Speaker
Description
Soil biodiversity is crucial for ecosystem functioning, yet its high spatial variability makes characterization difficult. Monitoring microbial diversity requires spatially explicit sampling strategies that incorporate ecological principles such as distance decay into their design. We present findings from the SpaceMic project within the framework of the German Biodiversity Exploratories, investigating how spatial sampling influences metabarcoding-derived biodiversity estimates in grasslands and forests.
Using 16S, 18S, and ITS marker genes, we analyzed the effects of sample number and spatial extent on alpha, gamma, and sample completeness across 54 plots in three German regions. We compared individual samples with homogenized composite samples to assess how sampling design alters observed diversity patterns.
Sampling scheme had a major impact: individual samples captured significantly higher diversity and preserved fine-scale spatial information, while composite samples showed markedly reduced richness. This highlights a loss of resolution and potential bias in composite samples, which do not reliably represent gamma diversity.
Sample number strongly influenced diversity estimates. As the number of individual samples increased, gamma diversity rose accordingly. However, rarefied gamma diversity — standardized for sequencing depth — plateaued, revealing a trade-off between sampling effort and richness detection.
Sample extent also affected gamma diversity: larger spatial coverage led to more species being detected. Still, when standardizing for sequencing depth (rarefaction), the impact of spatial extent was reduced, suggesting that sequencing effort partially compensates for spatial coverage.
Our findings emphasize the importance of using both individual and composite samples per plot and avoiding sole reliance on pooled samples.This approach maximizes information capture while ensuring comparability, both of which are essential for robust biodiversity research. Our findings offer practical guidelines for optimizing soil sampling, improving reproducibility, and strengthening ecological insight.
| Status Group | Doctoral Researcher |
|---|---|
| Poster Presentation Option | Yes, I’m willing to present as a poster. |
