Azkeneko hiru hamarkadetan Euskal Herriko kostaldean klima-aldaketak komunitate bentonikoetan (flora eta fauna) izan duen eragina

Abstract

Canopy-forming macroalgae are globally facing drastic declines and the consequences for ecosystem processes remain still little known. The present investigation analyses in a 20 years period the retreat of shallow subtidal rocky benthos communities in the southern Bay of Biscay, where the macrophyte Gelidium corneum has suffered a notable decrease. The rate of change of canopy retreat was investigated as well as the effects of the decline on the taxonomic and functional structure of canopy-dependent organisms (algae and invertebrates). Our results show that major changes occurred abruptly in 2008, and no signs of recovery have been recorded afterwards. Major losses arose in complex perennial macroalgal forms together with epiphytic and no epiphytic suspensivores while simple turf-forming algae proliferated. At the same time, species richness, algal density and both flora and fauna evenness increased. There exist groups of coherent species of flora and fauna that covary during the first part of the studied period. However, from 2008 onwards the new established community lacked algal-invertebrate specific associations. Our results highlight patterns between flora and fauna species help to better understand the consequences of the loss of key species and functional traits for the benthic ecosystem.