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The carbon sink capacity of tropical forests is substantially affected by tree mortality. However, the main drivers of tropical tree death remain largely unknown. Here we present a pan-Amazonian assessment of how and why trees die, analysing over 120,000 trees representing > 3800 species from 189 long-term RAINFOR forest plots. While tree mortality rates vary greatly Amazon-wide, on average trees are as likely to die standing as they are broken or uprooted-modes of death with different ecological consequences. Species-level growth rate is the single most important predictor of tree death in Amazonia, with faster-growing species being at higher risk. Within species, however, the slowest-growing trees are at greatest risk while the effect of tree size varies across the basin. In the driest Amazonian region species-level bioclimatic distributional patterns also predict the risk of death, suggesting that these forests are experiencing climatic conditions beyond their adaptative limits. These results provide not only a holistic pan-Amazonian picture of tree death but large-scale evidence for the overarching importance of the growth-survival trade-off in driving tropical tree mortality.

The carbon capture and storage (CCS) technologies that were proposed to mitigate environmental problems arising from anthropogenic CO2 emissions, also have potential environmental risks. An eventual CCS leak might induce very low pH values in the aquatic system. Due to the lack of knowledge of long-term CO2 exposures with very low pH values, this study aims to know the effects and consequences of such a situation for zooplankton, using the Daphnia magna experimental model. A CO2 injection system was used to provide the experimental condition. A twenty-one days experiment with control and low pH treatment (pH = 7) replicates was carried out under light and temperature-controlled conditions. Survival, individual growth, RNA:DNA ratio, and neonates production were analysed during the aforementioned period. No differences on survival (except last day), individual growth and RNA:DNA ratio were observed between both control and low pH treatments. However, clear differences were detected in neonates production and, consequently, in population growth rates and secondary production. The observed differences could be related with an energy allocation strategy to ensure individual survival but would have ecological consequences affecting higher trophic levels., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Abstract The ecological importance of great apes is widely recognised, yet few studies have highlighted the role of protecting great apes’ habitats in mitigating climate change, particularly through carbon sequestration. This study used GIS tools to extract data from various sources, including the International Union for Conservation of Nature database, to examine carbon quantity and great ape abundance in African great ape habitats. Subsequently, we employed a generalised linear model to assess the relationship between locally measured great ape populations abundance and carbon storage across areas with different levels of protection. Our findings showed a positive relationship between the abundance of great apes in their habitats and carbon storage, likely since conservation efforts in great apes habitats may be strengthened with higher great ape populations. The results reveal that gorilla habitats exhibited higher carbon storage than chimpanzee habitats. Specifically, the areas inhabited by gorillas are associated with a mean increase of 27.47 t/ha in carbon storage. Additionally, we observed a positive association between highly protected areas and carbon storage within great ape habitats. Our model indicates that highly protected areas increase the mean carbon stored by 1.13 t/ha compared to medium protected areas, which show a reduction of 15.49 t/ha. This highlights the critical role that protected areas play in both species conservation and carbon sequestration, contributing significantly to climate mitigation efforts. Furthermore, our study underscores the significant contribution of great ape habitats, extending beyond protected areas, to carbon storage, highlighting the potential for synergistic conservation strategies targeting both great apes and carbon sequestration. Protecting great apes is vital for reducing carbon emissions from deforestation and boosting tropical forest carbon sinks. Since nearly 90% of great apes live outside protected areas, targeted conservation in these low-protected areas is also crucial.

The conservation of endangered native species and climate change are currently the two most pressing environmental problems on the planet. Therefore, the general objective of the review was to synthesize evidence of the contributions of agroforestry systems to the conservation of native species, carbon sequestration, and livelihood benefits in Ethiopia. A total of 104 publications from 2000 to 2024 publication years were used to provide available evidence and research gaps on agroforestry contribution to native species conservation (n=21), carbon sequestration (n=33), and livelihood benefits (n=35) in Ethiopia. Furthermore, 38 papers from other parts of the world were used to support ideas and relevant evidence linked to the title. The review’s findings confirm that agroforestry can serve as in-situ conservation for endangered native species including Cordia africana Lam., Hagenia abyssinica (Bruce) J.F. Gmel., Acacia abyssinica Hochst. ex Benth, Croton macrostachyus Hochst. ex Delile, Ficus sur Forssk and Faidherbia albida (Delile) A. Chev. The review systematic review indicated that agroforestry systems store an average of 40.04 ± 10.4 Mg C ha −1 in biomass and 68.9 ± 9.9 Mg C ha−1 in soil in Ethiopia. Hence, the above-ground carbon was highest for coffee-based agroforestry (17.12 ± 6.3 Mg ha−1) followed by homegarden (16.6 ± 3.2 3 Mg ha−1) and woodlot (7.1 ± 1.09 Mg ha−1). Fuelwood, food, fodder, income, timber, fruits, and poles for construction were the main benefits of livelihood; which have been reported in 37, 30, 26, 25, 23, and 20,18 published articles, respectively. Empirical studies show that an agroforestry system, which can significantly reduce the vulnerabilities of households and store a large amount of carbon dioxide in the atmosphere, is an important strategy for climate adaptation and mitigation. Moreover, further scientific research on agroforestry on the sustainability of agroforestry is needed from responsible bodies in Ethiopia.

Soils store more carbon than other terrestrial ecosystems1,2. How soil organic carbon (SOC) forms and persists remains uncertain1,3, which makes it challenging to understand how it will respond to climatic change3,4. It has been suggested that soil microorganisms play an important role in SOC formation, preservation and loss5-7. Although microorganisms affect the accumulation and loss of soil organic matter through many pathways4,6,8-11, microbial carbon use efficiency (CUE) is an integrative metric that can capture the balance of these processes12,13. Although CUE has the potential to act as a predictor of variation in SOC storage, the role of CUE in SOC persistence remains unresolved7,14,15. Here we examine the relationship between CUE and the preservation of SOC, and interactions with climate, vegetation and edaphic properties, using a combination of global-scale datasets, a microbial-process explicit model, data assimilation, deep learning and meta-analysis. We find that CUE is at least four times as important as other evaluated factors, such as carbon input, decomposition or vertical transport, in determining SOC storage and its spatial variation across the globe. In addition, CUE shows a positive correlation with SOC content. Our findings point to microbial CUE as a major determinant of global SOC storage. Understanding the microbial processes underlying CUE and their environmental dependence may help the prediction of SOC feedback to a changing climate.

With the intensification of the greenhouse effect, the climate-mitigation role of marine carbon sequestration (blue carbon) is gaining more attention. Seaweed aquaculture, as an important nature-based solution that provides various ecosystem services while as a food source, have become the main way of marine biological carbon sequestration. As an emerging carbon dioxide removal strategy, sinking seaweeds to the deep sea for additional CO2 sequestration to contribute to Paris Agreement temperature goal have attracted much attention. Currently, the ecological value assessment of sinking seaweeds is immature, and there is also a conflict between with traditional food values. However, in the long term, the value of carbon sequestration will continuously rise as global emission reduction advance, and rapidly growing seaweed production will be able to fully satisfy food demand in the future. Therefore, sinking surplus seaweeds to convert excess food value into higher ecological value is more compatible with development prospects, and long-term planning for sinking seaweed is particularly important. As the largest seaweed farming country, China accounted for more than half of the world’s production in 2021, possessing a huge potential for carbon sequestration. Incorporating factors such as food requirements, emission reduction demands and population changes, this paper explored the feasibility and planning of sinking seaweeds to serve the achievement of climate goals under five SSP-RCP scenarios in 2020–2050. The results indicate that with the slowdown in population growth and increasing demand for climate mitigation, the ecological value of seaweeds has more development potential than the edible value, and thus the sunken seaweed task should be placed more in the later period (2041–2050 phase) to maximize the ecological benefits of seaweed farming. Sinking seaweed is able to serve the SSP1-2.6 and SSP2-4.5 scenarios relatively well, while the realization of the SSP1-1.9 scenario presents some challenges.

