Rapid Estimation of Mangrove Area and Carbon Sequestration in Land Subsidence Regions of Coastal Taiwan

Transitions in Ancient Inland Freshwater Resource Management in Sri Lanka Affect Biota and Human Populations in and around Coastal Lagoons

Situated in the Western Pacific Ocean, Taiwan is frequently affected by powerful typhoons. The present research evaluates the storm surges that could take place along the western coastline of Taiwan, and the design water level that will likely be required by coastal structures in the course of the 21st century to protect coastal settlements. To do so, the intensity of a given case study typhoon (Soudelor, which caused great damage to Taiwan in 2015) that could affect the target case study area (Yunlin county) was modified by taking into account climate change and sea level rise (SLR), by changing the sea surface temperature (SST), atmospheric air temperature (AAT), and relative humidity (RH) in an ensemble of 14 GCMs in CMIP5 according to RCP4.5 and RCP8.5, targeting the year 2041~2060 and 2081~2100 time horizons. The Advanced Research Weather Research and Forecasting Model (WRF-ARW) and the Unstructured Finite Volume Community Ocean Model (FVCOM) were utilized to simulate the typhoons and storm surges. The hindcasting of the historical typhoon showed good agreement with the observed data provided by the Central Weather Bureau (CWB) in Taiwan, and the simulations under future climate change scenarios forecasted an increase in typhoon intensity, especially the maximum wind speed. However, the storm surge simulations indicated a limited increase in storm surge height, and even a decrease when considering also SLR. Nevertheless, the estimated maximum water level, including both effect of SLR and future storm surge height, can increase up to 3.53 m and 3.84 m relative to mean sea level at the tidal stations in Yunlin and Chiayi County, respectively. The results showed that storm surges in the study area, characterized by a shallow bathymetry with many sandbars and land reclamation projects, are highly influenced by the change in water depth due to SLR and tidal changes, and the existence of the Central Mountain Range, which can greatly affect the accuracy of the simulated typhoon wind fields.

Potential impact of predicted sea level rise on carbon sink function of mangrove ecosystems with special reference to Negombo estuary, Sri Lanka

海平面上升影响下广西钦州湾红树林脆弱性评价

The effects of climate change are now becoming more detectable because of the alarming rate of observed changes in our planet. One of the more devastating outcomes of climate change has been sea level rise (SLR). The present study aims at developing preliminary models of SLR and its effects on the coastlines of Abu Dhabi Emirate. A second aim has also been to develop a natural vulnerability index for decision makers and stakeholders to develop action plans in areas most vulnerable to SLR. For urban areas, the level of damage due to SLR would rise to 9.45% and 15.89% in a potential 1.5 m and 2 m SLR scenarios; respectively. The maximum damage to the urban areas would reach about 40% in case SLR attains the 3 m level. Mangrove Ecosystems affected would reach 25.54 Km2 (or about 81.5% of the study area) under a 3 m SLR scenario. The total land areas that would be affected by the different SLR scenarios reaches a staggering 528 Km2 (or 30% of the study area) at the 3 m SLR scenario. More than 3% of the impacted area (when considering any of the SLR scenarios) is classified as very highly vulnerable. More than 7% is classified as highly vulnerable. It is strongly believed that any future interventions and preparations to alleviate the impact of SLR should take into account the vulnerable areas highlighted above (i.e. 10.3%). The estimates reported here highlight the gravity of the potential mangrove and land areas affected, even under the lowest SLR level. Early planning for longer term implications will certainly save both time and resources.

