Decadal increase in the ecological status of a North-Atlantic intertidal seagrass meadow observed with multi-mission satellite time-series

Seagrass meadows are monitored in the frame of several environmental programs worldwide, including the Water Framework Directive (WFD), to evaluate the ecological status of European coastal and transitional water bodies. The large size, spatial complexity, and interannual variability of seagrass eco...

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Main Authors: Maria Laura Zoffoli, Pierre Gernez, Laurent Godet, Steef Peters, Simon Oiry, Laurent Barillé
Format: Article
Language:English
Published: Elsevier 2021-11-01
Series:Ecological Indicators
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S1470160X21006981
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author Maria Laura Zoffoli
Pierre Gernez
Laurent Godet
Steef Peters
Simon Oiry
Laurent Barillé
author_facet Maria Laura Zoffoli
Pierre Gernez
Laurent Godet
Steef Peters
Simon Oiry
Laurent Barillé
author_sort Maria Laura Zoffoli
collection DOAJ
description Seagrass meadows are monitored in the frame of several environmental programs worldwide, including the Water Framework Directive (WFD), to evaluate the ecological status of European coastal and transitional water bodies. The large size, spatial complexity, and interannual variability of seagrass ecosystems significantly challenge field monitoring. In this study, a multi-mission satellite time-series was used to estimate long-term changes in seagrass status in a macrotidal system dominated by Zostera noltei, at Bourgneuf Bay (French Atlantic coast). Metrics of seagrass extent and density were obtained from Earth Observation (EO) using validated and inter-calibrated Landsat, SPOT and Sentinel2 data from 1985 to 2020. The information provided by satellite data made it possible to compute and compare several seagrass indicators currently in use in several European countries (France, Portugal and UK) within the WFD. Both the seagrass extent and meadow-averaged density displayed increasing trends since 1985. A time-series of merged observations from various satellites revealed a high degree of interannual variability in seagrass extent, with abrupt losses (up to 50% within one year) alternating with periods of slow recovery (typically 4–6 years). The seagrass meadow which was in a moderate status (sensu the WFD) in the 1980s, achieved an overall recurrent good or high status since the mid-1990s. Altogether, the methods and results presented here demonstrated that EO is a reliable source of information for mapping and assessing the status of intertidal seagrass, complementing in situ measurements by providing long-term, spatial view and standardized observation framework. We recommend the systematic use of EO time-series in complement to traditional field measurements in seagrass monitoring programs such as the WFD.
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spelling doaj.art-d2dfb4abdde6474b81be90d486aa2b7e2022-12-21T21:27:47ZengElsevierEcological Indicators1470-160X2021-11-01130108033Decadal increase in the ecological status of a North-Atlantic intertidal seagrass meadow observed with multi-mission satellite time-seriesMaria Laura Zoffoli0Pierre Gernez1Laurent Godet2Steef Peters3Simon Oiry4Laurent Barillé5Université de Nantes, Laboratoire Mer Molécules Santé, Faculté des Sciences, 2 rue de la Houssinière, 44322 Nantes, France; Corresponding author.Université de Nantes, Laboratoire Mer Molécules Santé, Faculté des Sciences, 2 rue de la Houssinière, 44322 Nantes, FranceCNRS, Université de Nantes, UMR LETG, B.P. 81223, 44312 Nantes, FranceWater Insight, 6709 PG 22 Wageningen, the NetherlandsUniversité de Nantes, Laboratoire Mer Molécules Santé, Faculté des Sciences, 2 rue de la Houssinière, 44322 Nantes, FranceUniversité de Nantes, Laboratoire Mer Molécules Santé, Faculté des Sciences, 2 rue de la Houssinière, 44322 Nantes, FranceSeagrass meadows are monitored in the frame of several environmental programs worldwide, including the Water Framework Directive (WFD), to evaluate the ecological status of European coastal and transitional water bodies. The large size, spatial complexity, and interannual variability of seagrass ecosystems significantly challenge field monitoring. In this study, a multi-mission satellite time-series was used to estimate long-term changes in seagrass status in a macrotidal system dominated by Zostera noltei, at Bourgneuf Bay (French Atlantic coast). Metrics of seagrass extent and density were obtained from Earth Observation (EO) using validated and inter-calibrated Landsat, SPOT and Sentinel2 data from 1985 to 2020. The information provided by satellite data made it possible to compute and compare several seagrass indicators currently in use in several European countries (France, Portugal and UK) within the WFD. Both the seagrass extent and meadow-averaged density displayed increasing trends since 1985. A time-series of merged observations from various satellites revealed a high degree of interannual variability in seagrass extent, with abrupt losses (up to 50% within one year) alternating with periods of slow recovery (typically 4–6 years). The seagrass meadow which was in a moderate status (sensu the WFD) in the 1980s, achieved an overall recurrent good or high status since the mid-1990s. Altogether, the methods and results presented here demonstrated that EO is a reliable source of information for mapping and assessing the status of intertidal seagrass, complementing in situ measurements by providing long-term, spatial view and standardized observation framework. We recommend the systematic use of EO time-series in complement to traditional field measurements in seagrass monitoring programs such as the WFD.http://www.sciencedirect.com/science/article/pii/S1470160X21006981Water Framework DirectiveInterannual variabilityEcosystem monitoringEarth ObservationRecoveryZostera noltei
spellingShingle Maria Laura Zoffoli
Pierre Gernez
Laurent Godet
Steef Peters
Simon Oiry
Laurent Barillé
Decadal increase in the ecological status of a North-Atlantic intertidal seagrass meadow observed with multi-mission satellite time-series
Ecological Indicators
Water Framework Directive
Interannual variability
Ecosystem monitoring
Earth Observation
Recovery
Zostera noltei
title Decadal increase in the ecological status of a North-Atlantic intertidal seagrass meadow observed with multi-mission satellite time-series
title_full Decadal increase in the ecological status of a North-Atlantic intertidal seagrass meadow observed with multi-mission satellite time-series
title_fullStr Decadal increase in the ecological status of a North-Atlantic intertidal seagrass meadow observed with multi-mission satellite time-series
title_full_unstemmed Decadal increase in the ecological status of a North-Atlantic intertidal seagrass meadow observed with multi-mission satellite time-series
title_short Decadal increase in the ecological status of a North-Atlantic intertidal seagrass meadow observed with multi-mission satellite time-series
title_sort decadal increase in the ecological status of a north atlantic intertidal seagrass meadow observed with multi mission satellite time series
topic Water Framework Directive
Interannual variability
Ecosystem monitoring
Earth Observation
Recovery
Zostera noltei
url http://www.sciencedirect.com/science/article/pii/S1470160X21006981
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