Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN 47907.
Department of Biological, Geological, and Environmental Sciences, Alma Mater Studiorum University of Bologna, Bologna 40126, Italy.
Proc Natl Acad Sci U S A. 2022 Feb 8;119(6). doi: 10.1073/pnas.2115329119.
One of the most fundamental questions in ecology is how many species inhabit the Earth. However, due to massive logistical and financial challenges and taxonomic difficulties connected to the species concept definition, the global numbers of species, including those of important and well-studied life forms such as trees, still remain largely unknown. Here, based on global ground-sourced data, we estimate the total tree species richness at global, continental, and biome levels. Our results indicate that there are ∼73,000 tree species globally, among which ∼9,000 tree species are yet to be discovered. Roughly 40% of undiscovered tree species are in South America. Moreover, almost one-third of all tree species to be discovered may be rare, with very low populations and limited spatial distribution (likely in remote tropical lowlands and mountains). These findings highlight the vulnerability of global forest biodiversity to anthropogenic changes in land use and climate, which disproportionately threaten rare species and thus, global tree richness.
生态学中最基本的问题之一是地球上有多少物种。然而，由于物种概念定义方面存在大规模的后勤和财务挑战以及分类学困难，包括树木等重要且研究充分的生命形式在内的全球物种数量在很大程度上仍然未知。在这里，我们基于全球地面源数据，估算了全球、大陆和生物群落层面的树种丰富度。研究结果表明，全球约有 73000 种树木，其中约有 9000 种有待发现。在尚未发现的树种中，约有 40%分布在南美洲。此外，预计将发现的所有树种中，近三分之一可能较为罕见，种群数量极低，空间分布有限（可能在偏远的热带低地和山区）。这些发现突出表明，全球森林生物多样性容易受到土地利用和气候变化的人为影响，而这些变化不成比例地威胁着稀有物种，从而威胁到全球树木的丰富度。
