Abstract
DNA-based techniques are increasingly used to assess biodiversity both
above- and belowground. Most effort has focussed on bioinformatics and
sample collection, whereas less is known about the consequences of
mixing collected environmental DNA (eDNA), post-extraction and pre-PCR.
We applied varying degrees of pooling to stand-alone eDNA samples
collected across a non-native plant invasion density gradient, and
compared the fungal communities of pooled and unpooled samples. Pooling
soil eDNA decreased observable fungal rarefied richness in our samples,
led to phylum-specific shifts in proportional abundance, and increased
the sensitivity of detection for the invasive plant’s overall impact on
fungal diversity. We demonstrate that pooling fungal eDNA could change
the outcome of similar eDNA studies where the aim is to: 1) identify the
rare biosphere within a soil community, 2) estimate species richness and
proportional abundance, or 3) assess the impact of an invasive plant on
soil fungi. Sample pooling might be appropriate when determining
larger-scale overarching responses of soil communities, as pooling
increased the sensitivity of measurable effects of an invasive plant on
soil fungal diversity.