Changes In Carbon Storage Research Articles

Growth Simulation of Agriculturally Dominant Cities by Incorporating Multiple Drivers into a CA-based patch-generating Land Use Simulation Model: A Case Study in Siracusa, Italy

Abstract. Understanding the historical trajectory of land use and land cover (LULC) and predicting future alterations is essential to advancing the SDGs. Current researches on LULC in agriculture-dominated cities primarily focuses on the spatiotemporal pattern analysis of carbon storage changes, with relatively little attention given to LULC simulation studies. Moreover, most studies employing cellular automata (CA) models concentrate on urban centers, overlooking the specific sustainable development of agricultural cities. This paper selects Siracusa, Italy, as a case study, incorporating multiple drivers and constructing four development scenarios. The patch-generating land use simulation (PLUS) model is employed to predict the LULC for Siracusa by 2030 and to examine potential transformations under each scenario. Our findings show that 60% of the land in Siracusa is designated as cropland, predominantly situated in flat regions. Our simulation results reveal that urbanization and demographic growth are the main factors driving cropland conversion to urban areas. Different development scenarios exhibit significant variations in future land use structures; the cropland protection scenario emphasizes the stability and sustainability of agricultural development, whereas the economic development scenario highlights the substantial impact of urban and industrial expansion on agricultural land. These insights are instrumental for land use planning and policy-making in Siracusa and other agriculture-centric cities, providing a framework to guide urbanization while promoting agricultural sustainability.

Estimating vegetation structure and aboveground carbon storage in Western Australia using GEDI LiDAR, Landsat and Sentinel data

Abstract Worsening climate change impacts are amplifying the need for accurate estimates of vegetation structure and aboveground biomass density (AGBD) to assess changes in biodiversity and carbon storage. In Australia, increasing wildfire frequency and interest in the role of forests in the carbon cycle necessitates biomass mapping across large geographic extents to monitor forest change. The availability of spaceborne Light Detection and Ranging (LiDAR) optimised for vegetation structure mapping through the Global Ecosystem Dynamics Investigation (GEDI) provides an opportunity for large-scale forest AGBD estimates of higher accuracy. This study assessed the use of the GEDI canopy height product to predict woody AGBD across five vegetation types in Western Australia: tall eucalypt forests, eucalypt open‒woodlands, low-lying heathland, tropical eucalypt savannas, and tussock and hummock grasslands. Canopy height models were developed using random forest regressions trained on GEDI canopy height discrete point data. Predictor variables included spectral bands and vegetation indices derived from synthetic aperture radar (SAR) Sentinel‒1 data, and multispectral Landsat and Sentinel‒2 data. AGBD was subsequently estimated using power-law models derived by relating the predicted canopy heights to field AGBD plots. Mapping was conducted for 2020 and 2021. The accuracy of canopy height predictions varied with height quantiles; models underestimated the height of taller trees and overestimated the height of smaller trees. A similar underestimation and overestimation trend was observed for the AGBD estimates. The mean carbon stock was estimated at 69.0 ±12.0 MgCha-1 in the tall eucalypt forests of the Warren region; 33.8 ± 5.0 MgCha-1 for the open eucalypt woodlands in the South Jarrah region; 7.1 ± 1.4 MgCha-1 for the heathland and shrublands in the Geraldton Sandplains region; 43.9 ± 4.9 MgCha-1 for the Kimberley eucalypt savanna; and 3.9 ± 1.0 MgCha-1 for the Kimberley savanna grasslands. This approach provides a useful framework for the future development of this process for fire management, and habitat health monitoring.

A Study on the Spatiotemporal Dynamics of Land Cover Change and Carbon Storage in the Northern Gulf Economic Zone of Guangxi Based on the InVEST Model

