Understanding how assemblages are structured in space and the factors promoting their distributions is one of the main goals in Ecology, however, studies regarding the distribution of organisms at ...larger scales remain biased towards terrestrial groups. We attempt to understand if the structure of stream fish metacommunities across a Neotropical ecoregion (Upper Paraná-drainage area of 820,000 km2) are affected by environmental variables, describing natural environmental gradient, anthropogenic impacts and spatial predictors. For this, we obtained 586 sampling points of fish assemblages in the ecoregion and data on environmental and spatial predictors that potentially affect fish assemblages. We calculated the local beta diversity (Local Contribution to Beta Diversity, LCBD) and alpha diversity from the species list, to be used as response variables in the partial regression models, while the anthropogenic impacts, environmental gradient and spatial factors were used as predictors. We found a high total beta diversity for the ecoregion (0.41) where the greatest values for each site sampled were located at the edges of the ecoregion, while richer communities were found more centrally. All sets of predictors explained the LCBD and alpha diversity, but the most important was dispersal variables, followed by the natural environmental gradient and anthropogenic impact. However, we found an increase in the models' prediction power through the shared effect. Results suggest that environmental filters (i.e. environmental variables such as climate, hydrology and anthropogenic impact) and dispersal limitation together shape fish assemblages of the Upper Paraná ecoregion, showing the importance of using multiple sets of predictors to understand the processes structuring biodiversity distribution.
Abstract Microplastics (MPs) contamination is a well-established impact in oceans, but integrated approaches combining simultaneous analyzes of biotic and abiotic components are scarce. This study ...addresses this gap, demonstrating Atherinella brasiliensis (fish species) ingestion of MPs and comparing with the contaminant presence in water and sediment. Three Ubatuba beaches (exposed, calm and sheltered estuary) were surveyed for fish, water, and sediment components in summer and winter. Environmental data evidenced spatial and seasonal differences (PCA/ANOVA). Presence of synthetic particles (SPs) in fish was high (~38%). Maximum concentrations occurred in the estuary, for water (490 SPs/m³), and in the exposed beach, for sediment (62 SPs/50g). Fibers format predominated in all components. Fish preference for blue color seems to occur. Significant statistical relationships were determined for fish length and SPs size and between SPs concentrations in water and fish. The chemical identities (μ-FTIR spectra) polypropylene, polyethylene, polyamide, polyester, and cardboard/cellulose predominated. Influences of local hydrodynamics (e.g., SPs sizes) and reduction in tourism during Covid-19 epidemic (e.g.,less SPs in summer) are discussed. This study confirms environmental contamination by SPs (mostly MPs) in Ubatuba beaches, affecting fish through direct water column ingestion. Urgent actions from authorities and changes in local user’s habits are crucial.
Resumo Contaminação por microplásticos (MPs) é um impacto bem estabelecido nos oceanos, embora sejam escassos enfoques combinando análises simultâneas dos componentes bióticos e abióticos. Este estudo foi direcionado para esta lacuna, demonstrando a ingestão de MPs por Atherinella brasiliensis (espécie de peixe) e comparando com a presença do contaminante na água e sedimento. Três praias de Ubatuba (exposta, calma e estuário abrigado) foram amostradas para os componentes peixe, água e sedimento durante o verão e o inverno. Dados ambientais evidenciaram diferenças espaciais e sazonais (ACP/ANOVA). A presença de partículas sintéticas (PSs) em peixes foi alta (~38%). Concentrações máximas ocorreram no estuário, para água (490 PSs/m³), e na praia exposta, para sedimento (62 PSs/50g). O formato fibra predominou em todos os componentes. Preferência dos peixes pela cor azul parece ocorrer. Relações estatísticas significativas foram determinadas para comprimento dos peixes e tamanho das PSs e entre concentrações de PSs na água e nos peixes. As identidades químicas (μ-FTIR spectra), polipropileno, polietileno, poliamida, poliéster e celulose/papelão predominaram. Influências da hidrodinâmica local (e.g., tamanhos das PSs) e da redução do turismo durante a epidemia de Covid-19 (e.g., menos PSs no verão) são discutidas. Este estudo confirma a contaminação por PSs (a maioria MPs) nas praias de Ubatuba, afetando os peixes através da ingestão direta na coluna d’água. Ações urgentes por parte das autoridades e mudanças de hábitos dos usuários locais são cruciais.
