基于HY-1C CZI影像光谱指数重构数据MNF变换的红树林提取

本文基于广西山口国家红树林生态自然保护区的HY-1C卫星的海岸带成像仪(Coastal Zone Imager，CZI)影像，分析了红树林与一般陆地植被的光谱特征及其光谱指数的相关性，采用归一化差值植被指数(Normalized Difference Vegetation Index，NDVI)、归一化差异水分指数(Normalized Difference Water Index，NDWI)、大气阻抗植被指数(Atmospheric Impedance Vegetation Index，ARVI)及利用CZI波段构建的光谱斜率比(CZI Visible Spectrum Slope Ratio，CVSSR)4个指数替代CZI原始波段形成重构数据，基于重构数据的最小噪声分离变换(Minimum Noise Fraction Rotation，MNF)结果分量，建立决策树并实现了红树林信息的自动提取。研究结果表明:结合本文所选光谱指数重构数据及MNF变换方法，能够有效增强CZI影像上红树林与一般陆地植被的光谱差异，基于MNF变换分量建立的决策树可有效提取红树林信息，经与专家解译结果比对，本文方法面积准确率达90%以上；经随机样本点验证，总体检测精度为88%。     

广西山口红树林保护区保护成效评估

文章以广西山口红树林保护区为研究对象,运用PSR模型构建红树林保护区保护成效评估指标体系,并收集相关数据、资料对其进行评价,在此基础上提出提高山口红树林保护区保护成效的建议。结果表明,山口红树林保护区在2008—2018年保护成效良好,生态系统健康状况良好,保护区管理工作开展较好。现阶段存在的主要问题是保护区内还存在部...     

面向对象的红树林信息提取

红树林是世界上最重要的生态系统之一,对于海岸带的保护起着非常重要的作用。然而,由于红树林所处的地理环境,对其进行实地调查是很困难的。遥感的出现,为我们研究红树林提供了一个很好的技术手段。但由于红树林的光谱信息与其他植被光谱信息的相似性,给红树林信息的提取带来了很大的困难。基于IKONOS卫星影像,采用面向对象的信息提取方法,利用简单的决策树分类方法进行了海岸带红树林信息提取的实验,得到了很好的结果,并与其他方法进行了比较。     

中美举行北部湾海洋生态管理项目第二轮会谈

根据中国国家海洋局与美国国家海洋大气局1999年7月在美国加利福尼亚州圣迭戈形成的中美海洋与海岸带管理协调小组第二次会议纪要和2000年6月底在中国广西南宁形成的中美海洋与海岸带管理协调小组长期项目研讨会议纪要以及其后双方多次的协商,美国派出了以佛罗里达州鲁克利湾河口研究保护区麦克·谢利博士为团长的4人代表团(其中包括国际自然保护同盟的代表1名),于2000年12月6日～14日,对中国广西合浦国家级山口红树林生态自然保护区、北海涠洲岛(斜阳岛)及其周围海域的珊瑚礁等进行了实地考察。考察期间,代表团与广西海洋局等中     

福建省红树林湿地海洋线虫的优势属及摄食类型

本文于2012年4月、7月与10月以及2013年1月与4月，对福建省云霄县漳江口、龙海市九龙江口、厦门市凤林湾、泉州市洛阳江口、宁德市湾坞5片红树林湿地的海洋线虫进行采样与优势属及摄食类型研究，主要研究结果如下:采样区域优势度大于等于5%的海洋线虫优势属依次为Sabatieria、Ptycholaimellus、Parasphaerolaimus、Terschellingia、Daptonema、Viscosia和Dichromadora，优势度依次为19.82%、7.88%、7.45%、7.26%、6.79%、6.00%和5.25%。在漳江口红树林、九龙江口红树林及洛阳江口红树林均以Sabatieria为第一优势属，优势度分别为27.87%、28.37%和23.40%；凤林红树林以Terschellingia为第一优势属，优势度为18.10%；湾坞红树林以Daptonema为第一优势属，优势度为22.86%。海洋线虫摄食类型数量的季节变化如下，漳江口红树林:1B>2A>2B>1A；九龙江口红树林:1B>2B>2A>1A；凤林红树林:1B>2A>2B>1A；洛阳江口红树林:2B>1B>2A>1A；湾坞红树林:2A>1B>2B>1A。在漳江口红树林、九龙江口红树林和凤林红树林中海洋线虫均以1B型为主导，在湾坞红树林中以2A型为主导，在洛阳江口红树林是2B型为主导，在5个区域内1A型海洋线虫的丰度均为最低。     

