Assessing the extent of mangrove change caused by Cyclone Vance in the eastern Exmouth Gulf, northwestern Australia

Changes in mangal area were quantified in the eastern Exmouth Gulf over six years (1999–2004) after Cyclone Vance using Landsat TM satellite imagery and aerial photography. Vance was the strongest tropical cyclone ever to impact the Australian mainland before 2006 and produced wind gusts of more than 280 km h⁻¹. Image data were processed using ENVI™ and IDRISI™ software. Three sets of Landsat TM images from 1999 (a few days before the cyclone), 2002 and 2004 were used, along with 2004 digital aerial photography. A ‘common’ subset of 904 km² was selected from all images and classification was developed using ISODATA™ unsupervised classification to identify spectrally distinct areas followed by principal component analysis (PCA), vegetation indices and supervised classification. Some 12,800 ha of mangrove habitat was present before the cyclone and approximately 5700 ha (44%) was removed by it. Most mangroves lost (74%) between 1999 and 2004 were converted either to bare sediment or to live saltmarshes and this occurred mostly between 1999 and 2002. Five basic categories of damage were conspicuous from imagery and field observations, and evidence suggests that much of the loss was due to the longer term consequences of sediment deposition or smothering, rather than the immediate effects of wind or waves. Mangroves exhibited accelerated recovery between 2002 and 2004, and around 1580 ha regenerated during this time, amounting to a return of 68% of their former coverage. At this recovery rate we estimate that they should have returned to their pre-cyclone area by 2009. Over half of the saltmarsh habitats (54%) were removed by the cyclone (4060 ha) but their recovery has been far more rapid than mangroves. After 5 years, saltmarshes had returned to 87% of their previous area. The 5700 ha of mangrove habitat damaged by Cyclone Vance exceeds any anthropogenic impact that has ever taken place in Western Australia by several orders of magnitude.     

Spatial analysis of the impact of shrimp culture on the coastal wetlands on the Northern coast of Sinaloa, Mexico

In the Mexican coasts, as in many tropical and subtropical coastal areas, shrimp culture grew exponentially over the last three decades. This process has produced an intense debate on the economic benefits but also about the extent and intensity of the impact of this activity on the coastal ecosystems, particularly the effects of pond construction on mangrove areas and other coastal wetlands. For the Northern coast of Sinaloa (Northwest Mexico), a region where shrimp culture is actively practiced and reproduces most of the shrimp controlled production model in Mexico, a land cover change-detection analysis, with Landsat images, outputs that 75% of the shrimp farming in this region has been built on saltmarshes while less than 1% was constructed on mangrove areas. Through the estimation of landscape metrics for different scenarios (with and without shrimp culture infrastructure), we find that in addition to direct removal of saltmarshes, shrimp aquaculture has significantly modified the spatial patterns of coastal wetlands, retreating wetland borders and fragmenting their patches. These last impacts are mainly related with the development of the linear infrastructure associated with shrimp culture (drainage channels and roads), rather than the construction of the ponds. Present findings and other from similar studies done in Northwest Mexico; allow us to estimate that 60% of shrimp farming in Mexico impacted directly on saltmarshes, contrasting with the 3% of shrimp farms built on mangroves.     

Coastal aquaculture,mangrove deforestation and blue carbon emissions: Is REDD+ a solution?

Globally, coastal aquaculture particularly shrimp farming has been under huge criticism because of its environmental impacts including devastating effects on mangrove forests. However, mangroves are ecologically and economically important forests, and the most carbon-rich forests in the tropics that provide a wide range of ecosystem services and biodiversity conservation. Carbon emissions are likely to have been the dominant cause of climate change and blue carbon emissions are being critically augmented through mangrove deforestation. Because of mangrove deforestation, different climatic variables including coastal flooding, cyclone, drought, rainfall, salinity, sea-level rise, and sea surface temperature have dramatic effects on coastal aquaculture. Mangrove forests have been instrumental in augmenting resilience to climate change. The “Reducing Emissions from Deforestation and forest Degradation (REDD)” program can help to restore mangroves which in turn increases options for adaptation to climate change. However, technical and financial assistance with institutional support are needed to implement REDD+.     

