Estado ecológico de los ríos incluidos dentro del parque Nacional de Ordesa y Monte Perdido (Cuenca del Ebro, Aragón), mediante indicadores de macroinvertebrados

Abstract

We provide information about the ecological status of Arazas, Bellos and Yaga rivers (Ordesa y Monte Perdido National Park), obtained from samples collected by volunteers during the 2013 spring-summer season, included in the “Volunteering activities in the Parks Network” program (MAGRAMA). In each river three points have been selected, all belonging to Type 27: High mountain rivers, except one that is Type 26: Humid calcareous mountain river. For each point several macroinvertebrate indexes (IBMWP, IASPT, NFAM, NFPLE and EPT) and their ecological quality ratios (EQR) were calculated. As a whole, 72% of the IBMWP measurements show Very good or Good quality, a 22% Moderate and a 6% Deficient . The Yaga River showed all the measures as Very Good-Good while in the Arazas River we found the three classes of quality cited. In general, for each river the values of the indexes are decreasing from mouth to source, while most of values are increasing in a temporal pattern (from spring to late summer) in each sampling point, except in two points, Arazas-3 and Bellos-2, that show the opposite pattern.