Assessing the indicator properties of zooplankton assemblages to disturbance gradients by canonical correspondence analysis

Abstract

The indicator properties of zooplankton assemblages in a coastal lagoon were evaluated, by means of canonical correspondence analysis, along environmental gradients of trophic state and marine influence caused by anthropogenic impact. Changes in zooplankton species composition were significant indicators of environmental heterogeneity patterns. Species diversity was insensitive to eutrophication but decreased with increasing marine influence. The rotifer species Brachionus plicatilis and Synchaeta bicornis as well as cirriped nauplii were good indicators of mesohaline conditions. The rotifer species Asplanchna brightwelli, Brachionus angularis, Brachionus falcatus, Filinia terminalis, and Polyarthra remata were good indicators of eutrophic conditions. The other species investigated were good indicators of oligohaline and mesotrophic conditions. The rotifer genus Brachionus proved to be a better indicator organism for these environmental gradients than the entire zooplankton assemblage. Hence, this taxon can be considered a target taxon for more intensive monitoring and conservation planning. The method used here to assess the indicator properties of species assemblages and to select target taxa can be widely applied in any aquatic ecosystems to any group of organisms, spatial and temporal scales, and environmental gradients.