Data from: Plant diversity and density predict belowground diversity and function in an early successional alpine ecosystem

Despite decades of interest, few studies have provided evidence supporting
theoretical expectations for coupled relationships between aboveground and
belowground diversity and ecosystem functioning in non-manipulated
naturalecosystems. We characterized plant species richness and density,
soil bacterial, fungal and eukaryotic species richness and phylogenetic
diversity (using 16S, ITS, and 18S gene sequencing), and ecosystem
function (levels of soil C and N, and rates of microbial enzyme
activities) along a natural gradient in plant richness and density in
high-elevation, C-deficient soils to examine the coupling between above-
and belowground systems. Overall, we observed a strong positive
relationship between aboveground (plant richness and density) and
belowground (bacteria, fungi, and non-fungal eukaryotes) richness. In
addition to the correlations between plants and soil communities, C and N
pools, and rates of enzyme activities increased as plant and soil
communities became richer and more diverse. Our results suggest that the
theoretically expected positive correlation between above- and belowground
communities does exist in natural systems, but may be undetectable in late
successional ecosystems due to the buildup of legacy organic matter that
results in extremely complex belowground communities. In contrast,
microbial communities in early successional systems, such as the system
described here, are more directly dependent on contemporary inputs from
plants and therefore are strongly correlated with plant diversity and
density.