title: Impact of the longitudinal and seasonal changes of the water quality on the benthic macroinvertebrate assemblages of the Andorran streams.
abstract: The ecological quality of the Andorran streams was assessed in 1998-1999, based on the survey of the water chemistry and the benthic macroinvertebrate assemblages. Two types of modification of the water quality were observed in the Andorran rivers: (i) a progressive degradation along the longitudinal gradient with a chronic degradation in the lower water courses; (ii) a seasonal modification in the mid-elevation sites. Two responses of the benthic macroinvertebrate assemblages to these disturbances were observed: an extreme simplification of the composition and a change of the trophic structure of the assemblages in the more impacted sites.
authors.affiliation: Laboratoire Dynamique de la Biodiversité, UMR 5172, bât. 4 R3, b1, Université Paul-Sabatier, 118, Route de Narbonne, 31062 Toulouse cedex 4, France. younes@cict.fr
authors.forename: Yasmina
authors.initials: Y
authors.lastname: Younes-Baraillé
authors.forename: Xavier-François
authors.initials: XF
authors.lastname: Garcia
authors.forename: James
authors.initials: J
authors.lastname: Gagneur
mesh_terms: D000725:Andorra; D000818:Animals; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D005618:Fresh Water; D006863:Hydrogen-Ion Concentration; D007448:Invertebrates / Q000145:classification / Q000502:physiology*; D010100:Oxygen / Q000032:analysis; D012621:Seasons; D013696:Temperature; D014195:Travel; D014873:Water Pollutants / Q000032:analysis; D014876:Water Pollution / Q000009:adverse effects*
chemical_list: D014873:Water Pollutants; D010100:Oxygen