Riqueza e composição da assembleia de Oligochaeta (Annelida) do rio Iguaçu : efeitos dos fatores ambientais e dos impactos antropogênicos.

• Autor(a) principal: Behrend, Rômulo Diego de Lima
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• dARK ID: ark:/35916/0013000006mgf
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/4904
• topic: Oligochaeta (Annelida); Comunidades; Gradientes ambientais; Gradientes geomorfológicos; Cascata de reservatórios; Ocupação humana; Fatores locais e regionais; Reservatórios; Zoobentos de água doce; Rio Iguaçu; Paraná (Estado); Brazil.; Geomorphologic gradient; Reservoir cascade; Human occupation; Local and regional factors; Iguaçu River; Paraná (State); Brazil.; Ciências Biológicas; Ecologia

This paper aimed at assessing alterations in richness and composition of Oligochaeta assemblage along Iguaçu River, taking into account the modification of environmental variables along geomorphologic gradient as well as reservoirs cascade. Bottom samples were collected along 11 stretch do Iguaçu River with a Petersen grab (0,0345 m2). ANOVA showed significant difference in species richness among stations belonging to Iguaçu River. Changes in environmental variables and in richness and composition of Oligochaeta were summarized by Canonic Correspondence Analysis (CCA). A total of 12.780 Oligochaeta individuals were registered belonging to 25 species and Enchytraeidae. Statistical analysis (MRPP) revealed that composition of Oligochaeta was clearly distinct among the stretch of Iguaçu River. Oligochaeta assemblage was primary determined by local environmental factors (conductivity, substrate type and temperature) and regional ones (altitude) and secondary by river regulation and human occupation. Along Iguaçu River, conductivity, nitrogen, mud and altitude decreased, while temperature increased. Oligochaeta composition showed significant spatial variation, with the highest species abundance of family Tubificidae and gender Dero (Naididae) in first plateau. In the second and third plateau there was predominance of few species, with increase in occurrence of species of family Naididae below reservoirs. In this study was showed a gradual change in Oligochaeta composition, as well as in environmental variables related to this strong environmental gradient. Both local and regional environmental variables and river regulation and human occupation were important to explain variation in richness and composition of Oligochaeta species.