Woody debris in north Iberian streams: Influence of geomorphology, vegetation, and management

The effect of stream geomorphology, maturity, and management of riparian fo rests on abundance, role, and mobility of wood was evaluated in 20 contrast ing reaches in the Aguera stream catchment (northern Iberian Peninsula). Du ring 1 year the volume of woody debris exceeding 1 cm in diameter was measu red in all reaches. All large woody debris (phi > 5 cm) pieces were tagged, their positions mapped, and their subsequent changes noted. Volume of wood y debris was in general low and ranged from 40 to 22,000 cm(3) m(-2) the ab undance of debris dams ranged from 0 to 5.5 per 100 rn of channel. Wood was especially rare and unstable in downstream reaches, or under harvested for ests (both natural or plantations). Results stress that woody debris in nor th Iberian streams has been severely reduced by forestry and log removal. B ecause of the important influence of woody debris on structure and function of stream systems, this reduction has likely impacted stream communities. Therefore, efforts to restore north Iberian streams should include in-chann el and riparian management practices that promote greater abundance and sta bility of large woody debris whenever possible.