The Biota of Intermittent Rivers and Ephemeral Streams: Algae and Vascular Plants

Intermittent rivers and ephemeral streams (IRES) support highly biodiverse primary producers, including algae, cyanobacteria, and aquatic and riparian plants. All these groups share common traits to cope with a harsh environment whose water table varies and where desiccation is common. Traits include morphological characteristics, life cycle adaptations, and physiological mechanisms to contend with hydric stress and increased water temperatures. Despite these environmental challenges, primary producers play ubiquitous roles in the fluxes of energy and material in IRES. They are the basis for ecosystem metabolism, expressed as episodic pulses of production that occur immediately following rewetting, when their abundant output of high-quality organic matter is critical for supporting consumers both in-stream and in the neighboring terrestrial system.