The Darwinian shortfall, i.e. the lack of knowledge of phylogenetic relationships, significantly impedes our understanding of evolutionary drivers of global patterns of biodiversity. Spatial bias in the Darwinian shortfall, where phylogenetic knowledge in some regions is more complete than others, could undermine eco- and biogeographic inferences. Yet, spatial biases in phylogenetic knowledge for major groups – such as plants – remain poorly understood. Using data for 337 023 species (99.7%) of seed plants (Spermatophyta), we produced a global map of phylogenetic knowledge based on regional data and tested several potential drivers of the observed spatial variation. Regional phylogenetic knowledge was defined as the proportion of the regional seed plant flora represented in GenBank's nucleotide database with phylogenetically relevant data. We used simultaneous autoregressive models to explain variation in phylogenetic knowledge based on three biodiversity variables (species richness, range size and endemism) and six socioeconomic variables representing funding and accessibility. We compared observed patterns and relationships to established patterns of the Wallacean shortfall (the lack of knowledge of species distributions). We found that the Darwinian shortfall is strongly and significantly related to the macroecological distribution of species' range sizes. Small-ranged species were significantly less likely to have phylogenetic data, leading to a concentration of the Darwinian shortfall in species-rich, tropical countries where range sizes are small on average. Socioeconomic factors were less important, with significant but quantitatively small effects of accessibility and funding. In conclusion, reducing the Darwinian shortfall and smoothen its spatial bias will require increased efforts to sequence the world's small-ranged (endemic) species.

中文翻译：

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植物的达尔文缺陷：系统发育知识由范围大小驱动

达尔文的不足，即缺乏系统发育关系的知识，极大地阻碍了我们对全球生物多样性模式的进化驱动因素的理解。达尔文短缺的空间偏差，其中某些地区的系统发育知识比其他地区更完整，可能会破坏生态和生物地理学推论。然而，对于植物等主要群体的系统发育知识的空间偏差仍然知之甚少。我们使用 337 023 种 (99.7%) 种子植物 (Spermatophyta) 的数据，根据区域数据制作了全球系统发育知识图谱，并测试了观察到的空间变化的几个潜在驱动因素。区域系统发育知识被定义为区域种子植物区系在 GenBank 核苷酸数据库中与系统发育相关数据的比例。我们使用同步自回归模型来解释基于三个生物多样性变量（物种丰富度、范围大小和特有性）和代表资金和可及性的六个社会经济变量的系统发育知识的变化。我们将观察到的模式和关系与华莱士短缺的既定模式（缺乏物种分布知识）进行了比较。我们发现达尔文的短缺与物种范围大小的宏观生态分布密切相关。小范围的物种拥有系统发育数据的可能性要小得多，导致达尔文的短缺集中在物种丰富的热带国家，这些国家的范围平均较小。社会经济因素不太重要，可及性和资金的显着但数量上很小的影响。总之，减少达尔文的短缺并消除其空间偏差将需要加大努力对世界小范围（地方性）物种进行测序。