Abstract
Restoring forest cover is a key action for mitigating climate change. Although monoculture plantations dominate existing commitments to restore forest cover, we lack a synthetic view of how ...carbon accumulates in these systems. Here, we assemble a global database of 4756 field-plot measurements from monoculture plantations across all forested continents. With these data, we model carbon accumulation in aboveground live tree biomass and examine the biological, environmental, and human drivers that influence this growth. Our results identify four-fold variation in carbon accumulation rates across tree genera, plant functional types, and biomes, as well as the key mediators (e.g., genus of tree, endemism of species, prior land use) of variation in these rates. Our nonlinear growth models advance our understanding of carbon accumulation in forests relative to mean annual rates, particularly during the next few decades that are critical for mitigating climate change.
With the growing recognition that effective action on climate change will require a combination of emissions reductions and carbon sequestration, protecting, enhancing and restoring natural carbon ...sinks have become political priorities. Mangrove forests are considered some of the most carbon-dense ecosystems in the world with most of the carbon stored in the soil. In order for mangrove forests to be included in climate mitigation efforts, knowledge of the spatial distribution of mangrove soil carbon stocks are critical. Current global estimates do not capture enough of the finer scale variability that would be required to inform local decisions on siting protection and restoration projects. To close this knowledge gap, we have compiled a large georeferenced database of mangrove soil carbon measurements and developed a novel machine-learning based statistical model of the distribution of carbon density using spatially comprehensive data at a 30 m resolution. This model, which included a prior estimate of soil carbon from the global SoilGrids 250 m model, was able to capture 63% of the vertical and horizontal variability in soil organic carbon density (RMSE of 10.9 kg m−3). Of the local variables, total suspended sediment load and Landsat imagery were the most important variable explaining soil carbon density. Projecting this model across the global mangrove forest distribution for the year 2000 yielded an estimate of 6.4 Pg C for the top meter of soil with an 86-729 Mg C ha−1 range across all pixels. By utilizing remotely-sensed mangrove forest cover change data, loss of soil carbon due to mangrove habitat loss between 2000 and 2015 was 30-122 Tg C with >75% of this loss attributable to Indonesia, Malaysia and Myanmar. The resulting map products from this work are intended to serve nations seeking to include mangrove habitats in payment-for- ecosystem services projects and in designing effective mangrove conservation strategies.
Mangrove forests capture and store exceptionally large amounts of carbon and are increasingly recognised as an important ecosystem for carbon sequestration. Yet land-use change in the tropics ...threatens this ecosystem and its critical 'blue carbon' (carbon stored in marine and coastal habitats) stores. The expansion of shrimp aquaculture is among the major causes of mangrove loss globally. Here, we assess the impact of mangrove to shrimp pond conversion on ecosystem carbon stocks, and carbon losses and gains over time after ponds are abandoned. Our assessment is based on an intensive field inventory of carbon stocks at a coastal setting in Thailand. We show that although up to 70% of ecosystem carbon is lost when mangroves are converted to shrimp ponds, some abandoned ponds contain deep mangrove soils (>2.5 m) and large carbon reservoirs exceeding 865 t carbon per hectare. We also found a positive recovery trajectory for carbon stocks in the upper soil layer (0-15 cm) of a chronosequence of abandoned ponds, associated with natural mangrove regeneration. Our data suggest that mangrove carbon pools can rebuild in abandoned ponds over time in areas exposed to tidal flushing.
Mangroves provide extensive ecosystem services that support local livelihoods and international environmental goals, including coastal protection, biodiversity conservation and the sequestration of ...carbon (C). While voluntary C market projects seeking to preserve and enhance forest C stocks offer a potential means of generating finance for mangrove conservation, their implementation faces barriers due to the high costs of quantifying C stocks through field inventories. To streamline C quantification in mangrove conservation projects, we develop predictive models for (i) biomass-based C stocks, and (ii) soil-based C stocks for the mangroves of the Asia-Pacific. We compile datasets of mangrove biomass C (197 observations from 48 sites) and soil organic C (99 observations from 27 sites) to parameterize the predictive models, and use linear mixed effect models to model the expected C as a function of stand attributes. The most parsimonious biomass model predicts total biomass C stocks as a function of both basal area and the interaction between latitude and basal area, whereas the most parsimonious soil C model predicts soil C stocks as a function of the logarithmic transformations of both latitude and basal area. Random effects are specified by site for both models, which are found to explain a substantial proportion of variance within the estimation datasets and indicate significant heterogeneity across-sites within the region. The root mean square error (RMSE) of the biomass C model is approximated at 24.6 Mg/ha (18.4% of mean biomass C in the dataset), whereas the RMSE of the soil C model is estimated at 4.9 mg C/cm3 (14.1% of mean soil C). The results point to a need for standardization of forest metrics to facilitate meta-analyses, as well as provide important considerations for refining ecosystem C stock models in mangroves.
