title: Predicted rainfall changes disrupt trophic interactions in a tropical aquatic ecosystem.
abstract: Changes in the distribution of rainfall and the occurrence of extreme rain events will alter the size and persistence of aquatic ecosystems. Such alterations may affect the structure of local aquatic communities in terms of species composition, and by altering species interactions. In many aquatic ecosystems, leaf litter sustains detrital food webs and could regulate the responses of communities to changes in rainfall. Few empirical studies have focused on how rainfall changes will affect aquatic communities and none have evaluated if basal resource diversity can increase resistance to such rainfall effects. In this study, we used water-holding terrestrial bromeliads, a tropical aquatic ecosystem, to test how predicted rainfall changes and litter diversity may affect community composition and trophic interactions. We used structural equation modeling to investigate the combined effects of rainfall changes and litter diversity on trophic interactions. We demonstrated that changes in rainfall disrupted trophic relationships, even though there were only minor direct effects on species abundance, richness, and community composition. Litter diversity was not able to reduce the impact of changes in rainfall on trophic interactions. We suggest that changes in rainfall can alter the way in which species interact with each other, decreasing the linkages among trophic groups. Such reductions in biotic interactions under climate change will have critical consequences for the functioning of tropical aquatic ecosystems.
authors.affiliation: Departamento de Ecologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Aliny P F
authors.initials: AP
authors.lastname: Pires
authors.affiliation: Departamento de Ecologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Nicholas A C
authors.initials: NA
authors.lastname: Marino
authors.affiliation: Department of Zoology, Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Diane S
authors.initials: DS
authors.lastname: Srivastava
authors.affiliation: Departamento de Ecologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.|Laboratorio Internacional en Cambio Global - LINCGlobal.
authors.forename: Vinicius F
authors.initials: VF
authors.lastname: Farjalla
mesh_terms: D057231:Climate Change; D017753:Ecosystem; D020387:Food Chain; D056127:Hydrobiology; D018515:Plant Leaves; D011891:Rain
keywords: aquatic ecosystems; climate change; insurance effects; litter diversity; natural microcosm; precipitation; tank bromeliads; trophic interactions