The insular nature and unique geographical set up of Andaman and Nicobar Islands has led to the evolution of variety of rare and distinct flora with high endemism. Despite several efforts to document the floristic richness of the islands, there are no efforts to understand the spatial patterns in the taxonomic and phylogenetic diversity, and thence to arrive at the biogeographic origin and evolutionary history of the vegetation of this Island archipelago. We used a fine scale spatial distribution and abundance data of woody plants documented from 841 grids along with their phylogenetic data and estimated metrics of taxonomic and phylogenetic similarity to identify taxonomically and phylogenetically distinct woody plant ‘phytoregions’ within Andaman and Nicobar Islands. We then arrived at the spatial patterns of the taxonomic richness and diversity and, of phylogenetic diversity across the entire Archipelago. We found that taxonomic richness and diversity of woody flora is high in Andaman and low in Nicobar Islands, whereas Nicobar Islands have a more phylogenetically diverse woody flora compared to Andaman. We identified three distinct woody plant ‘phytoregions’ within Andaman and Nicobar Islands. The three identified ‘phytoregions’ broadly match with the geographically isolated Island groups such as Andaman, Car Nicobar and Great Nicobar Islands; these ‘phytoregions’ also highlight the existence of two broadly distinct biogeographic zones of woody plants within the Islands. Our analysis provides new insights into the spatial patterns of diversity of woody flora in Andaman and Nicobar Islands. We show that (i) both taxonomic and evolutionary affinities identify distinct ‘phytoregions’ closely segregated across the geographic distribution of the major islands of the archipelago, and (ii) there are two distinct biogeographic zones, i.e. Andaman flora most closely allied with flora of South western Burma and Nicobar more related with the flora of Malayan peninsula and Sumatra.

中文翻译：

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印度安达曼和尼科巴群岛的木本植物分类和系统发育多样性的空间分布格局

安达曼和尼科巴群岛的岛屿性质和独特的地理环境，导致了具有高度流行性的稀有和独特植物群的进化。尽管为记录岛上的植物丰富性付出了许多努力，但没有做出任何努力来理解分类学和系统发育多样性中的空间格局，因此无法得出该岛群岛植被的生物地理起源和进化史。我们使用了从841格记录的木本植物的精细尺度空间分布和丰度数据，以及它们的系统发育数据以及分类学和系统相似性的估计指标，以识别在安达曼和尼科巴群岛内分类学和系统上不同的木本植物``植物区''。然后，我们得出了整个群岛上生物分类学丰富性和多样性以及系统发育多样性的空间格局。我们发现，安达曼群岛中木质植物区系的分类学丰富性和多样性较高，而尼科巴群岛则较低，而与安达曼市相比，尼科巴群岛的系统发育多样性更强。我们在安达曼和尼科巴群岛中确定了三个不同的木本植物“植物区”。三个确定的“植物区”与安达曼，尼古巴岛和大尼科巴群岛等地理上孤立的岛屿群体大致匹配；这些“植物区”也突显了群岛内木本植物两个明显不同的生物地理区域的存在。我们的分析为安达曼和尼科巴群岛的木质植物多样性的空间格局提供了新的见解。