Ha Of Mangroves Research Articles

Blue carbon habitats in Aotearoa New Zealand—opportunities for conservation, restoration, and carbon sequestration

Coastal marine habitats (i.e. mangroves, saltmarshes, and seagrasses) have a high capacity for carbon sequestration (termed “blue carbon”) and the potential to reduce the effects of greenhouse gas emissions. However, blue carbon habitats have historically decreased as a consequence of land conversion, coastal development, and pollution and are under threat in many locations. Restoration of these habitats can reverse historic losses and generate carbon credits through increased carbon sequestration. With a long coastline, we hypothesized that there would be significant opportunities for coastal blue carbon in Aotearoa New Zealand. Results revealed Aotearoa estuaries and coastal areas contain approximately 20,932 ha of saltmarsh, 30,533 ha of mangrove, and 61,340 ha of seagrass, estimated to sequester a total of approximately 57,800 tC/year. A further 87,861 ha of land was estimated to be potentially suitable for blue carbon projects via tidal restoration, of which 56,482 ha was suitable for saltmarsh restoration (equivalent to 60,435 tC yr if restored), 17,291 ha was suitable for mangroves (26,455 tC/year), and 14,087 ha was suitable for seagrass (4790 tC/year). Both existing extent and restoration opportunity varied throughout the country, with greater opportunity in some regions than others. Nationwide, the total sequestration potential for blue carbon restoration was estimated at 91,680 tC yr−1 if all potential areas were restored. Carbon credits generated by blue carbon projects could be traded on a carbon market in Aotearoa, generate revenue for landowners, provide an additional pathway to meet domestic and international climate change targets, and result in a diversity of other ecological, social, and cultural co‐benefits from coastal restoration.

A novel use of mangrove root collar height to infer soil surface elevation change following forest degradation and clearance

Current methods for monitoring changes in mangrove soil surface elevation over time are limited in their spatial extent, costly and often involve difficult survey design. We developed a simple, extensive, rapid and inexpensive method to monitor soil surface elevation changes in mangroves following degradation: measuring the distance between the soil surface and the root collar (defined here as the height of emergence of a stem that is representative of the cross-sectional area of the main tree stem) of both live trees and dead stumps (called Δd). Δd was measured for two species, Bruguiera gymnorrhiza and Ceriops tagal, within the study area, which was categorised into intact, degraded and deforested mangroves in Tsimipaika Bay, Madagascar. A total of 227 subplots, containing 3066 individual tree stumps and live trees were surveyed within our study site, which spans approximately 4000 ha of mangroves. We used a linear model to test relationships between Δd and forest status, species, and live trees or remnant stumps. When measured on B. gymnorrhiza stumps, Δd (cm, mean ± standard error) increased from intact (18.4 ± 2.6) to degraded (24.7 ± 1.5) and finally to deforested mangroves (31.6 ± 0.7), indicating increasing soil elevation loss. A similar pattern did not emerge for C. tagal due to anthropogenic exploitation of their stumps, selectively removing large individuals for charcoal production, thereby confounding estimates of Δd. In addition, we used Δd measurements to construct a spatial analysis of carbon (C) loss following mangrove degradation in the bay. Our analysis predicted a mean C loss of 25.6 Mg C ha−1 (standard error 3.64 × 10−4) representing a lower mean loss value with reduced variability compared to previous Malagasy studies based on limited replicates within deforested areas. Our study demonstrated the use of this simple, yet scientifically rigorous approach to monitor soil elevation loss over time or following severe degradation in mangrove forests. These data facilitate estimates of C emissions from soils and vulnerability to sea level rise when mangroves are degraded. The simplicity and cost-effectiveness of our approach also provide an opportunity to actively involve local communities and practitioners in mangrove management and promote citizen science.