In recent years, the international community has increasingly focused on the “dual carbon” issue, as human-induced land use changes significantly impact ecosystem structure and carbon cycling. This study analyzes land use changes in the economic zone of the northern Gulf of Guangxi from 1980 to 2020, utilizing the InVEST model to simulate spatiotemporal changes in carbon storage and conducting zoning studies through spatial analysis. The findings reveal that ① forest land and arable land dominate the northern Gulf of Guangxi’s land use, with notable changes observed in forest land, unused land, and construction land areas. Forest land and construction land have increased by 1761.5 km2 and 1001.19 km2, respectively, while unused land has decreased by 1881.18 km2 from 2000 to 2020. ② The total carbon storage values in the northern Gulf of Guangxi in 1980, 2000, and 2020 were, respectively, 504.91 × 106/t, 487.29 × 106/t, and 500.31 × 106/t, with the expansion of construction land and conversion of forest land being the main reasons for the decrease in carbon storage. ③ In the northern Gulf of Guangxi, there is a slight upward trend in total carbon storage values over time. Spatially, higher carbon storage values are observed in mountainous and hilly areas at high altitudes, while the central and southern coastal areas exhibit lower carbon storage values. ④ The local spatial autocorrelation results reveal that Pu Bei County exhibits high–high clustering of carbon storage, while He Pu County undergoes a transition from high–low to low–low clustering, and several other administrative areas in Beihai demonstrates low–low clustering. Due to the imperative of economic development, the expansion of urban construction land encroaches upon ecological land, resulting in a decline in carbon storage. Therefore, in the Northern Gulf of Guangxi, it is essential to implement measures such as reforestation and establish ecological protection areas such as forests, grasslands, and wetlands to develop effective carbon sequestration methods and compensate for the carbon loss caused by the expansion of construction land.

Unveiling mid-century conservation priorities: Co-occurrence of biodiversity, climate change exposure, and carbon storage in the Middle and Lower Yangtze River Basin, China

The global challenges of biodiversity loss and climate change necessitate the implementation of integrated conservation strategies. A forward-looking framework is necessary to reconcile climate change adaptation and mitigation efforts with biodiversity goals, supporting effective long-term planning and management of protected areas (PAs) network. This study develops a comprehensive approach to identify priority areas for biodiversity conservation until 2050, integrating assessments of species distributions, climate change exposure and carbon storage under distinct shared socioeconomic pathways. The Middle and Lower Yangtze River Basin (MLYRB) in China serves as a case study. Using an ensemble species distribution modeling (ESDM) method, we predicted the distributions of 435 threatened terrestrial vertebrate species and plants. We then mapped their richness in the MLYRB. Distance-based climate velocity analysis was performed to identify climate change coldspots and hotspots. The patch-generating land use simulation (PLUS) model and InVEST model were coupled to simulate carbon storage changes. Systematic conservation planning tool, Zonation, was used to prioritize species conservation hotspots. By examining the co-occurrence of these hotspots with climate change coldspots/hotspots and areas of high carbon storage, conservation priorities for the MLYRB were revealed. Our findings indicate that 18.27–24.94% of the MLYRB risks over 20% species richness declines by 2050 under various scenarios, while increases over 10% are projected for only 0.81–1.75% of the area. Co-occurrence analysis highlights significant associations, such as a 32.26% overlap between species conservation hotspots and climate change hotspots in SSP1-2.6. Particularly noteworthy is the substantial co-occurrence (57.93–59.50% across scenarios) between areas maximizing species conservation and carbon storage. The identified conservation priority areas, covering 41.95% of the MLYRB (441554km2), hold potential for long-term species conservation, climate resilience, and nature-based climate solutions by 2050. However, only 6.08% of these priorities currently benefit from protection. These results offer valuable guidance for region-specific landscape management and conservation policy aligned with international goals. The presented methodology provides a broader application, serving as a valuable resource for prioritizing conservation efforts in other regions integrating biodiversity, climate change adaptation, and mitigation goals.

Spatio-temporal variation and prediction of land use and carbon storage based on PLUS-InVEST model in Shanxi Province, China

AbstractCoal mining in Shanxi Province for many years has caused regional land-use changes, seriously affecting the local ecological environment. To promote the green and sustainable development of this area and achieve the goal of “double carbon”, the PLUS-InVEST model was used to analyze the nearly 20 year land-use types transfer and carbon storage changes in the region based on the five periods of land-use data of Shanxi Province from 2002 to 2022 in this study. Three scenarios were set up to predict the data in 2032, and the driving forces of spatial differentiation of the carbon storage were analyzed by geographical detector. The results showed that: (1) Land-use change had an important impact on carbon storage. Construction land in Shanxi Province expanded by 3068.47 km2 from 2002 to 2022, an increase of 59.33%, and the rest of the land types, except for forest, continued to decrease, resulting in a decline in total carbon storage of 228.88 × 104 t. (2) The natural development scenario shows the same transfer of land as before in 2032. Under the urban development scenario, the expansion of construction land in Shanxi Province is the largest, and carbon storage decreases instead of increasing; under the ecological protection scenario forest and grassland increase, and carbon storage increase the most, with a value of 738.67 × 104 t. (3) The dominant driving factors for the spatial differentiation of carbon storage in Shanxi Province were the land-use degree comprehensive index and night light index, with the explanatory power of 0.866 and 0.755, respectively, and the interaction of the land-use degree comprehensive index with other factors had the most significant effect on the change of carbon storage. The study suggested that the expansion of construction land into high carbon storage categories was the main reason for the loss of carbon storage, and Shanxi Province should optimize the land-use structure and adopt ecological protection works to increase carbon storage effectively.

