Community assembly of island plants is a central topic in island biogeography. Most previous studies have focused on seed plants, while our understanding of bryophytes is limited. Specifically, how dispersal limitation and habitat heterogeneity shape beta diversity of bryophyte communities on islands remains unknown. We used two datasets of bryophyte communities from an artificial (~60 yr of isolation) and natural archipelago (~8500 yr of isolation) to understand their beta diversity patterns. The null model, in which species could disperse randomly and colonize successfully between islands, but the number of species on each island and the frequency of each species occurrence across all islands remain unchanged, was used to calculate expected beta diversity. Although we found significant differences in species composition between the two archipelagos, the difference in observed beta diversity was negligible. Further, there was no significant difference between observed and expected beta diversity in each archipelago. The difference in island area, rather than isolation, was significantly correlated with the beta diversity of bryophytes in both archipelagos. Our results suggest that the dispersal limitation is not the major ecological process driving the assembly of bryophyte communities in both archipelagos, but the habitat heterogeneity related to island area determines the beta diversity of bryophytes.

中文翻译：

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类似的机制是两个群岛中不同隔离时间的苔藓植物的β多样性的基础

岛屿植物的社区聚集是岛屿生物地理学的中心主题。以前的大多数研究都集中在种子植物上，而我们对苔藓植物的理解是有限的。具体来说，尚不清楚岛上的苔藓植物群落的扩散限制和生境异质性如何影响β多样性。我们使用了人工（约60年隔离）和天然群岛（约8500年隔离）的苔藓植物群落的两个数据集来了解它们的β多样性模式。使用零模型，在该模型中，物种可以随机分散并成功在各岛之间定居，但是每个岛上的物种数量和所有物种在所有岛屿上的出现频率均保持不变，用于计算预期的β多样性。尽管我们发现两个群岛之间的物种组成存在显着差异，但观察到的β多样性差异却可以忽略不计。此外，在每个群岛中，观察到的β多样性与预期的β多样性之间没有显着差异。岛屿面积的差异而不是孤立，与两个群岛的苔藓植物的β多样性显着相关。我们的研究结果表明，扩散限制不是驱动两个群岛中苔藓植物群落聚集的主要生态过程，但是与岛屿面积有关的栖息地异质性决定了苔藓植物的β多样性。岛屿面积的差异而不是孤立，与两个群岛的苔藓植物的β多样性显着相关。我们的研究结果表明，扩散限制不是驱动两个群岛中苔藓植物群落聚集的主要生态过程，但是与岛屿面积有关的栖息地异质性决定了苔藓植物的β多样性。岛屿面积的差异而不是孤立，与两个群岛的苔藓植物的β多样性显着相关。我们的研究结果表明，扩散限制不是驱动两个群岛中苔藓植物群落聚集的主要生态过程，但是与岛屿面积有关的栖息地异质性决定了苔藓植物的β多样性。