Uncovering mangrove range limits using very high resolution satellite imagery to detect fine‐scale mangrove and saltmarsh habitats in dynamic coastal ecotones

AbstractMangroves are important ecosystems for coastal biodiversity, resilience and carbon dynamics that are being threatened globally by human pressures and the impacts of climate change. Yet, at several geographic range limits in tropical–temperate transition zones, mangrove ecosystems are expanding poleward in response to changing macroclimatic drivers. Mangroves near range limits often grow to smaller statures and form dynamic, patchy distributions with other coastal habitats, which are difficult to map using moderate‐resolution (30‐m) satellite imagery. As a result, many of these mangrove areas are missing in global distribution maps. To better map small, scrub mangroves, we tested Landsat (30‐m) and Sentinel (10‐m) against very high resolution (VHR) Planet (3‐m) and WorldView (1.8‐m) imagery and assessed the accuracy of machine learning classification approaches in discerning current (2022) mangrove and saltmarsh from other coastal habitats in a rapidly changing ecotone along the east coast of Florida, USA. Our aim is to (1) quantify the mappable differences in landscape composition and complexity, class dominance and spatial properties of mangrove and saltmarsh patches due to image resolution; and (2) to resolve mapping uncertainties in the region. We found that the ability of Landsat to map mangrove distributions at the leading range edge was hampered by the size and extent of mangrove stands being too small for detection (50% accuracy). WorldView was the most successful in discerning mangroves from other wetland habitats (84% accuracy), closely followed by Planet (82%) and Sentinel (81%). With WorldView, we detected 800 ha of mangroves within the Florida range‐limit study area, 35% more mangroves than were detected with Planet, 114% more than Sentinel and 537% more than Landsat. Higher‐resolution imagery helped reveal additional variability in landscape metrics quantifying diversity, spatial configuration and connectedness among mangrove and saltmarsh habitats at the landscape, class and patch scales. Overall, VHR satellite imagery improved our ability to map mangroves at range limits and can help supplement moderate‐resolution global distributions and outdated regional maps.

Flow of mangrove ecosystem services to coastal communities in the Brazilian Amazon

Mangrove forests are broadly recognized to support a variety of ecosystem services on coastal margins worldwide. These services may significantly contribute to the wellbeing of millions of people, but there is limited information about their importance in the Global South. This study mapped for the first time the flow of ecosystem services in Brazilian Amazon mangroves, which represent over 700,000 ha of mangroves in the country. We also identified the spatial changes in the flow of services across coastal landscapes, including urban, agricultural upland areas and coastal natural protected areas. Our matrix model indicated that mangroves, waterbodies, sandflats and mudflats are critical to the flow of multiple ecosystem services, including provisioning (fish, mariculture), cultural (historical and intrinsic value, research, and education), and regulation (climate, flood control, nursery, and breeding grounds). Social economic context, occupation, education, and residence time are important factors influencing villagers to identify the flow of ecosystem services, which could be compared across other coastal marine reserves in South America that have similar management of natural resources. Adjacent coastal upland habitats such as forests and croplands are important to support many provisioning ecosystem services to coastal villagers that would otherwise be obtained from mangroves, suggesting that protecting these connected habitats and supporting small-scale agriculture may help to avoid deforestation of mangrove forests. As over 80% of the mangroves in the country are managed as extractive reserves and may support communities with comparable socio-economic characteristics, we provide a foundation for the development and replication of ecosystem services assessments in Brazilian mangroves, which cover an area of over 1 million hectares. Our work highlights the importance of mangrove forests in providing food, and cultural services and to increase local climate resilience of coastal villages in the Amazon coast.

