankton Biomass Depletion Event Reveals the Importance of Small Pelagic Fish Top-Down Control in the Western Mediterranean Coastal Waters

The influence of hydrochemistry and trophic conditions on the coastal zooplankton community’s biomass and metabolic activities was investigated along the Spanish Mediterranean coastal waters, from Algeciras Bay to Barcelona, from autumn 2011 to autumn 2012. Two hydrographic regions were differentiated: NW Alboran (ALB) and W Mediterranean (MED). Zooplankton metabolism was assessed from measurements of the electron transport system (ETS) and aminoacyl-tRNA synthetases (AARS) activities, as proxies for potential respiration and somatic growth, respectively. Zooplankton showed three to fivefold higher biomass in ALB than in MED during autumn 2011 and spring 2012. However, in autumn 2012, a drastic decrease in biomass standing stock was observed in ALB, with no significant differences between the two regions. This biomass depletion event was not associated with environmental variables, food availability or zooplankton metabolic rates, but coincided with a twofold peak of Sardina pilchardus landings in ALB. A reduced standing stock coupled with high zooplankton growth rates suggests mortality by predation as the main cause for the low zooplankton biomass typically observed in MED, and in ALB during autumn 2012.

Water reuse potential for irrigation in Brazilian hydrographic regions

The present paper carried out an evaluation of the reuse potential of the Wastewater Treatment Plants (WWTPs) effluents for irrigation in the 12 Brazilian Hydrographic Regions (BHRs). For this purpose, initially, the WWTPs were categorized and the effluent flow rate was estimated. Category 1 represents secondary effluent with an efficiency of organic matter removal greater than 80%; Category 2 represents effluent that underwent some disinfection step; and effluents that perform less than the other categories were called ‘Uncategorized’. After that, the irrigation water demands for each BHRs were compiled, and finally, the production of water for reutilization was compared with the demand for irrigation. Thus, it was observed that all the sewage flow rates generated in Brazil classified in Categories 1 and 2 represent 9% of the total irrigation water demand in the country (1,078.71 m3/s) and it stands out that only 7% of the flows treated in Brazil undergo a tertiary treatment step.

Taxonomic Catalog of the Brazilian Fauna: order Trichoptera (Insecta), diversity and distribution

Caddisflies are a highly diverse group of aquatic insects, particularly in the Neotropical region where there is a high number of endemic taxa. Based on taxonomic contributions published until August 2019, a total of 796 caddisfly species have been recorded from Brazil. Taxonomic data about Brazilian caddisflies are currently open access at the “Catálogo Taxonômico da Fauna do Brasil” website (CTFB), an on-line database with taxonomic information on the animal species occurring in Brazil. The order Trichoptera at CTFB includes a catalog of species recorded for the country, with synonymic lists, distribution throughout six biomes, 12 hydrographic regions, and 27 political states (including Federal District) from Brazil. The database is constantly updated to include newly published data. In this study, we reviewed the taxonomic effort on Brazilian caddisflies based on data currently in CTFB database. The accumulation curve of species described or recorded from the country, by year, shows a strong upward trend in last 25 years, indicating that it is possible that there are many more species to be described. Based on presence/absence of caddisfly species at three geographic levels (biomes, hydrographic regions, and states), second order Jackknife estimated at least 1,586 species occurring in Brazil (with hydrographic regions as unities), indicating we currently know about 50% of the Brazilian caddisfly fauna. Species distribution by Brazilian biomes reveals that the Atlantic Forest is the most diverse, with 490 species (298 endemic), followed by the Amazon Forest, with 255 species (101 endemic). Even though these numbers may be biased because there has been more intense collecting in these two biomes, the percentage of endemic caddisfly species in the Atlantic Forest is remarkable. Considering the distribution throughout hydrographic regions, clustering analyses (UPGMA) based on incidence data reveals two groups: northwestern basins and southeastern. Although these groups have weak bootstrap support and low similarity in species composition, this division of Brazilian caddisfly fauna could be related to Amazon-Atlantic Forest disjunction, with the South American dry diagonal acting as a potential barrier throughout evolutionary time.

