This study tested biodiversity effects on ecosystem function in the process of reviving severely degraded and contaminated land, and found that “increasing plant diversity greatly enhanced the reclamation of these lands” [Jia 2020: 1].
Prior to implementing the reclamation experiment, the degraded mine wasteland investigated in this study was heavily impacted by past mining activities and was devoid of vegetation for more than a decade and the soil lacked structure, contained high levels of toxic metals and low levels of nutrients. … our results showed that higher plant species richness enhanced land reclamation across all standard measures of reclamation success and specifically resulted in higher vegetation coverage, biomass yield and stability for all 3 years [of the experiment] [Jia 2020: 6].
Furthermore, higher biodiversity plots had higher levels of organic carbon in the soil, higher soil microorganism abundance, lower fungal pathogens, and lower heavy metal concentrations in plant tissue.
The most striking impact of plant diversity on soil was on the microbial communities. Both soil fungal and bacterial OTUs [operational taxonomic units] increased significantly with plant species richness. More importantly, we found that higher plant species richness significantly increased the relative abundance of soil cellulolytic bacteria that degrade cellulose and are thus essential components of nutrient cycling [Jia 2020: 7].
Jia, Pu, et al., 2020, Plant diversity enhances the reclamation of degraded lands by stimulating plant-soil feedbacks, Journal of Applied Ecology, https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2664.13625.