University of Kansas, Lawrence, USA.
University of Gottingen, Göttingen, Germany.
Commun Biol. 2021 Sep 24;4(1):1128. doi: 10.1038/s42003-021-02649-2.
Plant colonization of islands may be limited by the availability of symbionts, particularly arbuscular mycorrhizal (AM) fungi, which have limited dispersal ability compared to ectomycorrhizal and ericoid (EEM) as well as orchid mycorrhizal (ORC) fungi. We tested for such differential island colonization within contemporary angiosperm floras worldwide. We found evidence that AM plants experience a stronger mycorrhizal filter than other mycorrhizal or non-mycorrhizal (NM) plant species, with decreased proportions of native AM plant species on islands relative to mainlands. This effect intensified with island isolation, particularly for non-endemic plant species. The proportion of endemic AM plant species increased with island isolation, consistent with diversification filling niches left open by the mycorrhizal filter. We further found evidence of humans overcoming the initial mycorrhizal filter. Naturalized floras showed higher proportions of AM plant species than native floras, a pattern that increased with increasing isolation and land-use intensity. This work provides evidence that mycorrhizal fungal symbionts shape plant colonization of islands and subsequent diversification.
岛屿上的植物定植可能受到共生体（特别是丛枝菌根真菌）可利用性的限制，与外生菌根和杜鹃花菌根以及兰科菌根真菌相比，丛枝菌根真菌的扩散能力有限。我们在全球范围内测试了这种在当代被子植物区系内的不同岛屿定植情况。我们发现，与其他菌根或非菌根（NM）植物物种相比，AM 植物经历了更强的菌根过滤，岛屿上的本地 AM 植物物种比例相对于大陆减少。这种影响随着岛屿的隔离而加剧，特别是对于非特有植物物种。与岛屿隔离相一致的是，内生 AM 植物物种的比例随着岛屿隔离而增加，这与通过菌根过滤留下的生态位多样化相一致。我们进一步发现了人类克服初始菌根过滤的证据。归化植物区系的 AM 植物物种比例高于本地植物区系，这种模式随着隔离度和土地利用强度的增加而增加。这项工作提供了证据表明，菌根真菌共生体塑造了岛屿上的植物定植和随后的多样化。
