# A Regionalization Approach Based on the Comparison of Different Clustering Techniques
## 4 Discussion
### Characterization of the Regions  
The main variables for the construction of the regions obtained with the accepted model (K-means++, k = 5, TSA) were Annual Mean Temperature (Bio1), Mean Temperature of the Coldest Quarter (Bio1), and Precipitation Seasonality (Coefficient of Variation) (Bio15). These parameters are those that have shown the greatest relative importance (see Table 4) after various adjustments using the gradient boosting algorithm. However, each bioregion has particular characteristics. In the following, we highlight the main characteristics of each region. The climate and precipitation values are obtained from the output of the K-means++, k = 5, TSA model. Region 1 This region extends mainly through the Cantabrian mountain range without reaching the Cantabrian coast. It is known as the Eurosiberian Orocantabrica region according to the classification of the Spanish National Institute of Geography (hereinafter ING) [62]. It makes an incursion through the Iberian system up to the Moncayo mountain. Throughout this area, oak and beach forests, cryotemperate grasslands, oro-cryotemperate vegetation on rocky fields and scree, supra-arid and high mountain pastures, Cantabrianhigh mountain scrubland, peatland vegetation, meso-supratemperate scrubland, meadows, and meso-supratemperate grasslands predominate [63]. It continues through the Pyrenees, where mixed and coniferous forests predominate [64], and extends to areas of the coastal mountain range of the Iberian Peninsula. It also occupies almost the entire French region, including the island of Corsica. The only areas not linked to this bioregion are Landes, western Brittany, and the area bordering the Mediterranean Sea from southwestern Provence to Girona. In the French area, the region includes different habitats where the vegetation is composed of conifers, mixed oak forests, and primeval beech forests in the central-eastern area [65]. The average annual precipitation in this region ranges from 700 mm to 1000 mm, and the average annual temperature is between 9 \({}^{\circ}\)C and 12 \({}^{\circ}\)C in mountainous areas, with minimum average values sometimes falling below 10 \({}^{\circ}\)C.  
_Region 2._ This region is divided into three main areas: one in the center of the Iberian Peninsula and a large part of the Balearic Islands; another in the center of Morocco; and the area bordering the Mediterranean Sea, from southwestern Provence to Girona. In the Iberian Peninsula, it extends from south to north, from Sierra Morena to the Northern Plateau, and from east to west, from the border of Spain with Portugal to the Valencian coast. It is characterized by different types of vegetation. In the most central part of the region, we find low scrub plains and silvopastoral forests with a strong presence of agricultural and livestock activity, according to the description of Iberian sclerophyllous and semi-deciduous forests by WWF [66]. Further south, we find pine forests and areas with significant plant diversity, such as Sierra Nevada, which has more than 2100 vascular plants, according to the description of Iberian conifer forests by WWF [67]. On the Moroccan side, the region stretches across the Atlas Mountains, from Jebel to include the northern part of the Sahara Atlas. It is described by WWF [68] as being dominated by high, arid plateaus with steppe grasslands, scrublands, dunes, seasonal salt lakes, and mountainous slopes with pine forests. This region in the Catalan-French part is characterized by sand dunes, salt lakes, and cliffs. Climatically, the ecoregion experiences very hot and dry summers and relatively mild winters on average. Average annual temperatures range from 12 \({}^{\circ}\)C to 15 \({}^{\circ}\)C, and average annual rainfall ranges from 300 mm to 525 mm. _Region 3._ Extending from the coast of Lisbon to La Rochelle and in the northwest of France, it is concentrated in Brittany, with similar edaphic-environmental areas also found in the southernmost part of the Iberian Peninsula, as well as in the north of Morocco, mainly in the Rif.