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。     

Overcoming the impacts of aquaculture on the coastal zone

The wide variety of goods and services provided by the coastal zone (food, medicines, nutrient recycling, control of flooding, typhoon protection) account for its many uses (fisheries, aquaculture, agriculture, human settlements, harbors, ports, tourism, industries). Aquaculture now provides a third of total fisheries production. Half of the total aquaculture yield comes from land-based ponds and water-based pens, cages, longlines and stakes in brackish water and marine habitats. But the opportunities for employment, income and foreign exchange from coastal aquaculture have been overshadowed by negative environmental and social effects. The environmental impacts include: mangrove loss, bycatch during collection of wild seed and broodstock, introductions and transfers of species, spread of parasites and diseases, misuse of chemicals, and release of wastes. The socioeconomic impacts include: privatization of public lands and waterways, loss of fisheries livelihoods, food insecurity, and urban migration. The paper gives recommendations on the attainment of responsible and sustainable aquaculture with emphasis on herbivorous and omnivorous species, polyculture, integration with agriculture and mangroves, and self-regulation in the form of codes of conduct and best management practices. Recommended approaches include holistic Integrated Coastal Zone Management based on stakeholder needs, mechanisms for conflict resolution, assimilative capacity of the environment, protection of community resources, and rehabilitation of degraded habitats, to improvements in the aquaculture sector pertaining to management of feed, water, and effluents.     

珠江口红树林基围养殖生态开发模式评述

起源于珠江三角洲的红树林基围(land-based enclosure)养殖传统模式是红树林可持续利用和生态开发范例之一。本文介绍了珠江口红树林基围养殖生态开发模式的3个个例: 仅存香港米埔红树林自然保护区的传统基围养殖运作历史和演变, 及其候鸟生境、养殖、观鸟、环境教育综合功能的实现; 珠海淇澳岛大围湾红树林传统和粗放式基围养殖试验和围内水位盐度等环境条件变化对红树林生长影响的研究; 伶仃洋东岸海上田园红树林海水种植-集约式养殖系统试验和红树林净化水质研究。在珠江口红树林保护管理及海域污染防治过程中建议重视红树林可持续利用模式的研究和推广, 建立新的基围养殖示范区, 大力推广红树林基围养殖的生态开发模式, 探索毁林养殖区红树林友好式整治模式, 改善红树林基围养殖技术提高养殖产量, 加强红树林基围养殖系统相关科学研究。     

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.     

A lesson from cyclone Larry: An untold story of the success of good coastal planning

When tropical cyclone Larry crossed the Queensland coast on 20 March 2006, commercial, recreational and naval vessels in the port of Cairns, 60 km north of the eye of the cyclone and others closer to the eye, were protected from the destructive winds by sheltering in deep mangrove creeks in Trinity Inlet and off other coastal rivers. The Trinity Inlet mangroves are protected under the comprehensive multi-use Trinity Inlet Management Plan, agreed by the local and state government agencies (Cairns City Council, the Cairns Port Authority and the Queensland Government). Using this Australian example and one from the town of Palompon in Leyte province, central Philippines, we show how long-term mangrove habitat protection resulting from well-conceived coastal planning can deliver important economic and infrastructure benefits.     

1991—2011年廉江红树林分布及变化的遥感分析

利用1991年的1景TM遥感数据，2000年的ETM+遥感数据和2011年HJ-1A遥感数据进行廉江红树林信息的提取。结果表明：1991，2000和2011年廉江的红树林分布面积分别为131.6，628.7和1 056.2 ha。自1991年至2011年红树林呈增加的趋势，共增加924.6 ha，20年间研究区域的红树林约增加了7倍。湛江红树林国家自然保护区的建立对于红树林湿地生态系统的保护和恢复起到极大的促进作用，研究区域红树林造林恢复成果显著，种植了大量的人工红树林。     

海南岛海水池塘养殖遥感监测与时空变化分析

以Landsat TM/OLI卫星影像为数据源,采用面向对象的分类方法对1990、2000、2010和2015年4个时相的海南岛海水池塘养殖信息进行提取,利用景观格局指数和质心迁移模型研究海水池塘养殖的时空变化特征及其对近岸生态环境的影响。结果表明,1990—2015年海南岛海水池塘养殖面积持续增长且区域差异明显;空间上表现为从西南向东北的迁移;养殖区景观格局趋于破碎化;池塘养殖的扩张侵占了红树林等自然湿地,严重破坏了沿岸生态环境。研究表明海南岛的海水养殖业需要合理的规划布局和科学的改造升级。     

Intertidal substrate modification as a result of mangrove planting: Impacts of introduced mangrove species on sediment microfacies characteristics

