Is Posidonia oceanica regression a general feature in the Mediterranean Sea?

Bonacorsi, Marina; Pergent-Martinì, Christine; Breand, Niels; Pergent, Gérard

doi:10.12681/mms.334

Cited by 45 publications

(41 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The five Mediterranean seagrasses are subject to natural and anthropogenic pressures and even if the decline of meadows seems, in general, to be relatively limited (between 0 and 10 % throughout the 20th century; Gonzalez-Correa et al, 2007;Boudouresque et al, 2009), more significant rates of decline (up to 5-8 % per year) were locally observed in places that are subjected to strong anthropogenic pressures (Marbà et al, 1996) while meadows growing in pristine sites remain stable (Bonacorsi et al, 2013). Along the highly urbanised coasts of Liguria, Italy, extensive coastal development during the 1960s led to an estimated 30 % regression of P. oceanica meadows (Bianchi & Peirano, 1995;Peirano & Bianchi, 1997).…”

Section: Decline Of Mediterranean Seagrass Meadowsmentioning

confidence: 99%

Climate change and Mediterranean seagrass meadows: a synopsis for environmental managers

Pergent¹,

Bazairi²,

Bianchi³

et al. 2014

Medit. Mar. Sci.

Self Cite

106

View full text Add to dashboard Cite

This synopsis focuses on the effects of climate change on Mediterranean seagrasses, and associated communities, and on the contribution of the main species, Posidonia oceanica, to the mitigation of climate change effects through its role of sequestering carbon dioxide. Whilst the regression of seagrass meadows is well documented, generally linked to anthropogenic pressures, global warming could be a cause of new significant regressions, notably linked to the introduction of exotic species, the rise of Sea-Surface Temperature (SST), and relative sea level. Seagrass communities could also be affected by climate change through the replacement of seagrass species having high structural complexity by species of lower complexity and even by opportunistic introduced species. Although it is currently very difficult to predict the consequences of these alterations and their cascade effects, two main conflicting trends in the functioning of seagrass ecosystems that could occur are acceleration of the herbivore pathway or of the detritivore pathway. The mean net primary production of the dominant species, Posidonia oceanica, is relatively high and can be estimated to range between 92.5 to 144.7 g C m-2 a-1. Around 27% of the total carbon fixed by this species enters the sedimentary pathway leading to formation, over millennia, of highly organic deposits rich in refractory carbon. At the Mediterranean scale, the sequestration rate might reach 1.09 Tg C a-1. The amount of this stored carbon is estimated to range from 71 to 273 kg C m-2, which when considered at the Mediterranean scale would represent 11 to 42% of the CO2 emissions produced by Mediterranean countries since the beginning of the Industrial Revolution. The greatest value of the P. oceanica ecosystem, in the context of mitigation of global climate change, is linked to this vast long-term carbon stock accumulated over the millennia, and therefore, efforts should be focused on preserving the meadows to keep this reservoir intact.

show abstract

Section: Decline Of Mediterranean Seagrass Meadowsmentioning

confidence: 99%

Climate change and Mediterranean seagrass meadows: a synopsis for environmental managers

Pergent¹,

Bazairi²,

Bianchi³

et al. 2014

Medit. Mar. Sci.

Self Cite

106

View full text Add to dashboard Cite

show abstract

“…Ten percent is the global decline (loss of area) generally accepted for P. oceanica over the last 100 years (Boudouresque et al, 2012) but a recent paper claims a reduction by 50% of the density or biomass within the Mediterranean over the last 20 years (Marb a et al, 2014a). Actually, the magnitude of the overall P. oceanica area loss over the last century ranges from 0 to 50 % depending on the author (Gonz alez-Correa et al, 2007;Boudouresque et al, 2009;Bonacorsi et al, 2013) but could reach 8% per year with possible functional extinction in 2059 according to others (Marb a et al, 1996;Jord a et al, 2012). The reality is difficult to assess because of a lack of reliable baseline data: quasi-absence of historical data, studies often only focusing on small spatial and temporal scales and/or using uncertain old maps (Montefalcone et al, 2013;Bonacorsi et al, 2013).…”

Section: Introduction Q1mentioning

confidence: 99%

“…Actually, the magnitude of the overall P. oceanica area loss over the last century ranges from 0 to 50 % depending on the author (Gonz alez-Correa et al, 2007;Boudouresque et al, 2009;Bonacorsi et al, 2013) but could reach 8% per year with possible functional extinction in 2059 according to others (Marb a et al, 1996;Jord a et al, 2012). The reality is difficult to assess because of a lack of reliable baseline data: quasi-absence of historical data, studies often only focusing on small spatial and temporal scales and/or using uncertain old maps (Montefalcone et al, 2013;Bonacorsi et al, 2013). These observed declines are mainly located near urban areas (Thomas et al, 2005;Boudouresque et al, 2012) and mostly associated with human activities even if they can sometimes be related to natural processes (e.g.…”

