bioRxiv Science⌕ Search

Biology subjects

Craine, J. M.

Publications and source records attributed to Craine, J. M..

4 recordsLinked to original sources

Airborne DNA reveals synchronized responses of tropical forest assemblages to precipitation

Tropical forests contain much of Earth's biodiversity, yet community-wide responses to seasonal climate transitions remain poorly resolved. We used weekly airborne environmental DNA sampling, supplemented by spatially intensive dry- and wet-season campaigns, to characterize fungi, plants, arthropods, and vertebrates across the dry-to-wet-season transition in a lowland tropical forest. All four assemblages shifted abruptly and nearly synchronously following rainfall late in the dry season, before the meteorological wet season began. These compositional transitions were largely independent of taxonomic richness and airborne DNA concentrations, indicating coordinated changes in detection patterns rather than simple seasonal gains in richness. Across all samples, we recovered more than 5,400 operational taxonomic units, including 2,148 fungi, 857 plants, 2,157 arthropods, and 239 vertebrates. We also recovered 949 full-length insect DNA barcodes, demonstrating compatibility with standard barcoding approaches and expanding opportunities for species discovery. Because the onset of the meteorological wet season showed no long-term trend at Barro Colorado Island, predicting future phenological and compositional shifts will require greater attention to dry-season rainfall variability and the cues that organisms track during this transition. Airborne environmental DNA offers a scalable, noninvasive framework for monitoring biodiversity and phenology across taxonomic groups.

ecology↗

Targeted hybridization capture enables comprehensive detection of freshwater bioassessment invertebrates from environmental DNA

Freshwater bioassessment relies on assessing aquatic assemblages to infer ecological conditions, yet conventional surveys require extensive field sampling, specimen processing, and specialized taxonomic expertise. Existing environmental DNA (eDNA) methods have not yet provided a practical alternative to conventional macroinvertebrate assays in part because current approaches cannot feasibly recover broad taxonomic diversity at sufficient taxonomic resolution. Here, we evaluated targeted hybridization capture of mitochondrial cytochrome oxidase I (COI) target sequences as a unified molecular approach for cross-phylum freshwater bioassessment. Environmental DNA was collected at 18 sites along 63 km of Boulder Creek spanning nearly 1,500 m of elevation from forested headwaters to agricultural plains. COI targets were enriched using custom RNA bait panels designed to target regional freshwater arthropods, annelids, and molluscs. Hybridization capture increased recovery of COI sequences [~]1,760-fold relative to unenriched shotgun libraries, generating Folmer-region COI contigs that averaged [~]400 bp. Across the watershed, we recovered sequences for approximately 450 macroinvertebrate genera across 8 phyla. Detected macroinvertebrate richness averaged 56 genera per site and increased down Boulder Canyon before declining downstream of the city. Macroinvertebrate assemblage composition from hybridization capture paralleled patterns observed with past conventional bioassessment. These results demonstrate that targeted hybridization capture enables robust, cross-phylum detection of species used for freshwater bioassessment from environmental DNA.

ecology↗

Globally unified analysis of riverine eDNA reveals common associations of fish biodiversity with drainage characteristics

Freshwater biodiversity is declining at a pace that outstrips the capacity of existing monitoring approaches both in temporal and spatial dimensions, highlighting the urgent need for rapid and scalable assessment and attribution of biodiversity states and changes. Here, we present one of the first global assessments and unified analyses of riverine fish biodiversity using environmental DNA (eDNA) collected from 1818 sites across 113 river systems. We quantified species richness, functional redundancy, phylogenetic diversity, and genetic sequence diversity, and related them to drainage characteristics. Our results showed that eDNA effectively captured global patterns of multi-faceted riverine fish biodiversity and disentangled the roles of climate and human activities in shaping biodiversity-area relationships. Catchments in warmer climates consistently enhanced biodiversity accumulation with area, while higher human activity intensity weakened this scaling. Species richness, functional, and genetic sequence diversity exhibited stronger negative responses to human activities in larger catchments. In contrast, phylogenetic diversity showed the strongest negative effects in smaller catchments with these impacts diminishing as catchment area increased, highlighting the facet-dependent nature of biodiversity responses to environmental gradients. Our findings demonstrate the power of eDNA-based datasets for harmonized, multi-faceted biodiversity assessments, offering a scalable approach for detecting and attributing biodiversity change and informing conservation strategies under accelerating global change.

ecology↗

Integrated reanalysis of global riverine fish eDNA datasets shows robustness and congruence of biodiversity conclusions

The analysis of environmental DNA (eDNA) has revolutionized biodiversity assessments in aquatic ecosystems, enabling non-invasive monitoring of fish communities across diverse regions. However, the global comparability of these eDNA datasets remains ambiguous due heterogeneous sampling protocols and bioinformatic workflows across studies, particularly regarding the robustness of their conclusions on biodiversity assessments. Here, we conducted a meta-analysis of 58 riverine fish eDNA metabarcoding datasets, covering 1,818 sampling sites worldwide, to evaluate the robustness of eDNA-derived biodiversity patterns. We found that species richness estimates and metrics of community structure derived under a common bioinformatic workflow were overall consistent with those of original analyses, despite the relatively high variability in bioinformatic analyses in the respective original studies. Contrastingly, congruence of species identity varied more extensively across datasets, mostly reflecting different completeness and regional relevance of reference databases. Restricting taxonomic assignment to basin-specific species pools improved species identification accuracy, while datasets lacking publicly accessible or well-curated reference data were more prone to mismatches. Year of sampling had a positive effect on taxonomic congruence, such that more recent studies showed increased robustness, also reflecting improved reference database coverage and enhanced species-level identification over time and overall method congruence in more recent years. Overall, the suitability and potential of eDNA for global biodiversity monitoring is corroborating overall robust biodiversity estimates, irrespective of the bioinformatic approaches. Our study underlines the effectiveness and need of further harmonization of bioinformatic workflows and strengthened region-specific reference databases for improved taxonomic resolution and comparability across studies.

ecology↗