A programme of mangrove planting has been undertaken around the island of Rodrigues (SW Indian Ocean) since the mid-1980’s involving the introduction of the species Rhizophora mucronata. We examined three coastal embayment sites (Baie Diamant, Anse Goeland and Anse Pansia) in which planting has been undertaken over different time periods within the past 20 years. Planting has met with variable success in the different sites, probably due to variations in fluvial and groundwater influence. At two sites (Baie Diamant – first planted in 1990, and Anse Pansia – first planted in 1995) ecological data indicates that the mangroves are becoming well-established, and sedimentary evidence suggests that relatively rapid modification of intertidal substrates has occurred. This is evident in the form of significant increases in sediment organic-matter content (especially fibrous organic-matter) and an increase in the accumulation of sediment fines inside the mangroves. A strong correlation exists between the magnitude and depth of substrate modification and mangrove forest density, especially root and sapling density. At the third site, Anse Goeland (first planted in 2001), mangrove establishment has not been successful, many of the seedlings have died and no secondary colonisation has occurred. Sediment substrates show no deviation from background levels in terms of organic content or weight % fines content, and we find no evidence for mangrove planting influencing sediment substrates. Despite evidence for the development of a distinctive mangrove facies at Baie Diamant and Anse Pansia there is, however, no evidence as yet for a marked change in substrate geochemistry such as would be demonstrated by evidence of active bioclast dissolution – a common process in many natural (mature) mangrove substrates. We infer this to be a function of the present relative immaturity of the still developing mangrove substrates, but may also be a function of the apparent paucity of burrowing crabs which play an important role in nutrient cycling and sediment geochemistry. Thus whilst the mangroves in some of the study sites are reaching a stage where they are producing distinctive sedimentary facies, the systems appear to be in a state of progressive sedimentary and diagenetic modification as the floral and infaunal components of the mangroves continue to develop.     

A Trophic Flow Model of the Caeté Mangrove Estuary (North Brazil) with Considerations for the Sustainable Use of its Resources

The Caeté Estuary lies within the world's second largest mangrove region, 200 km south-east of the Amazon delta. It has an extension of about 220 km²and is subjected to a considerable human impact through intensive harvest of mangrove crabs (Ucides cordatus) and logging of mangroves. In order to integrate available information on biomass, catches, food spectrum and dynamics of the main species populations of the system, a trophic steady state model of 19 compartments was constructed using the ECOPATH II software (Christensen & Pauly, 1992). Ninety-nine percent of total system biomass is made up by mangroves (Rhizophora mangle, Avicennia germinans andLaguncularia racemosa ), which are assumed to cover about 45% of the total area and contribute about 60% to the system's primary production. The remaining biomass (132 g m⁻²) is distributed between the pelagic and benthic domains in proportions of 10% and 90% respectively. Through litter fall, mangroves inject the main primary food source into the system, which is either consumed directly by herbivores (principally land crabs, Ucides cordatus) or, when already metabolized by bacteria, by detritivors (principally fiddler crabs, Uca spp.). These two groups are prominent in terms of biomass (80 g and 14·5 g m⁻²), and food intake (1120 g m⁻² yr⁻¹and 1378 g m⁻² yr⁻¹respectively). According to the model estimates, energy flow through the fish and shrimp compartments is of relatively low importance for the energy cycling within the system, a finding which is contrary to the situation in other mangrove estuaries reported in the literature. The dominance of mangrove epibenthos is attributed to the fact that a large part of the system's production remains within the mangrove forest as material export to the estuary is restricted to spring tides, when the forest is completely indundated. This is also the reason for the low abundance of suspension feeders, which are restricted to a small belt along the Caeté River and the small creeks which are watered daily. Phytoplankton, temporarily refloating benthic diatoms, neritic zooplankton and small pelagic fish dominate the (low) pelagic biomass. Total system throughput (10 559 g m⁻² yr⁻¹) and mean transfer efficiency between trophic levels (9·8%) calculated by the model fit well into the range reported for other tropical coastal ecosystems. The very high gross efficiency of the fishery (catch/net primary production) of 8·6% and its low trophic level (2·1) is explained by a high harvesting rate of mangroves and the fact that the main animal resource in the system are the mangrove crabs (Ucides cordatus), which feed at the first trophic level. The model was balanced asuming a turnover rate for the land crabs of P/B=0·25 (P/B: production per unit of biomass) which is possibly too high. If this value was replaced by a (possibly more realistic) lower value, the model would not balance, suggesting a situation in which more biomass is being harvested than produced, which hints to an overexploitation of this resource A ranking of the various system components in terms of their contribution to the system function (ascendency sensu Ulanowicz, 1997) revealed that detritus and associated bacteria contribute 34%, mangroves 19%, fiddler crabs 13%, phytoplankton and microphytobenthos 10%, mangrove crabs 10%, and the remaining 14 groups 14% to the total ascendency. Summary statistics of the model are given and compared with those of other coastal ecosystems.     