The long-term establishment of artificial grasslands is considered one of the most rational management models for restoring the ''Black Soil Beach, BSB'' which promotes ecological succession characterized by increased biodiversity and improved soil health in the BSB. However, the relationship between grassland productivity recovery and soil stoichiometric balance during the long-term establishment process remains unclear. To elucidate this relationship, this study explored the impact mechanisms of soil nutrients, carbon and nitrogen sequestration, and soil stoichiometric features on grassland biomass across eight establishment periods (BSB, 1 year, 2 years, 5 years, 6 years, 10 years, 11 years, and 20 years). The results indicated that compared to the baseline BSB conditions, the aboveground biomass in artificial grasslands showed an increase ranging from 237.48 % to 815.1 %. The soil organic carbon stocks (SOCS) for 1-year-old artificial grassland (AG1), 2-year-old artificial grassland (AG2), 5-year-old artificial grassland (AG5), 6-year-old artificial grassland (AG6), 10-year-old artificial grassland (AG10), 11-year-old artificial grassland (AG11), and 20-year-old artificial grassland (AG20) increased by 79.7 %, 62.8 %, 60.6 %, 59.9 %, 87.5 %, 38.5 %, and 59.3 %, respectively, and the soil nitrogen stocks significantly increased during the early and middle stages of establishment. Moreover, as the establishment period prolonged, the 0–30 cm soil stoichiometric ratios (C:N, C:P, C:K, N:K, and P:K) significantly improved. Structural equation modeling revealed that soil stoichiometric ratios did not directly affect biomass, while the establishment period influenced plant uptake of total and available soil nutrients by altering soil physical properties, ultimately affecting biomass. This study unveils the mechanisms by which soil carbon and nitrogen sequestration, soil nutrients, soil stoichiometric ratios, and plant characteristics affect the productivity of long-term established artificial grasslands. These findings contribute to the development of management strategies for the sustainable restoration and conservation of alpine meadow ecosystems.

Abstract Climate and land‐use change pose unprecedented threats to ecosystems, economies, and communities worldwide. To help mitigate the climate crisis, restoration is a rapidly growing industry used to offset carbon emissions. The most common approach is to plant fast‐growing monocultures with the aim of sequestering as much carbon as possible in the shortest time. However, there has been little economic analysis of planting options that explicitly address short and long‐term ecological risks such as fire, disease, and environmental change. Here we develop a method for quantifying ecological risks from fire to sequestration investments and show how these risks can be factored into an analysis of long‐term financial returns relative to opportunity costs. In the case study presented, we find that the apparent advantage of fast‐growing monoculture plantations is likely to be outweighed by the long‐term fire risks to the carbon stored in them. Our analytical framework provides a widely applicable approach to comparing planting options against each other and other land uses, considering key uncertainties. With climate change already manifesting through extreme weather events, rising sea levels, and shifting wildlife populations, our framework can be used to make informed decisions about the best solutions to increase carbon sequestration, reduce ecological risks, and reduce climate impacts with greater certainty.

Accurately accounting for soil organic carbon stocks is crucial in assessing the sequestration potential of arid and semi-arid rangelands. This study, conducted in the rangelands near Loving, southeastern New Mexico, aims to evaluate soil organic carbon stocks, assess the potential for soil organic carbon sequestration, and identify both biotic and abiotic factors influencing this process. To achieve these goals, soil samples were collected and subjected to analysis for soil particle size, bulk density, soil characteristic curve, as well as soil total carbon and inorganic carbon. Soil total carbon stock (STCS), soil organic carbon stock (SOCS), soil inorganic carbon stock (SICS), and soil total nitrogen stock (STNS) were determined. Soil depth, vegetation types, and coverages on each ranch were identified. Additionally, soil ion concentrations, soil cation exchange capacity (CEC), and soil sodium adsorption ratio (SAR) were assessed. The soil CEC ranged from 6 to 20 meq/100 g soil, and SAR from 0.02 to 0.58 cmol/kg^0.5. The concentrations of Na and Cl were 42 and 13 mg/l, at a depth of 0–20 cm, increasing to 74 and 34 mg/l at 20–32 cm depth, respectively. In October 2021, STCS measured 39 Mg/ha at 0–20 cm and 11 Mg/ha at 20–32 cm soil depth. SOCS ranged from 18 Mg/ha at 0–20 cm to 6 Mg/ha at 20–32 cm soil depth, while SICS ranged from 20 to 1 Mg/ha at 0–20 cm and 20–32 cm soil depth, respectively. STNS varied from 1 Mg/ha at 0–20 cm to 3.8 Mg/ha at 20–32 cm soil depth. In the 20 cm sandy loam soil depth, ranches 1, 7, 8, 9, and 11 exhibited the highest SOCS, increased with increasing clay content, particularly where honey mesquite was the dominant species. These findings emphasize the importance of exploring soil carbon storage fluctuations in southern New Mexico. The differences in SOCS among ranches under different vegetation underscore the considerable potential for storing soil organic carbon in the semi-arid rangelands of this region.

Forest thinning is an effective measure to improve carbon sequestration (CS) to adapt to and mitigate global warming. However, reducing forest cover could negatively affect other ecosystem services such as soil conservation (SC), making it difficult to effectively implement thinning strategies. This problem is exacerbated by a lack of previous research. Accordingly, after assessing thinning for two typical trees (Robinia pseudoacacia L. (RP) and Quercus L. (QL)) in Shaanxi Province, we propose a forest management framework that provides detailed thinning strategies and improves CS using a process-based biogeochemical model (Biome-BGCMuSo) by considering future climate change and SC constraints. After calibration for Biome-BGCMuSo, the average root mean squared error and percentage bias for the simulated results and observed data of RP and QL decreased (39.2–54.5 % and 66.0–86.9 %) and the correlation coefficient and Nash–Sutcliffe efficiency improved (11.6–12.3 % and 114.7–153.0 %,) respectively. Comparison between current (2001–2020) and future (2081–2100) conditions predicted overall future CS increase, and future SC would display either increasing or decreasing trends in different climatic scenarios and subregions. Partial correlation analysis showed precipitation as the dominant factor positively influencing SC, while temperature, precipitation, and CO2 concentration were the dominant factors positively influencing CS. Based on the proposed framework, RP and QL should be thinned three times every 7–11 and 3–11 years during the non-growing season with intensity ranges of 2–27 % and 1–9 %, respectively. Although the average CS during 2023–2100 with thinning increased slightly (0.1–2.6 %) compared with that without thinning, a notable potential to increase CS (0.2–7.7 %) was observed for thinning during a period at the end of this century predicted to experience the most warming. The proposed framework facilitates maximizing CS and maintaining SC. As the framework is based on a process-based biogeochemical model, it could be applicable to other regions.

Soil, the largest terrestrial carbon reservoir, is central to climate change and relevant feedback to environmental health. Minerals are the essential components that contribute to over 60% of soil carbon storage. However, how the interactions between minerals and organic carbon shape the carbon transformation and stability remains poorly understood. Herein, we critically review the primary interactions between organic carbon and soil minerals and the relevant mechanisms, including sorption, redox reaction, co-precipitation, dissolution, polymerization, and catalytic reaction. These interactions, highly complex with the combination of multiple processes, greatly affect the stability of organic carbon through the following processes: (1) formation or deconstruction of the mineral–organic carbon association; (2) oxidative transformation of the organic carbon with minerals; (3) catalytic polymerization of organic carbon with minerals; and (4) varying association stability of organic carbon according to the mineral transformation. Several pieces of evidence related to the carbon turnover and stability during the interaction with soil minerals in the real eco-environment are then demonstrated. We also highlight the current research gaps and outline research priorities, which may map future directions for a deeper mechanisms-based understanding of the soil carbon storage capacity considering its interactions with minerals.

Amid global warming and intensified human activities, the carbon sequestration (CS) capacity of terrestrial ecosystems faces significant pressure. Ecological Water Conveyance (EWC) projects, by altering land use patterns, have become a key approach to addressing this issue. Therefore, the critical question this study aims to solve is how to enhance regional CS by optimizing EWC measures, based on understanding the relationship between land use changes and CS. To address this, we propose an integrated framework that couples the PLUS-InVEST-OPGD models, adopting a ’past-future’ perspective to explore the relationship between CS and land use changes in the context of EWC. The study found that during the historical period (2000–2020), CS in the Tarim River (TR) area exhibited a pattern of ’ first increasing, then stabilizing.’ Between 2000 and 2010, the total CS increased by 3.5 × 10^6 Mg, accompanied by an expansion of forested areas along the riverbanks and within national parks. However, from 2010 to 2020, the total CS increased by only 0.3 × 10^6 Mg, with forested areas along the riverbanks and within national parks remaining relatively stable. Under three future development scenarios—Natural Increase (NIS), Farmland Protection (FPS), and Ecological Protection (EPS)—CS differences between NIS and FPS are minimal at 0.01 × 10^6 Mg, as both continue existing EWC policies without optimization, with NIS following natural growth and FPS prioritizing farmland preservation. In contrast, the EPS, which introduces optimized EWC strategies to limit urban expansion and enhance ecological sustainability, results in a significant CS increase of approximately 1.1 × 10^6 Mg, with farmland areas also expanding. Through single factor and interactive detection analyses, we found that potential evapotranspiration and annual average groundwater depth play crucial roles in vegetation restoration in arid regions, as EWC helps maintain groundwater levels, reducing plant water stress and supporting vegetation growth, while managing evapotranspiration ensures that the water provided through EWC is efficiently utilized for ecosystem recovery and CS. Under the current EWC model and prevailing climate and human activity conditions, the CS capacity of ecosystems appears to stabilize. To further enhance the region’s CS potential, optimizing EWC strategies is essential. It is recommended to construct a ’surface’ water conveyance network through engineering measures, in addition to the existing ’linear conveyance’ model, to improve water resource utilization efficiency. The findings of this study offer valuable insights not only for the TR region but also for other arid inland river basins worldwide, providing a replicable framework for ecological restoration and water management.