Spatio-temporal dynamics of mangrove extent in coastal Bekasi Regency, Indonesia

One of West Java’s largest mangroves is found alongside the shore of Bekasi Regency. Nevertheless, the primary issues are the high degree of waste contamination, extraction of mangrove products, and conversion of mangrove forests into aquaculture ponds. To determine the present state of mangroves on the coast of Bekasi Regency, research on the dynamics of the mangrove extent spatio-temporally must be conducted. Mangrove mapping has made extensive use of machine learning and satellite images. This study aims to calculate the mangrove area in the villages of Pantaibahagia and Pantaibakti along the coast of Bekasi Regency using Random Forest (RF) classification based on the Google Earth Engine (GEE) Platform. The RF classification results showed a significant loss in mangrove extent over a short period of time (seven years). In 2017, the tidal zone was primarily covered by mangroves. From the linear trend line, it is known that from to 2017-2023, the mangrove area tended to decrease, while in 2023, there was a decrease in the mangrove area, especially in the north coast area. In 2017, the total mangrove area was 305.03 ha. Until 2019, there has been a slight increment, reaching 366.41 ha of mangrove are. The most significant loss was found in 2020, in which the total loss reached 85.58 ha in one year. After 2020, the mangrove area has slightly improved, but it is not significant. We tested the produced map of the RF classification using a confusion matrix and kappa coefficient, which resulted in an Overall Accuracy (OA) of 90.50% and a Kappa coefficient of 0.8105.

Invasion in the Niger Delta: remote sensing of mangrove conversion to invasive Nypa fruticans from 2015 to 2020

AbstractInvasive species are a leading threat to biodiversity worldwide. Nypa palm (Nypa fruticans) has emerged as the predominant invasive species in the Niger Delta region of Nigeria. While endemic mangroves have high rates of carbon sequestration, stabilize coastlines and protect biodiversity, Nypa does not provide these services outside its native region of Southeast Asia. Oil exploration and urbanization in this region also exacerbate mangrove loss and Nypa spread. As Nypa is difficult to distinguish from endemic mangrove species in remotely sensed data, estimates of mangrove and ecosystem services losses in Nigeria are highly uncertain. Here, we analyse multisensor satellite data with machine learning to quantify the rapid expansion of Nypa from 2015 to 2020 in Nigeria. Using Landsat imagery and random forest classification, we quantify total potential Nypa extent in Nigeria in 2019. We then produced a Nypa extent map using iterative combinations of Sentinel‐1 SAR, Sentinel‐2 MSI and ALOS PALSAR. Random forest classifications using SAR data from ALOS and Sentinel‐1 were best suited for mapping Nypa extent with similar accuracies (78% and 75%, respectively). Based on data availability and accuracy, we focussed our change analysis on Sentinel‐1 SAR. Our results show ~28 000 ha of mangroves were converted to Nypa in Nigeria by 2020 and covered a larger extent than endemic mangroves, compounding the effect of the existing degradation and deforestation in the region. We also compared forest height and complexity estimates from Global Ecosystem Dynamics Investigation LiDAR to further distinguish between endemic mangroves and Nypa in three dimensions. Nypa structural variability, measured by top‐of‐canopy height, vegetation cover, plant area index, and foliage height diversity, was lower than that of mangroves. At current rates of Nypa expansion, the entire area of study would be invaded by Nypa by 2028, with potentially detrimental consequences to the ecosystem services provided by mangroves.

Identifikasi Sebaran Spasial dan Kerapatan Mangrove Gili Lawang menggunakan Citra Landsat 9 OLI-2/TIRS-2

Mangrove ecosystems have a great influence on the sustainability of human life and the environment. The high level of vulnerability of mangrove ecosystems has implications for the importance of quality planning. This study aims to identify the spatial distribution and density of mangrove forests in Gili Lawang using Landsat 9 OLI-2/TIRS-2 satellite imagery. Data processing is done with the help of the QGIS 3.30 application. Data processing consists of band combinations, image classification with the SVM algorithm, classification results accuracy test, NDVI value extract, and reclass NDVI. The results showed that the use of band 564 in Landsat 9 imagery visually resulted in an increase in sharpness in identifying mangrove ecosystems. Classification of objects with the SVM algorithm has overall accuracy and kappa accuracy > 80%. The identified area of Gili Lawang is 432.72 ha, consisting of 37.89 ha of mangroves, 58.11 ha of non-mangrove and 3.75 ha of water bodies. NDVI values at the study sites ranged from 0.068 to 0.87. The maximum NDVI value is found in mangrove objects, while the minimum NDVI value is found in water body objects. Mangrove density in Gili Lawang is dominated by high and very high density. The use of Landsat 9 OLI-2/TIRS-2 imagery in the future is expected to provide positive benefits in providing data and information related to natural resources.

