Key Laboratory of Digital Earth Science, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, China; International Research Center of Big Data for Sustainable Development Goals, Beijing 100094, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Key Laboratory of Digital Earth Science, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, China; International Research Center of Big Data for Sustainable Development Goals, Beijing 100094, China.
Sci Total Environ. 2022 Oct 20;844:157075. doi: 10.1016/j.scitotenv.2022.157075. Epub 2022 Jun 30.
Mangroves are coastal vegetation with high ecological and economic value that are mainly distributed in tropical and subtropical intertidal zones. In the past, they have been degraded by extensive deforestation for agricultural and aquatic land. In recent years, mangroves have been protected and sustainably used through considerable measures of conservation, restoration and afforestation, but the health trends of mangroves during this process are not clear. To identify the mangrove health conditions and dynamics, we investigated the spatial-temporal trends of global mangroves using the Moderate Resolution Imaging Spectroradiometer (MODIS) normalized difference vegetation index (NDVI) dataset during 2000-2018. The results illustrated that 1) Asian mangroves had the highest NDVI values, especially in Southeast Asia (0.80), while the average NDVI of African mangroves was the lowest (0.67). NDVI values higher than 0.80 were mainly located in Southeast Asia and South America, which accounted for 24.0 % and 7.1 % of the global mangrove area, respectively. 2) Globally, the proportion of mangrove forests that increased significantly (23.6 %, p value < 0.05) was approximately twice as large as the significant decrease (10.7 %, p value < 0.05). Asia, where mangroves are widespread, accounts for nearly half of the world's significant increase (10.8 %) and decrease (4.6 %). Generally, the annual average NDVI for global mangroves exhibited a slow increasing trend from 2000 to 2018 (p value = 0.13). 3) The global mangrove NDVI showed a positive correlation with precipitation (R = 0.79, p value < 0.01) and temperature (R = 0.37, p value < 0.01), while it was inhibited by sea surface salinity (R = -0.45, p value < 0.01) on a scale of 1° of latitude. 4) The results of the overall growth trend of mangroves indicated that global mangrove conservation appeared to achieve initial success, but direct or potential factors, such as salinity stress, natural disasters, small-scale deforestation, construction of coastal facilities, and sea level rise, still threaten the survival of mangroves, leading to a decline in their health status. This study provides information on the health status of mangrove ecosystems and can assist in formulating subsequent conservation and management measures.
红树林是具有高生态和经济价值的沿海植被，主要分布在热带和亚热带潮间带。过去，由于农业和水产养殖用地的广泛砍伐，红树林遭到了破坏。近年来，通过大量的保护、恢复和造林措施，红树林得到了保护和可持续利用，但在此过程中红树林的健康趋势尚不清楚。为了确定红树林的健康状况和动态，我们利用 2000-2018 年期间中分辨率成像光谱仪（MODIS）归一化植被指数（NDVI）数据集，调查了全球红树林的时空变化趋势。结果表明：1）亚洲的红树林具有最高的 NDVI 值，特别是在东南亚（0.80），而非洲红树林的平均 NDVI 值最低（0.67）。高于 0.80 的 NDVI 值主要位于东南亚和南美洲，分别占全球红树林面积的 24.0%和 7.1%。2）全球范围内，显著增加（23.6%，p 值<0.05）的红树林比例大约是显著减少（10.7%，p 值<0.05）的两倍。亚洲是红树林分布广泛的地区，占全球显著增加（10.8%）和减少（4.6%）的近一半。总的来说，2000 年至 2018 年期间，全球红树林的年平均 NDVI 呈缓慢增加趋势（p 值=0.13）。3）全球红树林 NDVI 与降水（R=0.79，p 值<0.01）和温度（R=0.37，p 值<0.01）呈正相关，而与海表盐度（R=-0.45，p 值<0.01）呈负相关，相关范围为 1°纬度。4）红树林整体生长趋势的结果表明，全球红树林保护似乎取得了初步成功，但盐分胁迫、自然灾害、小规模砍伐、沿海设施建设和海平面上升等直接或潜在因素仍然威胁着红树林的生存，导致其健康状况下降。本研究提供了有关红树林生态系统健康状况的信息，有助于制定后续的保护和管理措施。
