Aim: Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and in terms of responses to climate change. We quantified global patterns of tree palm relative abundance to help improve understanding of tropical forests and reduce uncertainty about these ecosystems under climate change. Location: Tropical and subtropical moist forests. Time period: Current. Major taxa studied: Palms (Arecaceae). Methods: We assembled a pantropical dataset of 2,548 forest plots (covering 1,191 ha) and quantified tree palm (i.e., ≥10 cm diameter at breast height) abundance relative to co-occurring non-palm trees. We compared the relative abundance of tree palms across biogeographical realms and tested for associations with palaeoclimate stability, current climate, edaphic conditions and metrics of forest structure. Results: On average, the relative abundance of tree palms was more than five times larger between Neotropical locations and other biogeographical realms. Tree palms were absent in most locations outside the Neotropics but present in >80% of Neotropical locations. The relative abundance of tree palms was more strongly associated with local conditions (e.g., higher mean annual precipitation, lower soil fertility, shallower water table and lower plot mean wood density) than metrics of long-term climate stability. Life-form diversity also influenced the patterns; palm assemblages outside the Neotropics comprise many non-tree (e.g., climbing) palms. Finally, we show that tree palms can influence estimates of above-ground biomass, but the magnitude and direction of the effect require additional work. Conclusions: Tree palms are not only quintessentially tropical, but they are also overwhelmingly Neotropical. Future work to understand the contributions of tree palms to biomass estimates and carbon cycling will be particularly crucial in Neotropical forests.

中文翻译：

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全球丰富的棕榈树

目标：棕榈树是热带生态系统中标志性的、多样的且通常丰富的组成部分，可提供许多生态系统服务。作为单子叶植物，棕榈树在进化上、形态上和生理上都与其他树木不同，这些差异对生态系统服务（例如碳固存和储存）以及对气候变化的响应具有重要影响。我们量化了棕榈树相对丰度的全球模式，以帮助提高对热带森林的了解并减少气候变化下这些生态系统的不确定性。位置：热带和亚热带湿润森林。时间段：当前。研究的主要分类群：棕榈科（Arecaceae）。方法：我们组装了一个包含 2,548 个森林地块（占地 1,191 公顷）和量化的棕榈树（即，≥ 10 cm 的胸高直径）相对于同时出现的非棕榈树的丰度。我们比较了生物地理领域中棕榈树的相对丰度，并测试了与古气候稳定性、当前气候、土壤条件和森林结构指标的关联。结果：平均而言，新热带地区和其他生物地理领域之间的棕榈树相对丰度高出五倍以上。新热带地区以外的大多数地区没有棕榈树，但在新热带地区的 80% 以上存在。与长期气候稳定性指标相比，棕榈树的相对丰度与当地条件（例如，更高的年平均降水量、更低的土壤肥力、更浅的地下水位和更低的地块平均木材密度）更密切相关。生命形式的多样性也影响了模式；新热带以外的棕榈组合包括许多非树（例如攀缘）棕榈。最后，我们表明棕榈树可以影响地上生物量的估计，但影响的大小和方向需要额外的工作。结论： 棕榈树不仅是典型的热带植物，而且绝大多数是新热带植物。了解棕榈树对生物量估算和碳循环的贡献的未来工作将在新热带森林中尤为重要。