Mangrove Loss Research Articles

Carbon stock potential in rehabilitated mangrove in Lubuk Kertang Village, North Sumatra, Indonesia

Mangrove forests are one of the most productive and efficient long-term natural carbon sinks, tropical natural resources that have social, economic and ecological benefits. Even though the area of mangrove forests is relatively large in of the world, the consequences of various anthropogenic cause various damages. Given their global significance as a large carbon sink, preventing mangrove loss would be an effective climate change adaptation and mitigation strategy. This research was conducted to analyze carbon stocks in mangrove forests resulting from the rehabilitation of former pond land in Lubuk Kertang Village, West Brandan District, Langkat, North Sumatra, Indonesia. The census method was applied in this study, to calculate the value of carbon stocks using an allometric equation with DBH > 5cm. The aboveground biomass was 15.54 Mg/ha. Soil sampling for organic carbon content by collecting a sub-sample 5 cm from the center of the core. The total value of the total carbon stock above and below the soil surface is 9.42 Mg/ha1 and soil carbon is 685 MgC/ha1.

Comments on Acosta-Velázquez et al. changes in mangrove coverage classification criteria could impact the conservation of mangroves in Mexico. Land Use Policy, 2023, 129, 106651

Accurate and up-to-date mapping of mangrove habitats is crucial for effective conservation and management strategies and policies. As a reply to the comparative assessment realized by Acosta et al. (2023) to the last map produced by the Mexican Mangrove Monitoring System (MMMS) and the conclusions resulting from it, we provide a comprehensive response addressing the concerns raised. We acknowledge that maps are not infallible and are subject to improvement, particularly in the rapidly advancing field of remote sensing technology used in long term monitoring system. The MMMS mapping efforts utilize state-of-the-art remote sensing technologies, such as high-resolution satellite imagery and advanced methodologies, to enhance precision and efficiency. Moreover, MMMS mapping integrates regional external expert knowledge to increase accuracy at uncertain locations. We emphasize the importance of accuracy and reliability in mangrove mapping due to the potential irreversible consequences of mangrove loss. The MMMS provides a valuable tool for monitoring deforestation rates, understanding spatial distribution, supporting management decisions, identifying conservation priorities, and facilitating targeted conservation actions. We highlight the application of the precautionary principle as an environmental imperative for the Mexican government. The inclusion of previously classified "Other wetlands" as mangroves in the MMMS mapping system implies the acknowledgment of their integral role in supporting biodiversity and climate change mitigation efforts. Technological progress and collaborative efforts have made this reclassification possible, enhancing our understanding and expertise in distinguishing mangroves from other wetland types. We conclude that our mapping efforts align with the objective of attaining high classification accuracy in remote sensing, and we remain committed to continuous improvement in our mangrove mapping endeavors.

People and Mangroves: Biocultural Utilization of Mangrove Forest Ecosystem in Southeast Asia

Mangroves provide diverse benefits for various coastal communities in Southeast Asia. Unfortunately, the same region exhibits the highest global rates of mangrove loss. Whilst studies exploring its value as a biocultural refugia remain lacking, the associated biocultural uses of mangroves are likewise under threat. Using the PRISMA approach, 33 studies passed the eligibility and screening process. The majority of biocultural studies were from Indonesia (60%), Malaysia (9%), Philippines (9%), and Thailand (9%) whilst the least were from Myanmar (6%), Vietnam (3%), and Timor-Leste (3%). We identified seven biocultural lenses for Southeast Asian mangroves; food source, cultural and spiritual use, livelihood source, construction materials, fuelwood and charcoal, medicinal use, and fish poison and fishing material. As a biocultural refugia, management of mangroves are intimately intertwined with traditional practices which stemmed from cultural and spiritual importance of mangroves. However, many Asian cultures remain undocumented and understudied. We, therefore, recommend a more culture-sensitive approach in various community-based mangrove conservation projects that respectfully integrate the indigenous and local knowledge systems (ILKS) and practices. Studies relating to the biocultural values, both tangible and intangible benefits of mangroves, should be further explored to promote the sustainable utilization and conservation of the remaining mangroves in Southeast Asia.

