Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Doctorat → Royaume-Uni → 2001 → Controls on landcover patterns in two adjacent stream catchments, south-east Spain

University of Liverpool (2001)

Controls on landcover patterns in two adjacent stream catchments, south-east Spain

Willshaw, Katherine Joan

Titre : Controls on landcover patterns in two adjacent stream catchments, south-east Spain

Auteur : Willshaw, Katherine Joan

Université de soutenance : University of Liverpool

Grade : Doctor of Philosophy (PhD) 2001

Résumé
The Sorbas basin lies within the Betic Cordillera of south-east Spain. It is a recently uplifted sedimentary basin with readjustment of drainage systems still occurring, and hence intense erosion is found in places. This erosion, coupled with a semi-arid climate and a history of human impact has led to a variably patchy vegetation cover throughout the catchment. This thesis examines controls on vegetation cover patchiness in a pair of adjacent catchments using a landscape ecology approach. These catchments display contrasting patterns of landcover and represent two stages in an erosion-stabilisation cycle driven by base level change on the Rio Aguas into which they both drain. Geology was found to be the most significant control on cover type distribution, closely followed by geomorphology and soil chemistry. Species type distribution is also strongly controlled by geology with geomorphological history being almost as significant, and soil chemistry controlling the distribution at a fine scale. Slope gradient and aspect were not particularly associated with either cover or species distribution. The classified landcover image, in which the six classes of cover ranged from very sparse to very densely vegetated, was analysed in conjunction with aspect, slope gradient and wetness to identify which of variable had the closest relationship with cover distribution. It was found that aspect had greatest association with cover, and wetness the least. However, all three show a statistically significantly relationship to cover class. The classified landcover image was then used in conjunction with FRAGSTATS, a landscape metrics program, and a class buffering technique was used in order to quantify the landcover patterns in the two catchments. The quantification of pattern enabled an assessment of the relative controls of each of the environmental variables on the cover pattern in both catchments. Geology was found to be the most important control on the cover distribution, with geomorphological history and aspect important at a finer scale.

Annonce : (EThOS)

Page publiée le 4 février 2015, mise à jour le 10 novembre 2019