Historical distribution and habitat characteristics of Ostrea edulis reefs in Europe
Data file descriptions:
1_Oyster_habitat_location.xlsx
This Excel data file contains the estimated locations of historical oyster reef habitats, details of their depth and assigned certainty of the record. This file contains a mixture of spatial data, quantitative and qualitative data.
Labelled columns:
UniqueID: assigned ID unique to each record.
Year_assigned: the estimated year (AD) when the habitat was either stated to exist or – if year or description was not provided – the year of publication. In instances where negative values are assigned this corresponds to BC e.g. -100 means 100BC.
Detailed_location: records where a specific location was provided, most typically a bay or village.
Location: records where a location was provided but which was typically non-specific, i.e. a region.
Estimated_coordinates: estimated location (decimal GPS coordinates) assigned by the authors, with a precision to 2 decimal places.
Description_location: historical descriptions of locations.
Description_fishery refers to historical descriptions of the fishery.
Ref_number: source reference as listed in file name “4_Oyster_reference_list.docx”
Depth: described depth, usually in metres or fathoms.
Habitat_certainty: the levels of confidence assigned to historical sources as to whether they were likely referring to biogenic oyster reef habitats (high or low), as opposed to scattered oysters, and confidence in the accuracy of the assigned location (high or low). These were assigned based on the following criteria:
High confidence of reef habitat, high location certainty (HH): record of habitat e.g., a bed or bank of oysters, or record of an active fishery using towed gears with no recorded active intervention, thus indicating an initial high abundance of oysters. We are confident of the location to within 10 km e.g., oyster presence within a bay or harbour.
High confidence of reef habitat, low location certainty (HL): we were confident a habitat existed, but the location is uncertain to > 10 km e.g., named open water locations without positioning detail.
Low confidence of reef habitat, high location certainty (LH): we know oysters were fished but the descriptions (or corresponding descriptions) do not provide evidence that the species formed biogenic reef in this location e.g., individuals were described as attached to rocks. We are confident of the location to within 10 km.
Low confidence of reef habitat, low location certainty (LL): we know oysters were fished, but the descriptions (or corresponding descriptions) do not provide evidence that the species formed biogenic reef in this location. The location is uncertain to > 10 km.
Centroid latitude: Central point of the 10km2 grid that overlays the original data point, in decimal GPS (latitude).
Centroid longitude: Central point of the 10km2 grid that overlays the original data point, in decimal GPS (longitude).
2_Oyster_habitat_extent.xlsx
This Excel data file contains the described extent (area or length) of historical oyster reef habitats, and their approximate location. This file contains a mixture of spatial data, quantitative and qualitative data.
Labelled columns:
UniqueID: assigned ID unique to each record.
Year_assigned: the estimated year (AD) when the habitat was either stated to exist or – if year or description was not provided – the year of publication.
Location: records where a location was described.
Estimated_coordinates: estimated location (decimal GPS coordinates) assigned by the authors, with a precision to 2 decimal places.
Description: historical descriptions of the extent.
Ref_number: source reference as listed in file name “4_Oyster_reference_list.docx”
Area_ha: extent of oyster bed calculated from source description, in hectares.
Length_km: length of oyster bed calculated from source description, in kilometres.
3_Oyster_habitat_descriptions.docx
This Word document provides qualitative descriptions of habitat, the estimated year, broad location referred to and the numbered references from which oyster reef descriptions were sourced (as listed in file name “4_Oyster_reference_list.docx”).
4_Oyster_reference_list.docx
This Word document lists the references from which oyster reef/fishery descriptions were sourced and the assigned number used for cross-referencing across files 1-4.
5_Oyster_historical_species_list.docx
This Word document provides a list of the species associated with historical oyster reefs and their taxonomic description. As not all historical descriptions provided quantitative species data this is a presence-only species list.
6_Geospatial_data_files
This folder contains shapefiles of: oyster habitat locations (file names starting with ‘01’), polygons transcribed from historical maps digitised and published online (file names starting with ‘6’; Joubin and Guérin-Ganivet 2009), and polygon centroids (file names starting with ‘7’).
References:
Joubin L, Guérin-Ganivet J (2009). Cartes des gisements de coquilles comestibles des côtes de France. Ifremer. https://doi.org/10.12770/c502ed30-0d7d-11de-a4b1-000086f6a603
