Can we accurately predict the distribution of soil microorganism
presence and relative abundance?
Abstract
Soil microbes play a key role in shaping terrestrial ecosystems. It is
therefore essential to understand what drives their distributions. While
multivariate analyses have been used to characterise microbial
communities and drivers of their spatial patterns, few studies focused
on modelling the distribution of Operational Taxonomic Units (OTUs).
Here, we evaluate the potential of species distribution models (SDMs),
to predict the presence-absence and relative abundance distribution of
bacteria, archaea, fungi and protist OTUs from the Swiss Alps. Advanced
automated selection of abiotic covariates was used to circumvent the
lack of knowledge on the ecology of each OTU. ‘Presence-absence’ SDMs
were successfully applied to most OTUs, yielding better predictions than
null models. ‘Relative-abundance’ SDMs were less successful, yet, they
were able to correctly rank sites according to their relative abundance
values. Archaea and bacteria SDMs displayed better predictive power than
fungi and protist ones, indicating a closer link of the latter with the
abiotic covariates used. Microorganism distributions were mostly related
to edaphic covariates. In particular, pH was the most selected covariate
across models. The study shows the potential of using SDM frameworks to
predict the distribution of OTUs obtained from environmental DNA (eDNA)
data. It underscores the importance of edaphic covariates and the need
for further development of precise edaphic mapping and scenario
modelling to enhance prediction of microorganism distributions in the
future.