Monitoring of 35-Year Mangrove Wetland Change Dynamics and Agents in the Sundarbans Using Temporal Consistency Checking

Mangrove wetlands are rapidly being lost due to anthropogenic disturbances and natural processes, such as sea-level rise (SLR), but are also recovering as a result of conservation efforts. Accurate and contemporary mangrove maps to detect their distribution and changes are urgently needed to understand how mangroves respond to global change and develop effective conservation projects. Here, we developed a new change detection algorithm called temporal consistency checking combining annual classification and spectral time series (TCC-CS) for tracking mangrove losses and gains. Specifically, mangrove change events were determined by measuring the deviation of greenness and wetness of candidate change segments from automatically collected mangrove reference samples. By applying to the world’s largest mangrove patches, we monitored the 35-year mangrove trajectory in the Sundarbans from 1988 to 2022 using all available Landsat images on the Google Earth Engine platform. In the Sundarbans, 18,501.89 ha of mangroves have been gained, but these have been offset by losses of 27,009.79 ha, leading to a net mangrove loss of 1.42% (8507.9 ha) in the past 35 years. We further mapped the pixel-level change agents and found that SLR-induced erosion and degradation, instead of human activities, were the major drivers of losses in the Sundarbans. Trend analysis on loss agents indicates that mangrove losses caused by human activities, such as the expansion of croplands and aquaculture ponds, have declined, but SLR is still a persistent threat to mangrove wetlands in this iconic mangrove area. Our study provides a computationally efficient methodology for examining large-scale mangrove changes, and the resultant annual mangrove maps provide strong support for mangrove conservation in the Sundarbans.

Black summer bushfires caused extensive damage to estuarine wetlands in New South Wales, Australia

SummaryThere is now considerable evidence that, as the climate continues to warm, bushfires are becoming more common and severe, particularly in regions such as south‐eastern Australia. The extraordinary Australian bushfires over the summer of 2019/2020 resulted in the burning of habitats such as highland peat swamps and intertidal estuarine wetlands over unprecedented spatial scales. Across New South Wales, these bushfires affected 183 ha of saltmarshes and 23 ha of mangroves in 19 estuaries. The percentage of fire‐affected saltmarsh ranged from 51% to 81% in the worst impacted estuaries, although typically ≤15% of mapped saltmarsh was damaged. Just over 50% of mangroves were burnt in Wonboyn Lake (although this constituted <0.2 ha), whereas in all other estuaries, ≤5% of mangroves were burnt. At the state‐wide scale, the likelihood of saltmarshes being affected by fire was unrelated to adjacent terrestrial vegetation; however, mangroves adjacent to burnt wet sclerophyll forest were more likely to burn than not. Burnt mangroves were almost exclusively associated with extreme or high severity fires in adjacent terrestrial vegetation, yet saltmarshes were also impacted in some cases by moderate or low‐intensity fires. Many species of saltmarsh plants had re‐sprouted or germinated after 6–24 months, but the extent of any recovery or changes in species composition were not quantified. The majority of fire‐affected mangrove trees appeared to be dead 24 months after the fires, despite observations of epicormic growth on some trees after six months. Bushfire impacts to estuarine wetlands are likely to become more frequent and results from our work can help target hazard reduction burning that might be considered for minimising damage to mangroves. More work is required to better understand potential longer term impacts and the capacity for natural recovery of estuarine wetlands from bushfires.

