Mangrove ecosystems dominate the coastal wetlands of tropical and subtropical regions throughout the world. They provide various ecological and economical ecosystem services contributing to coastal erosion protection, water filtration, provision of areas for fish and shrimp breeding, provision of building material and medicinal ingredients, and the attraction of tourists, amongst many other factors. At the same time, mangroves belong to the most threatened and vulnerable ecosystems worldwide and experienced a dramatic decline during the last half century. International programs, such as the Ramsar Convention on Wetlands or the Kyoto Protocol, underscore the importance of immediate protection measures and conservation activities to prevent the further loss of mangroves. In this context, remote sensing is the tool of choice to provide spatio-temporal information on mangrove ecosystem distribution, species differentiation, health status, and ongoing changes of mangrove populations. Such studies can be based on various sensors, ranging from aerial photography to high- and medium-resolution optical imagery and from hyperspectral data to active microwave (SAR) data. Remote-sensing techniques have demonstrated a high potential to detect, identify, map, and monitor mangrove conditions and changes during the last two decades, which is reflected by the large number of scientific papers published on this topic. To our knowledge, a recent review paper on the remote sensing of mangroves does not exist, although mangrove ecosystems have become the focus of attention in the context of current climate change and discussions of the services provided by these ecosystems. Also, climate change-related remote-sensing studies in coastal zones have increased drastically in recent years. The aim of this review paper is to provide a comprehensive overview and sound summary of all of the work undertaken, addressing the variety of remotely sensed data applied for mangrove ecosystem mapping, as well as the numerous methods and techniques used for data analyses, and to further discuss their potential and limitations.

Remote Sensing of Mangrove Ecosystems: A Review

Aquaculture: Relevance, distribution, impacts and spatial assessments – A review

In this project, the Marine Pollution Information System has been suggested with the help of Remote Sensing and GIS. This system provides pollution hot spot area and spread rate of the Tuticorin coastal area in Tamilnadu, India. The spread rate and hot spot analysis has been analyzed with the aid of  various Chemical, Biological and Physical parameters such as pH, Temperature, Total Suspended Sediments (TSS), Salinity, Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), Nitrate, Nitrite, Phosphorus as Phosphate PO4, Chlorophyll-a, Silicate, primary productivity and Ammonia. The Remote Sensing data plays vital role in pollution monitoring and analysis. The Geographic Information System and Remote Sensing facilitate to scrutinize various marine pollution such Industrial pollution, sewage pollution and anthropogenic pollution. The various pollution parameters are examined with the allusion of “General Coastal Cater Quality Standard”. The preliminary investigations of pollution spots were identified on the remote sensing data (IRS P6) through the visual interpretation techniques. From the visually interpreted data the major polluted spots were identified on the ground by ground survey method. The water samples were collected from the polluted spots. The various samples had undergone with diverse laboratory analysis and readings were stored in GIS database. The various pollution parameters reading are compared with General Coastal Cater Quality Standard values in GIS environment. The various parameters Map, Hot Spot Map and Spread Rate Map are generated with the assist of Weighted Overlay Analysis and Statistical Analysis in ARC-GIS.

Mapping and Analysis of Marine Pollution in Tuticorin Coastal Area Using Remote Sensing and GIS

A partir d'une typologie physionomique standardisee, cette these entend proposer une methode de
cartographie des mangroves de l'Outre-mer francais. Plusieurs jeux de donnees satellites sont ainsi exploites
en vue (i) de determiner l'extension des surfaces de mangroves, (ii) quantifier la fermeture de canopee, (iii)
quantifier la hauteur de la canopee et (iv) identifier les principales especes de paletuvier.
La determination des surfaces de mangroves se fait via l'exploitation des particularites spectrales des
paletuviers dans le moyen-infrarouge visibles sur les images Landsat et Sentinel-2.
La quantification de la fermeture de canopee est basee sur un algorithme doublement contraint (FCLSU) de
demelengeage lineaire des pixels d'images tres haute resolution Pleiades.
La quantification de la hauteur de canopee a ete effectuee quant a elle grâce a l'utilisation d'une analyse
photogrammetrique d'un couple d'images panchromatiques stereoscopiques WorldView-3 (0.3
metres de resolution). Enfin, la discrimination des principales especes de
mangroves a ete permise grâce a l'exploitation de releves spectraux effectues sur le terrain et calibration
des proprietes spectrales des differentes especes visibles sur les images satellites.