ARTICLE HIGLIGHTS - Agroforestry boosts carbon storage, reducing greenhouse gas emissions significantly. - Diverse tree-based farming enhances biodiversity, soil health, and climate resilience. - Carbon sequestration in agroforestry supports sustainable agriculture and environmental balance. - Agroforestry practices mitigate climate change by storing carbon in trees and soil. - Combining trees with crops provides multiple ecological and economic benefits. ABSTRACT One of the processes for compensating greenhouse gas emissions is atmospheric carbon removal and storage in the terrestrial biosphere. Agricultural systems to which trees are returned for careful management alongside crops and animals are thought to be substantial CO2 sinks. People are increasingly realizing the importance of agroforestry because it is good for the environment and farming. In this study, total carbon pools from the aboveground biomass carbon (ABGC), forest floor carbon (FFC), and soil organic carbon (SOC) were investigated and carbon storage data for some agroforestry practices native to Uttaradit in northern Thailand were analyzed. The role of these carbon pools in reducing CO2 concentrations in the atmosphere was also discussed. The results showed differences in the total carbon stock sourced from traditional agroforestry (TAF), applied agroforestry (AAF), and developed agroforestry (DAF). The total carbon store (ABGC + TFFC + SOC) of TAF, AAF, and DAF was 267.05 Mg C/ha, 226.48 Mg C/ha, and 324.70 Mg C/ha, respectively. SOC contributed 47.64%, 54.26%, and 44.81% and ABGC contributed 22.75%, 19.79%, and 23.90% to the total carbon stock in TAF, AAF, and DAF, respectively. The CO2 adsorption was 979.27 Mg CO2/ha, 830.50 Mg CO2/ha, and 1,190.6 Mg CO2/ha in TAF, AAF, and DAF, respectively. It is clear that agroforestry systems serve as carbon sinks in terrestrial ecosystems. Although the comparison of agroforestry practices and other land use types is important for carbon mitigation and the implementation of the “Land Use, Land Use Change, and Forestry” concept for CO2 sinks, it is also crucial to compare the potential of carbon sequestration in different CO2 pools.

ARTICLE HIGLIGHTS - High demand for environmental services makes the park vulnerable to human activities. - Both ecosystems are well regenerated; seedling > sapling > pole > tree (inverted J) - Both ecosystems show normal diversity conditions and stable species distribution. - Growth of Maesopsis eminii needs monitoring to preserve forest purity. - Montane forests have greater biomass, carbon stocks, less anthropogenic disturbance ABSTRACT The Gunung Gede Pangrango National Park (GGPNP) area is one of the vital ecosystems that support the environment in West Java Province, Indonesia. It is a unique area that has multiple forest ecosystems, including lowland rainforest and montane rainforest ecosystems. Despite the GGPNP’s status as a conservation area, the high demand for the GGPNP’s environmental services makes the region vulnerable to disturbances from human activities. Several studies have been conducted in the GGPNP area (lowland and montane forest ecosystems), however, the results of this study are still necessary to explain the forest dynamics and forest carbon sequestration in this location. The objective of this research was to analyze the structure, composition, and carbon sequestration of stands in the lowland and montane rainforest ecosystems in the GGPNP area. Data processing and analyses were conducted using diversity indices, biomass-carbon stock estimation, and carbon dioxide sequestration estimation. The results showed that the GGPNP lowland and montane rainforest ecosystems were well regenerated. The number of seedlings > saplings > poles > trees and the graph showed a reverse “J” pattern. The GGPNP lowland rainforest ecosystem was dominated by Neonauclea lanceolata and had relatively higher species diversity. The GGPNP montane rainforest ecosystem was dominated by Castanopsis acuminatissima with a higher individual density, denser canopy, and more complex canopy strata. The lack of regeneration in several species of trees heightens the threat to these species’ existence in the future. Biomass, carbon stocks, and carbon sequestration in the GGPNP montane rainforest were greater than those in the GGPNP lowland rainforest. The GGPNP montane rainforest ecosystem had older forest stands, a larger average tree diameter, and lower potential for anthropogenic disturbances.

Abstract Forestation is a key strategy for climate mitigation in China through its biogeochemical (BGC) effect of ecosystem carbon sequestration. Additionally, the BGC effect of forestation can be either reinforced or counteracted by concurrent biogeophysical processes (BGP effect) resulting in local land surface warming or cooling, which can be translated into CO2e (i.e., BGC effect) using a local transient climate response. Previous evaluations of the climate mitigation potential of future forestation in China have, however, focused on the BGC effect only and neglected the BGP effect, potentially leading to suboptimal forestation areas. Here, we determined priority forestation areas in China by incorporating both effects to maximize its global climate mitigation effect. Our results suggest an additional 167.2 Mha potentially suitable for forestation in China, exceeding the largest forestation target (86.8 Mha) possibly assumed by the government in 2060. The forestation‐induced BGP effect (18.7 ± 61.9 tCO2e ha−1) largely reinforces the BGC effect (458.2 ± 92.6 tCO2e ha−1) in China, yielding a total climate mitigation effect of 476.9 ± 114.2 tCO2e ha−1 over 40 years (2021–2060). Under the 2060 forestation target, considering both BGC and BGP effects will displace 17.7% (15.3 Mha) of the forestation area derived by considering the BGC effect alone. Integrating both BGC and BGP effects will lead to a CO2 uptake of 28.8 GtCO2e by 2060, 3.9 GtCO2e higher than the value obtained when considering the BGC effect only. Our results highlight the importance of considering BGP effect when making forestation policies for climate mitigation.

Aim. Data collection and analysis of the composition and productivity of vegetation and assessment of carbon sequestration by vegetation and soil in meadow steppe at a fallow site in the Bashkir Cis‐Urals, Russia. Material and Methods. The work is based on a survey of vegetation and soils of meadow steppe located in fallow areas, where post‐agrogenic restoration succession has been going on for more than 20 years. Results. The plant cover of the area studied is close to natural rich‐forb meadow steppes but differs in lower indicators of species richness and saturation, as well as the presence of weedy segetal species. The total plant biomass on the plot studied was estimated at 11.35 t/ha (including live aboveground biomass 2.98 t/ha, mortmass 3.11 t/ha, root weight 5.25 t/ha). The average stock of carbon in the plant biomass is 427.6 g/m2, and the total carbon stock in plant matter within the site is 36.88 tons. The soil cover of the area studied is Chernozem Calcic. The average levels of carbon stocks in short‐thickness soil at the 0–90 cm layer is 308 t/ha, while in medium‐thick soil it is 378 t/ha. Conclusions. A feature of the communities surveyed is a poor floristic composition, low productivity and low proportion of roots (47 % of the total plant biomass), which is caused by incomplete recovering of steppe vegetation and low thickness of the humus horizon. The soils of the site are close to virgin steppe lands in terms of carbon content and reserves.