基于GF-2影像的广西茅尾海红树林物种分类及盖度估算分析

为了掌握茅尾海红树林种类和盖度情况,基于GF-2 PMS1高分辨率卫星遥感影像数据,使用支持向量机(support vector machine,SVM)和回归模型方法开展了茅尾海红树林物种分类和植被盖度估算研究,并对其分布特征展开了详细分析。研究表明:(1)广西茅尾海红树林共有4个种类,分别是桐花树(Aegiceras corniculatum)、无瓣海桑(Sonneratia apetala)、秋茄(Kandelia candel)和茳芏(Cyperus malaccensis)。桐花树作为茅尾海红树林的优势种,面积为1228.612 ha,占总面积72.5%,散布在茅尾海潮间带。秋茄面积最少,仅有1.976 ha,零星分布于茅岭乡和尖山镇沿岸,多数与无瓣海桑和桐花树混生。(2)基于GF-2 PMS1卫星影像的NDVI植被指数建立的二次多项式盖度回归模型效果最好,决定系数最大为0.7644,均方根误差RMSE最小为0.0680。(3)植被盖度分布状况与植被类型有密切关系,植被种类纯生区的盖度要明显大于植被混生区的盖度。本研究结果为茅尾海国家海洋公园和自治区级自然保护区管理部门的决策提供理论基础。     

快速城镇化背景下的浙江省海岸带生态系统服务价值变化

从快速城镇化背景下土地利用变化的角度来分析浙江省海岸带生态系统服务价值(ESV)损益情况,将ESV的估算引入海岸带开发决策,对浙江省海岸带资源的可持续利用具有重要意义.以1990、2000、2010年遥感解译数据为基础,研究了快速城镇化背景下浙江省海岸带土地利用类型变化,并通过构建ESV估算模型,估算了1990~2010年间浙江省海岸带ESV变化.结果表明:1990~2010年间,由于城镇化速度不断加快,浙江省海岸带土地利用类型变化显著,主要表现为城镇建设用地大量增加,林地和耕地面积减少.期间浙江省海岸带ESV总量不断减少,从352.78亿元降至299.64亿元,降幅达15.06%.浙江省海岸带ESV空间分布不断由高价值区域向低价值区域转变.各土地利用类型价值系数(CS)均小于1,价值总量对价值系数弹性不大,所设置的ESV系数原始值较为合适.浙江省海岸带土地利用强度不断上升,其空间分布与ESV变化率空间分布具有一致性,无序增加的城镇建设用地占用林地和耕地而引起的土地利用结构转变是海岸带ESV不断减损的主要原因.     

2000～2010 年环渤海省市海岸带土地利用变化分析

作为陆海生态系统的交错带,海岸带是地表生态系统最为脆弱的地带,研究海岸带土地利用变化具有重要意义。以环渤海省市海岸带为研究区,基于2000、2005和2010年的Landsat TM/ETM遥感影像进行多时相海岸带土地利用制图,进而分析10 a间的土地利用变化特征,包括土地利用结构、土地利用动态度、土地利用程度区域差异和海陆梯度、海陆格局变化等特征。结果表明:(1)环渤海省市海岸带土地利用以耕地、建设用地和人工湿地为主,2010年比例分别为36.09%、17.16%和15.72%,不同行政单元及不同缓冲带之间土地利用结构空间差异明显。(2)2000~2005年、2005~2010年,土地利用发生转移的面积分别为2 126.419 km2和3 092.39 km2,建设用地扩展占用耕地、人工湿地和滨海自然湿地,以及滨海自然湿地变为人工湿地是主导的变化过程,但不同行政单元及不同缓冲带之间土地利用变化的空间差异明显。(3)2000~2005年、2005~2010年,综合土地利用动态度分别为0.73%和1.06%,17个地市级行政单元综合土地利用动态度以东营和天津较高,各缓冲带内综合土地利用动态度均为随时间不断增加,空间上则由海向陆波动下降。(4)2000~2010年,土地利用程度总体上不断升高,表明海岸带土地利用处于发展期,除沧州和潍坊,其他区域土地利用程度随时间不断上升;各缓冲带土地利用程度均随时间不同程度增长,空间上则由海向陆波动上升。     

海南岛海岸带生态系统退化及其保护对策研究

本文以海南岛海岸带为案例,分析了海岸带生态系统的特征及其变化趋势,探讨了海岸带生态系统退化的原因,提出海岸带生态保护对策和措施,以期为海岸带保护提供科学依据.结果表明,要防止海岸带生态系统退化需采取如下措施:强化海岸带管理立法和执法,科学制定海岸带土地利用规划和海洋功能区划,综合利用海岸带资源;发展生态农业和生态养殖业,防止珊瑚礁和红树林生态系统被破坏;加强采空矿区和土地开发的生态复垦,完善海岸带防护林体系;通过实施生态工程项目,控制陆地污染源及海上污染源的污染物排放,防止海洋污染等.     

