Ephemeroptera, Plecoptera e Trichoptera (EPT) como indicadores dos impactos ambientais da urbanização em riachos neotropicais.

Abstract

The impacts of urbanization on the community of Ephemeroptera, Plecoptera and Trichoptera (EPT) were evaluated in nine 1st, 2nd and 3rd order streams belonging to the Pirapó river basin, Paraná state, Brazil. Five categories of metrics encompassing measures of richness, composition, identity, food habits and life strategy, were evaluated according to their sensitivity to the impacts. In order to do that the intensity of change (sensitivity) between the reference and impacted environments as well as the consistency of the signal (robustness) between winter and summer were evaluated. The metrics used were species richness, total abundance, Simpson's evenness, average taxonomic diversity, the trophic guilds grazer, brusher, scraper, filterer, predator and shredder and the life strategy guilds of swimmer, clinger, climber and sprawler. Whenever possible an INDVAL analysis was performed to assist the identification of metrics correlated to the impacted and reference streams. The changes arising from environmental impacts were determined by a SIMPER analysis and its correlatio with the EPT community metrics was determined by a BIOENV analysis. A Taxonomic Sufficiency (TS) analysis was performed subsequently with the metrics of richness, composition and identity, to determine which taxonomic resolution of EPT provides the best cost/benefit assessment of the impacts. The metrics of taxonomic richness, total abundance, Anacroneuria, and the guilds predator, scraper and clinger had the highest sensitivity and robustness to the impacts studied illustrating the need to combine many aspects of biology and ecology of organisms (multimetry) to obtain a correct evaluation of environmental quality. The ST analysis showed that the taxonomic level of Family presented the best cost/benefit ratio to evaluated the impacts analysed allowing to say that this is the most suitable taxonomic resolution to biomonitoring programs of environmental quality using the EPT group.