Segregação espacial de macroinvertebrados bentônicos em um rio intermitente do semiárido brasileiro

• Autor(a) principal: Farias, Rafaela Lima de
• Data de Publicação: 2018
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFPB
• Texto Completo: https://repositorio.ufpb.br/jspui/handle/123456789/18726
• topic: Hierarquia espacial; Padrões espaciais; Variáveis ambientais; Assembleias de macroinvertebrados; Chironomidae; Beta diversidade; Spatial hierarchy; Spatial patterns; Environmental variables; Macroinvertebrate assemblages; Beta-diversity; CNPQ::CIENCIAS BIOLOGICAS::ZOOLOGIA

Streams in arid regions are seen as mosaics of spatio-temporal landscapes, providing high environmental heterogeneity and exert strong influence on the patterns, estructure and diversity of biotic communities in various spatial scales (e.g. segment, reach and microhabitat). In this context, the presente study aimed to evaluate the patterns of structuration of benthic macroinvertebrates assemblages and characterize the environmental variables in different spatial scales accross the longitudinal gradiente of the river. The study was conducted in a intermittent river (Paraíba river basin) in the semiarid Brazil. This area is considered of extreme biological importance and identified as prioritary for the conservation of the Caatinga Biome. Sampling of the environmental predictors and biotic communities was made hierarquically, including three segments of the river (Alto PB, Taperoá and Médio PB), three reachs by segment, and three sites by reach, making a total of 27 sampling points (pools). For the diversity partition analysis, the microhabitat scale was also considered (n=81). Thus, the diversity of macroinvertebrates was evaluated in four distinct spatial scales: river segments (β4), reachs (β3), sites (β2) and microhabitats (β1). The results showed that the habitat structure in aquatic systems in the Brazilian Semiarid is composed by a large diversity of elements that variate spatio-temporally, and that environmental factors in local and catchment scales are important for the structure of the marginal habitats. Also, scale-dependence spatial segregation was observed on macroinvertebrate assemblages, with the higher scales representing the source of variation. Environmental predictors in local (e.g. habitat structure and sediment composition) and reginal scales (e.g. elevation) that could explain the assemblages composition were identified. The diversity partitioning analysis reinforced the importance of highest spatial scales (β4) and the low importance of finest spatial scales (β1 and β2) for the regional diversity in the river. This study described the spatial patterns of benthic macroinvertebrates on the context of environmental heterogeneity in a semiarid river. It is also the last register of the Paraíba river before the anthropic modifications caused by the transposition of the São Fransisco River, which has altered the hydrological dynamics (from intermittent to perennial) with potential to modify the environmental parameters observed (water quality, river width, depth, sediment composition and habitat structure). The data obtained can inform future research that can evaluate the impacts of the Trasposition and consequently subsidize management and conservation measures for the Paraíba River Basin.