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Fish diversity is generally high in drainage networks in perennial systems. On the other hand, little is known about the importance of drainage networks in semiarid regions. The scant attention given to rivers in semiarid regions so far may in part be explained by the high intermittency and low ramification of these drainage networks and their incorrect classification as systems of low diversity and productivity. In this study, we investigated the importance of the drainage system of an intermittent river system in Brazil with regard to taxonomic and functional β-diversity. To do so, we evaluated the importance of both tributaries (branches) (12 sampling points) and the main stem (7 sampling points).We initially modeled the spatial structure within the branches and the main stem using asymmetric eigenvector maps. We then partitioned β-diversity values between local (biotic and abiotic) and spatial factors (positive spatial autocorrelation). The higher β-diversity values observed for branches were explained mainly by predation and environmental selection. On the other hand, in the main stem, β-diversity was best explained by a combination of environmental conditions and spatial factors. In general, local factors were more important in the functional approach than in the taxonomic approach, supporting their joint use in metacommunity studies. Our results suggest that fish metacommunity structure in branches may be responsible for maintaining regional patterns of β-diversity in semiarid river systems.

15 pages, 6 figures, 3 tables, supplementary material https://doi.org/10.1007/s10750-017-3432-8, Fish and invertebrates are introduced in freshwaters around the world for commercial purposes, despite widely known impacts on food webs and biological invasions. As a proxy for artificial environments, we modeled a typical reservoir in a Brazilian semiarid region using an ecosystem approach. We compared the role of native and non-native invasive species (NIS) in the food web, between dry and wet periods, and under the influence of an extreme drought period (from 2011 to 2015), simulating the variation in fish biomasses due to decreasing consumption. Key ecosystem groups were fishes (mainly NIS), birds, and insects. Nutrient cycling was dependent on invaders, while the trophic structure was detritus based during the drought. Biomass of detritivores was almost two times higher than herbivores, and native fish species decreased abruptly in response to invaders and volume variation. The dominance of low-trophic levels (TLII) and tilapia—Oreochromis niloticus (Linnaeus, 1758) and other tilapiines—resulted from interactions among invaders, feeding behavior on benthos, and environmental seasonality, tending toward biotic homogenization (“benthification”) at the ecosystem level. An increasing relevance of detritivores with cascading effects in ecosystems subject to drought, multiple introductions, and ubiquitous food sources has clear implications for the fisheries and the water quality, We are thankful to the Fundação Cearense de Apoio ao Desenvolvimento Científico e Tecnológico (FUNCAP, AE1-0052-00044.01.00/11 SPU nº: 11295057-4) for the funding to this project. Coordenadoria de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for granting the first author with scholarships and funding M. Coll (PVE A063-2013), and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for the funding to JRS Vitule (310850/2012-6 and 303776/2015-3)

Tidepools are considered ecosystems of high interchangeable fish biota. However, natural and anthropogenic actions that alter negatively marine ecosystems functioning (e.g., algal exploitation) are causing homogenization of fish biodiversity. Here, we describe the functional and taxonomic assembling of fishes in beach rocks of northeastern Brazil. Traits of fish species were retrieved from Fishbase and beta diversity was assessed by the dispersion of abundance, presence-absence and functional diversity in the multivariate space. We explained spatial-temporal variation in: alpha diversity, taxonomic and functional community composition; as well as temporal variation in functional, beta and gamma diversities. We found an annual stability in fish diversity and composition, and that fish biota was assembled mainly per tidepools’ depths. Substrate heterogeneity was correlated to depth, highlighting the role of local features as filters to organize the fish fauna vertically in tidepools, especially a cultivation of algae that influences the local assembling. We also highlight the uniqueness status of beach rocks in the Brazilian tropical region.

