Microbial community composition of translocated ancient woodland soil: a case study

Abstract

Soil translocation is an ecological habitat restoration technique which consists of moving the entire topsoil from a donor site to a chosen receptor site. We investigated changes in soil chemistry and microbiology three years following the salvage of semi-ancient woodland soil and materials (0.94 ha) to a nearby receptor pasture due to road widening works (Kent, UK). We sampled i) intact woodland soils adjacent to the area of soils that was translocated to represent the lost donor site, ii) the soil three years after it had been translocated, and iii) grassland soils adjacent to the translocated soil to represent the original receptor site. The intention was to ascertain if shifts in soil chemistry and microbial community composition (Phospholipid Fatty-acid analysis: PLFA) occurred due to soil translocation. PLFA signature biomarkers demonstrated the overall microbial community profile of the translocated and woodland soils were similar; however, salvaged soils had a 40% increase in the Arbuscular Mycorrhizal Fungi (AMF) bioindicator fatty acid 16:1ω5, a 10% decrease in the Gram-positive bacterial fatty acids, and increased pH (5.01-5.77) compared to the original donor woodland soil. The AMF bioindicator and the first Principal Component (PC1) of the PCA of PLFA data positively correlated with soil pH (r2=0.94 and r2=0.88 respectively) across all three experimental groups. Considering that soil pH increases with depth in this location, it is likely that mixing of soil horizons during translocation increased the topsoil pH causing changes in the soil microbial communities. We concluded that after three years, the chemical and microbial properties of the salvaged soil were characteristic of a woodland soil but showed signs of disturbance.