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 physically and chemically extreme blackwater pools, meiofaunal assemblages likely form critical trophic links but have never been described due to their small size and low public profile. This study used 18S environmental DNA metabarcoding to characterize invertebrate communities across three peatland sites. We detected 48 unique taxa across 10 phyla, including five invertebrate 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 larger hexapods, demonstrating that the methods target distinct components of the invertebrate community. Key life-history traits were shared across the detected meiofaunal communities, including rapid maturation, parthenogenetic reproduction, and dormancy capabilities. These traits likely enable rapid community recovery and ecosystem stabilization following fire disturbances characteristic of pyrophilic peatlands. Collectively, these taxa occupy a crucial and previously undocumented intermediary trophic link between microbial production and higher consumers. Our findings reveal a previously unrecognized diversity of invertebrate taxa and demonstrate the efficacy of using molecular tools to describe cryptic community assemblages.