Does mangrove vegetation structure reflect human utilization of ecosystem goods and services?

Avifaunal communities as indicators of silvicultural impacts in mangrove forests

Although the Matang Mangrove Forest Reserve (MMFR) in Malaysia is suggested to be a global reference for sustainable silviculture, the impact of greenwood extraction on local biodiversity and ecological functionality remains under-researched. To fill this gap, a rapid biodiversity assessment was conducted using birds as ecological indicators to investigate the effect of mangrove silvicultural management on avian communities. Changes in the diversity of bird species and dietary guilds in response to forest age and management were assessed using the point-count method with visual and auditory observations. This was done in both "productive" forests, consisting of even-aged Rhizophora plantations producing poles and charcoal, and in "protective" forests where extractive activities are prohibited. Remarkably, all avifaunal functional guilds were present in both young "productive" and "protective" forests, however the "productive" forests supported fewer bird assemblages in terms of species richness and total taxonomic diversity compared to the floristically rich and structurally complex "protective" forests. The bird species' response to silvicultural disturbances also varied, with adverse effects especially occurring in functionally specialized species. Furthermore, back mangroves and transition zones to terrestrial forests were found to support a higher avifaunal diversity, possibly because of the enhanced habitat heterogeneity. Finally, this study highlights the use of bird communities as ecological indicators for assessing the quality of mangrove forests, and emphasises the crucial role of habitat and landscape heterogeneity in supporting diverse avifauna and ecosystem functionality highlighting the need for more research integrating mangroves and adjacent ecosystems.

Perception of Mangrove Social–Ecological System Governance in Southeastern Cuba

This study examined local communities’ perceptions of mangroves in coastal southeastern Cuba. A variety of methods were employed, including mixed and structured questionnaire surveys, interviews with key informants, and document reviews. Data were gathered from 334 respondents living in communities adjacent to four mangrove social–ecological systems (SESs). The analysis focused on five variables: community use of mangrove resources, ecosystem services, threats to the ecosystem, management activities, and social–ecological relationships. To qualitatively assess the influence of social–ecological relationships and governance, a matrix was created based on anthropogenic activities identified by respondents and their perceptions of ecosystem services. A Spearman’s rank correlation analysis was performed between demographic variables and identified mangrove uses. The Kruskal–Wallis test was used to compare the frequency of mangrove uses and the perception of ecosystem services among the studied areas. The results indicate that, while local people recognise the uses and ecosystem services of mangroves, they do not rely on them for their livelihoods. Perceptions of ecosystem services vary significantly depending on the occupation of the respondents and the locality. They also showed moderate to full awareness of management responsibilities and activities at each site. The most commonly identified threats were climate change, drought, and deforestation. Three types of social–ecological relationships were identified based on the characteristics of the communities, their economic activities, and their impacts on the mangroves: urban–industrial, rural–agricultural, and rural–agricultural/tourism. Based on the results, recommendations are made for ecosystem governance in the southeast of Cuba.

Unravelling the impact of environmental variability on mangrove sediment carbon dynamics

Mangrove ecosystems represent low-cost climate-regulating systems through carbon storage in their sediments. However, considering the complex shifts in shallow coastal ecosystems, it is clear from just a few sets of environmental impacts on their carbon storage that there is a deficit in the information required for preserving this service. Here, we investigated the spatial and temporal variability of hydrographic factors (water temperature, pH, salinity, dissolved oxygen (DO), flow velocity, turbidity) and sediment characteristics (sedimentation rate and sediment grain size) on the intricate carbon dynamics of mangroves by examining which key variable(s) control mangrove sediment organic matter (OM). We used in-situ monitoring to assess the hydrographic dynamics, sedimentation rate, sediment organic content, and granulometry. Laboratory loss-on-ignition and granulometric methods were employed to quantify OM in trapped and bottom sediments and sediment grain size, respectively. Based on the findings, water pH, salinity, and DO were the key regulators of OM in sediments. Despite conventional expectations, the study observed positive effects of DO on OM, highlighting the possible role of aquatic plant photosynthesis and freshwater inflow. Sedimentation rates, usually considered crucial for OM accumulation, showed no significant relationship, emphasizing the importance of sediment content over quantity. Noteworthy findings include the role of sediment grain size in OM storage within mangrove sediments. Even though the grain size class of 63 μm diameter had the highest mean weight across the studied sites, there were significant positive correlations between Trap and Bottom OM with 500 and 2000 μm grain size classes, emphasizing the need to consider sediment characteristics in carbon dynamics assessments. Overall, this research provides valuable insights into the intricate environmental dynamics of mangrove ecosystems that are crucial to understanding and managing these vital coastal habitats.

