摘要
江苏省自1982年开始引种互花米草以来,滨海盐沼植被景观格局发生了巨大变化,芦苇和互花米草面积不断增长,挤占了碱蓬生态位,破坏了生态系统平衡。滨海盐沼湿地是三大蓝碳生态系统之一,具有高固碳和缓解温室效应的生态功能。利用遥感云平台手段监测滨海盐沼植被时空动态变化规律,可为滨海盐沼湿地生态系统保护以及修复提供科学支撑。本文选取植被类型丰富的江苏沿海地区为研究区,基于Google Earth Engine(GEE)平台,选取2000-2020年的Landsat 5、Landsat 7、Landsat 8以及Sentinel-2影像,提出了一种湿地植被提取方法。首先,构建盐城盐沼湿地地表覆盖分类体系,选取样本点,计算特征指数,进行地物分类;然后,利用时间谐波分析法对盐沼植被归一化植被指数(NDVI)变化特征进行分析,确定三类盐沼植被的物候差异;最后,基于物候特征,利用随机森林(Random Forest,RF)分类法提取盐城滨海湿地盐沼植被地表覆盖信息。结果表明:(1)相较传统监测方法,本文所构建的滨海盐沼植被精细化提取方法能够对滨海盐沼植被进行有效细分和监测;(2)2000-2020年,芦苇和互花米草面积呈扩张趋势,碱蓬面积不断缩减;(3)盐城三种典型盐沼植被NDVI值呈现不同变化特征;(4)降水对盐沼植被生长的影响较为显著,气温对盐沼植被生长的直接影响较小。研究结果可为盐城盐沼湿地自然遗产保护以及湿地生态可持续发展提供科学支撑。
Since the introduction of Spartina alterniflora in Jiangsu Province in 1982,the landscape pattern of coastal saltmarsh vegetation has changed dramatically.The area of Phragmites australis and Spartina alterniflora has increased continuously,squeezing the niche of Suaeda salsa and leading to the destruction of ecosystem.Coastal saltmarsh wetland is one of the three blue carbon ecosystems,playing an important ecological role in sequestering carbon and neutralizing greenhouse gas emission.Remote sensing is used to monitor the temporal and spatial dynamic changes of coastal saltmarsh vegetation,providing scientific support for the protection and restoration of coastal saltmarsh wetland ecosystems.In this paper,Jiangsu coastal areas with rich vegetation types are selected as the study area.Based on the Landsat 5,7,8 and Sentinel-2 images from 2000 to 2020 selected on the Google Earth Engine(GEE)platform,a wetland vegetation extraction method is proposed.First of all,the classification system of Yancheng saltmarsh wetland surface coverage is constructed,followed by the selection of sample points,calculation of characteristic indexes,and classification of surface features;Then,the time harmonic analysis method is used to analyze the change characteristics of normalized vegetation index(NDVI)of saltmarsh vegetation,and determine the phenological differences of the three types of saltmarsh vegetation;Finally,based on the phenological characteristics,random forest(RF)is used to extract the land cover information of saltmarsh vegetation in Yancheng coastal wetland in recent 20 years.The results show that:(1)compared with the traditional monitoring method,our proposed wetland vegetation extraction method can effectively subdivide and monitor the vegetation.(2)From 2000 to 2020,the area of reed and Spartina flora showed a trend of expansion,while the area of alkali canopy was constantly decreasing.(3)The NDVI values of the three typical salt marsh vegetation in Yancheng show different changing characteristics.(4)Precipitation has a significant impact on the vegetation growth of salt marsh,while temperature has little influence on the growth of salt marsh vegetation.The results provide scientific support for the protection of natural heritage of Yancheng marsh wetland and the sustainable development of wetland ecology.
作者
吕林
易文彬
崔丹丹
王楠
张东
谢正磊
LYU Lin;YI Wenbin;CUI Dandan;WANG Nan;ZHANG Dong;XIE Zhenglei(Key Laboratory of Coastal Salt Marsh Ecosystems and Resources,Ministry of Natural Resources,Nanjing 210017,China;College of Marine Science and Engineering,Nanjing Normal University,Nanjing 210023,China;Marine Economic Monitoring and Evaluation Center of Jiangsu Province,Nanjing 210003,China)
出处
《海洋通报》
CAS
CSCD
北大核心
2024年第1期114-126,共13页
Marine Science Bulletin
基金
国家自然科学基金(41861041)
自然资源部滨海盐沼湿地生态与资源重点实验室开放基金项目(KLCSMERMNR2021104)
江苏省海洋科技创新项目(JSZRHYKJ202203)。
