Investigating Patterns of Commonness in Tropical Forest Tree Communities

热带森林在全球碳和水循环中发挥着关键作用，影响着全球气候，储存着世界上大部分的陆地生物多样性，并支持着数百万人的生活。大量的树种给理解这些森林带来了巨大的挑战，因为人们对大多数热带树种知之甚少。然而，如果大多数物种是稀有的，而相对较少的树种是常见的，就像在亚马逊森林中看到的那样，专注于共同的物种可能会绕过这一挑战。为此，我分析了亚马逊、非洲和东南亚封闭树冠结构完好的古老热带森林的物种丰度数据，综合数据集包括1,003,805棵树。我估计，在非洲、亚马逊和东南亚的封闭树冠热带森林中，50%的个体树木分别只占每个大陆物种总数的2.2%、2.2%和2.3%。推算所有封闭树冠的热带森林的结果，我估计只有1053个物种构成了地球上8000亿棵直径大于或等于10厘米的热带森林树木的一半。总体而言，尽管生物地理、气候和人类历史不同，但我发现各大洲的物种数量模式惊人地一致。这种一致性表明，乔木群落聚集的基本规则适用于所有热带森林。重新采样分析表明，最常见的物种得到了可靠的识别，从而使有针对性的努力能够了解它们的生态。这些结果为了解世界上最多样化的森林提供了新的机会，通过关注构成其树木大部分的共同物种。

Tropical forests play critical roles in the global carbon and water cycles, affect global climate, store the majority of the world's terrestrial biodiversity, and support the lives of millions. The vast number of tree species presents a formidable challenge to understanding these forests, as very little is known about most tropical tree species. However, if the majority of species are rare and a relatively small number of tree species are common, as seen in Amazonian forests, a focus on the common species may circumvent this challenge. To this end, I analyse species abundance data from networks of inventory plots from closed-canopy structurally intact old-growth tropical forests in Amazonia, Africa, and Southeast Asia, the combined dataset including 1,003,805, trees. I estimate that 50% of individual trees in the closed-canopy tropical forests of Africa, Amazonia, and southeast Asia comprise just 2.2%, 2.2%, and 2.3% of the total number of species on each continent respectively. Extrapolating the results across all closed-canopy tropical forests, I estimate that just 1,053 species comprise half of Earth's 800 billion tropical forest trees greater than or equal to 10 cm diameter. Overall, despite differing biogeographic, climatic, and anthropogenic histories, I find strikingly consistent species-abundance patterns across the continents. This consistency suggests that fundamental rules of tree community assembly apply to all tropical forests. Resampling analyses show that the most common species are reliably recognised, allowing targeted efforts to understand their ecology. These results open new opportunities to understand the world's most diverse forests by focusing on the common species that comprise the majority of their trees.