Cartographie harmonisée des mangroves de l'Outre-mer français

In recent years, the pressure of increasing coastal industries and tourism activities has, in some areas, led to the clearing of many coastal habitats along the Qatar's shorelines for the construction of tourist resorts, tourism-related development and industrial facilities. Such threats are leading to the increasing demand for detailed mangrove maps for the purpose of measuring the extent of decline in mangrove ecosystems. Detailed mangrove maps at the community or species level are, however, not easy to produce, mainly because mangrove forests are very difficult to access. Without doubt, remote sensing is a serious alternative to traditional field-based methods for mangrove mapping, as it allows information to be gathered from the forbidding environment of mangrove forests, which otherwise, logistically and practically speaking, would be extremely difficult to survey. Remote sensing applications for mangrove mapping at the fundamental level are already well established but, surprisingly, a number of advanced remote sensing applications have remained unexplored for the purpose of mangrove mapping at a finer level. Consequently, the aim of this paper is to unveil the potential of some of the unexplored remote sensing techniques for mangrove studies. Temporal Landsat TM image of 1986, Landsat ETM image of 2000 and Resourcesat-1 LISS 3 image of 2008 are used to calculate percentage change in mangrove cover at Al Dhakira site using geometrically registered and radiometrically corrected historical Landsat and Resourcesat-1 images. Region masks are employed to isolate the unwanted area from the images. NDVI (normalized difference vegetation index) is used to detect mangroves using near-infrared and red bands which are computed from the satellite images. The ground-truthing visit to Al Dhakira site is conducted to confirm the results of the analysis. Change detection is applied and mangrove in the study area is found to have decreased by about 8.79% from 2000 to 2008.

Application of Remote Sensing for Mangrove Mapping: A Case Study of Al-Dhakira, the State of Qatar

Modern techniques such as remote sensing have been one of the main factors leading toward the achievement of serious plans regarding coastal management. A multitemporal analysis of land use in certain areas of the Colombian Caribbean Coast is described. It mainly focuses on environmental impacts caused by anthropogenic activities, such as deforestation of mangroves due to shrimp farming. Selection of sensitive areas, percentage of destroyed mangroves, possible endangered areas, etc., are some of the results of this analysis. Recommendations for a coastal management plan in the area have also resulted from this analysis. Some other consequences of the deforestation of mangroves in the coastal zone and the construction of shrimp ponds are also analyzed, such as the increase of erosion problems in these areas and water pollution, among others. The increase of erosion in these areas has also changed part of their morphology, which has been studied by the analysis of SPOT images in previous years. A serious concern exists about the future of these areas. For this reason new techniques like satellite images (SPOT) have been applied with good results, leading to more effective control and coastal management in the area. The use of SPOT images to study changes of the land use of the area is a useful technique to determine patterns of human activities and suggest solutions for severe problems in these areas.

Use of SPOT images as a tool for coastal zone management and monitoring of environmental impacts in the coastal zone

Use of modern techniques like remote sensing has been without doubts one of the main factors to take a forward step towards the achievement of serious plans regarding Coastal Management. A multi-temporal analysis of the land- use, in some areas of the Colombian Caribbean Coast, was done mainly focused in environmental impacts caused by anthropogenic activities like deforestation of mangroves due to shrimp farming. Selection of sensitive areas, percentage of destroyed mangroves, possible endangered areas, etc. have been some of the results of this analysis as well as some advises for a coastal management plan in the area. Some other consequences of the deforestation of mangroves in the coastal zone and the construction of shrimp ponds were also analyzed like increase of erosion problems in these areas and water pollution among others. The increase of erosion in these areas has also changed part of their morphology, which has also been studied by the analysis of SPOT images in different years. A serious concern exists about the future of these areas, for this reason new techniques like satellite images (SPOT) have been applied with good results and in this way a more effective control and coastal management in the area is taking place. The use of SPOT images to study changes in the land-use of the area was a useful technique in order to determine patterns of human activities and suggest solutions for severe problems in these areas.

Paola Almeida-Guerra

Papers

Use of SPOT images as a tool for coastal zone management and monitoring of environmental impacts in the coastal zone

Use of SPOT images as a tool for coastal zone management and monitoring of environmental impacts in the coastal zone