Restauración de suelos contaminados por elementos traza: efecto de la vegetación arbórea en las comunidades de hongos del suelo

The Guadiamar Green Corridor is an area contaminated by trace elements due to a mine spill in 1998. After this accident, a phytoremediation strategy was established with the aim of remediating and establishing a novel ecosystem. The first objective of this Doctoral Thesis was to evaluate the influence of the identity of the forested tree species in the Corridor on the composition and microbial activity. Soils were sampled under three tree species (wild olive, white poplar and stone pine) and in grassland soils, at two sites with different soil properties. Afforestation produced an increase in most microbial indicators. Each tree species produced specific effects on soil organic matter, pH and C:N ratio, with consequences on biomass and microbial activities. White poplar was the species that promoted a greater catabolic diversity, which could mean a greater mineralization of simple and complex carbon substrates in these soils. Furthermore, both stone pine and white poplar promoted greater enzymatic activity in these soils. The second objective of this Doctoral Thesis was to evaluate the effect of the different afforested tree species in the Corridor on the structure and composition of soil fungal communities. Afforestation of degraded soils with different plant species may promote the establishment of specific fungal diversity and functionality. Five different habitats were selected: under the canopy of three tree species (wild olive, white poplar and stone pine), on adjacent grassland soils and on non-remediated soils. We found that the phytoremediation measures promoted the fungal richness, diversity, taxonomy, and functionality along the Guadiamar Green Corridor, compared to non-remediated soils. White poplar was the tree species with the greatest diversity and richness compared to wild olive and stone pine. Ectomycorrhizal fungi were more dominant in the soils of the host species of these fungi, while saprotrophs were abundant in grassland and wild olive soils. T