Early colonization of constructed Technosols by macro-invertebrates

Abstract

Anthropogenic activities lead to soil degradation and loss of biodiversity, but also contribute to the creation of novel ecosystems. Pedological engineering aims at constructing Technosols with wastes and by-products to reclaim derelict sites and to restore physico-chemical functions. The biological (dynamics of soil and epigeic macroinvertebrate assemblages) and physical (chemical and physical fertility) properties have been studied in two constructed Technosols under grassland during 4 years after their implementation. The soils exhibited a moderate chemical fertility (high organic matter and calcium carbonate contents, low nitrogen content) and a good physical fertility that only slightly evolved over the monitored period. Macro-invertebrates have colonized these soils. This colonization was characterized by an increasing number of individuals and species over time. The diversity and abundance values fell within those quoted in the literature for similar natural soils. Epigeic invertebrates presented a succession, indirectly linked to changes in soil parameters. No succession was recorded for soil invertebrates. However, the proportion of soil detritivores, an important functional group for soil evolution, grew consistently. Questions about soil invertebrates’ functional complementarity/redundancy emerge in such artificially created ecosystem. The constructed Technosol, on which a meadow was sown and well-established after 4 years, can host numerous soil invertebrates. In addition, an increase in diversity was monitored throughout the duration of the study.