TY - JOUR T1 - Re-oligotrophication trajectories of macrophyte assemblages in Mediterranean coastal lagoons based on 17-year time-series A1 - Le Fur,Ines A1 - de Wit,Rutger A1 - Plus,Martin A1 - Oheix,Jocelyne A1 - Derolez,Valerie A1 - Simier,Monique A1 - Malet,Nathalie A1 - Ouisse,Vincent AD - Univ Montpellier, CNRS, MARBEC, Ifremer,IRD,CS 30171, F-34203 Sete, France. AD - Univ Montpellier, CNRS, MARBEC, Ifremer,IRD,CC093, F-34095 Montpellier, France. AD - IFREMER, Lab Ecol Pelag DYNECO PELAGOS, Ctr Bretagne, ZI Pointe Diable,CS 10070, F-29280 Plouzane, France. AD - IFREMER, Lab Environm Ressources Provence Azur Corse, Stn Corse, F-20600 Zi Furiani, Bastia, France. AD - UR - https://archimer.ifremer.fr/doc/00474/58555/ DO - 10.3354/meps12814 KW - Submerged aquatic vegetation KW - Recovery KW - Nutrient reduction KW - Restoration KW - Long-term data series KW - Resilience KW - Regime shift KW - Coastal lagoon N2 - Since the mid-20th century, Mediterranean lagoons have been affected by eutrophication, leading to significant changes in primary producers. In the early 2000s, management actions have been implemented to reduce nutrient inputs with the aim to achieve a good ecological status as requested by the EU water framework directive. As a result of these actions, a sharp decline in nutrient loads has been recorded in several lagoons leading to an oligotrophication of the water column. The analyses of a long-term data set (1998-2015) of 21 polyhaline and euhaline lagoons with contrasting trophic status allowed us to infer a general scheme for the changes in macrophyte assemblages during the oligotrophication process. Placing hypertrophic and oligotrophic conditions end to end, we inferred that the general pattern for the re-oligotrophication trajectory in Mediterranean coastal lagoons is described by the following sequence, with regime shifts between each state: (1) bare non-vegetated sediments, phytoplankton-dominated state; (2) opportunistic macroalgae; (3) seagrass and perennial macroalgae dominated state. However, we did not observe the latter regime shift for the most eutrophicated lagoons, which, so far, remained stuck in the opportunistic macroalgae state. So far, the shift from dominance of opportunistic macroalgae to a system dominated by seagrasses was only observed in a single lagoon where seagrasses had never completely disappeared, which possibly relates to resilience. More generally, the conditions favoring regime shifts from opportunistic macroalgae to seagrasses are still poorly understood. In conclusion, we describe a generic pattern for re-oligotrophication of Mediterranean coastal lagoons, although a full recovery from highly eutrophied to oligotrophic conditions may require more than a decade and may include conditions that remain so far poorly recognized. Y1 - 2019/01 PB - Inter-research JF - Marine Ecology Progress Series SN - 0171-8630 VL - 608 SP - 13 EP - 32 ID - 58555 ER -