Alterations in land uses based on amendments to the Brazilian Forest Law and their influences on water quality of a watershed

Brazilian Journal of Biology

Jl. Rodrigues-filho¹  Rm. Degani¹  Fs. Soares¹  Na. Periotto¹  Fp. Blanco¹  Ds. Abe¹  T. Matsumura-tundisi¹  Je. Tundisi¹  Jg. Tundisi¹ 

关键词: watershed;    diffuse load;    Forest Law;    bacia hidrográfica;    cargas difusas;    Código Florestal;   

DOI  :  10.1590/1519-6984.08813

来源: SciELO

【 摘 要 】

The amendments to the Forest Law proposed by the Brazilian government that allow partial substitution of forested areas by agricultural activities raised deep concern about the integrity of aquatic ecosystems. To assess the impacts of this alteration in land uses on the watershed, diffuse loads of total nitrogen (Nt) and total phosphorus (Pt) were estimated in Lobo Stream watershed, southeastern Brazil, based on export coefficients of the Model of Correlation between Land Use and Water Quality (MQUAL). Three scenarios were generated: scenario 1 (present scenario), with 30-meter-wide permanent preservation areas along the shore of water bodies and 50-meter-radius in springs; scenario 2, conservative, with 100-meter-wide permanent preservation areas along water bodies; and scenario 3, with the substitution of 20% of natural forest by agricultural activities. Results indicate that a suppression of 20% of forest cover would cause an increase in nutrient loads as well as in the trophic state of aquatic ecosystems of the watershed. This could result in losses of ecosystem services and compromise the quality of water and its supply for the basin. This study underlines the importance of forest cover for the maintenance of water quality in Lobo Stream watershed.

【 授权许可】

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