Fatores estruturadores das assembleias de peixes e desenvolvimento de ?ndice multim?trico para a avalia??o da condi??o bi?tica de riachos de Floresta Atl?ntica contribuintes da Ba?a de Guanabara

• Ano de defesa: 2013
• Autor(a) principal: Terra, Bianca de Freitas
• Orientador(a): Ara?jo, Francisco Gerson
• Banca de defesa: Caramaschi, ?rica Maria Pellegrini, Buchas, Rosana Mazzoni, Pereira, Marcos Callisto de Faria, Freitas, Andr? Felippe Nunes de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal Rural do Rio de Janeiro
• Programa de Pós-Graduação: Programa de P?s-Gradua??o em Ci?ncias Ambientais e Florestais
• Departamento: Instituto de Florestas
• País: Brasil
• Palavras-chave em Português: ictiofauna; monitoramento; sufici?ncia amostral
• Palavras-chave em Inglês: stream ecology; multimetric index; sampling effort
• Área do conhecimento CNPq: Ecologia
• Link de acesso: https://tede.ufrrj.br/jspui/handle/jspui/3467

The Tropical Atlantic Rain Forest is one of the most threatened biome in the world, including a variety of streams that have a highly diversified fish fauna, and they are under heavy pressure because of the intense use of their services. This study aimed to assess spatial and environmental influences at different scales (site and catchment) on the structure of fish assemblages, to determine the sampling sufficiency to assess the ichthyofauna, and to evaluate environmental condition of streams from Atlantic Rain Forest that drain to Guanabara Bay using multimetric approach based on fish assemblages. Standardized sampling were carried out in 48 sites which flow to Guanabara Bay streams, during dry (April-October) season in 2010 and 2011, with seven of those sites been resampled during wet season (February-March) of 2011, aiming the metrics selections. At each site, a stretch of 40 times the width wet channel was sampled, or a minimum of 100 m or a maximum of 500 m extent, via alternating current generator (3000 W, 220 V). Moreover, in each stretch, 11 equidistant cross-section transects were marked, defining 10 quadrats of the same length in which the physical habitat variables were measured (e. g., depth, width, substrate type, macrophytes cover, shading) and physico-chemical variables (water temperature, dissolved oxygen, conductivity and turbidity). A total of 19.293 individuals, representing 68 species distributed in 13 families were sampled. The number of recorded species ranged from 0 to 30 species at site. Astyanax taeniatus, Poecilia reticulata, Rineloricaria sp.1, Scleromystax barbatus, Characidium vidali, and Trichomycterus cf. zonatus comprised more than 50% of total abundance of all sampled sites. Partial Redundancy Analysis revealed that fish assemblages were more associated to site-scale variables than catchment-scale and spatial ones, with assemblages responding to a longitudinal gradient influenced mainly by altitude. Sampling in 40 channel wetted widths were not sufficient to estimate species richness in these systems. Presumably, due to the high number of rare species. However, such distance was sufficient to apply of other metrics of assemblage condition, being suitable to application of environmental assessment protocols in stream of Atlantic Tropical Rain Forest. Concerning the multimetric index (MMI), six metric were selected: % of Characiforms individuals, % of native water column individuals, % invertivorous benthic individuals, % detritivorous individuals % tolerant species, and % intolerant species. This index was validated with the Integrated Disturbance Index (IDI) and responded efficiently to the disturbance gradient. Thus, a most cost-effective alternative was produced that responded efficiently to overall anthropogenic pressure helping to assess the ecological status of Atlantic Tropical Rain Forest streams.