Australian Institute of Marine Science, UWA Oceans Institute, Crawley, WA 6009, Australia.
School of Mathematical Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, QLD 4001, Australia.
Curr Biol. 2015 Feb 16;25(4):500-5. doi: 10.1016/j.cub.2014.12.022. Epub 2015 Jan 29.
Global species richness, whether estimated by taxon, habitat, or ecosystem, is a key biodiversity metric. Yet, despite the global importance of biodiversity and increasing threats to it (e.g., we are no better able to estimate global species richness now than we were six decades ago. Estimates of global species richness remain highly uncertain and are often logically inconsistent. They are also difficult to validate because estimation of global species richness requires extrapolation beyond the number of species known. Given that somewhere between 3% and >96% of species on Earth may remain undiscovered, depending on the methods used and the taxa considered, such extrapolations, especially from small percentages of known species, are likely to be highly uncertain. An alternative approach is to estimate all species, the known and unknown, directly. Using expert taxonomic knowledge of the species already described and named, those already discovered but not yet described and named, and those still awaiting discovery, we estimate there to be 830,000 (95% credible limits: 550,000-1,330,000) multi-cellular species on coral reefs worldwide, excluding fungi. Uncertainty surrounding this estimate and its components were often strongly skewed toward larger values, indicating that many more species on coral reefs is more plausible than many fewer. The uncertainties revealed here should guide future research toward achieving convergence in global species richness estimates for coral reefs and other ecosystems via adaptive learning protocols whereby such estimates can be tested and improved, and their uncertainties reduced, as new knowledge is acquired.
全球物种丰富度，无论是按分类群、栖息地还是生态系统来估计，都是一个关键的生物多样性指标。然而，尽管生物多样性具有全球重要性，并且对其的威胁日益增加（例如，我们现在估计全球物种丰富度的能力并不比六十年前强。全球物种丰富度的估计仍然高度不确定，而且往往在逻辑上不一致。它们也很难验证，因为估计全球物种丰富度需要超出已知物种的数量进行推断。鉴于根据所使用的方法和考虑的分类群，地球上可能有 3%到>96%的物种仍然未被发现，因此这种推断，尤其是从已知物种的小百分比推断，很可能是高度不确定的。另一种方法是直接估计所有物种，包括已知和未知的物种。利用已描述和命名的物种的专家分类学知识、已发现但尚未描述和命名的物种以及仍有待发现的物种，我们估计全球珊瑚礁上有 83 万（95%可信区间：55 万-133 万）种多细胞物种，不包括真菌。围绕这个估计及其组成部分的不确定性往往强烈偏向于较大的值，表明珊瑚礁上的物种比许多人想象的要多得多。这里揭示的不确定性应该指导未来的研究，通过适应性学习协议实现珊瑚礁和其他生态系统的全球物种丰富度估计的收敛，通过这种协议可以测试和改进这些估计，并随着新知识的获取降低其不确定性。