Co-occurrence of biodiversity, carbon storage, coastal protection, and fish and invertebrate production to inform global mangrove conservation planning

Mangrove forests support unique biodiversity and provide a suite of ecosystem services (ES) that benefit people. Decades of continual mangrove loss and degradation have necessitated global efforts to protect and restore this important ecosystem. Generating and evaluating asset maps of biodiversity and ES is an important precursor to identifying locations that can deliver conservation outcomes across varying scales, such as maximising the co-occurrence of specific ES. We bring together global datasets on mangrove-affiliated biodiversity, carbon stocks, fish and invertebrate production, and coastal protection to provide insight into potential trade-offs, synergies and opportunities from mangrove conservation. We map opportunities where high ES provision co-occurs with these areas that could be leveraged in conservation planning, and identify potential high-value opportunities for single ES that might otherwise be missed with a biodiversity focus. Hotspots of single ES, co-occurrence of multiple ES, and opportunities to simultaneously leverage biodiversity and ES occurred throughout the world. For example, efforts that focus on conserving or restoring mangroves to store carbon can be targed to deliver multiple ES benefits. Some nations, such as Vietnam, Oman, Ecuador and China, showed consistent (although not necessarily strong) correlations between ES pairs. A lack of clear or consistent spatial trends elsewhere suggests that some nations will likely benefit more from complementarity-based approaches that focus on multiple sites with high provision of different services. Individual sites within these nations, however, such as Laguna de Terminos in Mexico still provide valuable opportunities to leverage co-benefits. Ensuring that an ES focused approach is complemented by strategic spatial planning is a priority, and our analyses provide a precursor towards decisions about where and how to invest.

Uncovering Dynamics of Global Mangrove Gains and Losses

Supporting successful global mangrove conservation and policy requires accurate identification of anthropogenic and biophysical drivers of mangrove extent, yet such studies are scarce. We apply a hybrid methodology, combining existing remote sensing mangrove maps with local expert knowledge of vegetation and land use dynamics. We conducted stratified random sampling in eight subregions, and local experts visually interpreted over 20,900 plots using high-resolution imagery in Collect Earth Online. Similar to previous estimates, we found 147,771 km2 (±1.4%) of mangroves globally in 2020 and that rates of mangrove loss have decreased from 2000–2010 to 2010–2020, largely driven by South and Southeast Asia. Anthropogenic drivers of loss have shifted across subregions, with oil palm cultivation emerging in South and Southeast Asia and aquaculture in South America and Western and Central Africa, highlighting the need for ongoing monitoring and adaptable conservation efforts. Natural expansion outpaced natural retraction in both periods. This is the first global study uncovering land use drivers of mangrove decline and recovery, only made possible by collaboration with local experts. Key breakthroughs include successfully discerning spectrally similar anthropogenic from biophysical drivers, such as aquaculture from natural retraction, and creating data collection approaches that streamline visual interpretation efforts.

The Spatial and Temporal Distribution of Mangrove Forest Cover from 1973 to 2020 in Chwaka Bay and Menai Bay, Zanzibar

Mangroves in Zanzibar have a high value for biodiversity and scenic beauty. However, mangroves are susceptible to anthropogenic and natural environmental disturbances. Although global mangrove monitoring systems exist, it is the practitioners focused on small mangrove areas who are knowledgeable about the area in which they work. This study examined the change in mangrove cover in Chwaka Bay and Menai Bay, between 1973 and 2020, using Landsat satellite data. The transformed divergence (TD) index and Jeffries–Matusita (J-M) distance were used to calculate separability of land cover classes before classification. The overall accuracies ranged between 82.5 and 92.7% for Chwaka Bay and 85.5 and 94.5% for Menai Bay. The kappa coefficients (ĸ) were in the range of 0.72–0.90, while the producer’s and user’s accuracies were between 72 and 100%. Chwaka Bay’s annual decrease in mangrove cover between 1973 and 2020 was 48.5 ha, compared to Menai’s 6.8 ha. The loss of mangroves in Zanzibar is linked to illegal timber/pole cutting, firewood collection, charcoal burning, unsustainable aquaculture, and agricultural and urban development. Others are changes in environmental conditions that are suitable for mangroves and climate change. This study is crucial in providing a basis for the ecological restoration and management of Zanzibar’s mangrove ecosystem.

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.

