title: Cover versus recovery: contrasting responses of two indicators in seagrass beds.
abstract: Despite being a highly valuable key-stone ecosystem, seagrass meadows are threatened and declining worldwide, creating urgent need for indicators of their health status. We compared two indicators for seagrass health: standing leaf area index versus relative recovery from local disturbance. Disturbance was created by removing aboveground biomass and recording the rate of regrowth for Zostera marina meadows exposed to contrasting wave regimes and nutrient stress levels. Within the experimental period, relative regrowth in gaps was around 50% in most plots, except for the ambient nutrient treatment at the sheltered site, where it exceeded 100%. The two indicators showed an opposite response to disturbance: the higher the standing leaf area index, the lower the relative recovery from disturbance. This conflicting response raises the question on the proper interpretation of such indicators to estimate seagrass health and resilience, and how to ideally monitor seagrass ecosystems in order to predict collapse.
authors.affiliation: Spatial Ecology Department, Royal Netherlands Institute for Sea Research (NIOZ-Yerseke), P.O. Box 140, 4400 AC Yerseke, The Netherlands. Electronic address: laura.soissons@nioz.nl.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Soissons
authors.affiliation: Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences (YIC-CAS), Chunhui Road 17, Laishan District, Shandong, China.
authors.forename: Qiuying
authors.initials: Q
authors.lastname: Han
authors.affiliation: Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences (YIC-CAS), Chunhui Road 17, Laishan District, Shandong, China.
authors.forename: Baoquan
authors.initials: B
authors.lastname: Li
authors.affiliation: Spatial Ecology Department, Royal Netherlands Institute for Sea Research (NIOZ-Yerseke), P.O. Box 140, 4400 AC Yerseke, The Netherlands; Department of Environmental Sciences, Institute for Wetland and Water Research, Faculty of Science, Radboud University Nijmegen, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
authors.forename: Marieke M
authors.initials: MM
authors.lastname: van Katwijk
authors.affiliation: Spatial Ecology Department, Royal Netherlands Institute for Sea Research (NIOZ-Yerseke), P.O. Box 140, 4400 AC Yerseke, The Netherlands.
authors.forename: Tom
authors.initials: T
authors.lastname: Ysebaert
authors.affiliation: Spatial Ecology Department, Royal Netherlands Institute for Sea Research (NIOZ-Yerseke), P.O. Box 140, 4400 AC Yerseke, The Netherlands; Department of Environmental Sciences, Institute for Wetland and Water Research, Faculty of Science, Radboud University Nijmegen, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
authors.forename: Peter M J
authors.initials: PMJ
authors.lastname: Herman
authors.affiliation: Spatial Ecology Department, Royal Netherlands Institute for Sea Research (NIOZ-Yerseke), P.O. Box 140, 4400 AC Yerseke, The Netherlands.
authors.forename: Tjeerd J
authors.initials: TJ
authors.lastname: Bouma
mesh_terms: D003247:Conservation of Natural Resources; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D011157:Population Dynamics; D035962:Zosteraceae / Q000254:growth & development*
keywords: Critical slowing down; Indicators for ecosystem health; Leaf area index; Nutrient enrichment; Recovery; Zostera marina