Development of spatial heterogeneity in vegetation and soil properties after land abandonment in a semi-arid ecosystem

To mitigate erosion on abandoned fields in semi-arid ecosystems, it is important to understand how vegetation and soil properties and patterns develop after land abandonment. Our objective was to investigate the development of spatial heterogeneity in vegetation and soil properties after land abandonment. We described the vegetation composition, collected soil samples and made detailed aerial photographs for two series of abandoned fields on marl and calcrete in Southeast Spain. The images were classified into bare and vegetated patches, and spatial metrics were calculated for each site. Our results showed that recovery of vegetation and change in soil properties after land abandonment are slow and take at least 40 years in such a semi-arid environment. Succession on calcrete appeared to be faster than on marl, probably because more water is available due to the higher rock fragment cover. Organic matter, aggregate stability and electrical conductivity were all significantly higher under vegetated patches. We found a clear linear relationship between vegetation cover and most spatial metrics, which offers the possibility of upscaling spotted vegetation patterns. The results of our integrated approach to study spatial heterogeneity in vegetation and soil properties can be used to improve predictions of runoff and erosion.