Analysis of Spatiotemporal Predictions and Drivers of Carbon Storage in the Pearl River Delta Urban Agglomeration via the PLUS-InVEST-GeoDetector Model

Land use and land cover change (LUCC) significantly influences the dynamics of carbon storage in thin terrestrial ecosystems. Investigating the interplay between land use alterations and carbon sequestration is crucial for refining regional land use configurations, sustaining the regional carbon balance, and augmenting regional carbon storage. Using land use data from the Pearl River Delta Urban Agglomeration (PRDUA) from 2010 to 2020, this study employed PLUS-InVEST models to analyze the spatiotemporal dynamics of land use and carbon storage. Projections for the years 2030, 2040, and 2050 were performed under three distinct developmental scenarios, namely, natural development (ND), city priority development (CPD), and ecological protection development (EPD), to forecast changes in land use and carbon storage. The geographic detector model was leveraged to dissect the determinants of the spatial and temporal variability of carbon storage, offering pertinent recommendations. The results showed that (1) during 2010–2020, the carbon storage in the PRDUA showed a decreasing trend, with a total decrease of 9.52 × 106 Mg, and the spatial distribution of carbon density in the urban agglomeration was imbalanced and showed an overall trend in increasing from the center to the periphery. (2) Clear differences in carbon storage were observed among the three development scenarios of the PRDUA between 2030 and 2050. Only the EPD scenario achieved an increase in carbon storage of 1.10 × 106 Mg, and it was the scenario with the greatest potential for carbon sequestration. (3) Among the drivers of the evolution of spatial land use patterns, population, the normalized difference vegetation index (NDVI), and distance to the railway had the greatest influence on LUCC. (4) The annual average temperature, annual average rainfall, and GDP exerted a significant influence on the spatiotemporal dynamics of carbon storage in the PRDUA, and the interactions between the 15 drivers and changes in carbon storage predominantly manifested as nonlinear and double-factor enhancements. The results provide a theoretical basis for future spatial planning and achieving carbon neutrality in the PRDUA.

Characteristics of Spatial and Temporal Changes in Carbon Stocks in the Middle and Upper Reaches of the Huaihe River Basin and Future Multi-scenario Simulation Prediction

The Huaihe River Basin is located in the north-south climate transition zone of China. The change of carbon storage in this area is of great significance for predicting the future ecological protection, mitigating climate change, and maintaining sustainable development of the Huaihe River Basin. The middle and upper reaches of Huaihe River Basin （above Bengbu station） were taken as the research area. Based on the land use data from 1980 to 2020, the PLUS model was used to simulate and predict the land use types in the study area from 2030 to 2100 under the scenarios of SSP1-2.6, SSP2-4.5, SSP5-8.5, and the continuation of land use status. The carbon module in the InVEST model was used to simulate and predict the carbon storage from 1980 to 2020 and the carbon storage from 2030 to 2100 under various scenarios, and the spatial and temporal changes of carbon storage in the middle and upper reaches of the Huaihe River Basin were compared and analyzed. The results showed that： ① From 1980 to 2020, the basin showed a decrease in both cultivated land and grassland,and the area of forest,water, construction, and unused land all increased, among which the area of cultivated land continued to decrease, with a total decrease of 4 699 km2 in 40 a. Construction land continued to increase, with a total increase of 4 592 km2 in 40 a. ② The carbon storage in the basin showed a downward trend, with a total reduction of 1.05×107 t from 1980 to 2020. ③ In the four scenarios, the area of each land type had different degrees of change, and that of the SSP1-2.6 scenario was relatively small out of the four scenarios. ④ Compared with the carbon storage in 2020, the carbon storage in the SSP1-2.6 scenario increased by 8.7×104 t, the carbon storage in the SSP2-4.5 scenario decreased by 1.42×107 t, the carbon storage in the SSP5-8.5 scenario decreased by 1.34×107 t, and the carbon storage in the current continuation scenario decreased by 1.22×107 t. The study can provide a scientific basis for land use structure management and ecological protection in the middle and upper reaches of the Huaihe River Basin （above Bengbu station） in the future.