In September 2015, member states of the United Nations unanimously adopted the Sustainable Development Goals (SDGs)-a set of 17 ambitions for the post-2015 global development agenda. The goals do not ...offer a prescriptive plan but establish levers of policy action that seek to improve the three pillars of sustainable development: society, environment, and the economy. To facilitate achieving the SDGs, it will be critical to identify context-specific opportunities and challenges for implementation. Tropical regions of the world currently host not only the highest levels of biodiversity but also some of the highest rates of urbanization and development globally. Moreover, tropical forest deforestation is a globally significant issue; it has adverse impacts on biodiversity, climate systems, and socioeconomic equality. Here, we provide a rapid overview and qualitative assessment of the academic and policy literature on development and tropical forests, using the framework of the SDGs to examine issues broadly relevant to both tropical forests and sustainable development. Our assessment gathers existing knowledge and reveals critical knowledge gaps. In doing so, we identify key synergies between SDGs and tropical forests. We also suggest potential pathways of influence to improve social, environmental, and economic conditions in these rapidly developing regions of the world.
Converting mangroves to other land cover types can induce large emissions of carbon dioxide, depending on the type of land use and land cover (LULC) change. However, mangroves may also recover their ...ecosystem carbon stocks rapidly following restoration, potentially offsetting carbon stock losses. While studies have quantified these tradeoffs at global scales using coarse metrics, fewer studies have quantified them at national scales at higher resolution. Here, we used high‐resolution data sets of LULC for mangroves in Thailand to quantify district‐level gross and net changes in mangrove carbon stocks from ~1960 to 2014. We found emissions based on gross gain and loss statistics (7.18 ± 0.24 million Mg C) to be greater than those associated with emissions based on net area change statistics (1.65 ± 0.26 million Mg C) by a factor of four. The difference in estimates arises from slower rates of carbon stock recovery following reforestation relative to carbon stock loss following LULC change. Overall, we found the greatest gains in mangrove carbon stocks to be from mangrove expansion in areas of accreting sediments, which were strongly correlated with district‐level extent of undisturbed mangroves. Our results show that net loss statistics may greatly underestimate emissions associated with LULC change in mangroves. Additionally, our findings suggest that gains in mangrove carbon stocks associated with natural establishment at the periphery of standing mangroves may offset substantial carbon stock losses at national scales.
Mangrove wetlands span broad geographical gradients, resulting in functionally diverse tree communities. We asked whether latitudinal variation, allometric scaling relationships and species ...composition influence mangrove forest structure and biomass allocation across biogeographical regions and distinct coastal morphologies.
Abandoned land: Overestimated potential Holl, Karen D; Bukoski, Jacob J; Curran, Sara R ...
Science (American Association for the Advancement of Science),
2023-Jul-21, 2023-07-21, 20230721, Letnik:
381, Številka:
6655
Journal Article
Management of mangrove ecosystems is complex, given that mangroves are both terrestrial and marine, often cross regional or national boundaries, and are valued by local stakeholders in different ways ...than they are valued on national and international scales. Thus, mangrove governance has had varying levels of success, analyzed through concepts such as principles of good governance and procedural justice in decision‐making. Although there is substantial research on case studies of mangrove management, global comparisons of mangrove governance are lacking. This research aims to fill this gap by comparing relationships among qualities of governance across mangrove social‐ecological systems worldwide. Through a systematic literature search and screening process, we identified 65 articles that discussed mangrove governance and conservation. Case studies in these articles, drawn from 39 countries, were categorized as top‐down, bottom‐up, or comanaged and thematically coded to assess the influence of eight principles of good governance in mangrove conservation success. Across all three governance systems, the principles of legitimacy, fairness, and integration were most important in determining conservation success or failure. These principles are closely related to the concept of procedural justice, highlighting the importance of stakeholder inclusion throughout all stages of mangrove management. Thus, we recommend clearly defined roles for all governance actors, transparent communication of policy development to stakeholders, fairness in both process and outcome, and careful consideration of sustainable access to conservation resources.
