DOI: 10.20350/digitalcsic/3861
title: Posidonia oceanica changes in the Mediterranean sea

description: Methodology: We compiled available data published in peer-review articles and grey literature reports until year 2009 as well as our own unpublished data. We searched for data with the engine ISI web of Knowledge, using the keywords Posidonia oceanica AND (regression OR decline OR progression OR recovery OR status OR cartography OR limits OR cover OR density OR biomass OR dynamics), and conducting a back search of cited papers. More information about the methodology to be found at: Calleja, M.L., N. Marbà, C.M. Duarte (2007). The relationship between seagrass (Posidonia oceanica) decline and sulfide porewater concentration in carbonate sediments. Estuarine coastal and shelf science 73: 583-588; Waycott M, CM. Duarte, T.J. B. Carruthers, R.J. Orth, W.C. Dennison, S. Olyarnik, A. Calladine, J.W. Fourqurean, K.L. Heck, Jr, A.R.ll Hughes, G A. Kendrick, W. J Kenworthy, F T. Short, S L. Williams (2009). Accelerating loss of seagrasses across the globe threatens coastal ecosystems. Proceedings of the National Academy of Science USA 106: 12377–12381; Moreno, D., P. A. Aguilera, H. Castro (2001). Assessment of the conservation status of seagrass (Posidonia oceanica) meadows: implications for monitoring strategy and the decision-making process. Biological Conservation 102: 325-332.
description: Content and values displayed: The data set includes general information of the study conducted: the year or period of years of the study, site, country, water depth; and of the seagrass meadow investigated: extent, depth of deep and shallow limit, cover, shoot density, meadow status -decline, expansion, steady-state-, rate of change, Index of Conservation, Moreno et al. 2001) and types of coastal pressures present. The data set includes qualitative and quantitative data, since it contains studies where changes in seagrass meadow extension, cover and /or density are identified from expert judgement as well as studies that quantified the magnitude and rates of the changes reported. The absolute and relative rates of change of seagrass extent, meadow depth limits, cover and shoot density are calculated as described in Marbà et al (submitted). The meadows are categorized as declining (final area &lt; 90% of initial area, net % cover abosolute change &lt; -10, or µ density &lt; -5% yr-1), increasing (final area &gt;110% of initial area, net cover change &gt; 10 % yr-1, or µ density &gt; 5% yr-1) or without detectable change (final area within &lt;90 % of initial area, -10 % yr-1 &lt; net cover change &lt; 10 % yr-1, or -5 % yr-1 &lt; µ density &lt; 5 % yr-1) following Waycott et al (2009) for area and Calleja et al (2007) for density criteria.
description: Access and reuse: This dataset is subject to a Creative Commons Reconocimiento-NoComercial-CompartirIgual 4.0 Internacional License.
description: This dataset compiles qualitative and quantitative information on the stability (i.e. decline, steady state, expansion) of the seagrass (Posidonia oceanica) in the Mediterranean Sea between years 1842 and 2009. Data on meadow extent, shallow and depth limits, cover and shoot density as well as rates of change for the study period are provided. A ReadMe file, the full list of references and explanation of dataset values are attached.