Sea-level rise caused by global climate change will have significant impacts on the coastal zone. On tropical and subtropical coasts, mangrove ecosystems occur in the intertidal zone and are particularly sensitive to sea-level rise. Taking the mangrove ecosystems in the coastal zone of Guangxi province, China, as a case study, the potential impacts of sea-level rise were analyzed by adopting the Intergovernmental Panel on Climate Change (IPCC) vulnerability definition. An indicator system for vulnerability assessment on coastal mangroves undergoing sea-level rise was developed, in which the rate of sea-level rise, subsidence/uplift rate, habitat elevation, mean daily inundation duration, intertidal slope and sedimentation rate were selected as the key indicators. A spatial assessment method based on a geographic information systems platform was established by quantifying each indicator, calculating the vulnerability index and grading the vulnerability. Vulnerability assessment, based on the projection of sea-level rise rates from the present trend and IPCC’s A1FI scenario, was performed for three time periods: short term (2030s), medium term (2050s) and long term (2100s). The results showed that, using the present SLR rate of 0.29 cm/year, the mangrove ecosystems in the coastal zone of Guangxi would be affected only in the long-term scenario up to 2100, but not in the short-term or medium-term scenarios. In the long-term scenario of the present trend, 5.4 % of the mangroves would be within areas of low vulnerability. Under the A1FI climate change scenario, with a sea-level rise rate of 0.59 cm/year, 25.8 and 37.3 % of mangroves were within areas of low vulnerability in the scenarios of up to 2030s and the 2050s, while 23.9 and 13.4 % of mangroves were within areas of low and moderate vulnerability in the 2100s, respectively. The development of this new methodology for vulnerability assessment and the results presented in this study could assist with the objective and quantitative assessment of the vulnerability of mangrove ecosystems undergoing the impacts of sea-level rise elsewhere. Without proper mitigation options, the potential decrease and loss of mangrove habitats and ecosystem services from the Guangxi coast are inevitable. Based on the results of this study, mitigation measures should be considered for securing the future of these mangrove ecosystems, which include the management of sedimentation, control of reclamation, and methods for habitat rehabilitation.

Sea level rise (SLR) due to global climate change negatively impacts coastal zones, in particular wetland and mangrove ecosystems. Mangroves in the Mekong Delta (MD) in Vietnam provide critical ecosystem services in the region; however, escalated relative SLR is likely to affect all ecosystems in the region, with mangroves probably more vulnerable than others. Given the fact that documented information and studies on SLR impacts on mangroves are limited for the region, this study aims to investigate potential changes in mangrove distribution in response to future SLR scenarios in the coastal area in the south of the MD using the Sea Level Affects Marshes Model (SLAMM). Wetland maps for 2013 derived from Landsat 8 OLI sensor, digital elevation model (DEM), and localized site-specific parameters (i.e., subsidence/accretion, erosion, historic trend of SLR, and over-wash) were used as input for the SLAMM to simulate spatial distribution of mangroves under different relative SLR scenarios (i.e., RCP2.6, RCP4.5, RCP8.5, more extreme SLR), and surface elevation change (i.e., subsidence, stable, and accretion) scenarios by the year 2100. Simulation results show that the average annual mangrove losses are likely to be 0.54% and 0.22% for subsidence and stable scenarios, respectively. The findings demonstrate the considerable impacts of SLR on MD mangrove ecosystems and the strong influence of subsidence processes. Inundation was also identified as a main driver responsible for the mangrove loss by the end of this century. Our results are in agreement with findings of other studies at global scales and observed data at regional scales. The results also demonstrate the potential of the approach developed herein for simulating mangrove dynamics under future relative SLR scenarios in the region with acceptable accuracy. The findings from the present study are useful sources for development of proper strategies for minimizing the impacts of SLR on mangrove ecosystems and their vital associated services, to protect and conserve the mangrove ecosystems in the region.

How far are mangrove ecosystems in Benin (West Africa) conserved by the Ramsar Convention?