Abstract Background Terrestrial ecosystems contain significant carbon storage, vital to the global carbon cycle and climate change. Alterations in human production activities and environmental factors affect the stability of carbon storage in soil. Carbon sequestration in plant phytoliths offers a sustainable method for long-term carbon stabilization. Carbon occluded in phytoliths (PhytOC) is a kind of carbon that can be stable and not decomposed for a long time, so it is crucial to conduct more in-depth research on it. Results We undertook a meta-analysis on PhytOC across global terrestrial ecosystems, analyzing 60 articles, encapsulating 534 observations. We observed notable differences in phytolith and PhytOC contents across various ecosystems. Bamboo forest ecosystems exhibited the highest vegetation phytolith and PhytOC content, while soil phytolith content was most prominent in bamboo forests and PhytOC content in croplands. Human activities, such as grassland grazing, had a lesser impact on soil PhytOC transport than actions like cutting and tillage in croplands and forests. Our study separated bamboo ecosystems, analyzing their PhytOC content and revealing an underestimation of their carbon sink capacity. Conclusions Notwithstanding our findings, phytoliths’ intricate environmental interactions warrant further exploration, crucial for refining ecosystem management and accurately estimating PhytOC stocks. This deepened understanding lays the foundation for studying phytoliths and the carbon sink dynamics.

Humification plays a significant role in converting phenolic pollutants and forming heterogeneous polymers, but few studies have been performed to investigate exolaccase-started humification (ESH). Herein, the influences of lignin precursors (LPs) on exolaccase-induced bisphenol A (BPA) removal and humification were explored. In particular, the architectural features and botanical effects of the formed humification products were also tested. ESH was extremely beneficial in boosting BPA removal in the presence of LPs. Compared with LP-free (58.49%), 100% of BPA was eliminated after the reaction with ESH for 72 h. Such a process was controlled by an exolaccase-caused random assembly of radicals, which generated a large number of hydrophobic polymers through nonspecific covalent binding of C–C and/or C–O. These humified polymers were extremely stable at pH 2.0–10.0 and −20 °C to 80 °C and displayed unique functions, i.e., scavenged 2,2-diphenyl-1-picrylhydrazyl/2,2′-azino-bis3-ethylbenzothiazoline-6-sulphonic acid radicals and exerted antioxidant capacities. More importantly, the functional polymers could act as auxin analogs to increase the germination index (>100%), plant biomass, and salt tolerance of radish seedlings. Our findings disclosed that ESH could not only be optimized to mitigate the ecological risks of phenolic pollutants and sequester organic carbon in environmental bioremediation, but the resulting abundant auxin analogs also contributed to agricultural productivity.

Nature-based Climate Solutions (NbCS) are managed alterations to ecosystems designed to increase carbon sequestration or reduce greenhouse gas emissions. While they have growing public and private support, the realizable benefits and unintended consequences of NbCS are not well understood. At regional scales where policy decisions are often made, NbCS benefits are estimated from soil and tree survey data that can miss important carbon sources and sinks within an ecosystem, and do not reveal the biophysical impacts of NbCS for local water and energy cycles. The only direct observations of ecosystem-scale carbon fluxes, for example, by eddy covariance flux towers, have not yet been systematically assessed for what they can tell us about NbCS potentials, and state-of-the-art remote sensing products and land-surface models are not yet being widely used to inform NbCS policymaking or implementation. As a result, there is a critical mismatch between the point- and tree-scale data most often used to assess NbCS benefits and impacts, the ecosystem and landscape scales where NbCS projects are implemented, and the regional to continental scales most relevant to policymaking. Here, we propose a research agenda to confront these gaps using data and tools that have long been used to understand the mechanisms driving ecosystem carbon and energy cycling, but have not yet been widely applied to NbCS. We outline steps for creating robust NbCS assessments at both local to regional scales that are informed by ecosystem-scale observations, and which consider concurrent biophysical impacts, future climate feedbacks, and the need for equitable and inclusive NbCS implementation strategies. We contend that these research goals can largely be accomplished by shifting the scales at which pre-existing tools are applied and blended together, although we also highlight some opportunities for more radical shifts in approach.

Evaluating the climate change mitigation potential of the forest sector requires a holistic approach based on forest carbon (C) sequestration, C storage in harvested wood products (HWP) and substitution on markets. High uncertainty is associated with substitution factors, that express avoided fossil greenhouse gas (GHG) emissions from the use of forest-based products in replacement of GHG-intensive materials and fossil fuels. Few studies have focused on the development of substitution factors in Canada, resulting in the use of unrepresentative generic data. Here, we provide a framework to reduce uncertainties related to substitution factors for primary wood products in a Canadian context. A life cycle assessment framework is used to quantify fossil GHG emissions for a baseline and a wood-intensive scenario. For solid product substitution, we focused on the construction sector and analyzed a range of innovative wood buildings with steel and reinforced concrete as alternative materials. We found non-weighted averages of 0.80 tC/tC for sawnwood and 0.81 tC/tC for panels. For energy substitution, we analyzed cases with different specifications on biomass product, facility type and alternative fossil fuel source in non-residential heat production and biofuel transportation sectors. We found a non-weighted average of 0.80 tC/tC for non-residential heat production and 0.51 tC/tC for biofuel transportation, that can be interpreted as 0.91 tC/tC for heavy fuel oil, 0.69 tC/tC for light fuel oil and 0.68 tC/tC for natural gas substitution. These results provide a benchmark for substitution factors in Canada, to help guide forest management strategies for climate change mitigation.

As soil fungi are major players in the carbon accumulation process, the two main fungal degraders in topsoil, Ascomycetes and Basidiomycetes, were investigated as indicators of land use effectiveness in increasing soil carbon accumulation and soil function. The study focused on the soil organic carbon content increase in a 20-year short rotation forest cycle with broadleaf woody plantations compared to a nearby arable cropping system. Total fungi, Ascomycota and Basidiomycota, were quantified in terms of DNA copy number, with specific probes using SYBR® Green I dye on the QuantStudio™ 3D digital PCR system (dPCR). Previously, next generation sequencing analysis using a general primer confirmed that Ascomycota and Basidiomycota were the most represented phyla and that fungal community composition significantly differed between treatments. A range of key soil enzyme activities for the C-cycle were also assessed. Total organic carbon content (TOC), microbial biomass in term of dsDNA and enzyme activities significantly increased in woody plantations compared to arable soil. The TOC increase differed significantly also between wood species, Salix and Robina gave the greatest increase (+30 and 20 % respectively), followed by Populus (+12), microbial biomass highly correlated with TOC showing the same trend. Total fungi, Ascomycota and Basidiomycota increased significantly in three woody plantations compared to the arable soil system. Ascomycota in the woody plantations increased two to four times (average 3144 n copies µl−1 of DNA) compared to the arable soil (1419 n copies µl−1); Basidiomycota were almost absent in arable soil (av. 94n copies µl−1) and increased five to six times in woody plantations (av. 490 n copies µl−1). Total fungi and ascomycetes correlated strongly with microbial biomass and TOC, whereas basidiomycetes did not. These findings showed that Ascomycota represent the largest portion of fungi in agricultural soils even after a 20-years short rotation forest cycle and they can be taken as indicators of carbon accumulation processes. Therefore, this study suggests that joining the Ascomycetes quantity in the topsoil to the Ascomycota:Basidiomycota ratio seems a good option when setting regional strategies for improving C accrual in farmland with the short-term afforestation.

Exploring the coupling coordinated development of carbon emission reduction and sequestration (CERS) and food security in agriculture is conducive to mitigating climate change and achieving sustainable development goals. However, there is little research on the coupling coordinated development of these two systems. Based on panel data of 31 Chinese provinces from 2001 to 2021, this study used the dynamic fuzzy set qualitative comparative analysis (fsQCA) method to analyze the levels and driving paths of coupling coordinated development between agricultural CERS and food security. The results revealed that (1) the coupling coordination degree increased from 0.443 in 2001 to 0.489 in 2021, showing an upward trend. (2) We identified three driving paths of coupling coordination development: technology-driven, finance-driven and urban-development-driven. (3) The grain sown area and unit yield are core variables, serving as fundamental pillars, and their combination with technology or financial expenditure enhances this coordinated development. Notably, the grain sown area and unit yield exhibit a complementary relationship, while agricultural technology and financial expenditure demonstrate a substitution relationship. (4) Temporal analysis showed a consistent trend in the technology-driven and finance-driven paths. Regional analysis revealed marked heterogeneity: the technology-finance synergy path predominates in the remote west, the technology-driven path lies in the mountainous southwest, the finance-driven path clusters in the north, and the urban-development-driven path is located in economically advanced regions. Policymakers should formulate policies according to these different driving paths to promote coupling coordinated development.

