A curated soil fungal dataset to advance fungal ecology and conservation research in Australia and Antarctica

DNA metabarcoding has advanced our understanding of soil fungal diversity and function. Through the Australian Microbiome Initiative, an extensive soil fungal metabarcoding dataset has been compiled from over 2000 plots across Australian and Antarctic ecosystems. However, integrating sequence data into biodiversity platforms requires rigorous approaches to address biases, including false positives and over-inflated diversity estimates. We analysed this fungal dataset following metabarcoding best practices and integrated it with over 100 predictor variables to facilitate data exploration. We validated our methodology through analyses of historical dataset versions. The resulting robust dataset on Australian soil fungi serves researchers studying biodiversity, biogeography, and conservation. This resource opens new opportunities for soil fungal research across the Southern Hemisphere and globally.

All primary data products produced from our study are available in eight files:

(1) Sample metadata file
(2) Sample metadata descriptor
(3) Sample-by-OTU matrix with absolute sequence abundances
(4) Sample-by-OTU matrix normalised to a minimum sequencing depth of 5000 reads
(5) Quality-filtered ITS1 reference sequences in FASTA format
(6) A taxonomy file without pseudotaxon names (pseudotaxa have been renamed 'unidentified')
(7) A taxonomy file with pseudotaxon names (pseudotaxa are taxon approximations for unidentified ranks based on similarity score cutoffs computed by DNABarcoder)
(8) An interactive KRONA chart showing the taxonomic distribution of the contemporary Australian Microbiome dataset

The sample metadata contains information on:

* Sample accession numbers and persistent links to source files
* Sample location
* Date of collection
* A range of measured soil physicochemical characteristics
* Georeferenced environmental variables
* Alpha-diversity statistics
* Estimated level of mould contamination

The taxonomy file contains information on:

* Representative taxon for each OTU
* Associated trait information
* Taxonomic assignment statistics

The original data we sourced were openly available for reuse and redistribution under a Creative Commons Attribution License. See the Australian Microbiome data sharing policy (https://www.australianmicrobiome.com/protocols/data-policy/) and references within Table 1 for the georeferenced grid data.