海平面上升和极端印度洋偶极子现象解释了马尔代夫红树林衰退的原因。

Sea-level rise and extreme Indian Ocean Dipole explain mangrove dieback in the Maldives.

作者信息

Carruthers Lucy, Ersek Vasile, Maher Damien, Sanders Christian, Tait Douglas, Soares Juliano, Floyd Matthew, Hashim Aminath Shaha, Helber Stephanie, Garnett Mark, East Holly, Johnson Jamie A, Ponta Gheorghe, Sippo James Z

机构信息

Department of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK.

Department of Coastal Studies, Coastal Studies Institute, East Carolina University, Wanchese, NC, 27981, USA.

出版信息

Sci Rep. 2024 Nov 12;14(1):27012. doi: 10.1038/s41598-024-73776-z.

DOI:10.1038/s41598-024-73776-z

PMID:39532894

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC11557579/

Abstract

Mangrove forests enhance Small Island Developing States' resilience to climate change, yet in 2020, a mangrove dieback impacted ~ 25% of mangrove-containing islands in the Maldives. Using remote sensing, dendrology and sediment geochemistry, we document a significant decrease in mangrove health post-2020 (NDVI: 0.75 ± 0.09) compared to pre-2020 (0.85 ± 0.04; P < 0.0001). Dead trees showed reduced stomatal conductance (δC: - 26.21 ± 0.11 ‰) relative to living ones (- 27.66 ± 0.14 ‰), indicating salinity stress. Critically, sea-level rise (30.50 ± 23.30 mm/year) outpaced mangrove sediment accretion (6.40 ± 0.69 mm/year) five-fold between 2017 and 2020. We attribute this dieback to salinity stress driven by record-high sea levels in 2020, linked to an extreme positive Indian Ocean Dipole event. These findings reveal the vulnerability of mangrove ecosystems to rapid sea-level rise and highlights the urgent need for adaptive conservation strategies in Small Island Developing States.

摘要

红树林增强了小岛屿发展中国家对气候变化的适应能力，然而在2020年，一次红树林衰退影响了马尔代夫约25%的有红树林的岛屿。利用遥感、树木学和沉积物地球化学方法，我们记录到2020年后红树林健康状况显著下降（归一化植被指数：0.75±0.09），相比2020年前（0.85±0.04；P<0.0001）。与活树相比，死树的气孔导度降低（δC：-26.21±0.11‰），而活树为（-27.66±0.14‰），这表明存在盐度胁迫。关键的是，在2017年至2020年期间，海平面上升速度（30.50±23.30毫米/年）比红树林沉积物堆积速度（6.40±0.69毫米/年）快了五倍。我们将这次衰退归因于2020年创纪录的高海平面引发的盐度胁迫，这与一次极端的正印度洋偶极事件有关。这些发现揭示了红树林生态系统对海平面快速上升的脆弱性，并凸显了小岛屿发展中国家迫切需要采取适应性保护策略。