Grassland degradation is a prevalent issue at the interface of shrubland and grassland ecosystems, particularly susceptible to environmental changes. To counteract the degradation, grazing exclusion has been proposed as a dominant restoration strategy on the Tibetan plateau, the world's largest and highest plateau. However, the impact of degradation and subsequent restoration on the carbon dynamics consist of carbon sink / source capacity of shrub-grassland ecotones remain unclear. Therefore, in this study, using a transparent chamber (0.8 m in length × 0.8 m in width × 0.6 m in height) attached to an infrared gas analyzer, the in situ field investigation was performed to measure the gross ecosystem primary productivity (GEP), ecosystem respiration (Re), net ecosystem CO2 exchange (NEE), and environmental factors over a four-year continuous period in lightly and heavily degraded shrub-grassland ecotones during recover process on the Tibetan Plateau. Our result showed that: 1). Shrub-grassland ecotone acts as a net CO2 sink, with the maximum NEE occurring in July during the growing season. 2). Ecotone degradation diminishes the carbon sequestration capacity. Specifically, the annual GEP, Re, and NEE rates decrease by 14.1 %, 7.3 %, and 27.2 %, respectively, in the heavily degraded ecotone compared to the lightly degraded counterpart. 3). Grazing exclusion positively influenced the carbon sequestration capacity, particularly in heavily degraded ecotone, which leads to a substantial increase in the annual GEP, Re, and NEE rates of 15.4 % and 33.4 %, 12.3 % and 20.9 %, 22.25 % and 64.9 % for lightly and heavily degraded ecotones, respectively. 4). A piecewise structural equation model reveals that soil moisture and soil temperature are pivotal drivers influencing NEE. 5) Correlation analysis shows that NEE was negatively correlated with soil temperature during April to June and September to October but was positively correlated with soil temperature during July to August. In contrast, NEE displays a consistent negative correlation with soil moisture throughout the growing season. This research provides new insights on grassland degradation and restoration for carbon sequestration in alpine shrub-grassland ecotones and highlights their implications for sustainable management of alpine ecosystems.

The proteoleaginous plants demand has seen significant growth, leading to an expansion of the sunflower (Helianthus annuus, L.) and industrial hemp (Cannabis sativa, L.) cultivation area in Italy. However, by-products obtained during seed oil extraction and agricultural residues are often unused due to the absence of a receptive market and nearby processing centers. The carbon footprint (CF) methodology was used to compare the two supply chains considering the soil incorporation of all crop residues and by-products. The boundary of the supply chains analyzed includes all the agricultural processes that occur during cultivation and the subsequent oil extraction phase. Furthermore, research explored the direct and indirect environmental benefits of incorporating by-products into the soil, in terms of reducing the need for mineral fertilizers to restore soil fertility due to the nutrients contained in the buried biomass, and the potential carbon sequestration achievable. Results show that 1 kg of sunflower and hemp oil release 4.49 kg CO2-eq and 23.34 kg CO2-eq, respectively. Agriculture represents the most impacting phase and, in particular, fertilization, tillage and harvest are responsible for high emissions. The different results between the two supply chains can be attributed mainly to yield and extraction efficiency. The use of by-products as amended in the soil (avoided fertilizers) contributes to a reduction of greenhouse gas (GHG) emissions by −0.53 kg CO2-eq and −7.87 kg CO2-eq per kg of sunflower and hemp oils, respectively. Additionally, the sequestration of carbon in biomass can result in a further reduction of −1.16 and −33.6 kg CO2-eq per kg of sunflower and hemp oil, respectively. In summary, sunflower oil production emits 74 % less CO2 than hemp oil. However, if all crop biomass is buried, hemp has the potential to be more sustainable. This phenomenon depends on many factors such as soil type, climate, and farming practices. The study outcomes can aid policymakers, farmers, and the agribusiness to make informed decisions on promoting and expanding sustainable sunflower and hemp cultivation in Italy.

The two most urgent and interlinked environmental challenges humanity faces are climate change and biodiversity loss. We are entering a pivotal decade for both the international biodiversity and climate change agendas with the sharpening of ambitious strategies and targets by the Convention on Biological Diversity and the United Nations Framework Convention on Climate Change. Within their respective Conventions, the biodiversity and climate interlinked challenges have largely been addressed separately. There is evidence that conservation actions that halt, slow or reverse biodiversity loss can simultaneously slow anthropogenic mediated climate change significantly. This review highlights conservation actions which have the largest potential for mitigation of climate change. We note that conservation actions have mainly synergistic benefits and few antagonistic trade-offs with climate change mitigation. Specifically, we identify direct co-benefits in 14 out of the 21 action targets of the draft post-2020 global biodiversity framework of the Convention on Biological Diversity, notwithstanding the many indirect links that can also support both biodiversity conservation and climate change mitigation. These relationships are context and scale-dependent; therefore, we showcase examples of local biodiversity conservation actions that can be incentivized, guided and prioritized by global objectives and targets. The close interlinkages between biodiversity, climate change mitigation, other nature's contributions to people and good quality of life are seldom as integrated as they should be in management and policy. This review aims to re-emphasize the vital relationships between biodiversity conservation actions and climate change mitigation in a timely manner, in support to major Conferences of Parties that are about to negotiate strategic frameworks and international goals for the decades to come.

Abstract Background Three-North Afforestation Program (TNAP) in China is the largest ecological restoration project on Earth (ongoing from 1978 to 2050), harboring a huge area of newly planted forests, which provides a wealth of goods and ecosystem services that benefit society at levels ranging from region to East Asia. This project-induced carbon (C) sink has been expected to be large, but its size and location remain uncertain. Results In this study, we investigated the changes in the C stocks of biomass, soil C and the C accumulation benefited from the ecological effects in the project areas from 1978 to 2017 within the Three-North regions (4.069 × 106 km2), and evaluated its project-induced C sequestration. Using a combination of remote sensing images, field observations and national forest inventory data, we estimated a total ecosystem sink of 47.06 Tg C per year (1 Tg = 1012 g) increased by the TNAP implementation. Importantly, we first found that the C sink via the ecological effects of this project could contribute to a high proportion up to 15.94%, indicating a critical role of ecological effects in shaping the distribution of C stocks in the protective forests. This finding suggests that it is necessary to explicitly consider carbon sequestration benefited from the ecological effects when estimating C sink and parameterizing C models of the restoration projects in China and globally. Conclusions Our results update the estimates of C pools in the world's largest ecological restoration project area, demonstrating that this project has substantially contributed to mitigating the climate change.

Arctic warming is affecting snow cover and soil hydrology, with consequences for carbon sequestration in tundra ecosystems. The scarcity of observations in the Arctic has limited our understanding of the impact of covarying environmental drivers on the carbon balance of tundra ecosystems. In this study, we address some of these uncertainties through a novel record of 119 site-years of summer data from eddy covariance towers representing dominant tundra vegetation types located on continuous permafrost in the Arctic. Here we found that earlier snowmelt was associated with more tundra net CO2 sequestration and higher gross primary productivity (GPP) only in June and July, but with lower net carbon sequestration and lower GPP in August. Although higher evapotranspiration (ET) can result in soil drying with the progression of the summer, we did not find significantly lower soil moisture with earlier snowmelt, nor evidence that water stress affected GPP in the late growing season. Our results suggest that the expected increased CO2 sequestration arising from Arctic warming and the associated increase in growing season length may not materialize if tundra ecosystems are not able to continue sequestering CO2 later in the season.

Agroforestry is seen as a land management technique that can address many of the issues faced by smallholder farmers, such as climate change adaptation and climate change mitigation. Agroforestry helps farmers adapt to extreme weather events, create resilient microclimates for crops and livestock across regions, and help combat climate change. An important role of agroforestry in tackling climate change may be to reduce CO2 emissions by actively sequestering carbon from the atmosphere. Soil stores the largest carbon stock (77%–92%) in agroforestry systems, with trees, herbaceous plants, and deciduous trees absorbing 7%–22% and 1%, respectively. Smallholder farmers in developing countries not only build resilient agroecological systems that actively absorb carbon, but also revert to more natural production systems that provide better ecological and social functions. By doing so, we can prevent climate change. Agroforestry not only reduces greenhouse gas emissions and improves the resilience of agricultural landscapes, but also can contributes to climate change mitigation and adaptation by promoting species migration to more favorable conditions and carbon sequestration. Climate projections could see production declines in much of sub-Saharan Africa, exacerbating food insecurity among citizens.