Resumo: Objetivo: Nosso estudo foi realizado para desenvolver um índice multimétrico adequado para riachos urbanos em Sorocaba, uma cidade de grande porte inserida na Mata Atlántica do sudeste do ...Brasil. Métodos: Vinte e sete trechos de riachos foram selecionados para avaliaçao ambiental e de peixes. Vinte métricas ecológicas foram testadas em um gradiente ambiental entre os trechos de referencia e degradados. As métricas candidatas foram selecionadas quanto a amplitude, capacidade de resposta e redundáncia. Calculamos um índice multimétrico de peixes (MFI) subdividido em cinco classes de qualidade: referencia > 0,8, 0,6 < bom <0,8, 0,4 < moderado < 0,6, 0,2 < pobre < 0,4 e ruim < 0,2. Resultados: Quatro métricas se mostraram adequadas para discriminar trechos com maior qualidade biótica daqueles degradados. Cinco trechos de riacho (18%) foram classificados como referencia ou bom e 16 (60%) como pobre ou ruim. Tres trechos de referencia podem ser usados para um programa de restauraçao hidromorfológica. Conclusoes: Esses resultados indicaram que muitos aspectos da integridade biológica foram alterados, indicativo de severa degradaçao. Nossos resultados podem ser úteis para um projeto de gestao e restauraçao da bacia hidrográfica do Sorocaba/Médio Tiete.
Understanding the influence of local and regional factors that structure biological communities can be useful in environmental conservation. Our objective was to verify whether a fish metacommunity ...in the Brazilian Atlantic Forest has a nonrandom structure along the longitudinal stream gradient. To do so, we applied the elements of metacommunity structure to examine fish distribution patterns at the micro-basin extent for 20 stream fish assemblages. Stream fish species were independently distributed following the Gleasonian pattern. The Gleasonian pattern suggested that the communities varied continuously over space, potentially reflecting the degree to which species tolerances overlap. The metacommunity structure may have resulted from the environmental gradient and has a high beta diversity. The upstream reaches have higher values from regional variables (confluence distance and declivity) and slower values on variables representing a local scale (temperature, conductivity, depth, and width). Knowing the type of structure and the drivers that shape a metacommunity, we suggested that ensuring the connectivity of streams is a good conservation strategy as the species move from one to another, being very dependent on the colonization source. This environmental management can affect biodiversity at local and regional scales, thus we would require devoting local conservation efforts to a large number of different reaches of streams and in a micro-basin regional scale.
Several tropical freshwater fish species are generally generalistic feeders, sometimes followed by a diet reduction during the period of decreased resource availability. This study aimed to analyze ...the dietary overlap between nektonic and benthic fish species. The stomachs of 82 obligatory nektonics and 52 benthic were removed. The diet composition for each individual was determined based on the analysis of the stomach content, and the contents were grouped into 11 categories. For the analysis of food items, the method of degree of food preference was used. To verify the niche overlap between benthic and nectonic, the Pianka index was applied. Benthic species consumed items across all 11 food categories and nektonic species consumed nine. The diet composition of species with nektonic and benthic habits showed a significant difference. Dietary overlapping suggests a supply of the same resources, as they are shared by both groups. The high concentration of water insect larvae in the food content of all sampled fish species, regardless of the position in the water column, shows the importance of insects in the water ecosystems. The composition of ecosystem diets is helpful towards understanding the community structure and can explain the coexistence between different fish’s groups where live in different micro-habitats and how tactics used to capture food which may minimize the effects of overlapping and competitive exclusion.
Issue Title: Agroforestry and biodiversity conservation: Traditional practices, present dynamics, and lessons for the future In the core region of Brazilian cocoa production, shade cacao plantations ...(so-called cabrucas) are important components of regional landscapes, constituting potential habitat for a vast array of the regional biota. This research focuses on the ability of cabrucas to harbor bird and bat species in two nearby districts - Una and Ilhéus - with contrasting landscapes. At Una, cabrucas represent less than 6% of the land and are surrounded by large tracts of forest, whereas at Ilhéus these shade plantations are the landscape's dominant feature. Bird and bat communities were richer in cabrucas located in Una compared to nearby forest, while cabrucas from the Ilhéus landscape were significantly poorer in species than nearby forest fragments. However, bird assemblages in cabrucas were characterized by the loss of understory specialists and the increase of more open area and generalist species, whereas forest dwellers still comprised most of the bat species reported in cabrucas. Species richness and composition differed between the two landscapes. Forest fragments and cabrucas from Ilhéus harbored fewer forest-dwelling species than similar habitats in Una. Our study shows that cabrucas support high species richness of birds and bats from the native assemblages but are no surrogates for intact forests, since the presence and representativeness of some forest species apparently depends on the existence of nearby forests. A landscape dominated by cabrucas with a minor portion of native forest is unlikely to ensure long-term conservation of many target species, particularly those of major conservation concern.PUBLICATION ABSTRACT
Abstract The Serranias Costeiras of the Ribeira de Iguape River basin comprise landscapes with steep slopes, where many streams are contained in protected areas. We evaluated the importance of these ...protected areas for stream fish diversity. We sampled the ichthyofauna during the dry season of 2010, 2018 and 2019 in 36 stream stretches. We used beta diversity measures and estimated species richness and dark diversity in streams from two types of protected areas (full protection, FP and sustainable use, SU) and outside (Out). The altitude-width and velocity gradient of the streams explained the species turnover. The PA type promoted the richness difference, with FP streams having less species richness than SU and outside. Streams from FP presented lower species richness and dark diversity. These results indicate that the few species in FPs are well protected. The FP streams contain a relevant proportion of the regional species pool and, therefore, are essential for conserving fish stream diversity in the study region. On the other hand, streams from SU or Out have higher species richness, but their fish fauna is more vulnerable. Due to longitudinal stream connectivity, we highlight the importance of rethinking the limits of protected areas.
