Soil bacterial activity and functional diversity as indicators of recultivation of alkaline settlements of a ‘Solvay’ process

Abstract

Purpose Many industries continuously produce large volumes of alkaline residues. After recultivation, former landfills can be an important element providing ecosystem services in highly urbanised areas. Materials and methods We studied the relationship between vegetation and soil bacterial characteristics using Biolog® ECO plates on recultivated areas of the Solvay heaps, and participation of invasive species in plant community in progressive succession. Results and discussion Bacterial activity and functional diversity indices were correlated with soil physicochemical properties (soil organic matter content, water holding capacity, total phosphorus content, and soil pH). Plots with a higher total number of vascular plant species, including forest floor species, and a higher Shannon–Wiener index of vegetation diversity H'plant, were characterised by a higher amino acid utilisation by soil bacteria. Soil bacteria CLPP (community-level physiological profiles) were most influenced by soil physical and chemical properties, but also by the proportion of invasive species in the total number of plant species. In conclusion, soil physical and chemical properties dominate vegetation characteristics in shaping the functional diversity of soil bacteria. Invasive species may be an influential component of ecosystems during spontaneous succession of degraded soils.