Simulating Changes in Ecosystem Carbon Storage and Analyzing Influencing Factors in the Central Zhejiang under the Background of LUCC

Central Zhejiang is the key ecological function area of Zhejiang Province and an important part of the Qiantang River ecological corridor. Conducting simulations of ecosystem carbon storage changes and analyzing influencing factors under land-use changes in this region is of significant importance for achieving the goals of "peak carbon" and "carbon neutrality" at an early stage. This study, based on the land use data of five periods from 1980 to 2020 in central Zhejiang, coupled the GeoSOS-FLUS and the InVEST model to analyze the spatiotemporal changes in carbon storage in the region over time and project for the year 2030. The study also explored the impact of socio-economic and natural factors on changes in carbon storage. The results showed that： ① Between 1980 and 2020, urban construction land in the Zhejiang Central Region increased by 289.91%, with cultivated land and forest land being the main sources, leading to a 3% decrease in ecosystem carbon storage, amounting to 588.88×104 tons. ② High-value areas of carbon storage in the Zhejiang Central Region were concentrated in P'an-an County, Jinyun County, Wuyi County, and other areas. ③ Under the two different scenarios of natural development and ecological protection, carbon storage in the research area was projected to decrease by 1.05% and 0.05%, respectively, by 2030 compared to that in 2020. ④ Natural factors dominated the distribution of carbon storage, but their influence was gradually decreasing over time. The impact of socio-economic factors was increasing, and the combined effect of socio-economic and natural factors far outweighed the influence of a single factor on carbon storage distribution. These findings can serve as a scientific reference and guide for mitigating carbon loss in ecosystems, promoting ecosystem protection, facilitating sustainable social development, and achieving the "dual carbon" goals in Zhejiang and other regions nationwide.

Spatial-temporal Change and Driving Force of Carbon Storage in Three-River-Source National Park Based on PLUS-InVEST-Geodector Model

Exploring the spatial-temporal changes, driving forces, and future development tendency of the carbon sequestration service function of the Three-River-Source National Park ecosystem has great significance for regional ecological protection and sustainable development. Historical land-use data of Three-River-Source National Park from 1990 to 2020 were selected at five-year intervals, and based on the PLUS-InVEST-Geodector model, the spatial-temporal changes of historical carbon storage were analyzed, and the driving forces of spatial-temporal variation were explored combined with multiple factors. The carbon storage of Three-River-Source National Park in 2030 was predicted under the scenarios of natural development and ecological protection. The results showed that： ① The carbon storage of Three-River-Source National Park showed a fluctuating characteristic of increase-decrease-increase-decrease from 1990 to 2020, the carbon storage was increased by 41.85×106 t overall, and the grassland took the largest contribution. ② The spatial distribution characteristics of carbon storage in Three-River-Source National Park had little change between 1990 to 2020, and the evolution of the spatial distribution was relatively stable. The contribution ratio of the Yangtze River source park, Lancang River source park, and Yellow River source park was 7∶1∶2, which was roughly equivalent to the park area. ③ The major driving factors of the spatial-temporal variation of carbon storage in Three-River-Source National Park from 1990 to 2020 were： FVC, soil type, and annual precipitation. The interactive detection of each driving factor showed dual-factor enhancement and nonlinear enhancement. ④ The carbon storage of Three-River-Source National Park was predicted to decrease by 4.87% and 3.98% from 2020 to 2030 under the scenarios of natural development and ecological protection, respectively, and the carbon storage reduction under the ecological protection scenario had a significant inhibitory effect. The findings can provide data support for national spatial planning of Three-River-Source National Park and the enhancement of terrestrial ecosystem carbon storage.