Abstract Nature‐based solutions (NbS) can prevent further climate change and increase local communities' capacity to adapt to the current impacts of climate change. However, the benefits obtained from implementing NbS are not distributed equally across people. Thus, it is key to further understand how people are impacted when implementing NbS. We developed a multi‐objective prioritization approach to identify changes in (i) the biophysical provision of ecosystem services, (ii) optimal allocation of NbS and (iii) monetary benefits when targeting climate mitigation versus climate adaptation goals. We used the increase in metric tons of carbon storage as representative of climate mitigation and the decrease in on‐site and downstream tons of sediment per year as representative of climate adaptation. Planning strategies that target climate mitigation or climate adaptation goals separately represent a loss of between 30% and 60% of the maximum possible carbon sequestration or sediment retention benefits. Conversely, targeting climate mitigation and climate adaptation goals at the same time captured more than 90% of the maximum possible benefits for all objectives. Priority NbS in the mitigation planning strategy included soil and water conservation and forest rehabilitation, while priority NbS in the adaptation planning strategy included grassland rehabilitation and hill terrace improvement. Targeting mitigation and adaptation goals at the same time captures 35M USD (89% of the maximum attainable) in value of carbon restored and retained, and 2M USD (100% of the maximum attainable) of avoided maintenance costs to the KGA hydropower plant. Conversely, failing to incorporate adaptation goals when developing climate plans only captures 1M of avoided maintenance costs to the KGA hydropower plant. Our approach can be replicated in other locations to promote cost‐effective investments in NbS able to secure both global and local benefits to people. This can improve the outcomes of international climate change financial schemes like the Green Climate Fund and the UN‐REDD+ program. Read the free Plain Language Summary for this article on the Journal blog.

Abstract U.S. forests, particularly in the eastern states, provide an important offset to greenhouse gas (GHG) emissions. Some have proposed that forest‐based natural climate solutions can be strengthened via a number of strategies, including increases in the production of forest biomass energy. We used output from a forest dynamics model (SORTIE‐ND) in combination with a GHG accounting tool (ForGATE) to estimate the carbon consequences of current and intensified timber harvest regimes in the Northeastern United States. We considered a range of carbon pools including forest ecosystem pools, forest product pools, and waste pools, along with different scenarios of feedstock production for biomass energy. The business‐as‐usual (BAU) scenario, which represents current harvest practices derived from the analysis of U.S. Forest Service Forest Inventory and Analysis data, sequestered more net CO2 equivalents than any of the intensified harvest and feedstock utilization scenarios over the next decade, the most important time period for combatting climate change. Increasing the intensity of timber harvest increased total emissions and reduced landscape average forest carbon stocks, resulting in reduced net carbon sequestration relative to current harvest regimes. Net carbon sequestration “parity points,” where the regional cumulative net carbon sequestration from alternate intensified harvest scenarios converge with and then exceed the BAU baseline, ranged from 12 to 40 years. A “no harvest” scenario provides an estimate of an upper bound on forest carbon sequestration in the region given the expected successional dynamics of the region's forests but ignores leakage. Regional net carbon sequestration is primarily influenced by (1) the harvest regime and amount of forest biomass removal, (2) the degree to which bioenergy displaces fossil fuel use, and (3) the proportion of biomass diverted to energy feedstocks versus wood products.

Carbon stock and diversity of species together address the two most pressing concerns for successful ecosystem functioning and management, namely climate change and biodiversity loss. Understory vegetation is a significant indicator of plant biodiversity, contributing to forest carbon storage, sustaining species, and providing many ecological services. However, little research has been done about the contribution of the understory carbon stock in the forests, most likely because these understory components only make up a small portion of the total carbon stock of the forest ecosystem. To fill this knowledge gap, the current study sought to study the baseline understory (shrub and herb) diversity and carbon stock from the Zabarwan Mountain Range. Data on the characteristics of the understory vegetation in five different forest types were gathered using a random sample method. Using the Pearson method, we calculated the correlation coefficient between the diversity parameters and the carbon stock. The calculated average total carbon stock in the understory was determined to be 3.93 Mg C/ha (1.55–9.2 Mg C/ha). The shrub layer contributed a maximum value of 82 % of carbon stock. The increasing trends in total understory carbon were Parrotiopsis forest Broad-leaved forest > Acacia forest > Pinus forest > Parrotiopsis forest. Overall, the data show that coniferous-dominated woodlands had higher understory carbon stocks than other kinds of woodlands. The data acquired highlights the importance of shrub carbon stock storage in the understory layer in this Himalayan region. The current research on understory vegetation provides strong evidence for maintaining forest management practices that enable and encourage the planting of multiple layers of vegetation in landscape restoration as approaches to improve biodiversity while increasing resistance to climate change.

In the context of carbon neutrality and urbanization, there is a notable research gap regarding the carbon sequestration benefits of urban forests and the identification of suitable tree species for achieving sustainable carbon sequestration. In this study, we examined the dynamics and drivers of urban forest carbon sequestration in Shanghai, one of the most urbanized cities in China. First, we compiled a comprehensive field inventory data set spanning 20 years for the Shanghai Green Belt. Second, we quantified and compared the total carbon accumulation and growth rates of six monoculture forests and two mixed forest types consisting of six common tree species. Third, we conducted drivers analysis of the effects of stand-related and anthropogenic factors on carbon accumulation and growth rates. Overall, our results revealed that each forest type exhibited a unique growth pattern of tree biomass carbon (TBC), with the Chapman–Richards growth function providing an accurate representation of carbon dynamics. During the early stages of development (within 20 years), the carbon accumulation rate of Populus L. reached 4.13 Mg ha−1 yr−1, which was approximately 127 % higher than that of broadleaf mixed forests. In late stages, the potential tree biomass carbon accumulation of broadleaf mixed forests reached 172.8 Mg ha−1, which was 34 % higher than that of Populus L. over the entire growth cycle. Forest types, stand age, canopy density class, ownership, closure management, strongly influence the accumulation rates of TBC. Overall, these findings contribute to the understanding of the advantages of mixed and monoculture plantations for carbon sequestration, and these results can be used to predict future patterns of carbon storage in urban forests in Shanghai.

Urban forests can absorb carbon dioxide for urban CO2 emission mitigation. However, the potential capacity of urban forest carbon sequestration (CS) and its drivers remain unclear in urban agglomerations under rapid urbanization. In our study, the net primary productivity (NPP) of built-up areas was reconstructed in the Harbin-Changchun urban agglomeration (HCUA) from 2000 to 2020 to reflect urban forest CS, and the drivers of spatial urban forest CS patterns were further explored using the Geodetector model. Our results showed that the HCUA has experienced rapid urbanization over the past 20 years. Across the urbanization gradient, the CS capacity was higher in new developing built-up areas than in the old developed built-up areas for all years. The CS capacity of urban forests increased gradually from 2000 to 2020, especially in large built-up areas. The urban forest CS was skewed toward low (300 g·m−2) show an overall increasing trend from 2000 to 2020, especially in small, low-altitude and old developed built-up areas. The total CS of built-up areas increased from 0.35 Mt·C·yr−1 in 2000 to 2.06 Mt·C·yr−1 in 2020, and the urban forests in the HCUA could offset approximately 2.23 % of urban carbon emissions in 2000, increasing to 5.08 % in 2020. Natural factors, such as temperature, mainly determined changes of the spatial urban forest CS distribution. In addition, we found that urban morphology factors, such as urban build-up area, construction height, population density, and gross national product, can significantly influence urban forest CS. We further found there may exist the threshold of urban built-up area and gross national product significantly affecting urban forest CS variation. The interaction between natural and anthropogenic factors had stronger explanatory power for the spatial variation of CS. Our study can help city managers formulate low-carbon development strategies to address the negative impacts of climate change and realize the low-carbon development of cities.

Enhancing forest cover is important for effective climate change mitigation. Studies suggest that drylands are promising areas for expanding forests, but conflicts arise with increased forest area and water consumption. Recent tree mortality in drylands raises concerns about carbon sequestration potential in tree plantations. Using Chinese dryland tree plantations as an example, we compared their growth with natural forests. Our results suggested plantation trees grew 1.6–2.1 times faster in juvenile phases, significantly shortening time to maturity (13.5 vs. 30 years) compared to natural forests, potentially stemming from simple plantation age structures. Different from natural forests, 74% of trees in plantations faced growth decline, indicating a short “prime period” for carbon sequestration and even a short lifespan. Additionally, a negative relationship between evapotranspiration and tree growth was observed in tree plantations since maturity, leading to high sensitivities of trees to vapor pressure deficit and soil water. However, this was not observed in natural forests. To address this, we suggest afforestation in drylands should consider complex age structures, ensuring a longer prime period for carbon sequestration and life expectancy in tree plantations.

