Intermittent rivers and ephemeral streams (IRES) are highly heterogeneous systems, where habitat conditions range from fully aquatic to fully terrestrial. The dynamics of these habitats culminate in variation in connectivity between sites, which has multiple consequences for populations, communities, and ecosystems. IRES can thus be best understood in the context of metasystems, where local dynamics are influenced by regional processes. In this chapter, we synthesize recent work describing how metapopulation, metacommunity, and metaecosystem dynamics are driven by the hydrological variability of IRES. To date, very few studies have considered metapopulation issues in IRES, and the same is largely true for metacommunity and metaecosystem research. IRES are excellent arenas to study metasystems in highly dynamic systems. Research on metasystem issues is important for developing and testing ecological theory and also necessary to manage and conserve biodiversity and ecosystem services in IRES in the face of global change.