Carbon isotope budget indicates biological disequilibrium dominated ocean carbon storage at the Last Glacial Maximum

Understanding the causes of the ~90 ppmv atmospheric CO2 swings between glacial and interglacial climates is an important open challenge in paleoclimate research. Although the regularity of the glacial-interglacial cycles hints at a single driving mechanism, Earth System models require many independent physical and biological processes to explain the full observed CO2 signal. Here we show that biologically sequestered carbon in the ocean can explain an atmospheric CO2 change of 75 ± 40 ppmv, based on a mass balance calculation using published carbon isotopic measurements. An analysis of the carbon isotopic signatures of different water masses indicates similar regenerated carbon inventories at the Last Glacial Maximum and during the Holocene, requiring that the change in carbon storage was dominated by disequilibrium. We attribute the inferred change in carbon disequilibrium to expansion of sea-ice or change in the overturning circulation.

Evaluation of driving effects of carbon storage change in the source of the Yellow River: A perspective with CMIP6 future development scenarios

Understanding how future climate scenarios impact land use/cover (LUC) and carbon storage (CS) is crucial for achieving carbon neutrality. However, research often overlooks the spatiotemporal impacts of future climate and socioeconomic changes on CS. This study integrates system dynamic (SD), patch-generating land use simulation (PLUS), the integrated valuation of ecosystem services and tradeoffs (InVEST) model, and the geographical detector to assess the LUC and CS evolution in the source of the Yellow River (SYR) from 2020 to 2060. Utilizing carbon density and LUC data, we explored the influence of natural and socioeconomic factors on CS under five shared socioeconomic pathways and representative concentration pathways (SSP-RCPs) scenarios. Our findings demonstrate that: (1) Ecological land, including woodland, grassland, and wetland, expanded more under SSP126 compared to SSP245, with SSP345, SSP460, and SSP585 showing a trend of degradation tied to deeper economic contribution. (2) By 2060, CS in terrestrial ecosystem under SSP126, SSP245, SSP345, SSP460, and SSP585 were 702.33 × 106 t, 700.33 × 106 t, 697.22 × 106 t, 696.03 × 106 t, and 691.21 × 106 t, respectively. This represents changes of 3.69 × 106 t, 1.69 × 106 t, −1.49 × 106 t, −2.68 × 106 t, and −7.43 × 106 t compared to 2020. (3) Soil type predominantly influenced the spatial differentiation of CS, with significant interactions with precipitation. This research provides new insights into land redistribution, economic strategies, and achieving carbon neutrality.

Dynamics of structural indices and organic carbon pool across a haplic acrisol under secondary tropical rainforest at Umudike Abia State

Differences in vegetation types over a landscape influences the structural behaviour and organic carbon pool of soils thereby affecting site-specific management decisions. This study aimed at establishing the differences in structural indices and organic carbon pool across a soil under secondary rainforest vegetation. Nine replicates of auger and core soil samples were randomly collected from the site at 0 – 20 cm depth. Soil samples were prepared and analysed at a laboratory. Data obtained were subjected to geospatial analysis using a Geographical Information System (GIS) software package. Results showed that changes in organic carbon storage ranged from 40 – 48 ton / ha, BD ranged from 1.39 – 1.42 mg / m3, clay flocculation index ranged from 50 – 68 %, aggregated silt + clay ranged from 9 – 12 %, clay dispersion index ranged from 32 – 42 %, dispersion ratio ranged from 26 – 32 %, mean weight diameter ranged from 0.75 – 1.05 mm, saturated hydraulic conductivity ranged from 3.1 – 3.8 cm / mins and total porosity ranged from 46.4 – 47.6 %. Regions of weak micro aggregaion dominated the land while regions of increased stability of macro aggregates were dominant. Regions of increased soil organic carbon storage occupied about half portion of the land. Greater portion of the land was noted for increased bulk density, reduced total porosity and saturated hydraulic conductivity. Consequently, there were changes in soil structural properties and organic carbon storage across the studied area.

Multi-scenario prediction and attribution analysis of carbon storage of ecological system in the Huaihe River Basin, China.

