Vegetation Response To Soil And Morphological Properties In An Arid Region Alluvial Fan Landscape. Pre-Andes Of San Juan, Argentina

Abstract

The Monte Desert is characterized by a great diversity of landforms created with fluvial, alluvial which the vegetation patterns are related to. The present work has the following objectives: 1: determine whether topographical attributes, surface characteristics, soil properties and vegetation patterns vary between alluvial landforms, and 2: define whether morphometric, soil and surface properties influence vegetation patterns along alluvial landscape. Morphometric data were obtained by processing a 5 m digital elevation model. The coverage of rock fragments, fine sediments and mulch was quantified. Observations and descriptions of the soil profiles were restricted to the uppermost 50 cm. Vegetation properties were calculated using a Point Quadrat Method. The relationship between variables was evaluated through multivariate statistical analysis. The main results show the presence of 45 plant species distributed in 19 families, where shrubs are dominant. The wind effect, topographic wetness and dissection of the landscape are limiting factors of diversity. The coverage of superficial rock fragments influence vegetation coverage through the distribution and availability of rainwater. Furthermore, the different soil textures reveal that the silt content favors an increase in vegetation coverage. The presence of V horizon could condition the installation and development of vegetation in the early stages of growth.