Benthic communities of streams related to different land uses in a hydrographic basin in southern Brazil.
Different land uses affect the characteristics of a hydrographic basin, reflected in the river water quality, and consequently affecting the aquatic biota. The benthic community closely reflects the alterations caused by different human activities. In this study, the effects of different land uses were evaluated by analysis of the benthic community structure in streams with urban, agricultural and pasturage influences, as well as areas in better-conserved regions. The abiotic parameters showed distinct seasonal variability, which did not occur with the benthic organisms. A degradation gradient was observed among the study sites, in the headwaters-agriculture-pasture-urban direction. By the CCA its possible to observe that the density of organisms tended to increase along this gradient, whereas richness, diversity, evenness, and EPT families decreased. The most intense effects of land use on the benthic community composition, richness, and diversity were observed in urban areas (F (1,4) = 16.0, p = 0.01; F (1,4) = 8.97, p = 0.04; respectively). In conclusion a trend in the benthic community is observed in to predict alterations caused for the different land uses, mainly, when the source point pollution, as the case of urban area.
Departamento de Ciências Biológicas, Universidade Regional Integrada do Alto Uruguai e das Missões-Campus de Erechim, Av. Sete de Setembro, 1621, Erechim, RS CEP 99700-000, Brazil. lhepp@uri.com.br
Luiz Ubiratan
LU
Hepp
Sandro
S
Santos
D000383:Agriculture; D000818:Animals; D044822:Biodiversity; D001938:Brazil; D002118:Calcium / Q000032:analysis; D004755:Enterobacteriaceae / Q000302:isolation & purification; D004784:Environmental Monitoring; D005843:Geography; D006863:Hydrogen-Ion Concentration; D007448:Invertebrates / Q000145:classification* / Q000254:growth & development / Q000378:metabolism; D008274:Magnesium / Q000032:analysis; D009573:Nitrites / Q000032:analysis; D010100:Oxygen / Q000032:analysis; D010758:Phosphorus / Q000032:analysis; D000644:Quaternary Ammonium Compounds / Q000032:analysis; D045483:Rivers / Q000737:chemistry* / Q000382:microbiology; D012621:Seasons; D014873:Water Pollutants / Q000032:analysis*
D009573:Nitrites; D000644:Quaternary Ammonium Compounds; D014873:Water Pollutants; D010758:Phosphorus; D008274:Magnesium; D010100:Oxygen; D002118:Calcium