Are the Sundarbans, the World's largest mangroves region under threat?—An ecosystem‐based geospatial approach to assess changes past, present, and future in relation to natural and human‐induced factors

AbstractThe World's most extensive mangrove region, the Sundarbans ecosystem, is highly biodiverse but severely stressed. Past, present, and future potential changes in Sundarbans mangroves have been assessed from multi‐temporal satellite data of 1980, 2000, and 2020, elevation data, and topographical maps using geospatial techniques, digital shoreline analysis system, land change modelling, and ground truth verification. The mangrove loss was 16,025 ha between 1980 and 2020 and is predicted to be 22,286 ha between 2020 and 2050. Major changes were observed in mangroves, waterbodies, mudflats, agriculture, and aquaculture. The shoreline change by endpoint rate indicated the erosion rate by 5.81 m yr−1 in 2000–2020 compared to −0.90 m yr−1 in 1980–2000. The weighted linear regression indicated the average erosion and accretion rate of −5.96 m‐yr −1 and 4.92 m yr−1, respectively, with erosion in 76% of transects and accretion in the remaining 24% between 1980 and 2020. A sea‐level rise by 1 m will inundate 17,486 ha of mangroves. The finding revealed the dynamic nature of mangroves, past and expected future loss, the severely eroding transects, hotspots, and the consequences of mangrove loss on depending the population. As fringe mangroves will be at greater risk, speedy measures are needed to stabilize the highly eroding regions.

Characterizing Global Patterns of Mangrove Canopy Height and Aboveground Biomass Derived from SRTM Data

Numerous studies have been done using remotely sensed data to produce global mangrove height and biomass maps; however, little is known about the worldwide pattern of mangroves in the Northern and Southern Hemispheres that corresponds to their height and biomass. The objective of this study was to investigate whether there is a specific pattern that can be seen between northern and southern mangroves according to height and biomass. Based on an empirical model, we processed Shuttle Radar Topographic Mission (SRTM) elevation data in combination with 450 field data points to produce a global mangrove height map and its corresponding aboveground biomass (AGB) per hectare at 30 m spatial resolution. We also refined the global mangrove area maps and provided a set of equations to determine the maximum mangrove height at any given latitude. Results showed that 10,639,916 ha of mangroves existed globally in the year 2000, with a total AGB of 1.696 Gt. Even though the areal coverage of mangroves was higher in the Northern Hemisphere, the total mangrove AGB was higher in the Southern Hemisphere. The majority of mangroves in both hemispheres were found to be between 6 and 8 m tall, although height distribution differed in each hemisphere. The global mangrove height equation for northern and southern mangroves produced from this study can be used by relevant stakeholders as an important reference for developing an appropriate management plan for the sustainability of the global mangrove ecosystem.

Is aquaculture development responsible for mangrove conversion in India? - A geospatial study to assess the influence of natural and anthropogenic factors on mangroves in the last three decades

Aquaculture was cited as the primary factor for the reduction of mangrove area worldwide. But, there is no data available on the extent of conversion of mangroves for aquaculture in India, the second largest country in global aquaculture production. The present study assessed the factors of changes in mangroves area between the pre aquaculture period and recent years. Landsat TM images of 1988, Sentinel 2 A images of 2018, geospatial analysis, ground truth verification, post-classification approach, and accuracy assessment were used for the assessment. Comparing the extent of mangroves area in 1988 with 2018, the gain and loss was 278% and 30% in Kerala, 859% and 19% in Karnataka, 204% and 18% in Maharashtra, and 4100 and 20% in Daman and Diu respectively. Mangrove extent has increased due to restoration activities, while lost due to coastal erosion and other developmental activities. Combining mangrove statistics drawn from this study with available data from earlier study, indicate that the aquaculture has converted 2052 ha of mangroves, which represents 0.66% of India's mangrove area. The extent of mangroves increased by 20.72% in India between 1988 and 2018. There is a possibility that part of the mangrove - converted lands are privately owned. Besides, Coastal Aquaculture Authority Act of 2005 prohibits the use of mangrove lands to aquaculture. The present study proves that shrimp aquaculture is not accountable for the large-scale changes in the mangrove lands of India, except in Andhra Pradesh State. However, it demands the land use policy to protect the mangrove lands in private owned lands by allocating alternate resource space, and monitoring periodically.

