(a) Panoramic view of the borreguil of San Juan valley. The particular zonation of this ecosystem depending on soil moisture is reflected in the different colours of the borreguil. (b) Schematic representation of the vegetal communities forming the borreguiles, including dry borreguil (4 Armerio-Agrostietum nevadensis), dense grassland (1 Nardo-Festucetum ibericae), incipient peat formations (2 Ranunculo-Caricetum intrincatae) and variants of borreguil in promontory areas (3 Ranunculo-Vaccinietum uliginosi). Modified from Losa-Quintana et al. (1986). Picture: JM Martín-Martín.