Prunus serotina and Robinia pseudoacacia are the most widespread invasive trees in Central Europe. In addition, according to climate models, decreased growth of many economically and ecologically important native trees will likely be observed in the future. We aimed to assess the impact of these two neophytes, which differ in the biomass range and nitrogen-fixing abilities observed in Central European conditions, on the relative aboveground biomass increments of native oaks Quercus robur and Q. petraea and Scots pine Pinus sylvestris. We aimed to increase our understanding of the relationship between facilitation and competition between woody alien species and overstory native trees. We established 72 circular plots (0.05 ​ha) in two different forest habitat types and stands varying in age in western Poland. We chose plots with different abundances of the studied neophytes to determine how effects scaled along the quantitative invasion gradient. Furthermore, we collected growth cores of the studied native species, and we calculated aboveground biomass increments at the tree and stand levels. Then, we used generalized linear mixed-effects models to assess the impact of invasive species abundances on relative aboveground biomass increments of native tree species. We did not find a biologically or statistically significant impact of invasive R. pseudoacacia or P. serotina on the relative aboveground biomass increments of native oaks and pines along the quantitative gradient of invader biomass or on the proportion of total stand biomass accounted for by invaders. The neophytes did not act as native tree growth stimulators but also did not compete with them for resources, which would escalate the negative impact of climate change on pines and oaks. The neophytes should not significantly modify the carbon sequestration capacity of the native species. Our work combines elements of the per capita effect of invasion with research on mixed forest management.

Of late, intensive agricultural practices are often associated with many negative implications for soil systems, such as decline in soil organic matter and biological diversity, and increase in the risk of soil erosion, and degradation of soil physical quality. However, conservation agriculture (CA) offers minimum soil disturbance, improving and creating more efficient use of natural resources, enhancing use efficiency of external inputs and increasing soil functioning, organic matter content, and biodiversity. However, CA practices need to be redefined at the specific field level or growing conditions to promote sustainable production system without deteriorating soil health, and to manage profitability. Therefore, a fixed-site field experiment was conducted to evaluate the effects of different tillage and residue management practices; CT0 (puddled transplanted rice followed by conventional tilled wheat sown with residue removal); CTR (puddled transplanted rice followed by conventional tilled wheat sown with residue retention); NT0 (direct seeded rice followed by zero-tilled wheat sown with residue removal); NTR (direct seeded rice followed by zero-tilled wheat sown with residue retention) on soil organic carbon (SOC) stock and grain yield of rice–wheat double cropping system. The results showed that the mean SOC stock increased by 31%, 21.9% and 15.3% and by 35.2%, 22% and 17% under NTR, CTR, and NT0 compared with CT0. Furthermore, the SOC sequestration rate in NTR was significantly higher than other treatments. Particulate organic carbon (POC) concentration was 58.4% higher in 0–15 cm than 15–30 cm soil layer, and the maximum concentration was recorded under NTR and minimum was under CT0. The highest average rice grain yield was recorded under CTR, which was 5.5%, 16.2% and 24.3% higher than CT0, NTR and NT0, respectively. Both NTR and CTR produced more average wheat yield, which was 8.4% and 8.5% higher than CT0 and NT0, respectively. Principal component analysis (PCA) also showed that cumulative cropping system yield and SOC were increased under CTR, NTR as compared to other treatments. Therefore, it can be drawn that residue retention could be a useful management practice to increase SOC stock and grain yield under both tillage practices in the rice–wheat cropping system.

Abstract In the context of global climate change mitigation, carbon storage in woody vegetation plays a crucial role. Recognising the value of the i‐Tree Eco model for carbon storage in urban and forestry settings, this study aimed to explore its applicability to rewilded landscapes. Using direct measurements from destructively sampled scrub from the Knepp Estate, our goal was to determine the model's suitability to this landscape. Our findings reveal that these methods are not appropriate for multi‐stemmed trees below browsing height, as we observed no significant relationship between stem basal diameter and height. The i‐Tree tool's assumption of below‐ground biomass being 26% of above‐ground biomass may not be applicable to herbivore‐influenced landscapes. Additionally, we found that, on average, scrub at Knepp had more biomass below the ground than above, with a root:shoot ratio of 1.07, which is more than four times the amount predicted by current models using the 0.26 estimate ratio. This study underscores the need for novel allometric approaches that consider species‐specific biomass and the impact of external factors, such as herbivory, on carbon storage. Accurate carbon accounting in future rewilding projects is essential for their contribution to both biodiversity enhancement and climate change mitigation. While the i‐Tree Eco model provides valuable insights for many ecosystems, our findings suggest that its applicability may be limited in scrubland ecosystems, especially in rewilded landscapes where natural processes create semi‐stable scrub and open wood pastures. Nonetheless, with suitable adjustments or when complemented with other methods, the i‐Tree Eco model could be a valuable tool for specific scrub or rewilding scenarios.

A new aim for grassland management is to increase soil organic carbon (SOC) and to offset CO2 emissions by companies. This practice of carbon ranching may be informed by grazing-induced shifts in plant biomass and diversity which may foretell changes in SOC. Unfortunately, little is known about how grazing-induced shifts in plant properties correspond with shifts in SOC stocks. To help fill this gap, we used data from a field experiment to test whether above-ground plant properties (i.e. biomass, species richness) act as leading indicators of grazing-induced SOC accrual in the Northern Great Plains. The 5-yr bovine grazing experiment had a randomized complete block design and pre-treatment data. Moderate summer grazing (control) is widely used in the Northern Great Plains, and treatments that may alter grassland vegetation and SOC included: severe summer grazing, moderate fall grazing, and severe fall grazing. Severe fall and summer grazing increased SOC but had no effect on plant species richness and biomass relative to controls. Fall moderate grazing increased above-ground plant biomass but had no effect on SOC relative to controls. Changes to grazing practices can affect SOC without measurably affecting plant properties and can affect plant properties without measurably affecting SOC. While two drivers of SOC are plant carbon inputs and microbial respiration, our study indicates that grazing-induced change in above-ground vegetation is not predictive of change in SOC.

The global demand for beef is rapidly increasing (FAO, 2019), raising concern about climate change impacts (Clark et al., 2020; Leip et al., 2015; Springmann et al., 2018). Beef and dairy contribute over 70% of livestock greenhouse gas emissions (GHG), which collectively contribute ~6.3 Gt CO2 -eq/year (Gerber et al., 2013; Herrero et al., 2016) and account for 14%-18% of human GHG emissions (Friedlingstein et al., 2019; Gerber et al., 2013). The utility of beef GHG mitigation strategies, such as land-based carbon (C) sequestration and increased production efficiency, are actively debated (Garnett et al., 2017). We compiled 292 local comparisons of "improved" versus "conventional" beef production systems across global regions, assessing net GHG emission data from Life Cycle Assessment (LCA) studies. Our results indicate that net beef GHG emissions could be reduced substantially via changes in management. Overall, a 46 % reduction in net GHG emissions per unit of beef was achieved at sites using carbon (C) sequestration management strategies on grazed lands, and an 8% reduction in net GHGs was achieved at sites using growth efficiency strategies. However, net-zero emissions were only achieved in 2% of studies. Among regions, studies from Brazil had the greatest improvement, with management strategies for C sequestration and efficiency reducing beef GHG emissions by 57%. In the United States, C sequestration strategies reduced beef GHG emissions by over 100% (net-zero emissions) in a few grazing systems, whereas efficiency strategies were not successful at reducing GHGs, possibly because of high baseline efficiency in the region. This meta-analysis offers insight into pathways to substantially reduce beef production's global GHG emissions. Nonetheless, even if these improved land-based and efficiency management strategies could be fully applied globally, the trajectory of growth in beef demand will likely more than offset GHG emissions reductions and lead to further warming unless there is also reduced beef consumption.

