Como utilizar bioindicadores de impactos antrópicos na gestão de recursos hídricos em escala nacional?

Abstract

The assessment of human pressure in river basins requires standardized and validated approaches on a regional scale to support decision-making by managers. Biological indicators are tools widely used in the largest water resources monitoring programs in the world, although they are still little used in official Brazilian monitoring. In this sense, the objective of this study is to evaluate the response of benthic bioindicators as a basis for assessing human pressure and for decision-making and management of water resources in a regional and national context. The study was conducted in 6 hydrological units located in the São Francisco and Paraná river basins. 260 sub-basins were studied, in which four indices that evaluated anthropogenic pressure were studied. Our same sites were evaluated as assemblages of benthic macroinvertebrates with the purpose of calculating a multimetric index (MMI) that integrates the responses of various components of the assemblages to anthropogenic impacts in a simple, but accurate response. The results show that the MMI response is similar in relation to the 4 indices, where the increase in anthropogenic pressure values ​​is reflected by the decrease in the MMI. These results are similar in the 6 hydrological units. Our results allow us to conclude that: (i) the use of bioindicators must be effectively implemented in Brazil; (ii) the MMI built with a standardized methodology can be used in different river basins; (iii) the approach presented here represents a practical, low-cost, simple, direct and efficiently proven tool to highlight the effects of anthropogenic impacts.