Contraction-expansion cycles in an internittent mediterranean streams. Structural and functional ecosystem responses

ACUNA, V.; ADONIS GIORGI; MUÑOZ, I.; OMELLA, M.; SABATER, F.; SABATER, S.

Lathi-Finlandia

Congreso; XXIX SIL; 2004

Asociacion Internacional de Limnologia

Stream ecosystem metabolism and macroinvetebrate community of an intermittent forested mediterranean stream were studied during the seasonal droughts in summer 2001 and 2003, and wetter than/average summer of 2002. Macroinvertebrate density increased during the drying process because of increase in habitat heterogeneity and detritus availability. However, watercourse fragmentation implied a swift decline. During the dryning period gross primary production declined steady while ecosystem respiration remained nearly constant. However, watercourse fragmentation resulted in large reduction of both processes. Post-drought recovery of ecosystem metabolism was stepped following discharge pulses and only reached stable values with the onset of baseflow.