红树林生态退化机制评估指标体系构建与漳江河口案例研究

通过总结目前红树林面临的各类生态退化机制,利用＂压力-状态-响应（PSR）＂分析模型,构建了红树林生态退化机制评估指标体系,并应用于福建省漳江河口红树林生态系统的案例研究.评价结果显示：漳江河口红树林生态退化压力仍处在较小的范围内,主要压力源来自生物入侵以及海岸带水产养殖和围垦;对影响显著的生态退化因子已经采取了有效的控制措施;保持并加强保护措施,将有助于当地红树林生态系统在未来维持稳定的状态.     

Wave attenuation in mangroves: A quantitative approach to field observations

Coastal mangroves, dwelling at the interface between land and sea, provide an important contribution to reducing risk from coastal hazards by attenuating incident waves and by trapping and stabilizing sediments. This paper focusses on relations between vegetation densities, wave attenuation rates, sediment characteristics and sedimentation rates in mangroves. These processes were studied along two cross-shore transects through mangroves fringing estuaries in the southern Andaman region of Thailand. Volumetric vegetation densities in these mangroves were ranging up to 32‰, depending on the water depth. Generalized total wave attenuation rates increased from 0.002 m^− 1 in the sparsely vegetated forest fringes with Avicennia and Sonneratia species, up to 0.012 m^− 1 in the dense Rhizophora vegetation in the back of the forests. The total wave attenuation rates integrate effects of shoaling and energy losses due to various bio-physical interactions within the mangrove ecosystem. Wave attenuation in the mangroves is presumably dominated by energy losses due to vegetation drag, since wave attenuation due to bottom friction and viscous dissipation on the bare mudflats is significantly lower than those inside the mangrove vegetation.Additionally, wave attenuation in the mangroves was found to facilitate enhanced net sediment deposition and a gradual fining of the bed material. These findings corroborate the coastal defence function of mangroves by quantifying their contribution to wave attenuation and sediment trapping. The explicit linking of these properties to vegetation composition and structure facilitates modelling studies investigating the mechanisms determining the coastal defence capacities of mangroves.     

Sedimentation within and among mangrove forests along a gradient of geomorphological settings

Coastal wetlands provide important ecological services to the coastal zone, one of which is sediment retention. In this study we investigated sediment retention across a range of geomorphological settings and across vegetation zones comprising coastal wetlands. We selected six coastal wetlands dominated by mangroves over a gradient from riverine to tidal settings in Southeast Queensland, Australia. Each site was comprised of three distinct vegetation communities distributed as parallel zones to the coast line: seaward fringe mangroves, landward scrub mangroves and saltmarsh/ cyanobacteria mat of the high intertidal zone. We measured suspended sediment retention and sedimentation rates. Additionally, in order to assess the origin of sediment transported and deposited in the mangroves, glomalin, a novel terrestrial soil carbon tracer, was used. Our results show a mean average sedimentation of 0.64 ± 0.01 mg cm⁻² spring tide⁻¹, which was variable within sites, regardless of geomorphological setting. However, geomorphological setting influenced spatial patterns of sediment deposition. Riverine mangroves had a more homogeneous distribution of sediments across the intertidal zone than tidal mangroves, where most sedimentation occurred in the fringe zone. Overall, the fringe zone retained the majority of sediment entering the coastal wetland during a tidal cycle with 0.90 ± 0.22 mg cm⁻² spring tide⁻¹, accounting for 52.5 ± 12.5% of the total sedimentation. The presence of glomalin in suspended sediments, and thus the relative importance of terrigenous sediment, was strongly influenced by geomorphological setting, with riverine mangroves receiving more glomalin in suspended solids than tidal mangroves. Glomalin was also differentially deposited within the vegetation zones at different geomorphological settings: primarily at the fringe zone of tidal mangroves and within the scrub zone of riverine mangroves. The differences we observed in the spatial distribution of sedimentation and the difference in the origin of the sediment deposited in riverine and tidal mangroves are likely to have an impact on ecological processes.     

