Optimizing Soil Core Sampling Strategies for Enhanced Soil Invertebrate Biodiversity Assessment through eDNA Metabarcoding

We aim to refine soil core sampling strategies for assessing soil invertebrate biodiversity using environmental DNA (eDNA) and metabarcoding techniques. The primary objective is to determine the optimal number of soil cores required to capture a specified fraction (e.g., 95%) of the total species diversity within a given habitat. Traditionally, individual soil cores are analyzed separately; however, this study explores the efficiency of grouping and pooling cores into composite samples for analysis to reduce the number of required analyses while ensuring comprehensive biodiversity assessment.

We investigate sources of variation in DNA marker diversity at multiple levels within composite soil samples, including horizontal variability across the sampling area, variation across sub-sample cores between different taxa. By increasing the number of soil cores combined into a composite sample, we hypothesize that overall variation decreases and a more accurate representation of the plot's DNA diversity is achieved.