Smithsonian Marine Station, 701 Seaway Drive, Fort Pierce, FL, 34949, USA.
Working Land and Seascapes, Smithsonian Institution, Washington, DC, 20013, USA.
Sci Rep. 2022 Feb 1;12(1):1695. doi: 10.1038/s41598-022-05847-y.
Mangroves form coastal tropical forests in the intertidal zone and are an important component of shoreline protection. In comparison to other tropical forests, mangrove stands are thought to have relatively low genetic diversity with population genetic structure gradually increasing with distance along a coastline. We conducted genetic analyses of mangrove forests across a range of spatial scales; within a 400 m parcel comprising 181 Rhizophora mangle (red mangrove) trees, and across four sites ranging from 6-115 km apart in Honduras. In total, we successfully genotyped 269 R. mangle trees, using a panel of 677 SNPs developed with 2b-RAD methodology. Within the 400 m parcel, we found two distinct clusters with high levels of genetic differentiation (F = 0.355), corresponding to trees primarily located on the seaward fringe and trees growing deeper into the forest. In contrast, there was limited genetic differentiation (F = 0.027-0.105) across the sites at a larger scale, which had been predominantly sampled along the seaward fringe. Within the 400 m parcel, the cluster closest to the seaward fringe exhibited low genetic differentiation (F = 0.014-0.043) with the other Honduran sites, but the cluster further into the forest was highly differentiated from them (F = 0.326-0.414). These findings contradict the perception that genetic structure within mangroves forests occurs mainly along a coastline and highlights that there is greater genetic structure at fine spatial scales.
红树林形成于潮间带的热带沿海森林，是海岸线保护的重要组成部分。与其他热带森林相比，红树林的遗传多样性相对较低，种群遗传结构随着沿海岸线的距离逐渐增加。我们在不同的空间尺度上对红树林进行了遗传分析；在一个 400 米的地块内包含 181 棵红树（Rhizophora mangle），以及在洪都拉斯四个相距 6-115 公里的地点进行了遗传分析。总共，我们使用 2b-RAD 方法开发的 677 个 SNP 面板成功地对 269 棵红树进行了基因分型。在 400 米的地块内，我们发现了两个具有高度遗传分化的不同集群（F = 0.355），对应于主要位于向海缘和深入森林内部的树木。相比之下，在更大的尺度上，在四个地点之间的遗传分化有限（F = 0.027-0.105），这些地点主要沿着向海缘进行采样。在 400 米的地块内，最靠近向海缘的集群与其他洪都拉斯地点的遗传分化较低（F = 0.014-0.043），但更深入森林的集群与它们的遗传分化很高（F = 0.326-0.414）。这些发现与红树林遗传结构主要沿着海岸线发生的观点相矛盾，强调了在精细的空间尺度上存在更大的遗传结构。