Topographical Mapping of a Bare Tidal Flat Outside a Mangrove Area based on the Waterline Method and an Iterative Hydrodynamic Model: A Case Study of Yingluo Bay,South China

A change in the elevation of bare tidal flats outside a mangrove area is an indispensable factor for the sustainable development of mangroves. Waterline extraction, as an effective and economical tool used in reconstructing the terrain of an intertidal zone, has been widely applied to open-coast tidal flats by constructing a digital elevation model (DEM). However, mangrove wetlands are usually located in wave-sheltered sites, such as estuaries and bays that have narrow tidal channels flanked by tidal flats. Changes in water level are affected by the dry-wet processes of complex landforms caused by tides. This article takes as a study case the area of Yingluo Bay, which covers the core region of the Zhanjiang and Shankou National Mangrove National Nature Reserve in southwestern China. Waterline extraction based on seventeen multisource and multispectral satellite images obtained from December 2014 to April 2015, combining the finite-volume coastal ocean model (FVCOM) hydrodynamic model in an iterative process, was used to generate a topographical map of the bare tidal flat outside the mangrove area in Yingluo Bay. The quality of the iterative DEMs was evaluated via six transects of a ground-based survey using Real - time kinematic (RKT) GPS in May 2015. The mean absolute error (MAE) and root mean square error (RMSE) of the DEM decreased with an increase in the number of iterations. In this study, the DEM in the third iteration was used as the final output because the difference from the previous iterative DEM satisfied an inversion-stopping criterion. The MAE and RMSE of the final DEM with the measured data were 0.072 and 0.09?m, respectively, without considering small tidal creeks. The method used in this study can be an effective and highly precise approach for detecting and reconstructing the historical terrain of a bare tidal flat outside a mangrove area. This work also has great importance regarding intertidal resource management and the sustainable development of mangroves facing the vulnerable coastal ecological environment.     

粤港澳大湾区红树林时空分布演变及现存林龄遥感分析

红树林作为热带、亚热带以红树植物为主体的海岸带生态系统,是重要的海岸湿地类型之一。本文使用多源、多时相遥感数据,形成了1969-2020年粤港澳大湾区岸线、围填海、养殖区、红树林分布数据图集,并利用联合红树林识别指数(CMRI)对大湾区现存红树林进行时序分析得到红树林林龄数据集。结果表明,通过多源遥感数据解译得到现存红树林数据集,结合CMRI时序数据可以建立现存红树林变迁历史,进而有效估算红树林林龄。粤港澳大湾区红树林的时空分布发生了明显变迁,现存红树林面积约为3 316 hm²,大湾区内部各地区存量林龄差异较大,整体林龄均值为20 a。近50年间,岸线整体向海移动,岸线变迁、围填海和养殖区变化显著影响红树林面积、空间分布及林龄大小,人工种植是近20年红树林恢复的主因。     

Using mangroves as a geological indicator of coastal changes in the Bragança macrotidal flat,Brazilian Amazon: A remote sensing data approach

A mangrove ecosystem shows close links between geomorphology and vegetation assemblage. In addition, the vegetation can change over time as landforms can accrete or erode, which is a direct response to coastal sedimentary processes. This demonstrates that significant changes can occur on short time scales and mangroves provide an excellent register of these modifications. Therefore, mangrove morphology and sedimentation are good indicators of interactions between relative sea level changes, coastal processes and sediment supply. These interactions are responsible for landward migration of the shoreline (erosion) and seaward migration of the shoreline (accretion), which is possible to detect from multi-date satellite data and field observations. Mangroves are one of the best geo-indicators in global coastal change research and they are an excellent procedure to detect and quantify coastal modifications.     

Optimizing Remote Sensing and GIS Tools for Mapping and Managing the Distribution of an Invasive Mangrove (Rhizophora mangle) on South Molokai,Hawaii

In 1902, the Florida red mangrove, Rhizophora mangle L., was introduced to the island of Molokai, Hawaii, and has since colonized nearly 25% of the south coast shoreline. By classifying three kinds of remote sensing imagery, we compared abilities to detect invasive mangrove distributions and to discriminate mangroves from surrounding terrestrial vegetation. Using three analytical techniques, we compared mangrove mapping accuracy for various sensor-technique combinations. ANOVA of accuracy assessments demonstrated significant differences among techniques, but no significant differences among the three sensors. We summarize advantages and disadvantages of each sensor and technique for mapping mangrove distributions in tropical coastal environments.     

