Department of Geography, National University of Singapore, Singapore.
Forestry and Wood Technology Discipline, Khulna University, Khulna 9208, Bangladesh.
Sci Total Environ. 2024 May 20;926:171690. doi: 10.1016/j.scitotenv.2024.171690. Epub 2024 Mar 19.
Mangrove shoreline retreat or advance is a natural process in a mangrove delta. However, due to various natural and anthropogenic stressors, mangrove shoreline retreat is the second largest cause of mangrove loss globally. It is important to understand the scale at which mangrove shoreline changes are causing biophysical changes along the mangrove shorelines and, in turn, understand if certain biophysical characteristics can explain the changes along the shoreline. This will help identify the response of mangroves to shoreline changes. Videography and spatial mapping were used to study temporarily and permanently changing mangrove shorelines in the Sundarbans, the largest mangrove forest in the world (~10,000 km), located in India and Bangladesh. Data was collected along a ~ 239 km shoreline at 54 sites. 36.4 % of all the studied shorelines were experiencing major retreat, 63.8 % and 27.2 % of all (major and minor) retreating areas had 1-25 % and > 25 % dead trees. The biophysical characteristics statistically (P < 0.0001) associated with retreating mangrove shorelines were - cliff-type shoreline profiles, number of dead trees, and absence of stream and grass, with shoreline profiles as the strongest predictor of shoreline retreat. Moreover, 68.7 % and 73 % of historically retreating shorelines had a cliff-type shoreline profile and Excoecaria agallocha as the dominating species, respectively. Moreover, due to the strong correlation between historical changes and current shoreline types, it was concluded that characteristics along the shoreline are partly a product of historical shoreline transitions. Thus, the present status of the shoreline can not only predict the history of the shoreline but can also give insights into the future biophysical changes in the mangrove forests.
红树林海岸线的后退或前进是红树林三角洲的自然过程。然而，由于各种自然和人为压力，红树林海岸线后退是全球红树林损失的第二大原因。了解红树林海岸线变化在多大程度上导致红树林海岸线沿线的生物物理变化，并进而了解某些生物物理特征是否可以解释海岸线沿线的变化，这一点很重要。这将有助于确定红树林对海岸线变化的反应。录像和空间测绘被用于研究位于印度和孟加拉国的世界上最大的红树林森林——孙德尔本斯（Sundarbans）中暂时和永久变化的红树林海岸线。在 54 个地点沿着约 239 公里的海岸线收集了数据。在所研究的所有海岸线中，有 36.4%经历了主要后退，在所有（主要和次要）后退区域中，有 63.8%和 27.2%分别有 1-25%和>25%的死树。统计上与后退的红树林海岸线相关的生物物理特征是 - 悬崖型海岸线剖面、死树数量和没有溪流和草，其中海岸线剖面是海岸线后退的最强预测因子。此外，68.7%和 73%的历史上后退的海岸线分别具有悬崖型海岸线剖面和海漆（Excoecaria agallocha）作为主导物种。此外，由于历史变化和当前海岸线类型之间存在很强的相关性，可以得出结论，沿海岸线的特征部分是历史海岸线转变的产物。因此，目前的海岸线状况不仅可以预测海岸线的历史，还可以深入了解红树林的未来生物物理变化。