Pemetaan dan analisis tingkat kerusakan hutan mangrove di Taman Nasional Kutai berdasarkan data satelit landsat ETM dan kerapatan vegetasi

Along with the increase in population in the Kutai National Park (Kutai NP) has raised the land issue of due to the need for living space and the exploitation of natural resources. This study is part of an effort to evaluate the condition of mangrove forests as a first step effort to protect mangrove forests as critical habitat for coastal Kutai NP. The research was conducted in March to April 2012, with the goal of evaluating and measuring vegetation cover and land use (Land use) mangrove forests in coastal Kutai NP. For this purpose, the data is used Landsat ETM + image with 7 bands that recorded in 2008. Process analysis using NDVI (Normalizet Difference Vegetation Index) composite channel by IR (bands 4 and 3), while the extent of the damage was analyzed using standard from Decree of Ministry of environment No. 201, 2004. Base on the research, Kutai National Park has the potential of ± 5192.54 ha of mangroves, mangrove forest ecological conditions in Kutai NP generally be in the grade is still good with vegetation density ranging between 967-1567 ind / ha, Kutai NP In some areas such as the Estuary Sangatta, bay and estuary Sangkima Lombok are areas that have experienced enough land conversion, overall mangrove forest that has been opened by ± 1845.85 ha or 26.2%. Mangrove forests are located close to residential vulnerable to land-use changes.

Assessment of Mangrove Restoration Potential in the North Western Province of Sri Lanka for Climate Change Mitigation

Over the geological time, the planet's climate has been changing constantly, with large variations in global average temperatures. Millions of people are already suffering as a result of natural disasters worsened by climate change. The Paris Agreement is an international climate change treaty, and countries will present their climate action plans, referred to as Nationally Determined Contributions (NDCs). In response to the Paris Agreement, Sri Lanka presented NDCs in 2016. In which the coastal and marine sector has a restoration target of 10,000 ha of mangroves as a coastal greenbelt with mitigation co-benefits. However, identification of potential lands for such restoration of mangroves has not been done. Therefore, identification of potential areas for mangrove restoration is most important because mangroves cannot be restored where they were not previously existed. The main objective of this research therefore was to identify potential areas for mangrove restoration within the North-Western Province. Identification of potential lands in North-Western Province were done by using Google Earth Pro and ArcGIS 10.2.2. Most important physicochemical parameters such as salinity, pH, soil organic matter content, soil water holding capacity were analyzed under laboratory conditions, samples were obtained by different sites of mangrove habitats. Soil salinity, pH were measured by using calibrated multiparameter. The loss of ignition method for soil organic matter content and a customized method for soil water holding capacity were used. All parameters were subjected to two-way ANOVA in MINITAB 14 after following Anderson Darling Normality test. The mean of soil salinity, pH, soil organic matter content, and soil water holding capacity were ranged respectively; 4.26% to 5.93%, 6.07 to 8.62, 3.40% to 9.31%, and 30.39% to 46.38%. The potential lands for restoring mangroves in North-Western Province were identified in Chilaw, Kalpitiya, Mundel, Panirendawa, Puttalam, Vanathawilluwa and Vennappuwa Divisional Secretariant Divisions. Among them, availability for historical images in Google Earth Pro there were specially chosen areas to restore the mangroves. There is no any significant difference of physicochemical parameters among mangrove habitats and an abandoned shrimp farm where there were previously mangrove plants existed. Hence, abandoned shrimp farms and salterns can be used to restore the mangrove plants and the assisted natural regeneration of mangroves in suitable abandoned shrimp farms by way of facilitating hydrology to be explored as the best option for mangrove restoration.
 Keywords: Mangrove restoration, Nationally Determined Contributions (NDCs), Assisted natural regeneration, Areas suitable for mangrove restoration