Evaluation of the threat from sea-level rise to the mangrove ecosystems in Tieshangang Bay, southern China

<p class="Els-Abstract-text">Bogowonto Lagoon has the largest mangrove ecosystem in southern coast of Yogyakarta, Indonesia. Several activities on mangrove restoration have been conducted to escalate this remnant mangrove forest area. Conversely, rapid increase of shrimp pond area become threat for mangrove ecosystem in Bogowonto lagoon since the early of 21<sup>st</sup> century. Hence, This study is aimed to investigate mangrove composition, distribution and abundance, progress of mangrove restoration program and shrimp pond extensification in 2002 to 2014. Conducted from April 2015 to May 2015, this research consists of several steps namely survey, vegetation analysis, literature study, sociological study using questionnaire, measurement of mangrove and shrimp pond area using Landsat 8 imageries and Arc GIS 10.1. We determined 15 sites along Bogowonto Lagoon using random sampling by quadratic plot (10 m × 10 m for tree, 5 m ×5 m for sapling) and total counts (for seedling). The result showed that there were seven species of mangrove and six species of associate mangrove. <em>Rhizopora mucronata</em> Lamb. was dominant in each growthform with clumped distribution. <em>R. mucronata</em> and <em>Avicennia marina</em> (<a title="Forssk." href="https://en.wikipedia.org/wiki/Forssk.">Forssk.</a>) <a title="Vierh." href="https://en.wikipedia.org/wiki/Vierh.">Vierh.</a> also dominate from backswamp to rivermouth. Satellite imageries revealed that there was a hope due to upward trends of mangrove area in last 12 yr (approximately 5 ha). However, the significant increase sof shrimp pond area (approximately 34 ha) surrounding mangrove area become current and future threat. Based on sociological study, most of people around Bogowonto Lagoon have high awareness, but less participated on mangrove restoration program. Besides, the river mouth covered by sand become another obstacle of it.</p><div><p class="Els-keywords"><em> </em></p><p class="Els-keywords"><em>Keywords:</em> Bogowonto lagoon, mangrove restoration, shrimp pond, vegetation analysis</p></div>

          Soil microorganisms, in association with mangrove trees, play an important role in supporting the foundation of the ecosystem functions. Understanding the microbial contributions to mangrove ecosystem function and stability is essential for effective conservation and management. Currently, mangroves face heightened vulnerability to the repercussions of global warming. Factors such as elevated temperatures, rising sea level, increased flooding frequency and duration, and salinity fluctuations impact microbial diversity within these ecosystems. Identification and understanding of the core microbiota and mangrove microbial biodiversity remains scarce, specifically in the arid region. This research aims to provide insights into microbial strategies for coping with environmental change, contributing to sustainable mangrove management and ecosystem resilience in the United Arab Emirates (UAE) and beyond.          The UAE government has initiated extensive mangrove afforestation efforts to safeguard coastal environments, yet comparisons between afforested and reforested strategies in terms of microbial community dynamics remain sparse. Considration of microbial communities in mangrove restoration projects is an important key enhance establishment, growth and stress tolerance of mangrove trees as well as enhance the success of the initiatives. In this study, two afforested sites (Ras Al Khor wildlife sanctuary and Jebel Ali wildlife sanctuary, Dubai) and a reforested site (Khor Al Beidah, Umm Al Quwain) in the UAE were selected, with their forest ages approximately >30, 14 years, respectively. Topsoil samples were collected from grey mangrove (Avicennia marina) forests and surrounding non-vegetated area and salt marshes for two seasons.          Current findings revealed that Jebel Ali site (

