Speaker
Description
Soil communities harbour exceptional diversity across the tree of life, yet their richness remains systematically underestimated due to methodological constraints in field sampling and sequencing. Physical homogenization of multiple soil cores into composite samples is standard practice in soil ecology, under the assumption that mixing more cores better captures plot-level diversity. However, the consequences of this practice for diversity estimation, and whether they differ across prokaryotic and eukaryotic communities, remain poorly understood.
We sampled 57 forest and grassland sites across three regions in Germany using a standardized 14-core cross-transect design and performed 16S and 18S rRNA gene metabarcoding on individual cores and physically homogenized composite samples. This allowed us to compare how sampling effort, physical homogenization, and sequencing depth standardization influence diversity estimates across bacterial and eukaryotic soil communities, which differ fundamentally in body size, spatial distribution, and dispersal capacity.
Plot-level richness increased continuously with sampling effort in both community types, with no evidence of saturation. Physically homogenized composite samples substantially underestimated plot-level richness and altered apparent diversity relationships between ecosystems in both datasets. However, the magnitude and direction of these biases differed between bacteria and eukaryotes, reflecting differences in spatial heterogeneity and body size distributions across community types.
These results demonstrate that sampling effort and homogenization fundamentally shape diversity estimates across soil kingdoms, and that the consequences are not uniform across community types. We recommend sequencing individual cores rather than composite samples and scaling sequencing depth to sampling effort, with particular attention to the body size distribution of the target community.
| Status Group | Doctoral Researcher |
|---|---|
| FOR TALKS: Poster Presentation Option | Yes, I’m willing to present as a poster. |