Warming weakens facilitative interactions between decomposers and detritivores, and modifies freshwater ecosystem functioning

Autor(es)

Bernabe, Tiago N. ^{[1, 2]} ; de Omena, Paula M. ^[2] ; dos Santos, Viviane Piccin ^[3] ; de Siqueira, Virginia M. ^[3] ; de Oliveira, Valeria M. ^[3] ; Romero, Gustavo Q. ^{[2, 4]}

Afiliação do(s) autor(es)

^[1] Univ Estadual Paulista, Posgrad Biol Anim, Sao Jose Do Rio Preto, SP - Brazil

^[2] Univ Estadual Campinas, Inst Biol, Dept Anim Biol, Lab Multitroph Interact & Biodivers LIMBIO, Campinas, SP - Brazil

^[3] Univ Estadual Campinas, Res Ctr Chem Biol & Agr CPQBA, Microbial Resources Div, Campinas, SP - Brazil

^[4] Brazilian Res Network Climate Change Rede Clima, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: GLOBAL CHANGE BIOLOGY; v. 24, n. 7, p. 3170-3186, JUL 2018.
• Citações Web of Science: 5

Resumo

Warming is among the major drivers of changes in biotic interactions and, in turn, ecosystem functioning. The decomposition process occurs in a chain of facilitative interactions between detritivores and microorganisms. It remains unclear, however, what effect warming may have on the interrelations between detritivores and microorganisms, and the consequences for the functioning of natural freshwater ecosystems. To address these gaps, we performed a field experiment using tank bromeliads and their associated aquatic fauna. We manipulated the presence of bacteria and detritivorous macroinvertebrates (control, bacteria, and bacteria+macroinvertebrates) under ambient and warming scenarios, and analyzed the effects on the microorganisms and ecosystem functioning (detritus mass loss, colored dissolved organic matter, and nitrogen flux). We applied antibiotic solution to eliminate or reduce bacteria from control bromeliads. After 60days incubation, bacterial density was higher in the presence than in the absence of macroinvertebrates. In the absence of macroinvertebrates, temperature did not influence bacterial density. However, in the presence of macroinvertebrates, bacterial density decreased by 54% with warming. The magnitude of the effects of organisms on ecosystem functioning was higher in the combined presence of bacteria and macroinvertebrates. However, warming reduced the overall positive effects of detritivores on bacterial density, which in turn, cascaded down to ecosystem functioning by decreasing decomposition and nitrogen flux. These results show the existence of facilitative mechanisms between bacteria and detritivores in the decomposition process, which might collapse due to warming. Detritivores seem to contribute to nutrient cycling as they facilitate bacterial populations, probably by increasing nutrient input (feces) in the ecosystem. However, increased temperature mitigated these beneficial effects. Our results add to a growing research body that shows that warming can affect the structure of aquatic communities, and highlight the importance of considering the interactive effects between facilitation and climatic drivers on the functioning of freshwater ecosystems. (AU)

• Processo FAPESP: 12/51143-3 - Mudanças climáticas globais e funcionamento de ecossistemas em fitotelmatas
• Beneficiário: Gustavo Quevedo Romero
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Regular
• Processo FAPESP: 14/04603-4 - Efeitos do aquecimento global na estrutura trófica e no funcionamento ecossistêmico em bromélias-tanque
• Beneficiário: Pablo Augusto Poleto Antiqueira
• Modalidade de apoio: Bolsas no Brasil - Doutorado