Resumo Os riachos das Serranias Costeiras da bacia do rio Ribeira de Iguape estão na região do estado de São Paulo com maior quantidade de áreas preservadas e com ictiofauna muito particular. Avaliamos a importância das áreas preservadas na diversidade da ictiofauna. Durante o período de seca de 2010, 2018 e 2019 coletamos a ictiofauna em 36 trechos de riachos em dois tipos de áreas protegidas (Proteção Integral, FP e Uso Sustentável, SU) e fora (Out). Utilizamos medidas de diversidade beta e estimamos a riqueza de espécies e a diversidade escura. A ictiofauna regional apresentou alta diversidade beta. O gradiente de largura e velocidade dos riachos e altitudinal explicou a substituição de espécies. A diferença de riqueza foi promovida pelo tipo de UC sendo que os riachos FP possuem menor riqueza de espécies que os SU e fora das UCs. Os riachos inseridos em FP contêm uma proporção relevante do pool regional de espécies e, portanto, são importantes para a conservação da diversidade de riachos na região de estudo. Por outro lado, os riachos que estão em SU ou Out possuem maior riqueza de espécies e sua fauna de peixes está mais vulnerável. Devido à conectividade longitudinal dos riachos ressaltamos a importância de repensar os limites das unidades de conservação.
Abstract Spintherobolus papilliferus is an endangered characid endemic of the Atlantic Rainforest, known from sparse locations in the upper rio Tietê basin around the metropolitan area of São Paulo ...city, and from an affluent of rio Itapanhaú, a coastal stream in Bertioga, São Paulo State. In 2020, S. papilliferus was sampled from the rio Ribeira de Iguape basin in Juquitiba, São Paulo State, representing a new distributional record. We compared 17 morphometric and six meristic characters from all specimens with data from the rios Tietê and Itapanhaú. An overlap in the morphological data from the three populations was detected, except for five measure whose values are lower in rio Ribeira de Iguape. MANOVA and LDA revealed that this population differs significantly from the other two, showing shallower body and caudal peduncle, among other features. These morphological differences may be due to environmental selective pressures since rio Ribeira de Iguape drainage is marked by fast waters which can influence the shape of fish bodies over time. DNA-barcoding of all Spintherobolus species corroborate that the rio Ribeira de Iguape population belongs to S. papilliferus. We also present a hypothesis for the disjunct distribution of S. papilliferus involving headwater capture and discuss the implications for the conservation of this endangered species.
Resumo Spintherobolus papilliferus é um caracídeo endêmico da Mata Atlântica e ameaçado de extinção, conhecido de localidades esparsas na bacia do alto rio Tietê, região metropolitana da cidade de São Paulo, e de um afluente do rio Itapanhaú, um riacho costeiro em Bertioga, Estado de São Paulo. Em 2020, S. papilliferus foi amostrada na bacia do rio Ribeira de Iguape em Juquitiba, São Paulo, representando um novo registro de distribuição. Comparamos 17 caracteres morfométricos e seis merísticos dos exemplares com dados dos rios Tietê e Itapanhaú. Houve sobreposição nos valores dos dados exceto em cinco medidas cujos valores são menores no rio Ribeira de Iguape. MANOVA e LDA revelaram que esta população difere significativamente das demais populações, sendo estes exemplares caracterizados pelas menores alturas do corpo e pedúnculo caudal, dentre outras características. Estas diferenças morfológicas possivelmente decorrem de pressões ambientais, pois a drenagem do rio Ribeira de Iguape possui ambientes de corredeiras velozes que podem influenciar no formato do corpo dos peixes. DNA-barcoding de todas as espécies de Spintherobolus corroborou que a população do rio Ribeira de Iguape pertence à S. papilliferus. Apresentamos também uma hipótese para a distribuição disjunta de S. papilliferus envolvendo captura de cabeceiras e discutimos implicações para a conservação dessa espécie ameaçada.
