Heterogeneidad espacial en la distribución de los macroinvertebrados a lo largo de un transecto en el rio Llobregat (Barcelona, España)

Abstract

LLOBREGAT RIVER (Barcelona, Spain)A stream transect was made in the Llobregat river iii Catalonia (NE Spain) taking surber samples.At the sampling location thc river was characterized by a patchy substratum of bedrock with C'1~dophor.a.macrophytes (Potc~rnoxclori pccrincrru.\) and sand.The seventeen sequential sample replicates yield a list of 100 taxa: 24 Chironomidae, 21 Oligochaeta.17 Epliemeroptera, 5 Trichoptera, 7 Mollusca, and other minor groups.The species abundance rank correlation matrix was clustered and yielded five groupes.most of which were clearly related to the substratum and related conditions thus: reophilic species clustered, sand and mud Oligochaeta clustered and Chirinomids asociated with Poturno,gc.ror~ clustered as well.Diversity values calculated with the Shannon Weaver index, heterogeneitb and diversity spectra allow us to describe community diversification and spacial heterogeneity.Such spacial heterogeneity should be considered by those who postulate a diversity decreasement with the increasement ofthe river order.