Mangrove ecosystems in Southeast Asia region: Mangrove extent, blue carbon potential and CO2 emissions in 1996-2020

This study aimed to analyze mangrove extent (ME), carbon stock, blue carbon potential, and CO2 emission from 1996 to 2020 in Southeast Asia region. The data was obtained through the Global Mangrove Alliance (GMA) on the platform www.globalmangrovewatch.org v.3. Furthermore, ME was analyzed descriptively and the triggers for mangrove land changes in each country were investigated through a relevant literature review. The spatial analysis was conducted for blue carbon potential, while CO2 emission was derived by multiplying net change by emission factor (EF) of mangrove ecosystem. The results showed that the total ME in Southeast Asia was 5.07 million hectares (Mha) in 1996, decreasing to 4.82 Mha by 2020 due to various land uses, primarily shrimp farming. The total carbon stock potential was 2367.68 MtC, while a blue carbon potential was 8682.32 MtCO2-e, consisting of 1304.33 MtCO2-e and 7377.99 MtCO2-e from above-ground and soil carbon. Indonesia contributed 5939.57 MtCO2-e to blue carbon potential, while Singapore and Timor-Leste had the lowest contributions of 1.05 MtCO2-e and 1.37 MtCO2-e, respectively. Carbon stock potential (AGC and SOC) in Southeast Asia was influenced by ME conditions. The relationship between ME and AGC was found to be exponential (AGC = 0.0307e0.8938x; R2 = 0.9331; rME-AGC = 0.9964, P < 0.01). Similarly, ME and SOC, or AGC and SOC showed a relationship where SOC = 0.2e0.8829x (R2 = 0.937, rME-SOC = 0.9965 and rAGC-SOC = 0.9989, P < 0.01). The average CO2-e emission in Southeast Asia reached 17.0760 MtCO2-e yr-1 and the largest were attributed to Indonesia at 16.3817 MtCO2-e yr-1. Meanwhile, Brunei and Timor Leste did not show CO2-e emission as mangrove in these countries absorbed more CO2 from the atmosphere at -0.034 MtCO2-e yr-1 and -0.0002 MtCO2-e yr-1, respectively.

Assessment of coastal and marine ecosystems in West Africa: The case of Ghana

Coastal and marine ecosystems, as integral component of social, ecological, and economic systems, are critical in providing essential ecosystem services that underpin human activities, including fishing and mining. Effective management of these ecosystems is paramount to safeguarding their vital contributions. This study adopts a socio-ecological framework, "Drivers (D) of human activities (A), associated Pressures (P), State change in coastal and marine environments, Impact (I) on human welfare (W) and Response (R) as measures (M) of management, (DAPSI(W)R(M))," to analyse the complexities of coastal and marine ecosystems in the Ghanaian context. The study identifies various drivers of anthropogenic activities, such as fishing, oil and gas production, and waste disposal. These anthropogenic activities create significant pressures, including selective extraction of living and non-living resources, as well as habitat degradation through substratum loss and pollution. Consequently, these pressures have led to changes in fish biomass and habitat quality, among other ecological shifts.

The composition, distribution, and socio-economic dimensions of Ghana's mangrove ecosystems

Mangrove ecosystems are recognised as one of the nature-based solutions to a changing climate. Notwithstanding the socio-ecological benefits of mangrove ecosystems, they are increasingly being destructed in some regions of the world. In Ghana, several studies have reported on the status, use, and management strategies of mangrove ecosystems in different sites of the country. However, these studies do not make it possible to appreciate the broader picture of Ghana's mangrove ecosystems since they are not synthesized into a single comprehensive report. This study uses the ROSES method for systematic reviews to report on Ghana's mangrove ecosystem distribution and species composition, as well as their socio-economic benefits, the anthropogenic and natural impacts on Ghana's mangrove ecosystems, and the management strategies and/or practices on Ghana's mangrove ecosystems. The study reveals there is no existing management strategy for Ghana's mangrove ecosystems, and therefore recommends the need to develop and implement policies and regulations that specifically target the protection and sustainable use of mangrove ecosystems in Ghana.