Estudio comparativo del estado ecol´ ogico de los r´ios de la cuenca del Ebro mediante macroinvertebrados y diatomeas

A comparative study of the ecological state of the Ebro watershed rivers by means of macroinvertebrates and diatoms During the summer of 2002 the water ecological status of 87 sample stations of different rivers along the Ebro River basin (Spain) was studied using different biotic indices based on benthic macroinvertebrates and diatoms. Most of the sample points studied in 2002 reached at least a “Good” ecological status but some differences between the different existing fluvial types were observed. Upper river stretches and mountain rivers had higher ecological status. In general the sampling stations with the worst ecological status level were mainly located downstream, close to urban and industrial areas, near agricultural or livestock areas or downstream dams. A positive, significant correlation was observed between macroinvertebrate and diatom indices, both concerning the values obtained and the resulting ecological status categories.