- Title
- Posidonia oceanica (Neptune grass)
- Abstract
Data from MEDISEH-MAREA project.
Posidonia oceanica distribution across the Mediterranean.
(More information at http://mareaproject.net/contracts/5/reporting/)
- Publication Date
- Sept. 1, 2014, 3:08 p.m.
- Type
- Vector Data
- Category
- Environment and Ecosystems
- Data related to environment and ecosystems
- Owner
- MEDISEH
- Maintenance Frequency
- There Are No Plans To Update The Data
- Restrictions
- This shapefile was provided by MAREA Consortium (framework contract MARE/2009/05 - Lot 2 (MEDISEH)) to be used inside ADRIPLAN Project. The geographical information is provided "as it is", and no warranty of any kind (express, implicit) is offered as to the information's accuracy. The information provided does not imply any opinion of the developers concerning the legal status of any country, territory or area, or concerning the delimitation of its frontiers or boundaries. The data cannot be used for legal, commercial (e.g. exploration of natural resources, consultancy work) or for navigational purposes. It is clarified that the raw data collected or provided to the consortium for the purposes of MEDISEH, are not allowed to be redistributed or provided to third parties (under any format e.g. GIS Shape files) for any reason, without the permission of the original data provider. Fisheries data collected within the Data Collection Framework cannot be redistributed for any reason. To access project's meta-analysis data (i.e. model output), please send a request to MEDISEH scientific coordinator and to the MAREA scientific coordinator (request form: http://mareaproject.net/medviewer/registration/register/). Please note that the request will also be forwarded to DG-MARE, for final approval by the European Commission Services. It has also to be recalled the provisions of Article II.10.3 of the Framework Contract: "Any distribution or publication of information relating to the Contract by the Contractor shall require prior written authorization from the Commission and shall mention the amount paid by the Union. It shall state that the opinions expressed are those of the Contractor only and do not represent the Commission's official position". The project's final report can be found at http://mareaproject.net/contracts/5/reporting/ (Mediterranean Sensitive Habitats (MEDISEH) (2013). Final report. Edited by M. Giannoulaki, A. Belluscio, P. Panayotidis, S. Fraschetti, M. Scardi, F. Colloca, C. Smith, V. Valavanis, M.T. Spedicato. DG MARE Specific Contract SI2.600741, Final Report, 557 p. Heraklion (Greece): Hellenic Centre for Marine Research.)
- Language
- English
- Supplemental Information
The dataset of Posidonia oceanica distribution across the Mediterranean derived from the compilation of published and unpublished information.
Data were provided in the form of polygon and point shapefiles.
P. oceanica modeling was carried out taking into account both presence and absence records and therefore the range of potentially useful modeling methods was very wide. The type of habitat modeling undertaken was of the “predictive” type, with a whole variety of variables, beyond the typical environmental/physical ones used to predict species occurrence.
Preliminary tests were performed on a subset of data in order to select the best approach among Classification Trees (both using CRT and CHAID algorithms), Artificial Neural Networks (multilayer perceptions) and Random Forests. While all the above mentioned methods provided acceptable results, Random Forests performed significantly better than other methods.
The overall results of the Random Forest model were validated on the basis of the comparisons between model predictions and known records in nine test areas that accounted for about 7% of the available data (i.e. about 50,000 pixels).- Spatial Representation Type
- vector data is used to represent geographic data
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