title: The leaf breakdown of Picramnia sellowii (Picramniales: Picramniaceae) as index of anthropic disturbances in tropical streams.
abstract: There are few studies in tropical regions exploring the use of leaf breakdown process as a functional tool to assess anthropic disturbance on aquatic ecosystems. We assessed the effects of water pollution due to human activities on the leaf breakdown rate of Picramnia sellowii in streams of the southeastern Brazil. The experiment was carried out for 60 days in three reference streams and three streams impaired by organic pollution and absence of riparian vegetation. Three litter bags were incubated in each stream containing 3 ± 0.05 g of P. sellowii leaves. The reference streams presented higher values of dissolved oxygen and lower values of nutrients, turbidity, electrical conductivity, total impermeable area and water temperature. The leaf breakdown rate (k) differed significantly between the reference (k = 0.014 ± 0.003 d-1) and impaired streams (k = 0.005 ± 0.001 d-1). The leaves incubated in the reference streams contained greater fungal biomass (measured as ergosterol concentration) and abundance of invertebrates, as well as greater presence of shredders, with k values being related to the biomass of these organisms. Overall, there were clear differences between the leaf mass loss in the reference and impaired streams. These results reinforce the negative effect of urbanization on leaf breakdown and fungal and shredder biomass.
authors.affiliation: Programa de Mestrado em Comportamento e Biologia Animal, Instituto de Ciências Biológicas, Juiz de Fora, MG, Brazil.
authors.forename: M P
authors.initials: MP
authors.lastname: Lopes
authors.affiliation: Programa de Mestrado em Comportamento e Biologia Animal, Instituto de Ciências Biológicas, Juiz de Fora, MG, Brazil.
authors.forename: R T
authors.initials: RT
authors.lastname: Martins
authors.affiliation: Programa de Mestrado em Comportamento e Biologia Animal, Instituto de Ciências Biológicas, Juiz de Fora, MG, Brazil.
authors.forename: L S
authors.initials: LS
authors.lastname: Silveira
authors.affiliation: Departamento de Zoologia, Instituto de Ciências Biológicas, Juiz de Fora, MG, Brazil.
authors.forename: R G
authors.initials: RG
authors.lastname: Alves
mesh_terms: D018533:Biomass; D001938:Brazil; D017753:Ecosystem; D019684:Magnoliopsida / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D045483:Rivers / Q000737:chemistry*; D012722:Sewage / Q000009:adverse effects*; D060753:Water Quality
chemical_list: D012722:Sewage