Cohen Marcelo C L, Ruiz Diana Paola Cardenas, Rodrigues Erika, Yao Qiang, de Souza Adriana V, Liu Kam-Biu, Pessenda Luiz C R, Aragón-Moreno Alejandro Antonio, Ryu Junghyung, Nunes Sérgio
Laboratory of Coastal Dynamics, Graduate Program of Geology and Geochemistry, Federal University of Pará, Brazil Federal University of Pará, Rua Augusto Corrêa, 01 - Guamá, 66075-110, Belém, PA, Brazil; Department of Oceanography and Coastal Sciences and Coastal Studies Institute, Louisiana State University, Baton Rouge, LA 70803, USA.
Laboratory of Coastal Dynamics, Graduate Program of Geology and Geochemistry, Federal University of Pará, Brazil Federal University of Pará, Rua Augusto Corrêa, 01 - Guamá, 66075-110, Belém, PA, Brazil.
Sci Total Environ. 2024 Dec 15;956:177345. doi: 10.1016/j.scitotenv.2024.177345. Epub 2024 Nov 7.
Hurricanes are considered some of the most devastating weather phenomena, causing deaths and destruction along the coast. Mangroves are perceived as natural defenses against coastal hazards. However, mangrove gaps, known as mangrove dieback, have occurred in southwestern Florida. This study implemented a spatial-temporal analysis based on satellite, lidar and unmanned aerial vehicle (UAV) images collected along the southwestern Florida coast between Tampa and Naples from 1994 to 2020 CE, and multi-proxy analyses on sediment cores sampled from two mangrove dieback sites to determine the cause(s) of mangrove death and the implications for the sustainability of these forests. The data indicated that out of the 86 identified dieback, 78 % arose between 2004 and 2017 CE, when one tropical storm and three hurricanes made landfall on the studied coast, suggesting hurricanes as the main driver for this mangrove degradation. Multi-proxy analysis indicated mangrove expansion since ∼600 cal yr BP due to relative sea-level (RSL) rise. However, hurricanes caused losses in the mangrove area between 1930 and 1950 CE, and during the last two decades in the studied sites. Ground topographic data and aerophotogrammetry revealed circular dieback with permanent ponds (∼30 cm depth) inhibiting mangrove recovery. The mangrove death occurred in <3 years, with a gradual dieback expansion due to positive feedback involving physicochemical processes in the sediments. In addition, recent hurricanes increased pre-existing dieback areas. Therefore, dieback sites are vulnerability hotspots for mangroves in the face of projected RSL rise and higher frequency of intense hurricane strikes. Mangrove dieback should be monitored on a temporal (seasonal - annual) and spatial (cm-m) resolution only possible through the combination of satellite and UAV data. Integrating remote sensing and stratigraphic analysis enabled us to identify mangrove diebacks on a decadal to centennial timescale, improving our comprehension of how catastrophic weather events affect these forests.
飓风被认为是最具破坏性的天气现象之一，会在沿海地区造成人员伤亡和破坏。红树林被视为抵御沿海灾害的天然屏障。然而，在佛罗里达州西南部出现了红树林缺口，即红树林衰退现象。本研究基于1994年至2020年在佛罗里达州西南部坦帕和那不勒斯之间海岸收集的卫星、激光雷达和无人机（UAV）图像进行了时空分析，并对从两个红树林衰退地点采集的沉积物岩芯进行了多指标分析，以确定红树林死亡的原因及其对这些森林可持续性的影响。数据表明，在86个已确定的衰退区域中，78%出现在2004年至2017年期间，当时一场热带风暴和三场飓风在研究海岸登陆，这表明飓风是导致这种红树林退化的主要驱动因素。多指标分析表明，由于相对海平面（RSL）上升，自约公元600年以来红树林一直在扩张。然而，在公元1930年至1950年期间以及研究地点的过去二十年中，飓风导致了红树林面积的减少。地面地形数据和航空摄影测量显示，有圆形衰退区域伴有永久性池塘（深度约30厘米），阻碍了红树林的恢复。红树林死亡发生在不到3年的时间内，由于沉积物中物理化学过程的正反馈，衰退区域逐渐扩大。此外，近期的飓风增加了先前已有的衰退区域。因此，面对预计的RSL上升和更频繁的强烈飓风袭击，衰退地点是红树林的脆弱热点地区。红树林衰退应仅通过卫星和无人机数据的结合，以时间（季节 - 年度）和空间（厘米-米）分辨率进行监测。整合遥感和地层分析使我们能够在十年到百年的时间尺度上识别红树林衰退，提高了我们对灾难性天气事件如何影响这些森林的理解。