Climate anomalies and human disturbances exert complex effects on regional carbon sequestration (CS), causing ecosystem CS to either increase or decrease due to factors such as vegetation greening, climate extremes, land use/land cover (LULC) changes, and farming systems. This study employs the patch-level land use simulation model to forecast changes in various land-use types in the Xinjiang Uyghur Autonomous Region, China, between 2020 and 2060 under different climatic conditions. The Intergovernmental Panel on Climate Change has proposed shared socioeconomic pathways (SSPs) as potential socioeconomic and environmental trajectories that might influence the region’s future land-use patterns. Three salient findings emerged: (1) LULC displayed considerable variation across future climate scenarios, with a notable rise in forest and grassland cover and a marked decrease in cropland areas under the SSP126 scenario. Conversely, the SSP585 scenario witnessed a substantial cropland expansion, paralleled by a decrease in forest and grassland areas; (2) CS exhibited significant disparities across different future climate scenarios. Xinjiang achieved a peak CS of 9.81 Pg between 2020 and 2060 under the SSP126 scenario, marking an increase of 335.22 Tg in 2060 compared to that in 2020. The SSP585 scenario registered the lowest CS at 9.41 Pg, indicating a decline of 50.07 Tg in 2060 relative to 2020; (3) The impacts of longitude and latitude on CS in Xinjiang predominantly arose from shifts in forest area and vegetation cover based on latitude, which positively influenced CS. In contrast, a decrease in vegetation cover and a subsequent decline in CS were evident with increasing longitude, particularly in the Altai, Tianshan, and Kunlun Mountains. These findings hold significant implications for formulating CS management strategies for terrestrial ecosystems and enhancing ecological preservation in Xinjiang.

Against the background of global warming, urban blue–green spaces (UBGS) are important carbon sequestration (CS) carriers that can reduce carbon emissions. However, previous studies on urban CS were mostly limited to urban green or blue spaces separately and lack a comprehensive consideration of the synergistic impact of UBGS on CS. In addition, research on the driving mechanism between urban blue–green spatial patterns (UBGSP) and CS has so far been insufficient. Therefore, in this study, we explored the correlation between UBGSP and CS, identified the affecting UBGSP factors, and proposed suggestions for planning design. We identified the UBGS of the central city of Nanjing based on Landsat-8, calculated the CS using the Carnegie-Ames-Stanford approach (CASA), and analyzed the relationship between the UBGSP and CS at both class and landscape levels by establishing sets of UBGSP indicators. At the class level, the percentage of landscape and aggregation index have positive effects on CS, whereas the landscape division and shape indexes have negative effects. Moreover, edge density and area-weighted patch fractal dimension do not correlate with CS. At the landscape level, connectance can promote the CS of UBGS. Finally, we found that the largest patch index, edge density, Shannon’s evenness index, patch cohesion index, and contagion have no significant effects. The results of this study contribute to the systematic optimization of UBGSPs, promote the integrated development of UBGSs, and provide references for urban planning practices and resource management.

Grasslands are ubiquitous globally, and their conservation and restoration are critical to combat both the biodiversity and climate crises. There is increasing interest in implementing effective multifunctional grassland restoration to restore biodiversity concomitant with above- and belowground carbon sequestration, delivery of carbon credits and/or integration with land dedicated to solar panels. Other common multifunctional restoration considerations include improved forage value, erosion control, water management, pollinator services, and wildlife habitat provisioning. In addition, many grasslands are global biodiversity hotspots. Nonetheless, relative to their impact, and as compared to forests, the importance of preservation, conservation, and restoration of grasslands has been widely overlooked due to their subtle physiognomy and underappreciated contributions to human and planetary well-being. Ultimately, the global success of carbon sequestration will depend on more complete and effective grassland ecosystem restoration. In this review, supported by examples from across the Western world, we call for more strenuous and unified development of best practices for grassland restoration in three areas of concern: initial site conditions and site preparation; implementation of restoration measures and management; and social context and sustainability. For each area, we identify the primary challenges to grassland restoration and highlight case studies with proven results to derive successful and generalizable solutions.

Carbon sequestration reflecting vegetation productivity is essential for global carbon cycle and terrestrial ecosystems. Exploring the spatial and temporal variation of carbon sequestration and corresponding ecological values yields insights for policy formulation to mitigate carbon emission and achieve carbon neutrality. Hence, taking Shaanxi China as the case study, we developed an integrated index (named C-GDP) based on vegetation carbon sequestration estimated by the CASA model and carbon prices acquired from carbon trading market in China to explore tradeoffs between economic and ecological development. The spatiotemporal distributions of carbon sequestration and C-GDP were characterized using hotspot analysis and variation coefficient during 2015–2020. The estimated carbon sequestrations were assessed with promising accuracy, depicting high values in the south and low values in the north, with provincial averages of 1761.37gC/m2a. Temporally, carbon sequestrations increased with fluctuation between 2015 and 2020, with significant seasonality. Summertime, especially July, has the highest sequestration, while winter is the season with the lowest values. The C-GDP calculated by carbon sequestration and carbon price exhibited a distinct pattern with sequestration, with the highest C-GDP in Central Shaanxi and the lowest in the south. The multi-year provincial-mean C-GDP is 20.44 billion yuan. The C-GDP exhibited an increase trend with miniscule fluctuation, peaking at 23.66 billion yuan in 2020. The results imply the ecological value of carbon sequestration monetizing by carbon prices is much lower than economical value of production, suggesting that strict carbon policies, such as improving carbon prices or taxes, may be warranted for China because of high carbon mitigation costs.

Carbon (C)-rich wetland soils are often drained for agriculture due to their capacity to support high net primary productivity. Increased drainage is expected this century to meet the agricultural demands of a growing population. Wetland drainage can result in large soil C losses and the concentration of residual soil minerals such as iron (Fe) and aluminum (Al). In upland soils, reactive Fe and Al minerals can contribute to soil C accumulation through sorption to poorly crystalline minerals and coprecipitation of organo-metal complexes, as well as C loss via anaerobic respiration by Fe-reducing bacteria. The role of these minerals in soil C dynamics is often overlooked in managed wetland soils and may be particularly important in both drained and reflooded systems with elevated mineral concentrations. Reflooding drained soils have been proposed as a means to sequester C for climate change mitigation, yet little is known about how reactive Fe and Al minerals affect C cycling in restored wetlands. We explored the interactions among soil C and reactive Fe and Al minerals in drained and reflooded wetland soils. In reflooded soils, soil C was negatively associated with reactive Fe and reduced Fe(II), a proxy for anaerobic conditions (reactive Fe: R2  = .54-.79; Fe(II): R2  = .59-.89). In drained soils, organo-Al complexes were positively associated with soil C and Fe(II) (Al R2  = .91; Fe(II): R2  = .54-.60). Soil moisture, organo-Al, and reactive Fe explained most of the variation observed in soil C concentrations across all sites (p

The stability of ecological communities is critical for the stable provisioning of ecosystem services, such as food and forage production, carbon sequestration, and soil fertility. Greater biodiversity is expected to enhance stability across years by decreasing synchrony among species, but the drivers of stability in nature remain poorly resolved. Our analysis of time series from 79 datasets across the world showed that stability was associated more strongly with the degree of synchrony among dominant species than with species richness. The relatively weak influence of species richness is consistent with theory predicting that the effect of richness on stability weakens when synchrony is higher than expected under random fluctuations, which was the case in most communities. Land management, nutrient addition, and climate change treatments had relatively weak and varying effects on stability, modifying how species richness, synchrony, and stability interact. Our results demonstrate the prevalence of biotic drivers on ecosystem stability, with the potential for environmental drivers to alter the intricate relationship among richness, synchrony, and stability.

Grasslands are subject to considerable alteration due to human activities globally, including widespread changes in populations and composition of large mammalian herbivores and elevated supply of nutrients. Grassland soils remain important reservoirs of carbon (C) and nitrogen (N). Herbivores may affect both C and N pools and these changes likely interact with increases in soil nutrient availability. Given the scale of grassland soil fluxes, such changes can have striking consequences for atmospheric C concentrations and the climate. Here, we use the Nutrient Network experiment to examine the responses of soil C and N pools to mammalian herbivore exclusion across 22 grasslands, under ambient and elevated nutrient availabilities (fertilized with NPK + micronutrients). We show that the impact of herbivore exclusion on soil C and N pools depends on fertilization. Under ambient nutrient conditions, we observed no effect of herbivore exclusion, but under elevated nutrient supply, pools are smaller upon herbivore exclusion. The highest mean soil C and N pools were found in grazed and fertilized plots. The decrease in soil C and N upon herbivore exclusion in combination with fertilization correlated with a decrease in aboveground plant biomass and microbial activity, indicating a reduced storage of organic matter and microbial residues as soil C and N. The response of soil C and N pools to herbivore exclusion was contingent on temperature - herbivores likely cause losses of C and N in colder sites and increases in warmer sites. Additionally, grasslands that contain mammalian herbivores have the potential to sequester more N under increased temperature variability and nutrient enrichment than ungrazed grasslands. Our study highlights the importance of conserving mammalian herbivore populations in grasslands worldwide. We need to incorporate local-scale herbivory, and its interaction with nutrient enrichment and climate, within global-scale models to better predict land-atmosphere interactions under future climate change.