Abstract:
The central Namib Desert is hyperarid, where
limited plant growth ensures that biogeochemical processes
are largely driven by microbial populations. Recent
research has shown that niche partitioning is critically
involved in the assembly of Namib Desert edaphic communities.
However, these studies have mainly focussed on
the Domain Bacteria. Using microbial community fingerprinting,
we compared the assembly of the bacterial, fungal
and archaeal populations of microbial communities across
nine soil niches from four Namib Desert soil habitats (riverbed,
dune, gravel plain and salt pan). Permutational multivariate
analysis of variance indicated that the nine soil
niches presented significantly different physicochemistries
(R
2
= 0.8306, P ≤ 0.0001) and that bacterial, fungal and
archaeal populations were soil niche specific (R
2
≥ 0.64,
P ≤ 0.001). However, the abiotic drivers of community
structure were Domain-specific (P < 0.05), with P, clay and
sand fraction, and NH4
influencing bacterial, fungal and archaeal communities, respectively. Soil physicochemistry
and soil niche explained over 50% of the variation in
community structure, and communities displayed strong
non-random patterns of co-occurrence. Taken together,
these results demonstrate that in central Namib Desert soil
microbial communities, assembly is principally driven by
deterministic processes.
