eDNA Detection of Observed and Hidden Biodiversity Across Microhabitats in the Fremont Peak Bowl Refugium, Western Mojave Desert

Traditional biodiversity survey methods (photography, camera traps, acoustic recording, iNaturalist observations) have documented over 150 species within the Fremont Peak Bowl Refugium, a conservation area in the Western Mojave Desert. However, the inherent limitations of visual and acoustic sampling — combined with evidence that desert ecosystems harbor substantial hidden biodiversity (Durant et al., 2012; Pärtel, 2014) — suggest that a significant fraction of the refugium's species richness remains undetected. Environmental DNA (eDNA) extraction from soil has been shown to reveal biological diversity not captured by conventional survey methods (Carrasco-Puga et al., 2021), and may similarly reveal both previously documented and previously undetected organisms across the full breadth of life present at a site. In addition, standardized insect sweep net collections enable high-throughput that can help reveal hidden biodiversity by leveraging automated assessment of insect diversity (e.g., via DiversityScanner-based sorting), with prioritized DNA sequencing and imaging of morphotypes lacking existing sequence data. This study will test two related hypotheses: (1) that an eDNA approach based on soil samples will detect both (A) organisms already documented at the refugium through traditional methods and (B) organisms not previously documented there, and (2) that sites with higher vegetative greenness will yield greater eDNA detected species richness. Soil eDNA constitutes the primary and guaranteed data stream. Insect sweep net collections constitute a complementary data stream: insects will be processed via automated sorting methods (e.g., DiversityScanner), and, where the CalATBI pipeline generates eDNA or sequence data from these insect samples, those data will be incorporated as an additional biodiversity readout but are not required for the confirmatory analyses.