Freshwater fish scale database Bánó, Bálint; Bolotovskiy, Aleksey; Levin, Boris ...
Data in brief,
06/2024, Letnik:
54
Journal Article
Recenzirano
Odprti dostop
Scales of the ray finned fishes can be used for multiple purposes. Beside others by their specific structure and elemental composition they are usable for age determination and food-web researches. ...Additionally, just their presence, absence, shape, location, or numbers could provide a reliable taxonomic information. The fish scales show remarkable size variation also, which characteristics provide reliable information about the environmental needs of freshwater fish. But till now this information was not interpretable and comparable in the absence of a sufficiently large and detailed database. In this study we provide a database which can facilitate the further complex comparative studies.
Our dataset consists of 2954 scale photos characterising 193 freshwater fish species. All photos have a uniquely identification code showing exactly which species the scale belongs to. In addition to the photos, our database includes a table showing the exact taxonomic classification of the studied species, the average body profile-index, and the relative scale size, as well as the ecological (flow and feeding habitat preferences) and life strategic characteristics (feeding and breeding guild memberships) of each species.
The sampled species have diverse origin, covering five biogeographical regions. An average of five adults from each species were selected for sampling. Three-to-four scales were collected from the anterior part of the body between the dorsal fin and the lateral line. The removed scales were cleaned and prepared to microscope slides, and after this process they were photographed or scanned. Our database can be used for both research and educational purposes. A large number of scale photos assigned of species can be an opportunity to create an automatic species identification system. Moreover, the subjectivity in morphometric measurements can be eliminated by analysing the database with artificial intelligence.
ABSTRACT Trophic structure of fish assemblages is one of the most sensitive indicators of changes in streams environments. Since it is crucial to understand the response of trophic groups to habitat ...alteration, our study aimed to address this research gap by assessing the influence of substrate composition, meso-habitat variability, and bank stability, on the richness, biomass, and number of individuals of carnivores, invertivores, omnivores, and herbivorous-detritivores. Using an electrofishing device, we sampled 13 Atlantic rainforest streams reaches in a degradation gradient, located in the upper Paranapanema river basin. Sample points were ranked using a physical habitat index. More pristine streams had high availability of twigs, trunks, rocks and boulders in the substrate, great meso-habitat variability, and the presence of roots, trunks, and rocks in the margins. Canonical correlations between habitat characteristics and trophic groups explained more than 90% of data variability. Richness and number of individuals of invertivores increased in more preserved stream reaches, while richness of carnivores and number of individuals of omnivores decreased. These results demonstrate that trophic structure varies according to level of degradation, and that invertivore richness represents the best indicator of fish trophic structure responses to physical habitat alterations in streams.
RESUMO A estrutura trófica da assembleia de peixes é um dos indicadores mais sensíveis a alterações ambientais em riachos. Considerando a relevância de entender a resposta de grupos tróficos à alteração ambiental, este estudo buscou preencher esta lacuna científica avaliando a influência da composição do substrato, variabilidade de meso-hábitats e estabilidade das margens sobre riqueza, biomassa e número de indivíduos de peixes carnívoros, invertívoros, onívoros e herbívoros-detritívoros. Amostramos com pesca elétrica 13 trechos de riachos de Mata Atlântica com estado de conservação variável, localizados na parte superior da bacia do alto rio Paranapanema. Os pontos amostrais foram ranqueados pelo índice de hábitat fisico. Riachos mais presevados apresentaram mais galhos, troncos, matacões e blocos no substrato, maior variabilidade de meso-hábitats e maior quantidade de raízes, troncos e rochas nas margens. As correlações canônicas explicaram mais de 90% da variabilidade dos dados. A riqueza e o número de indivíduos de invertívoros aumentaram em riachos mais preservados, enquanto que a riqueza de carnívoros e o número de indivíduos onívoros diminuíram. Estes resultados demonstram que a estrutura trófica varia em resposta ao nível de preservação, e que a riqueza de invertívoros é o melhor indicador de respostas da estrutura trófica às alterações do hábitat em riachos.
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