Data from: Energy and physiological tolerance explain multi-trophic soil diversity in temperate mountains

Aim – Although soil biodiversity is extremely rich and spatially variable,
both in terms of species and trophic groups, we still know little about
its main drivers. Here, we contrast four long-standing hypotheses to
explain the spatial variation of soil multi-trophic diversity: energy,
physiological tolerance, habitat heterogeneity, and resource
heterogeneity. Location – French Alps Methods – We built on a large-scale
observatory across the French Alps (Orchamp) made of seventeen elevational
gradients (~90 plots) ranging from low to very high altitude (280 - 3160
m), and encompassing large variations in climate, vegetation and
pedological conditions. Biodiversity measurements of 36 soil trophic
groups were obtained through environmental DNA metabarcoding. Using a
machine learning approach, we assessed 1) the relative importance of
predictors linked to different ecological hypotheses in explaining overall
multi-trophic soil biodiversity, and 2) the consistency of the response
curves across trophic groups.  Results – We showed that
predictors associated with the four hypotheses had a statistically
significant influence on soil multi-trophic diversity, with the strongest
support for the energy and physiological tolerance hypotheses.
Physiological tolerance explained spatial variation in soil diversity
consistently across trophic groups, and was an especially strong predictor
for bacteria, protists and microfauna. The effect of energy was more
group-specific, with energy input through soil organic matter strongly
affecting groups related to the detritus channel. Habitat and resource
heterogeneity had overall weaker and more specific impacts on biodiversity
with habitat heterogeneity affecting mostly autotrophs, and resource
heterogeneity affecting bacterivores, phytophagous insects, enchytraeids
and saprotrophic fungi. Main Conclusions – Despite the variability of
responses to the environmental drivers found across soil trophic groups,
major commonalities on the ecological processes structuring soil
biodiversity emerged. We conclude that among the major ecological
hypotheses traditionally applied to aboveground organisms, some are
particularly relevant to predict the spatial variation in soil
biodiversity across the major soil trophic groups.