A regional map of mangrove extent for Myanmar, Thailand, and Cambodia shows losses of 44% by 1996

Southeast Asia is home to some of the planet’s most carbon-dense and biodiverse mangrove ecosystems. There is still much uncertainty with regards to the timing and magnitude of changes in mangrove cover over the past 50 years. While there are several regional to global maps of mangrove extent in Southeast Asia over the past two decades, data prior to the mid-1990s is limited due to the scarcity of Earth Observation (EO) data of sufficient quality and the historical limitations to publicly available EO. Due to this literature gap and research demand in Southeast Asia, we conducted a classification of mangrove extent using Landsat 1-2 MSS Tier 2 data from 1972 to 1977 for three Southeast Asian countries: Myanmar, Thailand, and Cambodia. Mangrove extent land cover maps were generated using a Random Forest machine learning algorithm that effectively mapped a total of 15,420.51 km2. Accuracy assessments indicated that the classification for the mangrove and non-mangrove class had a producer’s accuracy of 80% and 98% user’s accuracy of 90% and 96%, and an overall accuracy of 95%. We found a decline of 6,830 km2 between the 1970s and 2020, showing that 44% of the mangrove area in these countries has been lost in the past 48 years. Most of this loss occurred between the 1970s and 1996; rates of deforestation declined dramatically after 1996. This study also elaborated on the nature of mangrove change within the context of the social and political ecology of each case study country. We urge the remote sensing community to empathetically consider the local need of those who depend on mangrove resources when discussing mangrove loss drivers.

Exploring sustainable mangrove management policy, challenges and structure: a case study of Nadi and Momi districts, Fiji Island

ABSTRACT Besides being socially and ecologically beneficial for Fiji’s human needs, mangrove management often clashes with development interests, such as tourism threatening their sustainability. To address these issues, the study analyzes mangrove management in practice, especially governance and institutional arrangements at the local level, to better understand how these arrangements function and influence mangrove resources. The study highlights the experiences of four villages within the Momi and Nadi districts, which gives us rich insight into the local-level dynamics of mangrove management within different types of arrangements over mangrove forests. A total of four types of surveys and analysis were conducted in this study including content analysis, talanoa sessions,, questionnaire surveys and an ecological survey. The study found that the existing legallframework indicated several challenges that have contributed to the poor management of mangroves over the years. This includes fragmented policy, lack of clarity on jurisdiction over mangrove resources among multiple ministries and these aspects are challenges highlighted in the study. The mangrove structure in the Nadi mangrove area changed drastically over the years, whilst in Momi, the changes are not visible, both indicated by the respondent .(Ecological survey shows that the Momi district`s mangorve forest has the highest tree densities when compared to Nadi district. The findings of this study are expected to substantially impact sustainable management strategies in addressing the environmental, social and economic impact of development on mangrove loss. The study recommends a mechanism such as PES to sustainably manage mangrove ecosystems and support policy implementation.

Assessment of aquatic food web and trophic niche as a measurement of recovery function in restored mangroves in the Southern Gulf of Mexico.

Mangroves are coastal wetlands with high biodiversity and productivity, with great interaction with coastal environments. In the face of worldwide mangrove loss, restoration projects attempt to recover ecosystem composition and functioning over time. Our objective was to examine and compare the food webs in mangrove areas with different restoration times and in a reference mangrove in Términos Lagoon, Mexico. We estimated the trophic structure, identified the carbon resources that maintain aquatic consumers through the analysis of stable isotopes, and compared the trophic niche of the restored mangroves with the reference mangrove. We analyzed environmental variables, trophic structure, and contributions of resources during three seasons: rainy, dry, and "nortes". Environmental changes and food structure changed in response to regional seasons. Bayesian mixing models indicated that food webs varied seasonally as a response to the primary productivity developed at Términos Lagoon. As expected, the assimilation of C3 plants in the reference mangrove was highest, as a primary ("nortes" season) and secondary resource (dry and rainy seasons). The restored mangroves depended mainly on allochthonous resources (seagrass, epiphytes, and phytoplankton). The assimilation of these resources highlighted the importance of connectivity and the input of sources of carbon from nearby coastal environments. Trophic niche analysis showed that the area with longer restoration time was more similar to the reference mangrove, which is evidence of the importance and efficacy of the restoration process, as well as the restoration of the ecosystem function over time.

