2.2 Microbial restoration: moving beyond interactions with
plants
Like invertebrates, it is generally assumed that microbial diversity and
function in revegetated areas will naturally attain the level maintained
in remnant sites. However, communities of microbes are monitored the
least of any organism group post-restoration (5% of projects) (Kollmannet al. , 2016). For microbes, targeted reintroductions aimed at
improving plant health are the focus: inoculation of single species of
non-native Arbuscular Mycorrhizal Fungi (AMF) is a common restoration
practice (Asmelash, Bekele and Birhane, 2016). Non-native AMF are used
to help revegetated plants establish and grow, but this practice ignores
all other components of soil biota. Indeed, it has been argued that AMF
inoculations could be improved by incorporating whole native communities
rather than using single non-native species (Asmelash, Bekele and
Birhane, 2016), and this hypothesis is now being tested through field
trials (Lance et al. , 2019). There are analogous developments in
fields that use cyanobacteria to improve soil processes. Emerging
studies examining the efficacy of whole community transfer of
cyanobacteria (Chiquoine, Abella and Bowker, 2016) are challenging the
traditional use of single-strains of laboratory reared species (Rossiet al. , 2017).
The implementation of both invertebrate and microbial rewilding projects
is impeded by knowledge gaps. Addressing these gaps would include
greater monitoring both post-restoration to identify which groups are
failing to recolonise revegetated areas and post-rewilding to determine
which groups have established (Table 1). Further, for ecological
restoration, it might make more sense to consider whole communities: the
ultimate success for restoration would be to reinstate biodiversity and
ecosystem function in its entirety. To do this, microbial rewilding will
need to venture from the plant focused singular AMF inoculation studies,
while invertebrate rewilding should broaden from earthworms to
communities that include a greater diversity of functional groups, such
as those found in litter (Figure 1).