Among Neotropical freshwater ecoregions, the Mid-Northeastern Caatinga (MNCE) is a fish knowledge gap. Its temporary drainages are receptors of the São Francisco interbasin water transfer project (SFR-IWT) in the Brazilian semiarid. We provide a comprehensive baseline of fish richness of the five SFR-IWT basins. Species richness, shared, endemic, threatened and non-native species were obtained using sampling, ichthyologic collections, literature and online repositories (306 localities). In total 121, species were recorded, 111 of them native, and 16 (14.41%) listed for all basins. Higher richness of native species (78, 70.27%) was recorded in the São Francisco lower-middle stretch (SFRE), including 23 endemic, 61 (54.95%) in MNCE basins (13 endemic), and 28 (25.23%) shared between both ecoregions. In the MNCE, 50 species were recorded in Jaguaribe (JAG), 39 in Piranhas-Açu, 36 in Paraíba do Norte, and 32 in Apodi-Mossoró (APO). The number of species shared between the SFRE and each receptor basin varied from 24 (23.08%, JAG) to 20 (22.22%, APO). JAG contains 81.97% of the receptor basins’ species. Its higher richness and endemism deserve special attention regarding the ongoing hydrological changes. This study will help detect possible modifications in the ichthyofauna of the main MNCE drainages. Resumo Dentre as ecorregiões dulcícolas neotropicais, a Nordeste Médio-Oriental (MNCE) é uma lacuna de conhecimento sobre peixes. Suas drenagens temporárias são receptoras do projeto de transposição do São Francisco (SFR-IWT) no semiárido brasileiro. Fornecemos uma linha de base abrangente da riqueza de peixes das cinco bacias do SFR-IWT. Riqueza de espécies, espécies compartilhadas, endêmicas, ameaçadas e não-nativas foram obtidas através de amostragem, coleções ictiológicas, literatura e repositórios online (306 localidades). No total, foram registradas 121 espécies, 111 nativas e 16 (14,41%) listadas para todas as bacias. A maior riqueza de espécies nativas (78, 70,27%) foi registrada no trecho sub-médio do São Francisco (SFRE), incluindo 23 endêmicas e 61 (54,95%) nas bacias da MNCE (13 endêmicas), e 28 (25,23 %) compartilhadas entre ambas ecorregiões. Na MNCE, foram registradas 50 espécies na Jaguaribe (JAG), 39 na Piranhas-Açu, 36 na Paraíba do Norte e 32 na Apodi-Mossoró (APO). O número de espécies compartilhadas entre SFRE e cada bacia receptora variou de 24 (23,08%, JAG) a 20 (22,22%, APO). JAG contém 81,97% das espécies das bacias receptoras. Sua maior riqueza e endemismo merecem atenção especial em relação às mudanças hidrológicas em curso. Este estudo ajudará a detectar possíveis modificações na ictiofauna das principais drenagens da MNCE.

Environmental and spatial factors are known as the main determinants of community variation in aquatic organisms. However, historical factors may interact with local processes to regulate community structure patterns. Here we compared historical, environmental, and spatial factors in a multi-scale approach in order to identify the main drivers structuring species composition and functional diversity of fish communities in forest enclaves across three hydrographic basins in semiarid Brazil Caatinga biome. We initially modeled spatial structure within each basin using asymmetric eigenvector maps (AEM). We then partitioned the explanation of the variation in local community structure into three groups of predictor variables: (1) environmental variables, (2) spatial variables, and (3) phylogenetic history. Biogeographical bias was assessed using a basin identity matrix as covariable. The combination of 1, 2, and 3 explained the variation in species composition, while pure spatial, phylogenetic, and environmental components explained the distribution of functional groups and their nested patterns. Our findings confirmed the importance of phylogenetic history, as well as the usefulness of robust methods in community studies in refining explanations of the processes determining variation in species composition and functional groups.