Evaluating the impact of large-scale human activities on carbon storage through land use changes is of growing interest in terrestrial ecosystem assessments. The Huaihe River Basin, a vital Chinese grain production area, has undergone marked land use changes amid socio-economic acceleration. Evaluating the impacts of land use change on carbon storage and future carbon sequestration is imperative for regional ecosystem sustainability and Chinese food security, simultaneously, furnishing data support to regional land use planning and decision-making processes. Nonetheless, the mechanisms linking land use changes to carbon storage and the future carbon reservoir responses remain unclear. We utilized a multi-source dataset and representative scenarios, integrating PLUS, InVEST models, and Geodetector to assess land use change impacts on carbon storage in the Huaihe River Basin (2000-2030). The data indicates the following: (1) from 2000 to 2020, cultivated land decreased by 28,344.69 km2, construction land increased by 26,914.56 km2, and other land types changed little. (2) Land use change resulted a carbon loss of 1.17 × 108 t, primarily due to the expansion of construction land. (3) All four simulation scenarios exhibited diminished carbon storage relative to 2020, with the economic development scenario recording the lowest at 4.98 × 109 t and the ecological protection scenario the highest at 5.06 × 109 t. (4) Elevation predominantly drives carbon storage changes, with its interaction with NPP having the greatest impact. The factors synergistically enhance their explanatory power. The research provides a scientific basis for strategies aimed at augmenting regional carbon sequestration and refining low-carbon land management, safeguarding ecosystem stability.

Analysis of the Spatiotemporal Evolution of Carbon Reserves in Shaanxi Province Under Different Scenarios in the Future

To understand the land use development trends in Shaanxi Province under different scenarios and effectively assess the spatiotemporal evolution of terrestrial ecological carbon stocks in Shaanxi Province under land use changes, the study used Markov-FLUS and InVEST models to analyze the impact of land use changes in Shaanxi Province from 2000 to 2020. The impact of carbon storage changes and the spatiotemporal changes in land use structure, carbon storage, and carbon density under three different scenarios were simulated and assessed in Shaanxi Province in 2025 and 2030. The results showed： ① The ROC values of various categories in the coupled Markov-FLUS model were all above 0.7, showing high accuracy and excellent classification performance. The model had a good ability to explain the land use driving factors in the study area, with high accuracy and excellent classification performance. ② From 2000 to 2020, the cultivated land in Shaanxi Province increased significantly. Forest land increased significantly, and the increase in forest land area with high carbon sequestration efficiency caused the carbon storage in Shaanxi Province to increase from 1 546.95 Tg to 1 616.25 Tg. The changes in various regions in Shaanxi Province from 2000 to 2020 were different, among which the carbon storage in Yan'an was significantly increased by 18.89 Tg, whereas the carbon storage in Yulin significantly decreased by 3.29 Tg in 20 years. ③ Altitude, precipitation, and temperature became the main factors affecting the spatiotemporal changes in carbon storage in Shaanxi Province from 2020 to 2030. In three of the years between 2025 and 2030, under different scenarios, the carbon stocks under the ecological priority scenario were 1 632.27 Tg and 1 647.43 Tg, respectively. The carbon storage and its growth rate were significantly higher than in the natural development scenario and the cultivated land protection scenario. ④ The proportion of carbon storage increase areas under the ecological priority scenario was high. In the cultivated land protection scenario, the proportion of reduction areas was lower than that of the natural development scenario, and the distribution of carbon storage was the most balanced. At the same time, the southern and northern areas of the Loess Plateau in northern Shaanxi need to focus on the protection of the ecological environment in future development. The research results can, to a certain extent, provide reference for promoting the construction of ecological Shaanxi and formulating carbon neutral strategic planning.

Changes in Soil Organic Carbon Density and Its Response to Climate Change and Human Activities Before and After the Grain for Green Project on the Loess Plateau

Accurately assessing the changes in soil organic carbon storage （SOCS） before and after the Grain for Green Project （GFG） in the Loess Plateau （LP） and exploring the relationship between its spatial and temporal distribution and the influencing factors were important references for the development of regional recycling as well as the formulation of ecological protection policies. Based on the data of climate, human activities, and SOCD in the surface （0-20 cm） and deep （0-100 cm） soil before and after GFG in the LP from 2001 to 2020, we investigated the changes in SOCD at different spatial and temporal scales by using the methods of trend analysis, the kriging method, and variance partitioning analysis. The results showed that： ① Before and after the GFG, the surface SOCS of the whole region increased by 8 338.7×104 t； the deep SOCS increased by 1 160.02×104 t. ② In each bioclimatic subregion, the whole-region average SOCD of Ⅰ （Semi-Humid Forest Region）, Ⅱ （Semi-Humid Semi-Arid Forest and Grassland Region）, and Ⅲ （Semi-Arid Typical Grassland Region） showed a significant increasing trend, with a decreasing trend in Ⅳ （arid semi-arid desert grassland area） and Ⅴ （arid desert area）. ③ The average surface SOCS increase in different ecosystems was ranked as follows： cropland > grassland > woodland > shrubs > bare land and sparse vegetation. The deep soil increase was ranked as follows： grassland > cropland > woodland > shrubs > bare land and sparse vegetation. ④ Climate factors were the most important driving factors for changes in SOCD； the annual average temperature and precipitation were significantly positively correlated with changes in SOCD. The results of the study could provide data support for regional ecological management and land use policy formulation to promote high quality development of the ecological environment in the LP.

