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Forested catchments generally present conserved aquatic ecosystems without anthropogenic disturbances; however, forest management operations can degrade these environments, including their water quality. Despite the potential degradation, few studies have analyzed the effects of forest management in subtropical regions, especially in forest plantations with intensive management, such as Eucalyptus plantations in Brazil. The intensive management of those plantations is characterized by fast-growing, short rotation cycles, and high productivity. This study aimed to assess the effects of Eucalyptus plantations harvesting on the concentration and exportation of nutrients and suspended solids in subtropical streams. Results showed that clear-cut harvesting and subsequent forest management operations do not alter most of the concentration of nitrate, potassium, calcium, and magnesium. The concentration of suspended solids increased during the first year after timber harvesting in all studied catchments, however, the increases were statistically significant in only two catchments. In the first year after harvest, it was observed an increment of water yield/precipitation ratio at three catchments, which also increased export of nutrients and suspended solids. Our results showed that harvesting of fast-growing Eucalyptus forest plantations partially affected sediment exports and did not compromise water quality in the studied catchments. However, the catchment land-use design, especially related to road density and land-use composition, showed significant relationship with sediment exportation.

We review the biologically driven decomposition processes that take place in riverine ecosystems.• We identify important gaps in our understanding of decomposition processes in rivers from temperate and tropical biomes. • We propose a novel analytical approach to predict decomposition processes from metabolic scaling theory. • Using metadata from 30 rivers, we demonstrate that the slope of community size spectra can predict rates of decomposition.

RESUMOAtualmente os reservatórios brasileiros vêm sofrendo grandes pressões devido à crescente demanda por água para diversos fins, sendo a eutrofização uns dos maiores problemas causados pelo homem. O reservatório de Itupararanga fornece serviços ambientais para mais de um milhão de pessoas e é um dos principais manancias da bacia do rio Sorocaba e médio Tietê. Desta forma, o presente trabalho teve como objetivo verificar a variabilidade espacial do grau de trofia e da biomassa fitoplanctônica do reservatório, assim como as concentrações de nutrientes e também verificar seu enquadramento conforme a resolução CONAMA 357/2005357/ (BRASIL, 2005. Para isto foi realizada uma coleta da água superficial em seis estações amostrais e medidas de pH, condutividade elétrica, oxigênio dissolvido, temperatura da água, transparência da água, fósforo total, fósforo total dissolvido, nitrito, nitrato, concentrações de clorofila-a e no sedimento foi realizada análises granulométricas. Os resultados indicaram que não houve variação espacial do grau de trofia do reservatório de Itupararanga, porém houve variação espacial das concentrações de nutrientes e clorofila-a, corroborando com modelos teóricos de compartimentalização de reservatórios. Palavras-chave: Reservatório. Itupararanga. Trofia. Nutrientes. CONAMA ABSTRACT Nowadays the Brazilian reservoirs has suffered great pressure due to increasing demand for water for diverse purposes, being one of the largest eutrophication problems caused by man. The Itupararanga reservoir provides environmental services to more than one million people and is one