Dinâmica do carbono alóctone, fluxo de energia e produção secundária de macroinvertebrados detritívoros

• Ano de defesa: 2017
• Autor(a) principal: Anna Carolina Fornero Aguiar
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; Brasil; ICB - INSTITUTO DE CIÊNCIAS BIOLOGICAS; Programa de Pós-Graduação em Ecologia, Conservacao e Manejo da Vida Silvestre; UFMG
• Palavras-chave em Português: Produção de biomassa; Matéria orgânica alóctone; Fragmentadores; Processos ecossistêmicos; Ecologia; Macroinvertebrados bentônicos; Biomassa; Matéria orgânica
• Link de acesso: http://hdl.handle.net/1843/36111

Allochthonous organic matter can represent an important source of energy and carbon to local fauna and a structuring element in low order streams covered by riparian vegetation. However, the role of organic matter as carbon source for benthic macroinvertebrates is not yet clear. Likewise, the role of shredders in litter breakdown is still an open question. Estimates of secondary production, which are necessary for approaches related to consumption and assimilation of resources and energy flux, are scarce in tropical lotic ecosystems. Aiming to understand the relationship among macroinvertebrate consumers, allochthonous organic matter dynamics and riparian vegetation, we analyzed along an 8-93% canopy cover gradient macroinvertebrate biomass and secondary production, organic matter availability and litter breakdown. This thesis was divided in two chapters, where the aims were (1) to analyze along an 8-93% canopy cover gradient the relationship among shredders biomass, leaf availability and breakdown rates; and (2) estimate litter consumption by shredders and analyze the relationship between potential consumer biomass and secondary production and availability of organic matter fractions. In chapter one we observed that despite the absence of pattern in shredder biomass, litter availability and breakdown related to canopy cover, shredders biomass, mainly represented by Triplectides (Trichoptera, Leptoceridae), was positively related to litter availability and breakdown rates. Additionally, despite low shredder diversity, the biomass of this group responded for up 40% of total macroinvertebrate biomass in most litter-banks. Our results suggest that biomass estimates represent a useful tool for analyzing functional feeding groups and ecosystem processes. To conclude, despite the lack of a pattern related to riparian vegetation, results indicate high biomass and importance of shredders macroinvertebrates on litter breakdown. In chapter two we observed the importance of allochthonous organic matter for the maintenance of benthic macroinvertebrates and positive relationship between functional feeding groups (FFG) and the availability of their potential resource. However, despite positive relationship between shredder secondary production and leaf availability, the ingestion of leaf material by this group corresponded to <15% of estimated leaf breakdown in most sites. Additionally, our secondary production estimates were higher than observations from tropical headwaters, but intermediate compared to temperate streams.