Do gypsum soils offer advantages for water availability for vegetation in dry areas? An approach based on satellite tools
Sara López Cadenas.
Gypsum soils are confined to arid and semi-arid climates where low precipitation prevents gypsum from being removed by leaching. These substrates present physical and chemical stressful conditions for vegetation, leading to a high specialization in plant species: the gypsophiles. The dynamic of these plant communities is determined by water availability in the soil because of being located in drylands. Additionally, the specific water properties of gypsum soils could result in an increase of water availability for the plants communities in drylands. Since water availability is a parameter closely related to net primary production (NPP), it would be expected that the vegetation of the gypsum outcrops in a water limited environments will show different dynamics in the productivity compared to the substrates around. In order to better understand the functioning of gypsum vegetation, we used a time-series satellite images of EVI (Enhanced Vegetation Index), as surrogate for NPP, from the period 2001-2014, to assess the differences in the dynamics of EVI in three gypsum outcrops comparing with the substrates around and along a dryness gradient in Andalusia. In the most arid area, gypsum shrublands were more productive and less seasonal than the other vegetation. Remote sensing tools revealed to be a good approach in the study of the dynamics of the primary production of the vegetation in gypsum outcrops along the dryness gradient.
Keywords: Functional attributes, Vegetation structure, EVI, Gypsum, Lithology, Net Primary Productivity