Field surveys and soil metabarcoding recover largely non-overlapping nivicolous myxomycete diversity in Ile-Alatau and Katon-Karagay National Parks (Kazakhstan)

Abstract Nivicolous myxomycetes fruit at snowmelt in mountains, while their amoeboid trophic stages persist unseen in soil. To assess to what extent different approaches capture their diversity, we combined 18S rDNA barcoding of 172 fruiting body collections (48 ribotypes) with soil metabarcoding of the same marker (187 samples, 730 myxomycete amplicon sequence variants, ASVs) along elevational and canopy gradients in Ile-Alatau (IANP, Tian Shan) and Katon-Karagay (KKNP, Altai) National Parks, Kazakhstan. Only 7.2% of nivicolous barcode variants were recovered by both methods; a second fruiting body survey of IANP added no further soil matches and shared only 26% of its ribotypes with the main IANP survey, so the approaches are complementary and neither alone provides an adequate inventory. Soil communities were hyperdiverse, dominated by ASV replacement and compositionally distinct between parks. Per-sample richness did not differ significantly between parks, but fine-scale turnover was higher in KKNP; canopy shaped composition in both parks but richness only in IANP, where open-canopy positions were richer. Nivicolous richness showed no elevational trend within the sampled gradients, whereas that of other myxomycetes declined with elevation in IANP. The largely park-specific ASV and ribotype pools support regional structuring of myxomycetes over unlimited gene flow.