Una Revisión Cualitativa de los Principios de Gestión para la Conservación de los Manglares
Resumen
El manejo de los manglares es complejo dado que son terrestres y marinos, con frecuencia cruzan las fronteras regionales o nacionales y están valorados por los actores de diferentes maneras de cómo son valorados en las escalas nacionales e internacionales. Por lo tanto, la gestión de los manglares ha tenido diferentes niveles de éxito al ser analizados con medidas como los principios de buena gestión de Lockwood et al. (2010) y con conceptos como la justicia procesal (O'Beirne et al. 2020) en la toma de decisiones. Aunque existe una cantidad sustancial de información de estudios de caso del manejo de manglares, existen pocas comparaciones mundiales de la gestión de los manglares. Este trabajo busca cerrar esta brecha mediante la comparación de relaciones entre la calidad de las gestiones en los sistemas socio‐ecológicos de manglares a nivel mundial. Identificamos 65 artículos que abordaban la conservación y gestión de los manglares mediante una búsqueda sistemática de la literatura y un proceso de análisis. Los estudios de caso en estos artículos, realizados en 39 países, fueron categorizados como gestión ascendiente, descendiente o de co‐manejo y codificados por tema para analizar la influencia de los ocho principios de buena gestión de Lockwood et al. (2010) en el éxito de conservación de los manglares. En los tres sistemas de gestión, los principios de legitimidad, equidad e integración fueron los más importantes para determinar el éxito o fracaso de la conservación. Estos principios están fuertemente relacionados con el concepto de justicia procesal, resaltando la importancia de la inclusión de los actores durante todas las etapas del manejo de los manglares. Por lo tanto, recomendamos que todos los actores gestores tengan papeles claramente definidos, que exista una comunicación transparente del desarrollo de las políticas a los actores, equidad tanto en el proceso como en los resultados y la consideración meticulosa del acceso sustentable a los recursos de conservación.
【摘要】
红树林生态系统的管理十分复杂, 因为红树林的位置既是陆地也是海洋, 经常跨越区域或国家边界, 且当地利益相关者对其重视程度往往与国家或国际层面上的不同。因此, 按照 Lockwood 等 (2010) 的良好治理原则和决策中程序正义 (O'Beirne 等, 2020) 等概念的衡量标准来分析, 红树林治理取得了不同程度的成功。虽然目前已有大量关于红树林管理的案例研究, 但仍缺乏对红树林治理的全球比较分析。本研究旨在通过比较全球红树林社会生态系统治理水平之间的关系来填补这一空白。我们通过系统性文献检索和筛选, 确定了 65 篇讨论红树林治理和保护的文章。我们将这些文章中来自 39 个国家的案例研究分为自上而下、自下而上或共同管理三类, 并进行了主题编码, 以评估 Lockwood 等 (2010) 提出的 8 项良好治理原则对红树林保护成功的影响。在以上三类治理系统中, 合法性、公平性和一体化原则对保护成功与否都最为重要。这些原则与程序正义的概念密切相关, 突出了在红树林管理各个阶段纳入利益相关者的重要性。因此, 我们建议明确划分所有治理者的角色, 将政策制定透明地传达给利益相关者, 确保过程和结果的公平性, 并认真考虑保护资源的可持续获取问题。【翻译: 胡怡思; 审校: 聂永刚】
Article Impact Statement: Synthetic analyses on qualities of governance systems can provide key insights across case studies and better inform conservation programs.
Estimating baseline carbon stocks is a key step in designing forest carbon programs. While field inventories are resource-demanding, advances in predictive modeling are now providing globally ...coterminous datasets of carbon stocks at high spatial resolutions that may meet this data need. However, it remains unknown how well baseline carbon stock estimates derived from model data compare against conventional estimation approaches such as field inventories. Furthermore, it is unclear whether site-level management actions can be designed using predictive model data in place of field measurements. We examined these issues for the case of mangroves, which are among the most carbon dense ecosystems globally and are popular candidates for forest carbon programs. We compared baseline carbon stock estimates derived from predictive model outputs against estimates produced using the Intergovernmental Panel on Climate Change's (IPCC) three-tier methodological guidelines. We found that the predictive model estimates out-performed the IPCC's Tier 1 estimation approaches but were significantly different from estimates based on field inventories. Our findings help inform the use of predictive model data for designing mangrove forest policy and management actions.
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