Made available in DSpace on 2018-11-30T03:55:49Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-09-19 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Several hypotheses are used to explain species richness patterns. Some of them (e. g. species- area, species-energy, environment-energy, water-energy, terrestrial primary productivity, environmental spatial heterogeneity, and climatic heterogeneity) are known to explain species richness patterns of terrestrial organisms, especially when they are combined. For aquatic organisms, however, it is unclear if these hypotheses can be useful to explain for these purposes. Therefore, we used a selection model approach to assess the predictive capacity of such hypotheses, and to determine which of them (combined or not) would be the most appropriate to explain the fish species distribution in small Brazilian streams. We perform the Akaike's information criteria for models selections and the eigenvector analysis to control the special autocorrelation. The spatial structure was equal to 0.453, Moran's I, and require 11 spatial filters. All models were significant and had adjustments ranging from 0.370 to 0.416 with strong spatial component (ranging from 0.226 to 0.369) and low adjustments for environmental data (ranging from 0.001 to 0.119) We obtained two groups of hypothesis are able to explain the richness pattern (1) water-energy, temporal productivity-heterogeneity (AIC = 4498.800) and (2) water-energy, temporal productivity-heterogeneity and area (AIC = 4500.400). We conclude that the fish richness patterns in small Brazilian streams are better explained by a combination of Water-Energy + Productivity + Temporal Heterogeneity hypotheses and not by just one. Univ Fed Para UFPA, Lab Ictiol Altamira, Altamira, Para, Brazil Univ Estadual Maringa, Nucleo Pesquisas Limnol Ictiol & Aquicultura Nupe, Maringa, Parana, Brazil Univ Estadual Paulista UNESP, Lab Ictiol, Sao Jose Do Rio Preto, SP, Brazil Univ Paulista, Sorocaba, SP, Brazil Univ Estado Rio De Janeiro, Dept Ecol, Rio De Janeiro, RJ, Brazil Univ Fed Ceara, Dept Biol, Ctr Ciencias, Fortaleza, Ceara, Brazil Univ Fed Ceara, Inst Ciencias Mar LABOMAR, Fortaleza, Ceara, Brazil Univ Fed Rio Grande do Norte UFRN, Dept Bot Ecol & Zool, Ctr Biociencias, Natal, RN, Brazil Univ Fed Lavras UFLA, Dept Biol, Lavras, MG, Brazil UFT, Porto Nacl, Tocantins, Brazil Univ Fed Para UFPA, Inst Ciencias Biol, Belem, Para, Brazil INPA, Coordenacao Biodiversidade, Manaus, Amazonas, Brazil Univ Brasilia, Dept Zool, Brasilia, DF, Brazil Univ Fed Sao Carlos, Sorocaba, SP, Brazil Pontificia Univ Catolica Goias, Programa Mestrado Sociedade Tecnol & Meio Ambient, UNIEvangel, Goias Ctr Biol Aquat, Goiania, Go, Brazil UFES, Dept Ciencias Agr & Biol, Ctr Univ Norte Espirito Santo CEUNES, Sao Mateus, ES, Brazil Univ Estadual Paulista, Inst Biociencias, Botucatu, SP, Brazil Univ Fed Minas Gerais, Dept Genet Ecol & Evolucao, Inst Ciencias Biol, Belo Horizonte, MG, Brazil Univ Fed Goias, Dept Ecol, Inst Ciencias Biol, Campus 2 UFG, Goiania, Go, Brazil Univ Estadual Paulista UNESP, Lab Ictiol, Sao Jose Do Rio Preto, SP, Brazil Univ Estadual Paulista, Inst Biociencias, Botucatu, SP, Brazil CNPq: 457463/2012-0 CNPq: 552009/2011-3 CNPq: 471283/2006-1 CNPq: 304002/2014-3 FAPEMIG: 304002/2014-3

