Genetic, evolutionary and biogeographical processes in intermittent rivers and ephemeral streams

Intermittent rivers and ephemeral streams (IRES) are strong drivers of evolution because they experience spatially variable and recurrent disturbances and succession processes. Alternating wet and dry phases exert strong selection that imposes trade-offs and leads to multiple strategies for spreading risk through space and time. IRES populations range from isolated to connected across landscapes, with contrasting effects on genetic structure and speciation, immigration, and extinction processes. IRES communities are characterized by continuously changing niche- and neutral-related factors, and the potential for allopatric diversification is high for species resistant to drying with low-dispersal ability. Flow intermittence determines the relative roles of local and regional factors controlling IRES community composition and diversity, which in turn influences ecosystem functions. Habitat contraction resulting from intermittence may also change the relative effects of different evolutionary processes acting through time. Consequently, IRES are ideal systems to advance our understanding of evolutionary ecology.