Habitat quality drives the species-area relationship of plants and soil microbes in an ocean archipelago

While the positive species-area relationship on islands is frequently observed, the mechanisms underlying this pattern remain poorly studied. By analyzing insular community diversity across spatial scales and the soil properties within the islands, we were able to explore potential mechanisms leading to the island species-area relationship of plants, as well as associated soil bacteria and fungi, from a tropical archipelago. We found that both plant and soil microbial communities showed similar positive species-area relationships across scales and the greater taxonomic diversity on larger islands was mainly driven by the higher richness within samples. These patterns arose primarily due to shifting habitat quality with island area, rather than spatial processes generally attributed to species-area relationships. Specifically, for plants, changes in soil total phosphorus content with island area were most explanatory, while changes in soil pH appeared to play the most important role in s..., , , ReadMe for 'Habitat quality drives the species-area relationship of plants and microbes in an ocean archipelago'. Our dataset was collected from the Paracel archipelago (i.e., Xisha islands, 15°46′ N to 17°08′ N and 111°11′ E to 112°54′ E) in the South China Sea. The Paracel archipelago comprises many small oceanic islands primarily made from coral and sand (Ye et al., 1985; Gong et al., 1996). The vegetation on these islands consists mainly of shrubs and herbs, with dominant plant species including Scaevola taccada, Guettarda speciosa, Tournefortia argentea and Morinda citrifolia. Although there are ~30 islands in the Paracel archipelago, many of them are too small or lack vegetation to meet the requirements for field surveys. Thus, in April 2023, ten representative islands were selected with an area ranging from 2 to 40ha that were minimally disturbed by human activities. On each island, woody plants, together with soil bacteria and fungi, were sampled simultaneously. This readme f...尽管岛屿上的正物种-面积关系（species-area relationship）已被广泛观测，但支撑该格局的潜在机制仍有待深入探究。本研究以一处热带群岛为研究对象，通过分析不同空间尺度下的岛屿群落多样性及岛屿内部的土壤理化性质，探讨了该群岛植物、伴生土壤细菌与真菌的物种-面积关系的潜在形成机制。研究发现，植物与土壤微生物群落在各空间尺度下均呈现出相似的正物种-面积关系，大岛屿上更高的分类多样性主要由样方内更高的物种丰富度所驱动。上述格局主要源于随岛屿面积变化的生境质量改变，而非通常被归因于物种-面积关系的空间过程。具体而言，对于植物来说，土壤全磷含量随岛屿面积的变化最具解释力，而土壤pH值的变化似乎在……中发挥了最为关键的作用，，，《生境质量驱动海洋群岛植物与微生物的物种-面积关系》说明文档。 本数据集采集自南海的西沙群岛（Paracel archipelago，即Xisha Islands，15°46′N至17°08′N、111°11′E至112°54′E）。西沙群岛由众多以珊瑚与砂质为主要基质的小型海洋岛屿组成（Ye等，1985；Gong等，1996）。这些岛屿上的植被以灌木和草本为主，优势植物物种包括Scaevola taccada、Guettarda speciosa、Tournefortia argentea及Morinda citrifolia。 尽管西沙群岛约有30个岛屿，但其中多数面积过小或缺乏植被，无法满足野外调查的要求。因此，本研究于2023年4月选取了10个受人类活动干扰极小、面积介于2至40公顷的代表性岛屿。在每个岛屿上，同步开展了木本植物、土壤细菌与真菌的采样工作。 本说明文档……