State Key Laboratory of Biocontrol, Guangdong Key Lab of Plant Resources, Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education Institutes, School of Life Science, Sun Yat-Sen University, Guangzhou, Guangdong, China.
Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment & Ecology, Xiamen University, Xiamen, Fujian, China.
Glob Chang Biol. 2018 Apr;24(4):1741-1748. doi: 10.1111/gcb.13968. Epub 2017 Nov 28.
The projected increases in sea levels are expected to affect coastal ecosystems. Tropical communities, anchored by mangrove trees and having experienced frequent past sea level changes, appear to be vibrant at present. However, any optimism about the resilience of these ecosystems is premature because the impact of past climate events may not be reflected in the current abundance. To assess the impact of historical sea level changes, we conducted an extensive genetic diversity survey on the Indo-Malayan coast, a hotspot with a large global mangrove distribution. A survey of 26 populations in six species reveals extremely low genome-wide nucleotide diversity and hence very small effective population sizes (N ) in all populations. Whole-genome sequencing of three mangrove species further shows the decline in N to be strongly associated with the speed of past changes in sea level. We also used a recent series of flooding events in Yalong Bay, southern China, to test the robustness of mangroves to sea level changes in relation to their genetic diversity. The events resulted in the death of half of the mangrove trees in this area. Significantly, less genetically diverse mangrove species suffered much greater destruction. The dieback was accompanied by a drastic reduction in local invertebrate biodiversity. We thus predict that tropical coastal communities will be seriously endangered as the global sea level rises. Well-planned coastal development near mangrove forests will be essential to avert this crisis.
预计海平面的上升将影响沿海生态系统。以红树林为基础、经历过频繁海平面变化的热带社区目前似乎很有活力。然而，对这些生态系统的恢复力持乐观态度还为时过早，因为过去气候事件的影响可能不会反映在当前的丰度上。为了评估历史海平面变化的影响，我们对印度-马来亚海岸进行了广泛的遗传多样性调查，该地区是一个拥有大量全球红树林分布的热点地区。对六个物种的 26 个种群的调查显示，所有种群的全基因组核苷酸多样性极低，因此有效种群大小 (N) 非常小。对三种红树林物种的全基因组测序进一步表明，N 的下降与过去海平面变化的速度密切相关。我们还利用中国南部亚龙湾最近发生的一系列洪水事件，测试了红树林对海平面变化的适应能力与其遗传多样性之间的关系。这些事件导致该地区一半的红树林死亡。值得注意的是，遗传多样性较少的红树林物种遭受了更大的破坏。这种衰退伴随着当地无脊椎动物生物多样性的急剧减少。因此，我们预测随着全球海平面上升，热带沿海社区将面临严重威胁。在红树林附近进行有计划的沿海开发对于避免这场危机至关重要。
