Distribución espacial y análisis ambiental de las plantas raras de los Pirineos

The recent digital edition of the Atlas of Pyrenean vascular flora, allow us to analyze some patterns of geographical distribution and environmental features of the most rare plant species. The aim of our study is to contribute to the knowledge of rarity and to the planning and implementation of plant conservation at a Pyrenean scale. Among the 363 selected taxa after applying the criteria of low occupancy (10% of the whole Pyrenean flora), 352 are present in less of the 2% of the territory and 11 occupy less than 4% distributed over a scarce number of populations (less than 30). Using a net of 10 x 10 Km UTM’s squares, rare plants appear represented in the 65% of the territory; the regions with highest rare plant density overlap those with the highest total plant number. The areas with the richest rare plants are placed at the East and West extremes (beside the Cap de Creus and at between San Sebastian and Irun respectively), at the center of the French National Park of the Pyrenees and the surroundings of the Spanish Monte Perdido area. Rare flora significantly differs from the whole flora in terms of taxonomic representation, altitudinal amplitude and distribution, chorology, life-forms, edaphic preference and habitats, but not in the naturalness of the habitats where they occur.