4.3 Unexpected consequences of the biotic barrier
The biotic barrier can manifest unforeseen results during restoration. Remediation research has shown that the establishment of beneficial microbial inoculants in soil communities is not strictly correlated with measurable macro-ecological outcomes (plant growth in this instance). At least two independent studies have reported beneficial plant growth outcomes even when the inoculant was lost from the soil (Kang et al. , 2013; Liu et al. , 2015). The beneficial effects are attributed to changes to the native community structure and function triggered by the addition, and subsequent demise, of the inoculum. This research highlights significant knowledge gaps in managing soil function and indicates that monitoring of soil communities post rewilding will be necessary to disentangle outcomes for ecosystem functions and the microbial community. Addressing these knowledge gaps can include more specific instances of rewilding soil microbial communities that extend beyond current soil inoculation methodologies (Box 2).