Acanthus ilicifolius is a widespread mangrove species in the Indo-West Pacific (IWP) with high ecological value. In this study, we analyzed the patterns of genetic variation in the species across its distribution range and assessed factors that may have influenced its genetic structure across the IWP using data from four chloroplast DNA fragments. Our results demonstrated high genetic diversity at the species level with little variation within populations, indicating restricted gene flow among A. ilicifolius populations. Strong genetic divergence was found between populations in the Indian Ocean and populations in the Pacific Ocean, likely due to the land barrier effect of the Malay Peninsula (or in the past, the Sundaland). Ecological niche modeling revealed no significant niche differentiation between the two groups, suggesting that ecological divergence was less responsible for the divergence of A. ilicifolius. Despite the ability for long-distance dispersal, genetic barriers identified within the Pacific Ocean suggested ocean currents to be a cryptic barrier for gene flow in this region. This study provides new insights into the historical population dynamics of mangrove species in the IWP region and is valuable for the long-term conservation of A. ilicifolius.

中文翻译：

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印度-西太平洋冬青红树林 Acanthus ilicifolius 的叶绿体 DNA 系统地理学

Acanthus ilicifolius 是印度-西太平洋 (IWP) 分布广泛的红树林物种，具有很高的生态价值。在这项研究中，我们分析了该物种在其分布范围内的遗传变异模式，并使用来自四个叶绿体 DNA 片段的数据评估了可能影响 IWP 中其遗传结构的因素。我们的结果表明，物种水平上的遗传多样性很高，种群内的变异很小，表明 A. ilicifolius 种群之间的基因流受到限制。在印度洋种群和太平洋种群之间发现了强烈的遗传差异，这可能是由于马来半岛（或过去的巽他大陆）的陆地屏障效应。生态位模型显示两组之间没有显着的生态位差异，表明生态差异对 A. ilicifolius 的差异负有较小的责任。尽管具有远距离传播的能力，但在太平洋内发现的遗传障碍表明洋流是该地区基因流动的一个神秘障碍。这项研究为 IWP 地区红树林物种的历史种群动态提供了新的见解，对 A. ilicifolius 的长期保护很有价值。