基于HY-1C卫星CZI数据的红树林长势遥感监测

红树林是一种以耐盐的红树植物为主体的潮滩湿地林生物群落,其生长状态对于海岸带具有重要意义,利用遥感技术对红树林进行监测已成为目前主要手段之一。本文以广西北海山口红树林为例,利用HY-1C卫星的海岸带成像仪数据,结合其纹理参数,提取红树林信息,并对红树林植被指数进行分析。结果表明:2018年10月至11月间,红树林的RVI值均大于1,其中部分区域大于5;红树林的NDVI值的变化处于0~0.01之间,NDVI均值都大于0.5;红树林的EVI指数值主要集中在0.2~0.7之间。不同的植被指数计算结果均表明山口红树林长势良好。     

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.     

Local and landscape effects on spatial patterns of mangrove forest during wetter and drier periods: Moreton Bay,Southeast Queensland,Australia

Land use/cover and mangrove spatial changes were assessed for ten sites and their sub-catchments in Southeast Queensland, Australia. Two time periods were involved: 1972–1990, a period of relatively high rainfall, and 1990–2004, which was significantly drier. Aerial photographs and Landsat satellite imagery were used to map the inter-tidal wetlands and classify the land use/cover in the sub-catchments. A Maximum Likelihood Classification was used to map three types of land cover: agriculture, built-up and plantation forest. Mangroves (mainly Avicennia marina) were the focus as they have been recorded over recent decades encroaching into salt marsh. The Mangrove-Salt marsh Interface (MSI) Index was developed to quantify the relative opportunity for mangroves to expand into salt marshes, based on the shared boundary between them. The index showed a consistent relationship with mangrove expansion and change. To address problems of high dimensionality and multi-collinearity of predictor variables, a Partial Least Squares Regression (PLSR) model was used. A key finding of this research was that the contribution of environmental variables to spatial changes in the mangroves was altered following a reduction in rainfall. For example, agriculture had more influence on mangrove expansion and change during the wet period than during the dry period.     

Evolution and paleobiogeography of mangroves

We reviewed the geological record of mangroves based on fossil pollen, fruits, and wood evidence of Nypa, Avicennia, Sonneratia, Rhizophoraceae, and mangrove associates to trace the origin, distribution, extinction, and range contraction of paleo‐mangroves during the Late Cretaceous–Miocene time. Our study region covers paleocoastal areas of Indo‐West Pacific (IWP) and Atlantic East Pacific (AEP) region. First, we compiled the mangrove fossil records from the Late Cretaceous till Miocene and identified the migration pattern for Nypa, Avicennia, Sonneratia, Rhizophoraceae members, and mangrove associates such as Acrostichum, Wetherellia, Pelliciera, Aegiceras, Heritiera, Excoecaria, and Barringtonia. Second, we interpreted the paleoclimate shifts which caused the dispersal/extinction of this specialized ecosystem. Lastly, we proposed the future consequences of mangrove diversity for restoration and conservation strategies. First mangroves appeared during the Late Cretaceous, 100–65 Ma, since then their evolution is closely related to sea‐level changes in geological times. The oldest geological record of Nypa palm which prefers broad ecological tolerance is a good example for pantropical distribution of mangroves. High sea‐level and humid climate offered sufficient coastal regions and climate for the development of 12 genera of mangroves in nine families and subsequent proliferation into newer areas during early to middle Eocene (~50–40 Ma). The Eocene/Oligocene boundary crisis heralds the beginning of a biogeographical split between the present‐day eastern and western provinces of mangroves with records of Sonneratia, Rhizophora, Pelliciera, Barringtonia, and Acrostichum. However, during Oligocene and Middle Miocene mangroves occupied the present geographical position with addition of Nypa, Avicennia, and Excoecaria species. Re‐evaluation of Cenozoic records suggests that the climatic conditions of Late Paleocene, end of Eocene, and middle Pliocene were the driving force that led to the evolution and expansion of mangrove flora. During the Neogene, latitudinal contraction, extinction, and migration of mangroves led to the present bipartite distribution. The Himalayan uplift and establishment of Asian summer monsoon toward Late Neogene further affected the coastal dynamics which tailored the mangrove distribution of the Indian subcontinent. Loss of ecological habitats and local extinction forming disjunct distribution of mangroves during the Quaternary have also affected its overall biogeography.     

