Key Words flooding, drying, human impact s Abstract Streams in mediterranean-climate regions (areas surrounding the 0066-4162/99/1120-0051$08.00 51 Annu. Rev. Ecol. Syst. 1999.30:51-81. Downloaded from arjournals.annualreviews.org by b-on: Universidade de evora (UEvora) on 02/03/09. For personal use only.