Bromeliads are tropical epiphytic plants that harbor small aquatic food webs between their leaves, consisting of protists and detritivorous and predatory insect larvae. We study these bromeliad food webs in rain forests in the Área de Conservación Guanacaste, Costa Rica, to elucidate mechanisms determining their structure, diversity, stability and to explore local adaptation as a mediator of effects. For example, we examine dispersal, resource input, predator presence and elevation as important factors influencing these metacommunities, both in observational and in experimental studies. This project is part of the DFG-funded project Mechanisms and consequences of change in aquatic protist communities. Relevant publications: Busse et al. 2018, Kratina et al. 2017, Petermann et al. 2015 Ecology, Petermann et al. 2015 PLoS ONE.