Shifts in arbuscular mycorrhizal fungal community composition and edaphic variables during reclamation chronosequence of an open-cast coal mining dump

Abstract

Arbuscular mycorrhizal fungi (AMF) contribute to the restoration of soil ecological functions and may facilitate the revegetation of degraded ecosystems by decreasing abiotic and biotic stresses on plants. The diversity and composition of AMF communities on the revegetation were assessed during an open-cast mining dump reclamation chronosequence of the soil at <1, 5, 10, 15 and 20 years after reclamation began. Total glomalin (TG), easily extractable glomalin (EEG), soil pH, electrical conductivity, soil organic carbon (SOC), total nitrogen (TN), available phosphorus (AP), and C:N:P stoichiometry were measured. Based on high-throughput sequence analysis on partial Glomeromycota 18S rRNA, 156 AMF operational taxonomic units were identified, which belonged to 12 genera and nine families. AMF diversity indices were significantly different between the community early in reclamation (<1 year) and later (P < 0.05), and were correlated with TN, AP, TG, N/P, C/P, EEG/SOC and TG/SOC ratios (P < 0.05). Network analysis and nonmetric multidimensional scaling analyses revealed that AMF community composition was significantly different early in the process of reclamation (<1 year) and at the end of reclamation (20 years) (P < 0.05), but were similar in the intermediate reclamation stages (5–15 years). Overall, the study suggests the rapid and stable re-establishment of a species-rich AMF community on a degraded ecosystem over time, following artificial re-vegetation.