Nigeria has an estimated mangrove area of 10,515 Km2, which forms about 5.8% of world total mangrove area, and the largest in Africa. Nigeria also ranks fourth among the eight countries where large mangrove reserves still exist, behind Indonesia, Brazil and Australia. With the exception of Nigeria, these countries with very large areas of mangroves have significant number of mangrove protected areas while still promoting mangrove afforestation and reforestation projects. Nigeria, on the contrary, has no gazetted mangrove-protected areas, neither are there mangrove restoration projects at present. Global forests including mangroves are depleting at an alarming rate. Climate change and its impacts are evident in our country. It is common knowledge that mangrove ecosystem offers great resilience to climate change impacts. It is also common knowledge that coastal regions are most vulnerable to climate change effects. Therefore, policy and legislation are urgently needed for the conservation and restoration of Nigeria’s mangrove ecosystem, which not only supports rural livelihoods but also provides protection from climate change-related hazards, especially of ocean origin. Such policies and legislations will establish implementation strategies including inventory of the mangrove resources, developing the framework for a “National Mangrove Park”, instituting mangrove restoration programmes with requisite monitoring and evaluation mechanisms, and promoting community awareness. Community-based approach has been adjudged the most successful in natural resources conservation globally, and is therefore recommended for this proposal. Keywords: Mangrove; Ecosystem; Restoration; Conservation; Climate change; Nigeria Introduction Mangroves are known to occupy the tropical and subtropical belts of the world. The mangrove ecosystem is both dynamic and fragile. In many countries of the tropics, coastal livelihoods are supported through utilization of the resources provided by this unique ecosystem. This ecosystem has the highest biological diversity compared to any part of the sea. It is estimated to contribute about 25% of global biological productions [1]. Azariah and Govindasamy [2] reported that more than 2145 species of plants and animals have been identified in this ecosystem on worldwide basis. The mangrove ecosystem is also known to support most of the world’s [3]. It provides excellent pedagogic and research resources. Above all, the role of mangroves (one of the so-called blue carbon ecosystems) in climate change mitigation in terms of carbon sequestration is significant [4-6]. Also, the role of mangroves in coastline protection against sea-level rise and storm surges is unique [7,8]. However, since the end of World War II, new technologies and methodologies have been introduced to achieve greater financial returns from mangrove areas, providing quick gains at the cost of permanent wealth [9]. Hence, mangroves are being overexploited for various industrial, domestic and medicinal uses. The immediate outcome of mangrove habitat destruction and/or modification is the decline of biodiversity. Unfortunately, the rate of destruction is still ahead of conversation and management for longterm sustained production. Protection of mangroves means protection of biodiversity, and sustained provision of the various socioeconomic needs and services, but any loss of biodiversity is an irrevocable loss. The present paper

Mangrove ecosystems play a critical role in climate regulation, carbon sequestration, and pollution mitigation. However, their long-term resilience to accelerating sea-level rise (SLR) under global climate change scenarios remains uncertain. Vertical soil accretion is a critical factor in determining the vulnerability of mangrove wetlands to SLR. In this study, vertical soil accretion rates in a mangrove wetland in the Beilun estuary were measured using a 210Pbex dating method. Based on recently acquired data and previously available data, we conducted the first systematic assessment of SLR risk in mangrove wetlands in the Guangxi coastal zone in the context of increasing global climate change and extreme weather. The results show that the vertical soil accretion rate of 6.72 ± 1.91 (4.22–10.54) mm/a in the Beilun estuary is slightly higher than SLR rate in the Guangxi coastal zone. Concurrently, our results indicate that mangroves with thriving root systems enhance soil accretion through biotic controls in the Beilun estuary, while significant changes in soil sources and hydrodynamic forces during the 1980s and 2000s contributed to adaptation to SLR. Additionally, by linking sedimentation dynamics with SLR projections, we reveal that current accretion rates in some mangrove areas in the Guangxi coastal zone are insufficient to offset the projected SLR by the end of 2050 and 2100. This finding offers a new perspective on the traditional assumption of inherent resilience in mangroves while revealing the adaptive capacity of mangroves in the Beilun estuary and Guangxi coastal zone under projected SLR scenarios. It underscores the need for integrated management strategies that balance sediment supply maintenance and ecological restoration, which are critical to ensuring the long-term resilience of mangrove ecosystems, in line with sustainability principles.

