Streams with Riparian Forest Buffers versus Impoundments Differ in Discharge and DOM Characteristics for Pasture Catchments in Southern Amazonia
Higo J. Dalmagro,
Michael J. Lathuillière,
Fernando da S. Sallo,
Maurel F. Guerreiro,
Osvaldo B. Pinto,
Paulo H.Z. de Arruda,
Eduardo G. Couto,
Mark S. Johnson
Affiliations
Higo J. Dalmagro
Programa de Pós-Graduacão em Ciências Ambiental, Universidade de Cuiabá, Cuiabá, Mato Grosso 78.025-300, Brazil
Michael J. Lathuillière
Stockholm Environment Institute, Stockholm 10451, Sweden
Fernando da S. Sallo
Programa de Pós-Graduacão em Ciências Ambiental, Universidade de Cuiabá, Cuiabá, Mato Grosso 78.025-300, Brazil
Maurel F. Guerreiro
Programa de Pós-Graduacão em Ciências Ambiental, Universidade de Cuiabá, Cuiabá, Mato Grosso 78.025-300, Brazil
Osvaldo B. Pinto
Programa de Pós-Graduacão em Ciências Ambiental, Universidade de Cuiabá, Cuiabá, Mato Grosso 78.025-300, Brazil
Paulo H.Z. de Arruda
Programa de Pós-Graduação em Física Ambiental, Universidade Federal de Mato Grosso (UFMT), Cuiabá, Mato Grosso 78060-900, Brazil
Eduardo G. Couto
Departamento de Solos e Engenharia Rural, Faculdade de Agronomia, Medicina Veterinária e Zootecnia, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso 78060-900, Brazil
Mark S. Johnson
Institute for Resources, Environment and Sustainability, University of British Columbia Vancouver, BC V6T 1Z4, Canada
Forest to pasture land use change following deforestation in Southern Amazonia can result in changes to stream water quality. However, some pasture streams have riparian forest buffers, while others are dammed for farm ponds. Stream corridor management can have differential effects on hydrology and dissolved organic matter (DOM) characteristics. We examined rainfall-runoff patterns and DOM characteristics in a pasture catchment with a forested riparian buffer, and an adjacent catchment with an impoundment. Total streamflow was 1.5 times higher with the riparian buffer, whereas stormflow represented 20% of total discharge for the dammed stream versus 13% with buffer. Stream corridor management was also the primary factor related to DOM characteristics. In the impounded catchment, DOM was found to be less structurally complex, with lower molecular weight compounds, a lesser degree of humification, and a larger proportion of protein-like DOM. In the catchment with a forested buffer, DOM was dominated by humic-like components, with fluorescence characteristics indicative of DOM derived from humified soil organic matter under native vegetation. Our results suggest that differences in stream corridor management can have important implications for carbon cycling in headwater pasture catchments, and that such changes may have the potential to influence water quality downstream in the Amazon basin.