Vertical accretion rates of mangroves in northeast Brazil: Implications for future responses and management

Northeast (NE) Brazil has a semi-arid climate and low plant diversity mangroves confined to estuaries influenced by a meso-tidal regime (∼2.5 m). Whilst these mangroves are protected by state and federal legislation, large areas have been lost to urban encroachment and shrimp farms, a situation continuing today. This work discusses the potential impacts of sea level rise on mangroves in three estuaries in NE Brazil. The three sites witness decreasing annual precipitation associated with global climate change, which will have the dual effect of increasing water and salinity stress, decreasing productivity, as well as reducing inputs of allochthonous fluvial material. Simultaneously, since the 1990's local sea level rise (3.5 mm/yr) has been greater than the global average (3.2 mm/yr). Average accretion rates, derived from 137Cs and 210Pb dating in fringing mangroves in this study, are likely to be insufficient to maintain surface elevation and keep pace with sea level rise. Notwithstanding, historical data suggest that there has been no recorded mangrove loss as a result of sea level rise and in some areas a recorded gain in the upper estuarine mangrove reaches. At present there are limited inputs from the watershed in all three estuaries, mostly due to decreasing annual rainfall and river damming, limiting the transport capacity and hampering the export of sediments to the fringing mangroves and the sea and limiting the ability of the fringing mangroves to respond to sea level rise. However, this has been suggested to result in the accumulation of soils along river margins further upstream forming new islands and potentially expanding estuarine mangroves upstream. Both the fringing and the estuarine mangroves are surrounded by both licensed and unlicensed settlements, as well as dunes preventing expansion into higher elevation areas as a response to sea level rise. Recent changes to legislation protecting these ecosystems put a further strain on adaptation and resilience capacity, increasing the threat to these important coastal systems and the ecosystem services they provide.

Remote sensing reveals unprecedented sublethal impacts of a 40-year-old oil spill on mangroves

Oil spills cause long-lasting mangrove loss, threatening their conservation and ecosystem services worldwide. Oil spills impact mangrove forests at various spatial and temporal scales. Yet, their long-term sublethal effects on trees remain poorly documented. Here, we explore these effects based on one of the largest oil spills ever recorded, the Baixada Santista pipeline leak, which hit the mangroves of the Brazilian southeastern coast in 1983. Historical, Landsat-derived normalized difference vegetation index (NDVI) maps over the spilled mangrove reveal a large dieback of trees within a year following the oil spill, followed by a eight-year recolonization period and a stabilization of the canopy cover, however 20–30% lower than initially observed. We explain this permanent loss by an unexpected persistence of oil pollution in the sediments based on visual and geochemical evidence. Using field spectroscopy and cutting-edge drone hyperspectral imaging, we demonstrate how the continuous exposure of mangrove trees to high levels of pollution affects their health and productivity in the long term, by imposing permanent stressful conditions. Our study also reveals that tree species differ in their sensitivity to oil, giving the most tolerant ones a competitive advantage to recolonize spilled mangroves. By leveraging drone laser scanning, we estimate the loss of forest biomass caused by the oil spill to be 9.8–91.2 t ha−1, corresponding to 4.3–40.1 t C ha−1. Based on our findings, we encourage environmental agencies and lawmakers to consider the sublethal effects of oil spills on mangroves in the environmental cost of these accidents. We also encourage petroleum companies to use drone remote sensing in monitoring routines and oil spill response planning to improve mangrove preservation and impact assessment.

Thinning, selective harvesting and mangrove protection forests: Lessons learned and recommendations from the Vietnamese Mekong Delta

To date, there have been controversies over the effects of thinning and selective harvesting (SH) on mangrove forests. Recently, thinning and SH regulations have been updated with limitation on intensity rates and the requirements for mangrove transplantation for mangrove protection forests of Vietnam. Crucial questions remain unanswered regarding whether upgraded thinning and SH have contributed to the mangrove loss, and whether they have resulted in longer-term negative effects on mangrove protection forests. We used the example of Kien Giang mangrove protection forest (KGMPF), Kien Giang, Vietnam as an appropriate case study to address the above questions. Modified Normalized Difference Water Index, Water Frequency Index, and Normalized Difference Vegetation Index were calculated to understand the effects of upgraded thinning and SH on mangrove protection within KGMPF. The findings reveal that upgraded thinning and SH did not contribute to the loss of mangrove forests in KGMPF between 2005 and 2015. Likewise, these two silvicultural techniques have not created any negative effects on vegetation cover in the districts between 2005 and 2015. In addition, these techniques have not resulted in longer-term effects on the vegetation cover in KGMPF, with the vegetation cover being gradually increased in all four districts between 2020 and 2022. The findings of this study provide solid evidence that the termination of upgraded thinning and SH in Vietnam, Kien Giang and wider region may not be required.