Changes in biotic and abiotic processes following mangrove clearing

Mangrove forests, important tropical coastal habitats, are in decline worldwide primarily due to removal by humans. Changes to mangrove systems can alter ecosystem properties through direct effects on abiotic factors such as temperature, light and nutrient supply or through changes in biotic factors such as primary productivity or species composition. Despite the importance of mangroves as transitional habitats between land and sea, little research has examined changes that occur when they are cleared. We examined changes in a number of biotic and abiotic factors following the anthropogenic removal of red mangroves (Rhizophora mangle) in the Panamanian Caribbean, including algal biomass, algal diversity, algal grazing rates, light penetration, temperature, sedimentation rates and sediment organic content. In this first study examining multiple ecosystem-level effects of mangrove disturbance, we found that areas cleared of mangroves had higher algal biomass and richness than intact mangrove areas. This increase in algal biomass and richness was likely due to changes in abiotic factors (e.g. light intensity, temperature), but not biotic factors (fish herbivory). Additionally the algal and cyanobacterial genera dominating mangrove-cleared areas were rare in intact mangroves and included a number of genera that compete with coral for space on reefs. Interestingly, sedimentation rates did not differ between intact and cleared areas, but the sediments that accumulated in intact mangroves had higher organic content. These findings are the first to demonstrate that anthropogenic clearing of mangroves changes multiple biotic and abiotic processes in mangrove forests and that some of these changes may influence adjacent habitats such as coral reefs and seagrass beds. Additional research is needed to further explore the community and ecosystem-level effects of mangrove clearing and their influence on adjacent habitats, but it is clear that mangrove conservation is an important aspect of managing tropical coastal systems.     

Assessment of aquaculture impact on mangroves of Mahanadi delta (Orissa), East coast of India using remote sensing and GIS

Aquaculture is one of the fastest growing food industries. However, the rapid growth of aquaculture worldwide has resulted in growing concerns about its impact on important ecosystems. The expansion of aquaculture farms in the coastal areas has led to conversion of mangroves, more rapidly. To assess the impact of aquaculture on mangroves, the present study has been undertaken in Mahanadi delta of Orissa, East coast of India which is famous for its distinctive mangrove ecosystem. It has undergone tremendous changes due to the development of aquaculture and agriculture activities during last two decades. For this, satellite data of different time periods (Landsat MSS of 1973, Landsat TM of 1990 and IRS P6 LISS III of 2006) were used. It was found that the delta was occupied by dense mangrove (12.6%), open mangrove (3.3%), aquaculture (12.9%) and agriculture (30.9%) in 2006. A loss of 2606 ha mangrove area and an increase of 3657 ha aquaculture area was observed from 1973 to 2006 clearly depicts the augment of aquaculture industry. It is suggested that, regular monitoring of the mangroves and effective implementation of coastal management laws be strictly undertaken to prevent the further loss mangroves in Mahanadi delta.     

雷州半岛红树林边缘效应及其对海岸有机碳库的影响

作为滨海湿地与邻近海区之间物质循环、能量和物种流动及其相互作用的重要界面,红树林的边缘效应对研究海陆生态系统相互作用,滨海湿地生物地貌形成过程以及海岸带有机碳库分布格局等方面的具有重要意义。文章以雷州半岛东岸红树林4种典型地貌分布区为重点,通过调查红树林前缘光滩,林缘及林内植被及土壤理化特征的变化,探讨红树林边缘效应的表现及其对土壤有机碳库的影响。结果表明,不同地貌类型红树林边界区的群落结构及土壤理化因子分布特征有所不同。边界区群落特征表现为林缘的冠层低于林内,叶面积指数低于林内,物种丰富度林内高于林缘(除河口区外),且林缘的植被盖度受风浪影响显著,表现出河口区>内湾区>岛屿区>前沿浪击区。土壤理化性质边缘效应表现为林缘的pH值、粒度低于光滩,氧化还原电位、盐度高于光滩(除内湾区外),而林内的土壤理化性质波动较大,可能受林缘植被演替及地貌双重影响。不同地貌单元红树林边界区的土壤表层有机碳含量,有机碳密度均表现为林内>林缘>光滩。综合影响表层土壤有机碳的主要生物及非生物因子进行主成分分析和相关分析,结果显示土壤表层有机碳密度与环境第一主成分呈显著负相关,即受植被盖度,叶面积指数和土壤pH因子影响密切。红树林土壤有机碳沉积虽然受到不同水文地貌的影响,但总体而言,红树林初级生产输入和土壤酸性环境对红树林林下土壤有机碳库的富存贡献显著。