Forest type shapes regional metacommunity structure
Community composition of soil microarthropods across Troodos was largely
explained by forest type, irrespective of spatial and topoclimatic
variation (Table 2; Table S6; Figure 4), suggesting a primary role of
habitat filtering as a driver of regional metacommunity structure. The
importance of habitat type in shaping the composition of soil
microarthropod assemblages has been demonstrated by previous research
comparing forest vs. grassland habitats (Arribas et al., 2021b;
Caruso et al., 2012) or different grass and shrub species (Coulson,
Hodkinson, & Webb, 2003; see also Doblas-Miranda, Sánchez-Piñero, &
González-Megías, 2009), but to our knowledge, this is the first study to
compare different forest types in a systematic way. Given the mosaic
nature of Troodos (Figure 1), our sampling scheme revealed high turnover
among nearby sampling sites of different woodland habitats (Figure 3),
highlighting a major role of underlying forest-specific edaphic features
for the community assembly of soil microarthropods (Eissfeller,
Langenbruch, Jacob, Maraun, & Scheu, 2013). Leaf litter and vegetation
type are documented to influence the soil environment through changes in
microhabitat availability and physico-chemical edaphic properties (Berg
& McClaugherty, 2008), and such local abiotic features might be driving
a scenario of species sorting (Leibold et al., 2004) or even the
existence of largely separate metacommunities inhabiting each forest
type. In contrast to the general pattern, the communities of the two
highland habitats of Black Pine (Pn ) and Stinking Juniper
(Jn ) are more similar to each other (Figure 3; although still
significantly different based on pairwise comparisons), suggesting that
harsh climatic conditions at those high altitudes might be imposing a
stronger environmental filter than forest-associated soil attributes.
Alternatively, the spatial configuration of this highland woodland
(composed of isolated small stands of Stinking Junipers embedded in a
much larger Black Pine matrix) might facilitate dispersal among habitat
patches and partly counteract the effects of habitat filtering (Leibold
et al., 2004; Logue, Mouquet, Peter, & Hillebrand, 2011). These two
hypotheses are not mutually exclusive and may jointly contribute to the
higher similarity in community composition between these highland
assemblages.