Functional traits of trees and effects on soil functions and ecosystem services

Abstract

Tree-soil interactions are complex and depend on the site conditions. The functional diversity of trees will affect differently the soil functions and ecosystem services. Here we present results from the Guadiamar Green Corridor (Sevilla, Spain). A former cropland was affected by a mine-spill (in 1998), then the soil was cleaned-up, remediated and afforested with several native shrub and tree species. In 2014 we studied functional traits of leaves and roots in seven of the afforested tree species, with contrasted leaf habit: deciduous (Populus alba, Celtis australis, Fraxinus angustifolia) and evergreen (Quercus ilex, Olea europaea, Ceratonia siliqua and Pinus pinea). We sampled five replicates of each tree species and the soil underneath in a random block design, including adjacent open soils as reference. We studied the differential effects of the contrasted tree functional traits on two ecosystem services: 1) the regulation of soil quality by immobilization of trace elements (the remediation technique called “phytostabilization”), and 2) the mitigation of climate change by carbon sequestration in biomass and soils.