Navegando por Autor "BENONE, Naraiana Loureiro"

Agora exibindo 1 - 4 de 4

Acesso aberto (Open Access)
Do local environmental factors structure the trophic niche of the splash tetra, Copella arnoldi? a test in an Amazonian stream system
(Instituto Nacional de Pesquisas da Amazônia, 2020-03) SOARES, Bruno Eleres; BENONE, Naraiana Loureiro; ROSA, Daniela Cristina Oliveira; MONTAG, Luciano Fogaça de Assis
Environmental variation affects the availability of spatial and trophic resources in Amazonian streams and may be important factors structuring the diet of fishes. We analyzed the diet composition and trophic niche breadth of the lebiasinid splash tetra, Copella arnoldi, aiming to evaluate how environmental variation in Amazonian streams affects the species’ trophic niche. Fish were captured and environmental factors were recorded in 20 streams in the Caxiuanã National Forest, in the eastern Amazon, in November 2010. We made a semi-quantitative analysis of stomach contents of 200 individuals. Copella arnoldi exhibited an omnivorous diet composed mainly of detritus and allochthonous invertebrates. Environmental variation (stream width, stream depth, canopy cover and flow) did not affect the diet composition or trophic niche breadth of the species, possibly due to the regional integrity of the forest within the boundaries of the protected area. Riparian cover probably minimizes the effect of the small-scale variations in food resources, thus leading to a locally homogeneous diet composition in the splash tetra C. arnoldi.
Acesso aberto (Open Access)
Efeitos do espaço e do ambiente sobre assembleias de peixes de igarapés da Amazônia oriental
(Universidade Federal do Pará, 2012) BENONE, Naraiana Loureiro; MONTAG, Luciano Fogaça de Assis; http://lattes.cnpq.br/4936237097107099
The amazon streams have harsh environmental characteristics for several fish species due to their oligotrophic conditions. In spite of that, these watercourses possess a rich and diversified ichthyofauna, resulting from the various microhabitats found in streams. In ria lake systems, the rivers and streams suffer a natural impoundment, which provokes a lowering on current velocity values. This could homogenize the environment, since current velocity affects many of the streams features. Thereby, distance between streams could have its importance emphasized as a structural factor of stream fish assemblages. This study aimed to analyze the influence of space and environment on the structure of fish assemblages in drowned streams of Caxiuanã, in Eastern Amazon. The fishes were caught during the period of drought of 2010, including 34 transects of drowned streams. Eight abiotic factors were measured to test the effect of the environment. To analyze the effect of the space, space filters were calculated based on the geographical coordinates, as well as the distance among the streams following the watercourse. The analyses showed that the environment was the only factor to influence the beta diversity, refuting the hypothesis of the space as a structuring factor and reinforcing the paper of the ecological niche in the distribution of species. Nevertheless, the abiotic factors explained a low percentage of the variation in the fish composition, what shows that other variables can affect these assemblages.
Acesso aberto (Open Access)
Effect of waterfalls and the flood pulse on the structure of fish assemblages of the middle Xingu River in the eastern Amazon basin
(Instituto Internacional de Ecologia, 2015-08) BARBOSA, Thiago Augusto Pedroso; BENONE, Naraiana Loureiro; RUFFEIL, Tiago Octavio Begot; GONÇALVES, Alany Pedrosa; SOUSA, Leandro Melo de; GIARRIZZO, Tommaso; JUEN, Leandro; MONTAG, Luciano Fogaça de Assis
The structure of fish assemblages in Neotropical rivers is influenced by a series of environmental, spatial and/or temporal factors, given that different species will occupy the habitats that present the most favourable conditions to their survival. The present study aims to identify the principal factors responsible for the structuring of the fish assemblages found in the middle Xingu River, examining the influence of environmental, spatial, and temporal factors, in addition to the presence of natural barriers (waterfalls). For this, data were collected every three months between July 2012 and April 2013, using gillnets of different sizes and meshes. In addition to biotic data, 17 environmental variables were measured. A total of 8,485 fish specimens were collected during the study, representing 188 species. Total dissolved solids, conductivity, total suspended matter, and dissolved oxygen concentrations were the variables that had the greatest influence on the characteristics of the fish fauna of the middle Xingu. Only the barriers and hydrological periods played a significant deterministic role, resulting in both longitudinal and lateral gradients. This emphasizes the role of the connectivity of the different habitats found within the study area in the structuring of its fish assemblages.
Acesso aberto (Open Access)
Heterogeneidade ambiental e diversidade de peixes de riachos na Amazônia
(Universidade Federal do Pará, 2017-09-07) BENONE, Naraiana Loureiro; MONTAG, Luciano Fogaça de Assis; http://lattes.cnpq.br/4936237097107099; ESPOSITO, Maria Cristina; http://lattes.cnpq.br/2112497575917273
Amazon streams are highly heterogeneous systems that encompass a remarkable diversity. Due to the increasing threats to these systems, it is necessary to understand how ecological process in natural areas affect streams and their fish biota. This thesis was divided in three chapters and aims to answer the following questions: 1) How much do catchment variables affect the physical habitat of small streams in the Amazon? 2) What is the relative contribution of environmental and spatial variables on taxonomic and functional alpha and beta diversity of stream fish? 3) How much are distinct components of biodiversity (species diversity, taxonomic distinctness, and functional diversity) congruent and how much can they be predicted from catchment variables? Fifty seven streams were sampled across six river basins in the Amazon region. For environmental characterization, a standardized protocol was used to obtain more than 140 local variables, and 11 catchment variables were obtained from aerial images. Fish assemblages were sampled with hand nets during a six-hour period. Stream catchments were divided in two groups based on altitude and slope. These two variables influenced streams habitats, regulating flow velocity and the types and proportions of substrates. The taxonomic and functional patterns of fish assemblages were affected by environmental filters operating at the catchment scale. Nonetheless, variables at the local scale were particularly important to taxonomic and functional alpha diversity. Despite the significant role of environmental filters, limited dispersal was the main driver of variation in fish diversity, indicating a strong biogeographic factor. Finally, various components of diversity exhibited intermediate congruence, which suggests that no single component can describe patterns of fish diversity. In addition, catchment variables alone could not accurately predict diversity patterns, and therefore it is recommended that additional explanatory variables, including descriptors of local environmental conditions, are important to include in studies of stream fish diversity.