A survey of heath vegetation of the Iberian Peninsula and Northern Morocco: a biogeographic and bioclimatic approach
Loidi, Javier; Biurrun, Idoia; Campos, Juan Antonio; García-Mijangos, Itziar; Herrera, Mercedes
The present study attempts to carry out a biogeographic and bioclimatic approach using a specialized vegetation type such as that of heathlands (Calluno-Ulicetea class) in the Iberian Peninsula and Northern Morocco. The territories in which this vegetation occurs have been divided into 63 small units based on the accepted biogeography of the area. The heathland flora of each unit was surveyed using phytosociological data from bibliography and other sources. Finally, each of the territorial units has a list of species drawn up being representative of the floristic composition of their heathland vegetation. The total amount of plants was limited to 289, as rare plants were discarded. Species from this list were classified into 12 groups according to their phytosociological affinity (Calluno-Ulicetea, Quercetea ilicis, Querco-Fagetea, Festuco-Brometea, etc.) in order to identify the floristic influences in each of the territories. The original matrix with 63 columns and 289 rows was set and several ordinations were carried out, particularly PCA and canonical RDA. The floristic composition of the list of total species for each territory, strongly reflects the biogeographic and bioclimatic conditions. This is valid for the genuine Calluno-Ulicetea flora as well as for the rest of the floristic groups. The main climatic parameters which explain the differences between the heathland flora of the territories considered are mostly P (annual precipitation), It (thermicity index) and Ic (continentality index). Rainy areas, located in the Cantabrian and Atlantic areas, have a large number of Calluno-Ulicetea plants, whilst continental areas, particularly in the Eastern Pyrenees, have low numbers.