Identificação de Estilos Fluviais na Bacia do Rio Macabu (RJ) a Serem Aplicados na Gestão dos Recursos Hídricos

A pesquisa foi desenvolvida na Bacia do Rio Macabu que integra a Região Hidrográfica IX do Baixo Paraíba do Sul e Itabapoana e, assim como várias regiões hidrográficas fluminenses, apresenta longo histórico de intervenções antrópicas dentro e fora dos canais fluviais. O objetivo do trabalho é apresentar mapeamento dos Estilos Fluviais identificados na Bacia do rio Macabu, considerando-se a dinâmica atual dos processos geomorfológicos e hidrogeomorfológico a serem aplicados na gestão dos recursos hídricos. O mapeamento e classificação dos segmentos dos rios e suas tipologias foram realizados com base na aplicação de parâmetros morfométricos, para a avaliação dos controles regionais e locais sobre a forma e o comportamento do rio, no confinamento do vale, na forma em planta de toda a extensão do canal e nas unidades geomorfológicas do fundo de vale. Os resultados mostram que a compartimentação do relevo possibilita a ocorrência de diferentes feições fluviais, exerce controle regional no sistema fluvial e tem influência sobre característica do vale. Dessa forma, a configuração espacial dos compartimentos determina os padrões de comportamento em cada setor. Foram identificados oito Estilos Fluviais cuja diferenciação entre os segmentos permite compreender como os processos e formas se caracterizam, integram e se distribuem dentro do sistema fluvial. De um modo geral, a bacia do rio Macabu se expressa como um ambiente múltiplo e complexo, com muitas problemáticas relacionadas aos seus usos e modificações. Os resultados representam parte dos subsídios necessários para uma gestão eficiente e eficaz e para a tomada de decisão. Identification of River Styles in the Macabu Basin (RJ) to be Applied in Water Resource Management A B S T R A C TThe research was developed in the Macabu Basin that integrates the Lower Paraíba do Sul and Itabapoana Hydrographic Region and, as well as several basin of fluminense hydrographic regions, presents a long history of anthropogenic interventions inside and outside channels. The objective of this present work is bringing forward mapping of the River Styles in the Macabu Basin to be applied in the management of water resources, considering the current dynamics of geomorphological and hydrogeomorphological processes. The mapping and the classification of river segments and their typologies were performed based on the application of morphometric parameters for the evaluation of regional and local controls on the river shape and behavior, valley confinement, river planform, channel length and valley bottom geomorphological units. The results show that the relief compartments allows the occurrence of different fluvial features, exerts regional control in the fluvial system and influences the valley characteristics. Thus, the spatial configuration of the compartments determines the patterns of behavior in each sector. Eight River Styles have been identified whose differentiation allows understanding how processes and forms are characterized, integrated and distributed within the river system. In general, Macabu Basin is a multiple and complex environment with many issues related to its uses and modifications. The results represent part of the inputs needed for efficient and effective management and decision-making.Keywords: Fluvial Geomorphoplogy; River Classification; Morphometric Index; Valley Setting.

Copula-Based Multivariate Frequency Analysis of the 2012–2018 Drought in Northeast Brazil

The 2012–2018 drought was such an extreme event in the drought-prone area of Northeast Brazil that it triggered a discussion about proactive drought management. This paper aims at understanding the causes and consequences of this event and analyzes its frequency. A consecutive sequence of sea surface temperature anomalies in the Pacific and Atlantic Oceans, at both the decadal and interannual scales, led to this severe and persistent drought. Drought duration and severity were analyzed using run theory at the hydrographic region scale as decision-makers understand impact analysis better at this scale. Copula functions were used to properly model drought joint characteristics as they presented different marginal distributions and an asymmetric behavior. The 2012–2018 drought in Ceará State had the highest mean bivariate return period ever recorded, estimated at 240 years. Considering drought duration and severity simultaneously at the level of the hydrographic regions improves risk assessment. This result advances our understanding of exceptional events. In this sense, the present work proposes the use of this analysis as a tool for proactive drought planning.