A dataset with complete geographic distributions of eight zonal monospecific forest types in mainland Spain

Distribution area and surface are both parameters of paramount importance for habitat management, monitoring and conservation. Here we present the distribution of eight zonal forest types of mainland Spain that are consistent with the Habitat Types (HT) listed in Annex I of the European Union Habitats Directive 92/43 EC. Their dominant species and HT codes are Fagus sylvatica (9120, 9130 and 9150), Quercus robur and Q. pyrenaica (9230), Q. suber (9330), Pinus uncinata (9430), P. nigra ssp. salzmannii (9530) and P. pinea (subset of 9540). These distributions are based on tesserae from the 1:50,000 Spanish Forest Map and are the result of sorting assisted by supplementary databases. The distributions are presented as vector coverages, and provide three information levels of increasing detail: geographic distribution, basic forest type and structural forest patch. Two R scripts are also included with the dataset. They implement a segmented regression approach to investigate forest fragmentation on these or other patch-like data.

© 2020 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ ) Table   Subject Nature and Landscape Conservation Specific subject area Biogeography and spatial distribution of habitat types Type of data Geospatial: vector coverages in shapefile format How data were acquired 1) Basic forest types found by progressive sorting of two implementations of the

Value of the Data
• The distributions found are crucial for ecological studies dealing with the forest types concerned. • Potential users include ecologists fitting predictive distribution models to investigate climate and land use change, foresters working at the patch level and conservation practitioners seeking to optimize conservation networks. • The fine-scale patches provided enable studies on spatial structure and fragmentation of these forest types. • Beyond simply indicating the geographic distributions of these European Habitat Types, this dataset adds two higher levels of detail: basic forest types and structural forest patches.

Data Description
This dataset consists of complete distributions observed at the 1:50,0 0 0 scale of eight zonal forest types of mainland Spain. These distributions are built up from explicitly identified forest patches. These forest types are consistent with Habitat Types (HT) listed in Annex I of the European Union Habitats Directive 92/43 EC [1] . More details about them are available in the reference interpretation manual [2] . Their HT codes and names are shown in Table 1 .
Distributions are provided as vector coverages in shapefile format, which can be directly imported by most Geographic Information Systems (GIS) software. Each coverage is labeled with its HT code, and consists of five files: three mandatory ones (.shp, .shx and .dbf, respectively conveying feature geometry, positional index and attribute table), and two optional (.prj and .qpj, both containing the projection description). The coordinate reference system is EPSG 25830: datum ETRS89 and projection UTM zone 30 N.
Coverages features are polygons corresponding to forest patches, which in turn, correspond to tesserae in the Spanish Forest Map (MFE50) [4] . The attribute table contains the following fields: The attribute table can be linked to the MFE50 source database (through the link field POLIGON), to check other forestry attributes of each polygon. The fields EFT [5] and EUNIS_3 [6] enable wider harmonisation and use for EU level mapping efforts and projects.
In addition to coverages, two scripts in R language [7] are provided with the dataset. These correspond to the fragmentation analyses made in the related research article: determination of the Korcak exponent by segmented regression. This is a method to determine patchiness by exploring patch frequency as a function of patch size. The novelty here is that such an exploration is done by size intervals, leading to the identification of area thresholds. Both scripts can be easily adapted for equivalent purposes according to user needs by following the instructions in the annotated headings. Whilst the scripts develop insights on the use of coverages, they are not required if used for other purposes.

Experimental Design, Materials and Methods
The cartographic base for this dataset was the MFE50. It is a comprehensive mapping, made by photointerpretation and fieldwork, of forest and shrub lands of Spain. Its tesserae are associated with distinct forest patches and have fields describing total and only-tree canopy density, structural vegetation type, spatial grouping of vegetation, up to three dominant species and their cover density, land use, etc. However, whilst complete structural information is readily available in the MFE50, this product cannot be used directly to depict the distribution of forest HTs. The dataset presented here is an evolution of the MFE50 to fill precisely this need.
In a first step, forest tesserae were separated from scrub, pasture or dehesas . Then, all forest tesserae were sorted, retaining only those with a tree canopy cover of over 10% [8] . After that, monospecific forests were differentiated from mixed forests [ 9 , 10 ] by selecting only the tesserae where the occupation of the dominant species was over 70%. Afforestation and dehesas were distinguished from the monospecific forests using the afforest ation maps in the Spanish Information System of Forest Tree Species [11] in addition to the information provided by the MFE50 itself, and discarded. Finally, all remaining tesserae were assigned to a basic forest type following the classification by Sainz Ollero and Sánchez de Dios [12] . Additional national and regional lithological, geomorphic and vegetation maps were also used for this [3] . The basic forest types were then grouped into HTs.
That process resulted in 24 basic forest types grouped into the eight HTs presented in this article ( Table 1 ). The data are comprehensive for each HT except in the case of 9540, which includes only Pinus pinea forests. This cartography adds ecological value with respect to the sources used, because it combines the species distribution from MFE 1:50,0 0 0 with environmental and biogeographic variables on climate, substrate and altitudinal vegetation belts.
It is worth mentioning that this dataset was a benchmark exercise done within the framework of a Spanish Forest Administration project, for setting up a nationwide Spanish habitat surveillance and monitoring system. The overall outcome is expected to contain 78 monospecific and 32 mixed forest types for all of Spain, grouped into 22 EUNIS HTs. More information can be found in [3] , within the project website [13] .

Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships which have, or could be perceived to have, influenced the work reported in this article.