The three-spot gourami, Trichopodus trichopterus (Pallas, 1770), is naturally distributed in Southeast Asia: Indonesia and in the Mekong river basin (Low and Lim, 2012). Under natural conditions is found in slow-flowing streams, shallow lakes and swamps with lush riparian vegetation (Rainboth, 1996), tolerates large pH and temperature fluctuations and low levels of dissolved oxygen due to a suprabranchial labyrinth (Low and Lim, 2012; Blank and Burggren, 2014). The juveniles eat mainly zooplankton and benthonic algae, while adults are opportunistic omnivores (Low and Lim, 2012). Due to its usefulness in the fight against mosquito larvae and its popularity as an ornamental fish, the species has been introduced in many regions worldwide (Webb et al., 2007). The present study constitutes the second report of T. trichopterus from the Mid-Northeastern Caatinga fish ecoregion, and first report of a species of the genus Trichopodus in the state of Ceará (Northeastern Brazil). On 16 November 2015 and 19 November 2015, specimens of T. trichopterus were captured in the Santo Anastácio (SA) reservoir during monitoring of the ecosystem conducted by the Laboratory of Aquatic Ecology (LEA/UFC). Located in the Metropolitan basin, within Federal University of Ceará (UFC), the reservoir is part of the Maranguapinho river basin (Figure 1). Following capture with a sieve among aquatic macrophytes, the

The relationship between functional and taxonomic diversity is a major issue in ecology. Biodiversity in aquatic environments is strongly influenced by environmental gradients that act as dispersion and niche barriers. Environmental conditions act as filters to select functional traits, but biotic interactions also play a role in assemblage structure. In headwater streams, the relationship between functional and taxonomic diversity remains unclear. In this study we investigated how environmental conditions, taxonomic diversity and biotic interactions influence the spatial distribution of traits and functional diversity in stream fish species. Standardized sampling of fish species was carried out in 50 m sections of 16 streams located in rainforest enclaves in a semiarid region of Brazil (Caatinga biome). The functional diversity indices displayed different responses to the predictor variables used. Functional richness was mainly influenced by environmental conditions, while functional evenness was mostly determined by taxonomic diversity. On the other hand, functional dispersion was explained by a combination of environmental conditions and taxonomic diversity. The spatial distribution of fish species with the same functional traits was random, indicating that biotic interactions are not a strong predictor in these ecosystems. Channel width, pH and substrate were the most important variables in the spatial distribution of the functional traits of the fish species. Our results suggest that the functional structure of fish assemblages in headwater streams depends mainly on environmental conditions and taxonomic diversity.

The effects of a disturbance by sandbank opening on the fish fauna community were evaluated through a long-term study in the Imboassica coastal lagoon, Rio de Janeiro State, Brazil. The fish and salinity samples were conducted between 1993 and 2004, with the goal of characterizing the structure and effects of four sandbank openings on this community, such as resilience and resistance measurements. During three sandbank openings, between the years of 1993 and 1996, the resilience time of the fish community could not be identified due to the short time period between openings, their magnitude and the discontinuity of the fish sampling. Monitoring studies previously conducted between 1993 and 2004, indicated that factors structuring the fish fauna of Imboassica lagoon are due to salinity fluctuations, influenced by the sandbank openings to which this environment is subjected. These events were indicated by the recolonization of primary freshwater species, oligohaline salinity values, and small variations in the composition and abundance on the fish community. Due to the magnitude and frequency of the disturbance, the ichthyic populations available that enter the lagoon from the adjacent ocean plus the resistance of this environment to salinity variations, determined the resilience and resistance of the fish fauna in the Imboassica lagoon. Thus, the resilience of the fish fauna in this lagoon was indicated in groupings of: a) Spearman probability values lower than 0.05 between the pairs of communities pre and post-disturbance; b) presence of freshwater species that indicate resilience; c) salinity values varying between 0 and 5; and d) small alterations in the abundance of fish populations Indicadores de la influencia de salinidad en la resistencia y resiliencia de la ictiofauna en laguna costera tropical (sudoeste de Brasil). Los efectos del disturbio de cuatro aberturas de la barra de arena en la laguna costera Imboassica, localizada en el municipio de Macaé, estado de Río de Janeiro, Brasil, en la comunidad de peces fueron evaluados en un estudio a largo plazo. Entre los años 1993 y 2004, colectas de peces y valores de salinidad fueron obtenidos con el objetivo de caracterizar la estructura y los efectos de las aberturas de barra sobre esta comunidad, como medidas de resiliencia y resistencia. Durante las aberturas de la barra realizadas entre los años de 1993 y 1996, el tiempo de resiliencia de la comunidad no fue identificado debido a los cortos intervalos de aberturas, a la magnitud del disturbio y a la discontinuidad de los muestreos de peces. Estudios realizados entre 1993 y 2004 indicaron que los factores que estructuran la ictiofauna de la laguna Imboassica son consecuencia de las variaciones de la salinidad, influenciadas por las aberturas de la barra a que este ambiente es sometido. Estos eventos fueron indicados por la recolonización de las especies primarias de agua dulce, valores de salinidad oligohalinos y bajas alteraciones en la composición y abundancia de la comunidad de peces. Debido a la magnitud y frecuencia de los disturbios, las poblaciones evaluadas de peces que entran en la laguna provenientes del océano adyacente, más la resistencia de este ambiente a las variaciones de salinidad, determinan la resiliencia y resistencia de la fauna de peces en la laguna. Así, la resiliencia de la fauna íctica en la laguna Imboassica fue indicada por el conjunto de: a) valores de probabilidad de Spearman menores de 0.05 entre los pares de comunidades pre y pos disturbio; b) presencia de especies de peces de agua dulce indicadoras de resiliencia; c) intervalos de salinidad variando entre 0 y 5; y d) bajas alteraciones en la abundancia de las poblaciones de pece

