eDNA metabarcoding reveals invertebrate diversity in the blackwater pools of southeast Queensland peatlands

Despite harbouring a disproportionate diversity of rare and endemic species, the pyrophilic peatlands of southeast Queensland remain poorly characterized, particularly regarding their invertebrate communities. In the physiochemically extreme blackwater pools, microscopic invertebrate assemblages likely form critical trophic links but have never been described due to their low public profile, small size and cryptic nature. This study used 18S environmental DNA metabarcoding to characterize invertebrate communities across three peatland sites, revealing significantly greater taxonomic breadth than conventional surveys. 63 taxa across 10 phyla were detected, including five microscopic phyla previously unrecorded in these ecosystems (Cnidaria, Rotifera, Platyhelminthes, Nematoda and Gastrotricha). Metabarcoding exceeded the resolution achieved by field surveys for morphologically cryptic microcrustaceans, however field surveys achieved better resolution for hexapods, demonstrating that the methods target complementary niches, each focused at distinct components of the invertebrate community. The documented microfauna overlap in key life-history traits, including rapid maturation, parthenogenetic reproduction, and dormancy capabilities, occupying the crucial intermediary trophic link between microbial production and higher consumers. These traits likely enable rapid community recovery and ecosystem stabilization following fire disturbances characteristic of pyrophilic peatlands. Our findings reveal a previously unrecognized diversity of invertebrate taxa and demonstrate the efficacy of molecular tools in the description of cryptic community assemblages.