Mangrove ecosystems are among the most efficient natural carbon sinks on Earth. Overall global mangrove loss between 2000 and 2016 was 3363 km2 (2.1%) owing to land-use and land-cover change. It is predicted that global greenhouse-gas emissions will reach 2391 Tg CO2 eq by 2100. The conversion of mangrove forests for various activities has reduced vegetation abundance, which has an impact on the global carbon cycle because of changes to the carbon dynamics in each climate zone. We will create a revised systematic protocol built on the systematic protocol of Sasmito et al. (2016) by adding information on species’ ability to absorb carbon to contribute to the global climate cycle, particularly, in relation to land-use and land-cover change of mangrove forests. Our primary question will be how do local climate characteristics (micro-meteorological) associated with land-use and land-cover change affect the carbon dynamics of mangrove species? Our protocol will focus on carbon dynamics, including absorption ability, stocks, fluxes and sequestration, in particular climate zones, to assess species’ distribution and diversity, using spatial mapping to identify suitable species for restoration programmes across Asia and the Pacific. The review will include peer-reviewed and grey literature (including unpublished studies) since 2019 onwards combined with references from Sasmito et al. 2016 from 1970 onwards specific to carbon dynamics of mangrove species. The output of our review will be geographical mapping of species’ distribution and diversity together with estimation of carbon absorption capacity, stocks, fluxes and sequestration in different climate zones, noting latitude, longitude and characteristics of the habitats. Rhizophora sp. — one of the most dominant species — has higher carbon absorption ability than Bruguiera sp. of the same age undergoing tropical monsoon mangrove-cover changing to fishponds and housing in Indonesia. Rhizophora sp. also store high amounts of carbon owing to strong carbon uptake ability compared to Octornia octodonta, Sonneratia alba, Ceriops tagal and Avicennia marina in tropical northwest monsoon areas. In contrast, Kandelia obovata has the highest carbon density (148.03 t ha-1) followed by Avicennia marina (104.79 t ha-1) and Aegiceras corniculatum (99.24 t ha-1) in another tropical monsoon climate in China. The carbon stocks of vegetation in subtropical mangroves show lower rates compared to tropical mangroves. The ability of species to absorb carbon is affected by the climate zone and its characteristics — which has a strong impact on carbon dynamics and affects global climate regulation — particularly, in disturbed mangrove forests. Mangrove ecosystems are home to coastal flora and fauna with high quantities of carbon stored and sequestered as part of major global carbon cycles. Consequently, it is essential to assess the carbon dynamics of mangrove species and the association with ecosystem services as part of land-use and land-cover change in various mangrove ecosystems.

Sea level rise is the inevitable outcome of global warming, climate change and other catastrophic events like tsunami, land tilt, cyclones etc which lead to sudden change in sea level.As the sea level is rise mangroves are the first responders that affect in the coastline.Mangrove plays an important role in preventing coastal erosion, as it is an authentic matter this study was performed for analysing some of the mangrove species are sensitive to catastrophic sea level rise and its resulting inundation.Coastal areas of Flat bay were taken for this study where it is estimated that 46% of coastline was covered by mangroves.December 2004 tsunami and tectonic tilt of South Andaman results in inundation of the flat bay coastal regions and the raised sea level doesn't retrieve it leads to drastic changes in the mangrove environment of sippighat creek and nearby areas.Satellite image shows submerged and affected mangroves in the inundation caused by tsunami.In this area on comparing 1998 and 2011 satellite images out of 388.81 ha of mangroves 176.92 and 57.67 ha are affected and submerged respectively due to inundation and sea level rise.Submergence and degradation takes place in the seaward mangroves and the landward or riverine mangroves consequently invade to the land results in changes of mangrove distribution.Rejuvenation of mangroves occurs rapidly in the inundated areas of sippighat coast where 9.18 ha of mangrove community habitat at juvenile and sapling stage were observed in the field.The present status of mangroves in flat bay coast was calculated as 163.40 ha.These field investigations were compared with geospatial analysis and concluded the impacts of sea level rise on mangroves.Finally from the field survey and geospatial analysis evaluated that seaward mangroves are degraded more and landward mangroves are migrating landward.