Arbuscular Mycorrhizal Fungi with different life strategies in an ancient and abandoned Pb-Zn-Ag mine in Andes Mountain

Abstract

Mining industry causes strong alterations in soils such as heavy metal (HM) pollution, thereby impacting on plant communities and their rhizospheric microorganisms, including arbuscular mycorrhizal (AM) fungi. The old polymetallic mine Paramillos de Uspallata, located in the Andes mountains, represents the first mining exploitation in Argentina. Due to the nature of its original substrate and the exhausted mining activity, the soils exhibited high concentrations of HM and vegetation disturbance, exerting a selective pressure on AM fungal communities. In this work, we compared the mycorrhizal status of vegetation, the abundance and diversity of AM fungi within the mining site with a nearby unexploited area, thereby associating mycorrhizal traits with environmental parameters. A higher proportion of mycorrhizal plants was observed outside the mine and in some exploited areas. The unexploited and urban ruins area showed higher richness and diversity of AM fungal species, with a prevalence of the Glomeraceae and Claroideoglomeraceae families across all areas, except for the highly impacted exploitation area where Entrophosporaceae family was abundant. Ancestral (or stress-tolerant) species and rhizophilic (or ruderal) species dominated Paramillos de Uspallata mine, while edaphophilic (competitors) and rhizophilic species were abundant outside mine. This study contributes to understanding the impact of prolonged mining activities on AM fungal communities, and the capacity for tolerance and resilience exhibited by some AM species after more than 30 years of mining cessation. The Paramillos de Uspallata mine represents a reservoir of HM-tolerant AM fungi, valuable for ecological restoration of post-mining lands.