Estudio de la variabilidad espacio-temporal de las comunidades de macroinvertebrados bentónicos en los ecosistemas fluviales de Cantabria. Repercusiones para la aplicación de la Directiva Marco del Agua

Resum

The present thesis aims to determine the spatio-temporal variability patterns of macroinvertebrate communities in Cantabrian rivers, applying this knowledge to the ecological status assessment processes. Macroinvertebrate distribution patterns in Cantabrian rivers are mainly determined by the structural complexity of the habitat, the feeding resource availability and the hydraulic stress. Moreover, hydromorphological impacts and organic enrichment of water produce important changes in the structure and composition of macroinvertebrate communities, increasing the ratio non-insect/insect taxa. At seasonal level macroinvertebrate communities are mainly affected by the hydraulic conditions predictability and the feeding resource availability. Macroinvertebrate metrics correlate better with the antrophic stress gradients in low flow period. LIFE and ICMi are the best metrics to indentify the hydromorphological stress gradient, while EPTt, EPt, ASPT, Rhet and AsMet, do not show significant seasonal differences and are the best metrics to identify the organic pollution gradient