Navegando por Autor "RUFFEIL, Tiago Octavio Begot"

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Acesso aberto (Open Access)
Avaliação dos efeitos de monocultura de palma de dendê na estrutura do habitat e na diversidade de peixes de riachos amazônicos
(Universidade Federal do Pará, 2018-03-30) RUFFEIL, Tiago Octavio Begot; MONTAG, Luciano Fogaça de Assis; http://lattes.cnpq.br/4936237097107099
In the Amazon, oil palm plantation has been growing exponentially in recent years, altering the landscape natural characteristics and being a possible threat to biodiversity. This environmental impact extends to aquatic ecosystems, which because they are highly related to the adjacent vegetation, also suffer the impacts resulting from this agricultural action, such as habitat structure alterations, affecting the species distribution and ecosystem processes. Thus, studies to test the impact of this monoculture in the Amazon are important to support more efficient strategies for reducing impacts and maintaining biodiversity. Therefore, this thesis aims to answer the following questions: I) How the presence of oil palm cultivation around the streams affect their habitat structure and fish assemblage structure in relation to streams that drain through forested areas present along of this anthropogenic landscape? II) What are the effects of the substitution on landscape of primary forest on the oil palm in the habitat physical structure and on the taxonomic diversity of neotropical stream fish? III) How do the patterns of taxonomic and functional diversity of Amazon stream fish assemblages responds to the habitat and landscape changes caused by oil palm plantation? To answer these questions, we sampled and analyzed 39 streams in the Eastern Amazon. For the habitat characterization, an extensive protocol of the evaluation was applied, resulting in 238 habitat variables, besides that, was used landscape characteristics based on the percentage of land uses adjacent to the streams. For fish collection was used hand net for six hours in each stream. Morphological measures and ecological information of fish species were taken for later calculation of the functional attributes related to the third chapter. The results showed that oil palm plantation affect the stream habitat structure, modifying mainly the channel morphology, the substrate structure and shelter availability, such as woods and roots, for fish assemblage. Consequently, the fish species distribution was affected, resulting in changes in the assemblage structure. On the other hand, no changes were registered in the functional structure of these assemblies. Finally, we showed that the oil palm plantation modifies the stream habitat natural characteristics, as well as the distribution of the species, however the functional structure of the fish assemblages is maintained.
Acesso aberto (Open Access)
Ecomorphological patterns of the fishes inhabiting the tide pools of the Amazonian Coastal Zone, Brazil
(2013) SOARES, Bruno Eleres; RUFFEIL, Tiago Octavio Begot; MONTAG, Luciano Fogaça de Assis
The present study was based on the identification of the ecomorphological patterns that characterize the fish species found in tide pools in the Amazonian Coastal Zone (ACZ) in the Pará State, Brazil. Representatives of 19 species were collected during two field campaigns in 2011. The dominance, residence status, and trophic guild of each species were established, and morphometric data were obtained for up to 10 specimens of each species. A total of 23 ecomorphological attributes related to locomotion, position in the water column, and foraging behavior were calculated for the analysis of ecomorphological distance. Principal Component Analysis (PCA) was utilized for the evaluation of ecomorphological attributes that explained the variation among species. Mantel Test was used to correlate the taxonomic distance with species' morphological patterns and a partial Mantel Test to analyze the correlation among trophic guilds and ecomorphological patterns, controlling the effects of taxonomic distance among species. The analyses revealed two principal axes of the variation related to locomotion, correlated with the width of the caudal peduncle and the shape of the anal fin, as well as the influence of taxonomic distance on the ecomorphological characteristics of the different species. The dominant and resident species both presented a reduced capacity for continuous swimming. The two principal axes identified in relation to the position of the fish in the water column were correlated with the position of the eyes, the area of the pelvic fin, and body shape, with evidence of the influence of taxonomic distance on the morphology of the species. PCA grouped species with pelagic habits with benthonic ones. In the case of foraging behavior, the two principal axes formed by the analysis correlated with the size of the mouth, eye size, and the length of the digestive tract. Species of different guilds were grouped together, indicating a weak relationship between morphology and foraging behavior, and no relationship was found with taxonomic distance. The resident and dominant species in the tide pools of the ACZ present sedentary habits, with little evidence of the influence of taxonomic distance on the use of habitats or morphology, which was a poor indicator of foraging strategies, and showing that phylogenetically distant species could present similar ecomorphological patterns.
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)
A ictiofauna de poças rochosas de maré: padrões de distribuição associados ao espaço e ambiente
(Universidade Federal do Pará, 2012) RUFFEIL, Tiago Octavio Begot; MONTAG, Luciano Fogaça de Assis; http://lattes.cnpq.br/4936237097107099
Within studies of biological communities the search for occurrence and distribution patterns is acquiring space in researches in recent decades. Knowledge of the community structure and their relations, associated with interaction of these organisms with the environment, give necessary subsidies for the maintenance of these communities and relevant information for conservation and management plans. This way, the aim of this work was analyze the effect of environment and space on the structuration of the fish assemblage of rocky tidepools, describing the occupation patterns of these species in this environment and testing the hypothesis of the space having strong effect on the ichthyofauna organization. It was sampled 80 rocky tidepools in Amazon coastal zone, being 40 of the rainy period and 40 of the dry period of 2011. These pools are localized in five beaches of the Pará coastal zone and their volume, distance of the margin and physical-chemical parameters of the water (as pH, temperature and salinity) were measured. A total of 1.311 fishes were sampled, being 633 individuals of rainy season and 648 of dry season. The specimens represent nine orders, 14 families and 21 species. Perciformes was the most abundant order, within B. soporator and L. jocu as the most representative species. Obtained results in BioEnv process showed that abiotic variables (pH, temperature and volume) are not responsible for the organization of the community. Calculation of β diversity evidenced a wide variation of the data, including since the total substitution of the species to identical communities, considering the occurrence and abundance. DCA pointed that the pluviometric period is not determinant on species distribution, as result of the lack of difference in the composition among periods. The effect of space and environment on the community was low, since the larger part of variation was not explained with environmental variables, as the second analysis, where it was utilized the variables defined with the BioEnv process. Following the same pattern, the partial RDA used with the most correlated variables showed that: 6% explained by environment, 4% by space, 2% by environment and space, and 88% by other factors. The obtained results in these analyses prove that abiotic factors measured, likewise the distance among samples, are not determinant in composition and distribution of tidepools ichthyofauna. These data refute the hypothesis of the space having influence on the organization of the ichthyofauna, since the environmental conditions experience constant disturbances caused by tidal movement. In doing so, the species that occupy this environment showed themselves adapted, and for this reason they would not have their distribution affected by the variation of environmental parameters at this scale, responding only for the space effect.