PT - JOURNAL ARTICLE AU - Ane Kirstine Brunbjerg AU - Hans Henrik Bruun AU - Lars Brøndum AU - Aimée T. Classen AU - Lars Dalby AU - Kåre Fog AU - Tobias G. Frøslev AU - Irina Goldberg AU - Anders Johannes Hansen AU - Morten D.D. Hansen AU - Toke T. Høye AU - Anders A. Illum AU - Thomas Læssøe AU - Sarah Siu Tze Mak AU - Gregory S. Newman AU - Ida Broman Nielsen AU - Carlotta Pietroni AU - Lars Skipper AU - Ulrik Søchting AU - Rasmus Ejrnæs TI - A systematic survey of regional multitaxon biodiversity: evaluating strategies and coverage AID - 10.1101/158030 DP - 2019 Jan 01 TA - bioRxiv PG - 158030 4099 - http://biorxiv.org/content/early/2019/06/11/158030.short 4100 - http://biorxiv.org/content/early/2019/06/11/158030.full AB - Background In light of the biodiversity crisis and our limited ability to explain variation in biodiversity, tools to quantify spatial and temporal variation in biodiversity and its underlying drivers are critically needed. Inspired by the recently published ecospace framework, we developed and tested a protocol for environmental and biotic mapping that is scalable to habitats, ecosystems and biomes. We selected study sites (40×40m) across Denmark using stratified random sampling along the major environmental gradients underlying biotic variation. Using standardized methods, we collected site species data on vascular plants, bryophytes, macrofungi, lichens, gastropods and arthropods. To evaluate sampling efficiency, we calculated regional coverage (relative to the known species number per taxonomic group), and site scale coverage (i.e., sample completeness per taxonomic group at each site). To extend taxonomic coverage to organisms that are difficult to sample by classical inventories (e.g., nematodes and non-fruiting fungi), we collected soil for metabarcoding. Finally, to assess site conditions, we mapped abiotic conditions, biotic resources and habitat continuity.Results Despite the 130 study sites only covering a minute fraction (0.0005 %) of the total Danish terrestrial area, we found 1774 species of macrofungi (54% of the Danish fungal species pool), 663 vascular plant species (42%), 254 bryophyte species (41%) and 200 lichen species (19%). For arthropods, we observed 330 spider species (58%), 123 carabid beetle species (37%) and 99 hoverfly species (33%). Overall, sample coverage was remarkably high across taxonomic groups and sufficient to capture substantial spatial variation in biodiversity across Denmark. This inventory is unprecedented in detail and resulted in the discovery of 143 species with no previous record for Denmark. Comparison between plant OTUs detected in soil DNA and observed plant species confirmed the usefulness of carefully curated environmental DNA-data. Species richness did not correlate well among taxa suggesting differential and complex biotic responses to environmental variation.Conclusions We successfully and adequately sampled a wide range of mega-diverse taxa along key environmental gradients across a large region using an approach that includes multi-taxon biodiversity assessment and ecospace mapping. Our approach is applicable to assessments of biodiversity in other regions and biomes.