Community metabarcoding reveals the relative role of environmental
filtering and dispersal in metacommunity dynamics of soil
microarthropods across a mosaic of montane forests
Abstract
Disentangling the relative role of environmental filtering and dispersal
limitation in driving metacommunity structure across mountainous regions
remains challenging, as the way we quantify spatial connectivity in
topographically and environmentally heterogeneous landscapes can
influence our perception of which process predominates. More empirical
datasets are required to account for taxon- and context-dependency but
relevant research is often compromised by coarse taxonomic resolution.
We here employed haplotype-level community DNA metabarcoding, enabled by
stringent filtering of Amplicon Sequence Variants (ASVs), to
characterize metacommunity structure of soil microarthropod assemblages
across a mosaic of five forest habitats on the Troodos mountain range in
Cyprus. We found similar β diversity patterns at ASV and species (OTU,
Operational Taxonomic Unit) levels, which pointed to a primary role of
habitat filtering resulting in the existence of largely distinct
metacommunities linked to different forest types. Within-habitat
turnover was correlated to topoclimatic heterogeneity, again emphasizing
the role of environmental filtering. However, when integrating landscape
matrix information for the highly fragmented Golden Oak habitat, we also
detected a major role of dispersal limitation imposed by patch
connectivity, indicating that stochastic and niche-based processes
synergistically govern community assembly. Alpha diversity patterns
varied between ASV and OTU levels, with OTU richness decreasing with
elevation and ASV richness following a longitudinal gradient,
potentially reflecting a decline of genetic diversity eastwards due to
historical pressures. Our study demonstrates the utility of
haplotype-level community metabarcoding for characterising metacommunity
structure of complex assemblages and improving our understanding of
biodiversity dynamics across mountainous landscapes worldwide.