Assessment of Coastal Lagoon Quality with Taxonomic Diversity Indices of Fish, Zoobenthos and Macrophyte Communities

Abstract

Lagoons and marshes account for more than 50% of the coastal area in the Languedoc Roussillon region (South of France, Mediterranean Sea). The lagoons are very different in their physical and chemical characteristics, eutrophication level and resource exploitation mode. In this study, different levels of taxonomic diversity and two indices (D + and K + ) based on macrophyte, zoobenthos and fish communities are used to compare three lagoons (Ingril, Pre´vost and Mauguio). Whilst the taxonomic diversity of the fish community seems not influenced by the lagoon characteristics, the benthos community is strongly related to their eutrophication status. With the same sampling effort we identified 7 benthic species in Mauguio, the most impacted lagoon, while 24 species were found in the Ingril lagoon, which is the less impacted one. Overall, the variance of taxonomic distinctness K + appeared as the best indicator of the lagoon eutrophication level. This index is always highest for the Mauguio lagoon, whatever the biotic compartment considered. In a more stable environment like in the Ingril lagoon (lower variations of salinity, temperature or turbidity), K + is low, i.e., the structure of the taxonomic tree is very regular with a relatively homogeneous partition of species among phyla. By contrast, when salinity variations are wide, like in the Mauguio lagoon, the taxonomic tree becomes irregular with some lineages less constrained (many species belonging to the same family), while others are more impacted with a limited number of species in these phyla.

Three main stressors acting on the Ria Formosa lagoonal system (Southern Portugal): Physical stress, organic matter pollution and the land–ocean gradient

“…Bazairi et al (2005) reported 147 taxa to a smaller Moroccan lagoon. In some Greek brackishwater lagoons the maximum number of invertebrate taxa was 84 (Reizopoulou and Nicolaidou, 2004), and in southern France the total number of zoobenthos in the less eutrophicated lagoon was only 24 (Mouillot et al (2005). In Portugal, taxa richness was 268 in Santo André lagoon (da Fonseca et al, 1989) and 119 in Óbidos lagoon .…”

Multi-element otolith fingerprints unravel sea−lagoon lifetime migrations of gilthead sea bream Sparus aurata

“…Al though those studies indicated a major role of lagoons in the successful completion of the species' life cycle, lagoon abiotic and biotic conditions in the area have changed considerably over the intervening years (IFREMER 2009), due to local increases in both climatic and anthropogenic pressures on the littoral zone (Mouillot et al 2005b). The resulting environmental degradation in certain lagoons, notably Mauguio (IFREMER 2009), has caused many authors to question the suitability of lagoons as habitats for juvenile fishes (Quignard et al 1984, Labourg et al 1985, Brusle & Cambrony 1992).…”

“…Moreover, the last studies of lagoon use by S. aurata in the area were carried out in the 1970s (Lasserre 1976). Since then, intensification of climatic and anthropogenic pressures in the coastal zone (Vitousek et al 1997, Boesch et al 2001 have resulted in a significant increase in eutrophication and anoxic crises in the lagoons (Aliaume et al 2007, IFREMER 2008, and a corresponding loss in biodiversity (Mouillot et al 2005b). These alterations of lagoon environmental conditions have reduced their quality as habitats for juvenile fish (Quignard et al 1984, Labourg et al 1985, Brusle & Cambrony 1992, and might have affected S. aurata migratory behavior in the area.…”

Abundance and diversity of amphipods (Crustacea: Peracarida) on shallow algae and seagrass in lagoonal ecosystem of the Mediterranean Tunisian coast

“…Wetlands are ecologically very important and extremely productive ecosystems, however very sensitive essentially in transitional locations subject to environmental and anthropogenic constraints (Mouillot et al 2005;Rossi et al 2006;Blanchet et al 2008). The Tunisian lagoons, like several Mediterranean wetlands, are subject to an increasing pressure in the anthropogenic activities (urbanization, industry, pollution, aquaculture, tourism, and overfishing).…”