O efeito do folhiço nos processos de escoamento superficial e potencial erosivo: uma abordagem funcional em busca de mecanismos

• Ano de defesa: 2018
• Autor(a) principal: Rajão, Pedro Henrique Medeiros
• Orientador(a): Dias, André Tavares Corrêa
• Banca de defesa: Rosado, Bruno Henrique Pimentel , Fernandes, Nelson Ferreira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade do Estado do Rio de Janeiro
• Programa de Pós-Graduação: Programa de Pós-Graduação em Ecologia e Evolução
• Departamento: Centro Biomédico::Instituto de Biologia Roberto Alcantara Gomes
• País: BR
• Palavras-chave em Português: Serapilheira; Processos hidrológicos; Escoamento superficial; Propriedades hidrológicas; Estoque e drenagem; Processos erosivos; Deslocamento de sedimentos; Abordagem funcional; Ecohidrologia; Ecologia florestal; Hidrologia
• Palavras-chave em Inglês: Litter; hydrological processes; Surface runoff; Hydrological properties; Storage and dranaige; Erosive processes; Sediment displacement; Functional approach; Ecohydrology
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::ECOLOGIA::ECOLOGIA DE ECOSSISTEMAS
• Link de acesso: http://www.bdtd.uerj.br/handle/1/5890

The litter plays a fundamental role in the generation of surface runoff and erodibility. There is evidence that this role is determined by the hydrological properties of storage and drainage, which, in turn, are regulated mainly by properties of the litter layer and leaf traits of the present species. Structural properties of the litter layer, such as mass and depth, were observed influencing the generation of surface runoff. However, we still do not know which species traits determine litter hydrologic properties and their impact on hydrological and erosive processes. Here, we addressed this question by reviewing the literature (Chapter 1) and by conducting a rain simulation experiment (Chapter 2). Based on our literature review, we hypothesized that species leaf traits can significantly alter hydrological processes. More specifically, we expected leaf area (size and shape spectrum - SSS) to negatively affect storage capacity (C) and to positively affect lateral drainage, with consequent negative effects on runoff and sediment yield. Additionally, we expect leaf water repellency (as part ot the hydrological spectrum - HS) to affect runoff and sediment yield in the same direction of leaf area, while leaf water retention and water-holding capacity (also HS) inverse relationship. Our results showed that litter from different plant species strongly differ in their storage capacity (C), surface runoff (RUNOFF) and sediment yielding (SEDIM). We also showed that species traits can explain the variation in C (R² = 0.60, p < 0.0001), lateral drainage (R² = 0.54, p < 0.001), RUNOFF (R² = 0.59, p < 0.001) and SEDIM (R² = 0.17, p = 0.01). Our models confirm, in part, our hypotheses except for our predictions for leaf water repellency. These results demonstrate the action of capillarity and cohesion / adhesion forces concomitantly on the generation runoff in different litter layers with contrasting functional composition. In addition, only traits from the HS, more specifically leaf retention and water-holding capacity, affected SEDIM, reducing the amount of sediment yield. Understanding of the effect of these traits on hydrological and erosive processes makes it possible to predict the behavior of different plant communities in hydrological functioning in different ecosystems. In this way, our discoveries can have important implications as management tool for forest restoration programs, conservation of biodiversity and ecosystem engineering