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Accueil du site → Doctorat → Royaume-Uni → 2000 → Relationships between surface crusts and erosion in the Tabernas Badlands, Almeria, S.E. Spain

University of Wolverhampton (2000)

Relationships between surface crusts and erosion in the Tabernas Badlands, Almeria, S.E. Spain

Downward, Kenneth

Titre : Relationships between surface crusts and erosion in the Tabernas Badlands, Almeria, S.E. Spain.

Auteur : Downward, Kenneth.

Université de soutenance : University of Wolverhampton

Grade : Doctor of Philosophy (PhD) 2000

Résumé
The Tabernas Badlands in Almeria Province, south-east Spain, constitute the driest area in western Europe. The current eroding geological parent material is fined grained mudstone of marine origin, which readily weathers to form a regolith of shards and mainly silt-sized particles. The surface is differentiated into a mosaic of surface types, including, at the pioneer stage, a bare mineral crust, brown algal crust and lichenised crust. Landscape readjustment by dissection is severe, due to the nature of the parent material, the semi-arid climate and the resultant paucity of higher vegetation cover to ameliorate erosive forces. Pedestals, rills and gullies are major erosion features within the landscape. A significant amount of research has been performed on runoff processes, but there are no data on the effects of raindrop splash on pioneer surfaces.A research project was initiated in 1997, investigating the physical and chemical characteristics of badland pioneer surfaces at the El Cautivo field site, on the southern margins of the Tabernas Basin. Two main hypotheses were tested : (i) that erosion is inversely related to crust biological development, and (ii) that the three crusts represent a sequence of biological succession. It is postulated that rills, gullies and valleys provide niches for the proliferation of pioneer crust organisms on northerly facing slopes, giving rise to very high densities of terricolous lichens. The organisms thrive in a cooler microclimate, which receives less direct insolation than southerly facing slopes. Southerly facing slopes are more arid and erosion is more severe. The interactive and mutually adjusting effects of biological crusts on landscape readjustment are discussed.

Annonce : EThOS

Accès au document : Proquest Dissertations & Theses

Page publiée le 18 février 2015, mise à jour le 6 février 2017