As time goes by: 20 years of changes in the aquatic macroinvertebrate metacommunity of Mediterranean river networks

Aim: to analyse temporal metacommunity dynamics in river networks in relation to hydrological conditions and dispersal. Location: 15 river reaches from the Llobregat, Besòs and Foix catchments in the North-Eastern Iberian Peninsula. Taxon: aquatic macroinvertebrates belonging to 99 different families. Methods: we sampled aquatic macroinvertebrate communities during spring in 20 consecutive years. We built two environmental distances (one related with water chemistry and another one with river flow regime) and two spatial distances (network distance and topographic distance). Then we used Mantel tests (accounting for spatial autocorrelation) to relate macroinvertebrate dissimilarity with environmental and spatial distances. Additionally, we determined the dry and wet years using the Standardised Precipitation Index (SPI) and we classified macroinvertebrate families based on their ability to fly and to drift. Finally, we ran a linear regression model including the correlation value (r) of...