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 sampling design for environmental and biotic mapping. We selected 130 study sites (40 × 40 m) 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. 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 nationally 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. Correlations among species richness for taxonomic groups were predominantly positive, but did not correlate well among all taxa suggesting differential and complex biotic responses to environmental variation. We successfully and adequately sampled a wide range of diverse taxa along key environmental gradients across Denmark 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 where species are structured along environmental gradient.

中文翻译：

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区域多类生物多样性的系统调查：评估策略和覆盖范围

鉴于生物多样性危机以及我们解释生物多样性变化的能力有限，因此迫切需要用于量化生物多样性及其潜在驱动因素的时空变化的工具。受最近发布的生态空间框架的启发，我们开发并测试了用于环境和生物制图的采样设计。我们采用分层随机抽样方法，沿着生物多样性背后的主要环境梯度，选择了丹麦的130个研究地点（40×40 m）。使用标准化方法，我们收集了维管植物，苔藓植物，大型真菌，地衣，腹足动物和节肢动物的站点物种数据。为了评估采样效率，我们计算了区域覆盖率（相对于每个分类组的已知物种数）和站点规模覆盖范围（即，每个站点上每个分类组的样本完整性）。为了将分类学范围扩展到传统清单难以采样的生物（例如，线虫和非结实真菌），我们收集了土壤以进行条码编码。最后，为了评估场地条件，我们绘制了非生物条件，生物资源和栖息地的连续性图。尽管有130个研究地点仅占丹麦陆地总面积的一小部分（0.0005％），但我们发现了1774种大型真菌（占丹麦真菌物种库的54％），663种维管植物物种（占42％），254种苔藓植物物种（41％）和200种地衣（19％）。对于节肢动物，我们观察到330种蜘蛛（58％），123种甲壳虫（37％）和99种蚜蝇（33％）。总体而言，整个分类学类别的样本覆盖率非常高，足以捕获整个丹麦生物多样性的实质性空间变化。该清单的详细信息在全国范围内是前所未有的，并导致发现了143种，而丹麦以前没有任何记录。在土壤DNA中检测到的植物OTU与观察到的植物物种之间的比较证实了精心挑选的环境DNA数据的有用性。生物分类群物种丰富度之间的相关性主要是正相关的，但在所有分类群之间的相关性不强，这表明对环境变化的生物反应具有差异性和复杂性。我们使用包括多分类群生物多样性评估和生态空间作图的方法，成功地和充分地采样了整个丹麦主要环境梯度上的多种多样的分类群。我们的方法适用于评估其他物种沿环境梯度构造的区域和生物群落中的生物多样性。