Global Mangrove Watch: Monthly Alerts of Mangrove Loss for Africa

Current mangrove mapping efforts, such as the Global Mangrove Watch (GMW), have focused on providing one-off or annual maps of mangrove forests, while such maps may be most useful for reporting regional, national and sub-national extent of mangrove forests, they may be of more limited use for the day-to-day management of mangroves and for supporting the Global Mangrove Alliance (GMA) goal of halting global mangrove loss. To this end, a prototype change mangrove loss alert system has been developed to identify mangrove losses on a monthly basis. Implemented on the Microsoft Planetary Computer, the Global Mangrove Watch v3.0 mangrove baseline extent map for 2018 was refined and used to define the mangrove extent mask under which potential losses would be identified. The study period was from 2018 to 2022 due to the availability of Sentinel-2 imagery used for the study. The mangrove loss alert system is based on optimised normalised difference vegetation index (NDVI) thresholds used to identify mangrove losses and a temporal scoring system to filter false positives. The mangrove loss alert system was found to have an estimated overall accuracy of 92.1%, with the alert commission and omission estimated to be 10.4% and 20.6%, respectively. Africa was selected for the mangrove loss alert system prototype, where significant losses were identified in the study period, with 90% of the mangrove loss alerts identified in Nigeria, Guinea-Bissau, Madagascar, Mozambique and Guinea. The primary drivers of these losses ranged from economic activities that dominated West Africa and Northern East Africa (mainly agricultural conversion and infrastructure development) to climatic in Southern East Africa (primarily storm frequency and intensity). The production of the monthly mangrove loss alerts for Africa will be continued as part of the wider Global Mangrove Watch project, and the spatial coverage is expected to be expanded to other regions over the coming months and years. The mangrove loss alerts will be published on the Global Mangrove Watch online portal and updated monthly.

Species richness, extent and potential threats to mangroves of Sarangani Bay Protected Seascape, Philippines.

Mangroves form one of the most vital tropical ecosystems that support many species and surrounding communities. The Sarangani Bay Protected Seascape (SBPS) in the south of Mindanao Islands in the Philippines is home to a large number of mangrove species, which have not been fully explored. We updated the list of true mangrove species for SBPS from 10 to 24 by integrating the results of our survey and other past mangrove assessments. A practical spatial analysis approach was used to estimate the current mangrove forest extent of SBPS at 514 ha, as compared to 479 ha and 332 ha in 1998 and 2016, respectively, from other independent reports. Mangrove cover was negatively related to built area, cropland, bare ground, rangeland and total human population, but positively related to the number of fishing boats and total tree cover. In addition, we identified other potential anthropogenic threats to mangroves and categorised them into forest clearing or deforestation, over-extraction and pollution. The benefits of mangrove cover expansion, adoption of mangrove-friendly aquaculture and revitalising degraded mangrove forests outweigh their constraints. Our work provided a locally relevant understanding of the potential causes of mangrove loss and the values of human actions in mangrove dynamics, which will contribute to reliable and informed decision-making for the conservation of mangrove species and restoration of mangrove forests in SBPS.

Annual Mangrove Vegetation Cover Changes (2014–2020) in Indian Sundarbans National Park Using Landsat 8 and Google Earth Engine

Mangrove ecosystems have high ecological and economic value mainly because of their ability to sequester large amounts of carbon and protect shorelines. Monitoring such ecosystems with earth observation data analytics is necessary to achieve deeper insight and subsequent conservation strategies. The Sundarbans is the world’s largest contiguous mangrove forest, and Sundarbans National Park is a part of this world-famous mangrove forest in India. To examine vegetation change in this region, we used a planetary-scale tool, the Google Earth Engine. A time series of the surface reflectance product of Landsat 8 between 2014 and 2020 was analysed using annual median images. NDVI and dNDVI were derived to monitor vegetation cover change. While we noticed no major changes in the vegetation cover throughout the study area, the coastal regions, especially the southern end, showed significant changes. There were both mangrove vegetation gains due to land accretion and mangrove loss due to erosion and cyclone damage. This study will be useful for long-term monitoring of the imperiled Sundarbans ecosystem to measure any major changes.