Forest soil carbon storage in 10‐year‐old Douglas‐fir plantations of western Oregon and Washington remains similar to pre‐harvest

AbstractForests around the world, and in the case of this study, the coastal Pacific Northwest United States, store large amounts of carbon, both above ground in the trees and below ground in soils. Understanding the effects of forest disturbance, including timber harvesting, is important in order to evaluate the role that forestry plays in the global carbon cycle. Soil carbon can be difficult to assess with enough precision to detect the kinds of changes that are expected, yet a series of small changes over time in the same direction could have important cumulative effects. In this study, eight randomly selected Douglas‐fir forest stands in Oregon and Washington were sampled at 300 points each using a fixed‐depth sampling approach to attempt to detect a 5% or higher change in soil carbon storage to 1 m, longitudinally from pre‐harvest to 10 years post‐harvest. There was moderate variability in results over time at individual sites, with some sites decreasing slightly and others increasing slightly. Only two sites achieved lower than the 5% minimum detectible difference target. The remaining six sites were able to detect 5.7%–10.7% differences. In one case, an unexpectedly large increase in mineral soil carbon 10 years post‐harvest occurred without clear explanation. On average, forest floor carbon stores were 20% larger 10 years post‐harvest than pre‐harvest. Even with the large increases excluded, both the fixed‐depth approach and equivalent soil mass correction showed there was no significant change in mineral soil carbon stores to 1 m at 10 years post‐harvest in the region.

Analysis of the Spatiotemporal Changes in Cropland Occupation and Supplementation Area in the Pearl River Delta and Their Impacts on Carbon Storage

In recent years, the “dual carbon” issue has become a major focus of the international community. Changes in land use driven by anthropogenic activities have a profound impact on ecosystem structure and carbon cycling. This study quantitatively assesses the spatiotemporal changes in cropland occupation and supplementation in the Pearl River Delta from 2000 to 2020 using the InVEST model, analyzing the spatial clustering of carbon storage changes caused by variations in cropland area. The PLUS model was employed to simulate land-use patterns and the spatial distribution of carbon storage in four future development scenarios. The results indicate the following: (1) From 2000 to 2020, the net change rate of cropland area in the Pearl River Delta was −0.81%, with a decrease of 16.49 km2 in cropland area, primarily converted to built-up land and forest land. (2) Carbon storage in the Pearl River Delta exhibited a pattern of lower values in the center and higher values in the periphery. The terrestrial ecosystem carbon storage in the Pearl River Delta was 534.62 × 106 t in 2000, 518.60 × 106 t in 2010, and 512.57 × 106 t in 2020, showing an overall decreasing trend. The conversion of cropland and forest land was the main reason for the decline in total regional carbon storage. (3) The area of carbon sequestration lost due to cropland occupation was significantly greater than the area of carbon loss compensated by new cropland, indicating an imbalance in the quality of cropland occupation and supplementation as a crucial factor contributing to regional carbon loss. (4) Under the ecological priority scenario, the expansion of built-up land and the reduction in ecological land such as cropland and forest land were effectively controlled, resulting in the minimal loss of carbon storage. The soil organic carbon pool of cropland is the most active carbon pool in terrestrial ecosystems and has a significant impact on carbon storage. Clarifying the relationship between “cropland protection measures–land use changes–ecosystem carbon storage” will improve cropland protection policies, provide references for regional carbon sequestration enhancement, and support sustainable socio-economic development.

Ecosystem carbon storage assessment and multi-scenario prediction in the Weihe River Basin based on PLUS-InVEST model.