ADVERSE EFFECTS OF CLIMATE CHANGE ON INDIAN MANGROVES: A SOCIOECONOMIC CRISIS AND A THREAT TO THE RURAL DEVELOPMENT

Mangroves are highly loaded with immense nutrient and always share it with adjoining coastal habitats. Interestingly this system supports number of endemic and endangered species throughout the tropical coast. India has more than 7500 km coastal line within this, it supports 4, 87,100 ha of mangroves and harbours 3985 species of flora and fauna. During late 80s India lost considerable areas of its mangrove cover due to several anthropogenic pressures [1]. The ongoing climate change turned out to be a potential threat to the remaining Indian mangroves and other coastal ecosystem. Ironically there is no sound study till date about the impacts of ongoing climate change on Indian mangroves [2]. The loss of mangroves will spread its impact on the adjoining system in a significant way. So, the mangrove loss will negatively influence the fishery resource of the tropical region and initiate regional and global socioeconomical crisis. KEYWORDS :- Climate Change, Mangroves, Biodiversity loss, Socioeconomic Crisis

Analysis of land use change in Mangrove of the Barra San José, Chiapas, Mexico

Mangroves are the most productive ecosystems in the world, since they provide ecosystem services, are biological filters, stabilize the coastline and are the habitat of important fishing species and migratory birds nest. However, the inadequate implementation of agricultural, livestock and tourism development policies has implied the loss of biodiversity, habitat fragmentation and deforestation. The objective of this work is to evaluate the dynamics of changes in mangrove cover and land use in Barra San José, Chiapas, Mexico, in the period 1978-2017. The detection of the changes was carried out by means of a post-classificatory multitemporal study, through the superposition of digital cartographic bases of land use of the series III and VI of the INEGI. Maps of change processes, deforestation rates, and change matrices were obtained. The results indicate a loss of 574 ha of Mangroves in 39 years, with a deforestation rate of -0.41%, where human settlements and agriculture accounted for 90% of the changes. The conversion of Mangroves to grasslands was very marked, showing the fragmentation and loss of habitat to which the forests are exposed in the study area. The results of this analysis should be considered in the establishment of management and conservation policies for this ecological region.

Total Ecosystem Carbon Stocks of Mangroves in Lamu, Kenya; and Their Potential Contributions to the Climate Change Agenda in the Country

Mangroves are carbon-rich ecosystems found in tropical and subtropical areas around the world. However, they are threatened by a combination of natural and human-induced factors. When mangroves are lost or degraded, their co-benefits to human society are greatly diminished along with the ecosystem’s ability to sequester carbon. The current study assessed mangrove cover and cover change, as well as measuring carbon stocks and their emissions levels from the mangroves of Lamu County, Kenya. We sampled above-and below-ground carbon pools, including soil organic carbon (SOC), in 191 plots distributed throughout the study area. Lastly, we evaluated the economics of avoiding mangrove deforestation based on the carbon-offset market. The total carbon stock of mangroves in Lamu was estimated at 20 million Mg C, with an average density of 560.22 ± 79.79 Mg C ha–1. Southern swamps recorded significantly higher carbon densities (p < 0.05) than other mangrove management blocks in Lamu. At least 1,739 ha of mangroves in Lamu were lost between 1990 and 2019 due to anthropogenic activities, representing a decline of 60 ha yr–1. Total emissions from loss and degradation of mangroves in Lamu is estimated at 140.1 Mg C ha–1; which translates to 30,840.1 Mg CO2e yr–1. Assuming an offset price of US$10/Mg CO2e, the estimated costs of avoided emissions in Lamu is US$308,401 yr–1 plus other co-benefits such as fishery functions and shoreline protection. Mainstreaming mangroves and associated blue carbon ecosystems into national development and climate change agenda could accelerate Kenya’s achievements of both Sustainable Development Goals (SDGs) and the Paris Agreement.

