Effect of Slope Aspect on Soil and Vegetation Properties Along an Aridity Transect

Abstract

This study has investigated the effect of south-and north-facing hillslopes (SFS and NFS, respectively) on soil and vegetation properties along a climatic transect that covers four climatic zones: Mediterranean, semiarid, arid, and extreme-arid. The results indicate that differences between NFS and SFS in organic matter and soil moisture contents were significantly higher in the Mediterranean zone than in any other site along the climatic transect, particularly at the end of the rainy season. Both soil properties were higher on NFS than on SFS. Similarly, differences between the opposite hillslopes in species richness along the climatic transect were found significant only in the Mediterranean zone, where species richness was higher on the SFS than on the NFS. However, species diversity on SFS was significantly higher than that on NFS at all sites, except for the semiarid zone, where no significant difference between aspects was found. Species diversity on SFS changed along the climatic transect at an almost linear rate, while on NFS there was a sharp increase from the extreme-arid zone to the semiarid zone, followed by a decline moving towards the Mediterranean zone. Vegetation cover along the climatic transect was higher on NFS than on SFS, except for the extreme-arid zone, where no significant difference was found. The general conclusions are: (a) The most significant differences in soil and vegetation properties between NFS and SFS are found in the Mediterranean zone, mainly at the end of the rainy season; in the semiarid, arid, and extreme-arid zones the differences are small and generally negligible. (b) The spatial and seasonal differences on SFS are smaller than those on NFS.

GIS and Remote Sensing applications for abandoned quarries rehabilitation: A case study in the Akreuch Region, Rabat, Morocco.

“…The colonization of plants varies in the northern hemisphere, from north to south (Bochet et al, 2009). North-facing slopes are wetter, and their soils are characterized by greater organic matter content (Poesen et al, 1998;Kutiel & Lavee, 1999;Hammada et al, 2004). Pedology: Soil analysis is essential to effective revegetation management.…”

Transitions between community complexes: a case study analysing gradients through mountain ridges in south Hungary

“…ARMESTO and MARTÍNEZ 1978, SZABÓ 1990, KUTIEL and LAVEE 1999, STERNBERG and SHOSHANY 2001, BÁTORI et al 2011, ERDÄS et al 2012. However, differences are pronounced under some climatic conditions, but they are negligible in others.…”

“…In contrast, under Mediterranean and Continental (as well as sub-Mediterranean and sub-Continental) conditions, trees are much more abundant on north-facing than on south--facing slopes, resulting in great structural and compositional differences between the community complexes of the different slopes (cf. JAKUCS 1972, KUTIEL and LAVEE 1999, STERNBERG and SHOSHANY 2001.…”

“…However, differences are pronounced under some climatic conditions, but they are negligible in others. For example, humid Atlantic conditions in western Europe favour the existence of closed forests on both north-facing and south-facing slopes (JAKUCS 1972), while all slopes tend to be mostly treeless in arid and extreme-arid environments (KUTIEL and LAVEE 1999). In contrast, under Mediterranean and Continental (as well as sub-Mediterranean and sub-Continental) conditions, trees are much more abundant on north-facing than on south--facing slopes, resulting in great structural and compositional differences between the community complexes of the different slopes (cf.…”

Analysis of dry periods along a pluviometric gradient in Mediterranean southern Spain

“…Firstly, dry periods between torrential rainfall events play an important role in geomorphological, hydrological, and ecological processes, particularly in relation to soil moisture conditions (Baver, 1956;Hillel, 1971). Secondly, soil moisture controls the water available for plant growth, and influences soil characteristics and processes including aggregate stability and soil degradation (Mbagwu and Bazzoffi, 1988;Caron et al, 1992;Lavee et al, 1996Lavee et al, , 1998Lado et al, 2004), runoff and water erosion (Le Bissonnais and Singer, 1992;Kuhn and Bryan, 2004;Arnold et al, 2005), aeolian erosion (Fécan et al, 1999), the generation of flows (Sittner et al, 1969;Sidle et al, 1995), soil biological activity (Li and Sarah, 2003;Belnap et al, 2004), and the evolution of vegetation communities (Kutiel and Lavee, 1999). There have been numerous studies showing the varied responses of ecogeomorphological systems along pluviometric gradients, which can be summarized from a functional point of view as an impoverishment of the soilwater-plant relationship in areas receiving less rainfall (Lavee et al, 1998;Ceballos et al, 2004;.…”