Land use changes are the main cause for the changes of carbon storage, which is of great importance for maintaining regional carbon balance to make multi-scenario projections of future land use change and explore its impacts on carbon storage. In recent years, under the combination of natural factors and policies, with the land use changing significantly, carbon storage of the Weihe River Basin has also changed. Based on the PLUS-InVEST model, we assessed and predicted the spatial and temporal variations of ecosystem carbon storage in the Weihe River Basin and explored the impacts of land-use change. The results showed that land use distribution pattern of the Weihe River Basin did not change much from 2000 to 2020, which was characterized by the decreases of cropland area and the increases of the area of the remaining land use types. The main ways of land use type conversion were cropland to built-up land and inter-conversion of cropland, forest, grassland. Carbon storage in the Weihe River Basin showed an upward trend from 2000 to 2020, with a total increment of 15.31×106 t. The areas with high carbon storage presented the characteristics of "northeast patch-western scatter-central and southern belt", while low carbon storage distributed in the Guanzhong Plain urban agglomeration located in the lower basin. Compared to 2020, carbon storage in the Weihe River Basin in 2030 would increase under the four scenarios. Carbon storage would increase the least under the economic development scenario, and the most under the ecological protection scenario. The variation of carbon storage in spatial distribution would be embodied in the staggered zone of cropland, forest, and grassland in the upper basin. The results could provide data support for land use management decisions and carbon storage enhancement in the Weihe River Basin.

Demographic but not competitive time lags can transiently amplify climate-induced changes in vegetation carbon storage.

How terrestrial ecosystems will accumulate carbon as the climate continues to change is a major source of uncertainty in projections of future climate. Under growth-stimulating environmental change, time lags inherent in population and community dynamic processes have been posed to dampen, or alternatively amplify, short-term carbon gain in terrestrial vegetation, but these outcomes can be difficult to predict. To theoretically frame this problem, we developed a simple model of vegetation dynamics that identifies the stage-structured demographic and competitive processes that could govern the timescales of carbon storage and loss. We show that demographic lags associated with growth-stimulating environmental change can allow a rapid increase in population-level carbon storage that is lost back to the atmosphere in later years. However, this transient carbon storage only emerges when environmental change increases the transition of adult individuals into a larger size class that suffers markedly higher mortality. Otherwise, demographic lags simply slow carbon accumulation. Counterintuitively, an analogous tradeoff between maximum adult size and survivorship in two-species models, coupled with environmental change-driven replacement, does not generate the transient carbon gain seen in the single-species models. Instead lags in competitive replacement slow the approach to the eventual carbon trajectory. Together, our results suggest that time lags inherent in demographic and compositional turnover tend to slow carbon accumulation in systems responding to growth-stimulating environmental change. Only under specific conditions will lagged demographic processes in such systems drive transient carbon accumulation, conditions that investigators can examine in nature to help project future carbon trajectories.

Estimating terrestrial ecosystem carbon storage change in the YREB caused by land-use change under SSP-RCPs scenarios

Terrestrial ecosystems, as an essential carbon sink of atmospheric CO2, play an important role in balancing the global carbon cycle. Land-use and land-cover changes (LUCCs) are the major factors in terrestrial ecosystem carbon storage (TECS) change. However, they are not yet sure how future LUCCs would affect the TECS in the Yangtze River Economic Belt (YREB) to meet China's carbon-neutral goal. We simulated eight land-use change scenarios and used these to estimate the YREB's TECS and its 2020–2060 variation by coupling the spatially explicit projections of LUCCs under the latest IPCC, combining shared socioeconomic pathways (SSPs) and representative concentration pathways (RCPs) with datasets on terrestrial ecosystem carbon density dataset. Results show that: 1) the total TECS of the YREB in 2020 is ∼28.07 Gt. Spatially, TECS in the YREB focused on Sichuan and Yunnan (∼13.35 Gt), which plays a crucial role in balancing the regional carbon cycle; its losses are in Jiangsu, Zhejiang, and Hunan provinces; Yunnan is the potential region with future carbon sink enhancement in the YREB. 2) Compared to the TECS change under eight land-use scenarios, the low-carbon and sustainable development pathways are the priority chosen by humans. 3) The replacement of vast forest land with cropland and urban expansion are the key factor of TECS change in the YREB. 4) Land management policies (i.e., Cultivated land requisition-compensation balance) should balance the conflicts between food self-sufficiency and the carbon sink rather than only the dynamic balance in quantity. Our study aims to provide data support for the government in planning future development pathways and refining carbon emission reduction strategies to assist in carbon trading and compensation and achieve the YREB's dual-carbon goal.