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.     

Response of the barrier island coastal region of southwestern Nigeria to climate and non-climate forcing

Despite threats emanating from the influence of climate and non-climate forcing on the barrier island coastal region of southwestern Nigeria, the extent of the coastal erosion is poorly understood. We report evidence of coastal erosion and sediment accumulation in the region over a 34-year period (1973–2017), using Landsat imagery at intervals of approximately six years. Landsat image corrections and various water-extraction algorithms were used to systematically delineate coastal erosion and accumulation in the area. The region was subdivided into western and eastern subregions separated by Lagos Harbour. In the west, erosion took place during the periods 1973–1979, 1979–1984, 1990–1999 and 2005–2011, whereas in the east, erosion occurred during 1973–1979, 1990–1999 and 1999–2005. Coastal sediment accumulation occurred in the east during 1979–1984, 1984–1990, 2005–2011 and 2011–2017, whereas gains in the west occurred during 1984–1990, 1999–2005 and 2011–2017. The study revealed substantial net erosion of 1 228.1 ha in the region as a whole, over the full period. Sediment accumulation accompanying the coastal erosion appears to be linked to longshore drift. Erosion between 1973 and 2011 was probably attributable to climate change (storms and tidal conditions), longshore drift, the inflow and outflow of water at Lagos Harbour, coastal morphology and, possibly, human impacts. However, the coastal changes between 2011 and 2017 were more obviously associated with human activities, such as development of the Eko Atlantic construction project. Coastal surveillance, together with the use of environmentally sensitive protective measures, could possibly help to reduce coastal erosion in the region. Careful coastal management practices, including artificial nourishing and the installation of resilient structures (e.g. seawalls), should be undertaken to protect human settlements that are already at risk from sea-level rise.     

Remote Sensing of Mangrove Change Along the Tanzania Coast

This article contributes to the understanding of the changes in distribution and total area of mangrove forests along the mainland Tanzania coast over the past decade. Mangroves are recognized as critical coastal habitat requiring protection and special attention. The Tanzania coastline forms a suitable habitat for establishment of mangrove forests. Mangrove forests are distributed from Tanga in the north to Mtwara in the south covering approximately 109,593 hectares from 1988-1990 and about 108,138 hectares in 2000. The largest continuous mangrove stands are found in the districts of Rufiji, Kilwa, Tanga-Muheza, and Mtwara. Comparison of data between these two time periods shows that the geographic coverage of mangroves has no dramatic change in the past decade. The Tanzania Mangrove Management Project and other closely related programs and efforts pertaining to mangrove conservation contribute to direct restoration and natural regeneration of mangroves. This study documents the changes of mangroves and demonstrates that remote sensing and GIS offer important data and tools in the advancement of coastal resource management and ecosystem monitoring. Application of geographic information technologies is critical for improved coastal resources management and decision making for sustainable development in Tanzania.     

Remote Sensing of Mangrove Change Along the Tanzania Coast

This article contributes to the understanding of the changes in distribution and total area of mangrove forests along the mainland Tanzania coast over the past decade. Mangroves are recognized as critical coastal habitat requiring protection and special attention. The Tanzania coastline forms a suitable habitat for establishment of mangrove forests. Mangrove forests are distributed from Tanga in the north to Mtwara in the south covering approximately 109,593 hectares from 1988-1990 and about 108,138 hectares in 2000. The largest continuous mangrove stands are found in the districts of Rufiji, Kilwa, Tanga-Muheza, and Mtwara. Comparison of data between these two time periods shows that the geographic coverage of mangroves has no dramatic change in the past decade. The Tanzania Mangrove Management Project and other closely related programs and efforts pertaining to mangrove conservation contribute to direct restoration and natural regeneration of mangroves. This study documents the changes of mangroves and demonstrates that remote sensing and GIS offer important data and tools in the advancement of coastal resource management and ecosystem monitoring. Application of geographic information technologies is critical for improved coastal resources management and decision making for sustainable development in Tanzania.