The Arid Southeast

Abstract

The Southeast of the Iberian Peninsula presents large tracts of arid land with many species and plant communities with the closest relationships to the North African ones in the whole of Western Europe. This territory has been considered a special biogeographical province, the Murcia-Almería province. The area lies in SE Spain between 36.67° – 38.66° N and 0.1° E – 3.04° W, encompassing the area from the surroundings of Benidorm city until the Baetic massifs of the Sierra de Gádor and the Alpujarras. The macrobioclimate of the area is Mediterranean, with bioclimates ranging from xeric oceanic to desertic oceanic. The geology is complex and there are many different rock types, predominantly rich in calcium. The flora of the area is essentially Mediterranean, but is very special, with a high percentage of endemic taxa and also an interesting component of plants with Iberian-North African distribution areas. A great deal of the endemic taxa of the Murcia-Almería province is concentrated in a few genera (Helianthemum, Limonium, Sideritis, Teucrium and Thymus), and most of the endemics are restricted to particular soils (gypsaceous, marly, rocky, volcanic acid, sand dunes, saline and subsaline). The potential natural vegetation types are usually not true forests, but shrublands, with more or less scattered trees, belonging to the Pistacio-Rhamnetalia alaterni. The seral scrub of this territory, locally called “tomillar”, is open-structured and low-sized, but extremely diverse and rich in endemics. Most of the associations are grouped in the endemic order Anthyllidetalia terniflorae. Perennial grasslands with Stipa tenacissima and Lygeum spartum as prominent species are very common on slopes and plains. There are also annual pastures that, from fall to spring, cover the open areas between perennial vegetation; they are rich in Iberian-African species, and mainly belong to the Stipion retortae alliance. Among the special environments, the riparian vegetation is remarkable, with the narrowest African relations in Europe, as well as the nitrophilous bushes, of the almost exclusive Haloxylo-Atriplicion alliance.