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

Mangroves around the world provide humanity with a variety of ecosystem services. However, rising populations coupled with human activities jeopardize the sustainable management of these ecosystems. Climate change is also expected to have a severe impact on mangrove ecosystems, especially in Benin, West Africa. Since 2000, several initiatives for the conservation of mangroves have been established under the Ramsar Convention on Wetlands. Land use/land cover (LULC) changes were used at Ramsar Site 1017 in Benin for periods in 1995, 2005 and 2015 to assess the impact of the Ramsar Convention on mangrove ecosystem conservation. The observed changes during 1995–2005 and 2005–2015 were considered to predict LULC change towards 2070 using the Markov chain model. During 1995–2005, a total area of 3.43 ha of mangroves was degraded, while during the 2005–2015 period 2.65 ha were restored. Future scenarios predicted that the area of mangroves was expected to decrease by more than half between 1995 and 2070, assuming the dynamic of 1995–2005, and increase by 1.1% of the 2005 area by 2070 with the dynamic of 2005–2015. Implementation of conservation policies, projects and awareness-raising activities could contribute to the effective restoration of the mangrove ecosystems.

Niger Delta Remediation – Complex Balancing among the Local Community, Government Agencies, NGOs, Cleanup Contractors, and the Petroleum Industry; An Example from Bodo Ogoniland, Nigeria.

ABSTRACT Oil-related damage to productive mangrove habitat is prevalent in most areas of the Niger Delta where oil operations (drilling, pipelines and oil export) are present. The remediation and restoration of these areas is one of the most intractable problems confronting the oil industry and government today. The formation of the Bodo Mediation Initiative (BMI) with a partnership between the various parties has been mostly successful to date and offers a path forward to other parts of the Delta. Ogoniland, where Bodo is located, has a long history of agitations against the oil industry as a result of dwindling livelihoods and deteriorating public health largely perceived to be caused by the degradation in environmental quality due to oil spills. In 2008, two large oil spills occurred from operational breaks in the Trans Niger Pipeline and subsequently ~1000 ha of mangroves were directly killed by the spills. From 2009 onward, spills from illegal activities (oil theft, transport and refining) became common, inhibiting potential mangrove recovery further affecting the livelihood of many Bodo residents. The BMI was formed in 2013 under the auspices of the Dutch Ambassador to Nigeria with a focus on building trust between the pipeline operating oil company and the local community, in order to initiate cleanup and restoration of the damaged mangrove habitat around Bodo. The mediation process of the BMI was fraught with difficulties due to internal community squabbles arising largely from a misperception regarding the attendant benefits to the community. After a series of delays and mediation efforts, cleanup began in 2017 and continues until present (2019) with planned continuance to 2020. While the Project has obtained many successes, the inability to prevent continuing oil theft and illegal refining is a notable failure, causing continued spillages to the area and setbacks to the cleanup and restoration program being undertaken.

Impact of logging on the biodiversity and composition of flora and fauna in the mangrove forests of Bintuni Bay, West Papua, Indonesia

The mangrove ecosystem of Bintuni Bay, West Papua, Indonesia is one of the largest in the world covering more than 250,000 ha. In the southern part of the bay, ± 82,120 ha of mangroves and surrounding area is managed and harvested under a 30-year rotation cycle to produce wood chips, with strict compliance to sustainable forest management standards. Flora and fauna have been continuously monitored for a period of 10 years (2009–2018), to assess the effectiveness of environmental management programs on the biological aspect. Mangrove flora and fauna recorded in the area comprise 28 true mangrove species representing 11 families along with 103 birds (40 families), 9 reptiles (6 families) and 7 mammals (5 families). Results confirm previous studies that secondary mangrove forest shows significant growth and recovery, with 5 true mangrove species consistently becoming dominant species in primary and secondary mangrove forest. Logging on mangroves significantly impacted the biodiversity of flora as Rhizopora apiculata become more dominant in secondary forest covering 69% of total species composition. Abundance and diversity of fauna in secondary forest was higher in younger forests as compared to older stands. About 18% of total fauna individual was categorized as keystone species. Fauna composition was not significantly impacted by logging most likely due to the abundance of habitat (untouched forest) remaining in the surrounding harvest area. With appropriate environmental management programs, impact of logging on mangrove forest can be minimized and the ecosystem could be restored effectively to provide adequate habitat for flora and fauna.