Sustainable natural resource management must recognise community diversity

ABSTRACT Deforestation and overexploitation of mangrove forests are affecting the livelihoods of millions of families that rely on their ecosystem services. Understanding local perceptions about the status and threats to mangroves is therefore crucial in addressing this issue. This research aims to enhance understanding of how sociodemographic factors influence resource use and perceptions of environmental changes through a questionnaire survey (n = 592 households) in five locations in Lamu County, home to 62% of Kenya’s mangroves. The results highlight the variability of mangrove use, ecosystem service recognition, and perceptions and drivers of change across locations, which are influenced by sociodemographic factors such as gender, education, and occupation. Although 89% of respondents reported using mangrove products, only 56% were able to identify mangrove ecosystem services, with those without formal education being less likely to recognize them. Interestingly, 50% of respondents perceived an increase in mangrove cover, contrary to research showing mangrove loss in the area over the last decade. Results show that communities are diverse and perceptions vary between groups, suggesting that implementing uniform management measures may be incomplete or ineffective. Awareness campaigns and capacity-building efforts must be tailored to reduce misperceptions about the state of local resources and to address the specific needs and challenges faced by different groups. Recommendations made here are widely applicable to promote more inclusive and sustainable community engagement in the management of natural resources in developing countries worldwide.

Mangrove Reforestation, Protection, and Conservation Initiatives: The Case of Sorsogon Bay Rompeolas, Philippines

Mangrove losses have been observed in several parts of the world including the Philippines despite its explicit directive through Republic Act 8550 or the Philippines Fisheries Code (PHILIPPINES, 1998) in ensuring the conservation, protection, and sustained management of the country’s fishery and aquatic resources. This qualitative research made use of a case study design at Sorsogon Bay Rompeolas through observation, field visits, and interviews to describe and evaluate the milestones and challenges encountered in the mangrove reforestation and protection initiatives among volunteer stakeholders. The study found out that the post-implementation (monitoring) phase of the project was the least participated activity while the project implementation phase was the fully participated activity of the different stakeholders involved in the project. Waste pollution, unsustained participation of residents, and natural calamities are the challenges encountered by the project. The Local Government Units (LGUs) in collaboration with the concerned national authorities may adopt blended infrastructure projects with the environmental protection program in the preservation and enhancement of the current state of the coastal ecosystem for future generations.

SPATIO-TEMPORAL ANALYSIS OF DECADAL MANGROVE COVER AND FRAGMENTATION IN REGION IV-B MIMAROPA, PHILIPPINES

Abstract. Mangroves are important vegetation that provides coastal protection and basic life necessities to humans and different marine organisms. Studies have observed that mangrove deforestation is occurring in the Philippines. Thus, monitoring of mangrove extent and fragmentation for rehabilitation planning is necessary to prevent further mangrove cover loss. The utilization of free satellite imagery in mangrove monitoring helps in this enterprise as it reduces the need for expensive field activities. Furthermore, it allows researchers to perform spatio-temporal analyses to observe patterns with respect to time and location. This study analyzed the mangrove loss and growth patterns from 2000 to 2020 in Region IV-B MIMAROPA, Philippines – known to house large amounts of mangrove cover – using Landsat 5, 6, 8. Since fragmentation is associated with deforestation, it was also analyzed using the ZonalMetrics toolbox for ArcGIS Pro 2.8. The results showed that Region IV-B experienced mangrove cover increase with only a few cities/towns that suffered significant deforestation. The change pattern analysis showed that most cities/towns were able to strongly preserve the mangroves, with more mangrove gain than loss. The cities/towns are then categorized for their increasing/decreasing mangrove area and fragmentation in the form of a quadrant. Many of the cities/towns experienced an increase in fragmentation metric values over time. However, the increase in mangrove areas in these cities/towns, especially in areas that previously did not have them, suggests that there is little fragmentation of existing mangrove patches, but rather conversion from non-mangrove land cover to mangrove cover. Still, there are a few towns that do not belong to this category that show signs of deforestation and fragmentation, which needs urgent action.

Living under ecosystem degradation: Evidence from the mangrove–fishery linkage in Indonesia

This study examines the impacts of ecosystem degradation on social welfare, focusing on the mangrove–fishery linkage in Indonesia. Using nationally representative household data combined with satellite information on spatiotemporal mangrove loss, the study finds that fishery households experienced a decline in annual income ranging from 5.3% to 9.8% in response to a 1% increase in mangrove loss in the region. Under the income shock, fishery households increased their labor input and decreased their non-food consumption; however, they continued being part of the fishery industry. Furthermore, according to a back-of-the-envelope calculation, the potential economic value of mangrove conservation, estimated in terms of fishery production reached 22,861 US$/hectare/year. This makes conservation substantially more cost-effective than alternative land uses, such as aquaculture and oil palm plantations. These findings highlight the need to support mangrove forest conservation to achieve sustainable development and ecosystem conservation.