Humid highland forest enclaves are remnants of Atlantic Forest found in tablelands within the Caatinga biome (Northeastern Brazil), which emerged during interglacial periods in the Pleistocene. These ecosystems have a highly diverse and endemic fish fauna. Most earlier surveys have focused on the tableland of Borborema (Pernambuco and Paraíba States). In this study we surveyed the fish fauna of the humid forest enclaves in the tablelands of Ibiapaba and Araripe, based on samples collected in the rainy season (March and April) between 2009 and 2014. The 45 sampling points covered rivers, streams and reservoirs in five river basins belonging to three ecoregions. The species were listed according to drainage divide, and endemism was determined for each ecoregion and for the Caatinga. Our area was more species-rich (n=59) than Borborema (n=27). The samples included five introduced species and 29 species endemic to the Caatinga (49.1% of the sampled species). The distribution of Parotocinclus haroldoi was expanded to the Mid-Northeastern Caatinga ecoregion (Timonha river basin, Ceará State). Our study intends to make a significant contribution to current knowledge of the ichthyofauna in humid highland forest enclaves of semiarid Northeastern Brazil, identified as a priority in the conservation of the biodiversity in the Caatinga. Resumo Florestas úmidas são enclaves de Mata Atlântica em regiões elevadas inseridas no bioma Caatinga que surgiram no Pleistoceno em eventos interglaciais. Esses ecossistemas abrigam alta diversidade de espécies para diversos táxons e elevadas taxas de endemismo. A maioria dos levantamentos de peixes nesses ecossistemas foi realizada no Planalto da Borborema, nos Estados de Pernambuco e Paraíba. Dessa forma, visando conhecer a ictiofauna de dois enclaves de florestas úmidas no nordeste brasileiro, foram feitas coletas no período chuvoso (Março e Abril) entre 2009 e 2014 no Planalto da Ibiapaba e na Chapada do Araripe. Foram amostrados 45 pontos em rios, riachos e reservatórios em cinco bacias hidrográficas e três ecorregiões. A lista de espécies por drenagem e o endemismo foi definido para cada ecorregião e para a Caatinga. A riqueza de peixes (59 espécies) foi superior quando comparada a dos enclaves da Borborema (27), com cinco espécies introduzidas e 29 endêmicas para a Caatinga, o que representa 49,1% das espécies capturadas. Destaca-se a expansão de ocorrência de Parotocinclus haroldoi para a ecorregião do Mid-Northeastern Caatinga, na microbacia do rio Timonha, no Estado do Ceará. Este estudo pretende contribuir com informações inéditas para o conhecimento ictiofaunístico dos ecossistemas aquáticos dos brejos de alitude do semiárido brasileiro, apontadas como prioritárias para conservação da biodiversidade da Caatinga.