Section: Introduction Q1mentioning

confidence: 99%

The impact of 85 years of coastal development on shallow seagrass beds (Posidonia oceanica L. (Delile)) in South Eastern France: A slow but steady loss without recovery

Holon¹,

Boissery

Guilbert³

et al. 2015

Estuarine, Coastal and Shelf Science

View full text Add to dashboard Cite

Keywords: seagrass meadows decline consequences of urbanization large-scale decrease of seagrass meadows loss of marine meadows human-driven impacts anthropogenic pressures a b s t r a c t Shallow Posidonia oceanica beds (0 to À15 m), the most common seagrass in the Mediterranean, were mapped from aerial photographs dating from the 1920's and from 2012 along 800 km of coastline in South-Eastern France (Provence-Alpes-Côte-d'Azur region). Changes in P. oceanica bed spatial distribution (limits and extent) during these 85 years were analyzed in terms of concordance (remaining areas), positive discordance (expanding areas) or negative discordance (lost areas). Lost areas were linked with direct or indirect impacts of coastal development (artificialized coastlines (namely harbours, ports of refuge, landfills, artificial beaches, groynes and pontoons, submarine pipelines and aquatic farms) visible on the photographs. The comparison showed that 73% of the shallow limits have declined. Considering spatial extent, remaining seagrass meadows areas accounted for the major part (85%), while lost areas accounted for 13% and expanding areas for 1.1%. Lost areas were mainly linked with artificial coastlines but 44% remained with undetermined causes (invisible pressures and/or mixed effects). The analysis of 96 coastal facilities creating the artificial (namely man-made) coastlines showed that the highest impact over the longest distance (5 km) was caused by harbours. Only artificial beaches had such a distant impact. Pontoons were the least surrounded by lost seagrass meadows areas. These quantitative data offer important information for marine conservation.

show abstract

“…However, in areas characterized by moderate anthropogenic pressures, P. oceanica seascapes have a relatively low percentage of patches that result from human impact. For example, in Corsica (France), patches resulting from anthropogenic impact comprise only a maximum 6% of the total seagrass area and no further significant regression has been recorded Bonacorsi et al, 2013).…”

Section: Available Literature On Posidonia Oceanica Seascape Ecologymentioning

confidence: 99%

Seascape ecology in Posidonia oceanica seagrass meadows: Linking structure and ecological processes for management

Abadie

Pace

Gobert

et al. 2018

Ecological Indicators

View full text Add to dashboard Cite

A B S T R A C TSeagrass meadows constitute marine habitats in shallow water temperate and tropical coastal areas worldwide that have a high ecological and economic importance. Amongst the 60 or so seagrass species, the endemic Mediterranean species Posidonia oceanica forms meadows that are arguably the most important shallow water coastal habitat in the region but which are subjected to high anthropogenic pressures. Because of the relatively large size of the plant, the meadows formed by this seagrass have high architectural and morphological complexity, which results in different morphotypes or seascapes. While numerous studies of P. oceanica architectural characteristics for continuous meadows of the seagrass are available, few works have addressed seascape ecological features and the influence of environmental factors (natural and anthropogenic) thereon. In the present review, we give an overview of P. oceanica meadow architectural and morphological characteristics and how these contribute to Mediterranean landscapes and seascapes. Studies addressing the influence of natural and anthropogenic factors on morphometric features of different meadow types and landscape ecological characteristics of P. oceanica habitat are also reviewed, as well as their influence on ecosystem processes. Finally, by considering the available data and tools for seascape studies, we present a discussion on methods to assess seagrass seascapes within the framework of coastal management. Our review highlights several gaps in P. oceanica seascape ecology knowledge such as the lack of data on the spatial distribution of this engineer species, and the possibility to use modern techniques and procedures for analysing structural and ecosystemic data.

show abstract

Is Posidonia oceanica regression a general feature in the Mediterranean Sea?

Cited by 45 publications

References 38 publications

Climate change and Mediterranean seagrass meadows: a synopsis for environmental managers

Climate change and Mediterranean seagrass meadows: a synopsis for environmental managers

The impact of 85 years of coastal development on shallow seagrass beds (Posidonia oceanica L. (Delile)) in South Eastern France: A slow but steady loss without recovery

Seascape ecology in Posidonia oceanica seagrass meadows: Linking structure and ecological processes for management

Contact Info

Product

Resources

About