Terrestrial Forest Research Articles

Deciphering nitrogen concentrations in Metasequoia glyptostroboides: a novel approach using RGB images and machine learning

Recent advances in spectral sensing techniques and machine learning (ML) methods have enabled the estimation of plant physiochemical traits. Nitrogen (N) is a primary limiting factor for terrestrial forest growth, but traditional methods for N determination are labor-intensive, time-consuming, and destructive. In this study, we present a rapid, non-destructive method to predict leaf N concentration (LNC) in Metasequoia glyptostroboides plantations under N and phosphorus (P) fertilization using ML techniques and unmanned aerial vehicle (UAV)- based RGB (red, green, blue) images. Nine spectral vegetation indices (VIs) were extracted from the RGB images. The spectral reflectance and VIs were used as input features to construct models for estimating LNC based on support vector machine, random forest (RF), and multiple linear regression, gradient boosting regression and classification and regression trees (CART). The results show that RF is the best fitting model for estimating LNC with a coefficient of determination (R2) of 0.73. Using this model, we evaluated the effects of N and P treatments on LNC and found a significant increase with N and a decrease with P. Height, diameter at breast height (DBH), and crown width of all M. glyptostroboides were analyzed by Pearson correlation with the predicted LNC. DBH was significantly correlated with LNC under N treatment. Our results highlight the potential of combining UAV RGB images with an ML algorithm as an efficient, scalable, and cost-effective method for LNC quantification. Future research can extend this approach to different tree species and different plant traits, paving the way for large-scale, time-efficient plant growth monitoring.

Carbon cycling through plant and fungal herbarium specimens tracks the Suess effect over more than a century of environmental change

Although the anthropogenic decline in atmospheric carbon stable isotope ratios (δ13C) over the last 150 years (termed the Suess effect) is well-studied, how different terrestrial trophic levels and modes reflect this decline remains unresolved. To evaluate the Suess effect as an opportunistic tracer of terrestrial forest carbon cycling, this study analyzed the δ13C in herbarium specimens collected in Minnesota, USA from 1877 to 2019. Our results suggest that both broadleaf trees and ectomycorrhizal fungi relied on recent photosynthate to produce leaves and sporocarps, while saprotrophic fungi on average used carbon fixed from the atmosphere 32–55 years ago for sporocarp construction. The δ13C values of saprotrophic fungal collections were also sensitive to the age of their plant carbon substrate, with sporocarps of twig specialists tracking changes in atmospheric δ13C more closely than saprotrophs growing on logs. Collectively, this study indicates that natural history collections can quantitatively track carbon cycling among plants and fungi over time.

Variations and trade-offs in leaf and culm functional traits among 77 woody bamboo species

BackgroundWoody bamboos are the only diverse large perennial grasses in mesic-wet forests and are widely distributed in the understory and canopy. The functional trait variations and trade-offs in this taxon remain unclear due to woody bamboo syndromes (represented by lignified culm of composed internodes and nodes). Here, we examined the effects of heritable legacy and occurrence site climates on functional trait variations in leaf and culm across 77 woody bamboo species in a common garden. We explored the trade-offs among leaf functional traits, the connection between leaf nitrogen (N), phosphorus (P) concentrations and functional niche traits, and the correlation of functional traits between leaves and culms.ResultsThe Bayesian mixed models reveal that the combined effects of heritable legacy (phylogenetic distances and other evolutionary processes) and occurrence site climates accounted for 55.10–90.89% of the total variation among species for each studied trait. The standardized major axis analysis identified trade-offs among leaf functional traits in woody bamboo consistent with the global leaf economics spectrum; however, compared to non-bamboo species, the woody bamboo exhibited lower leaf mass per area but higher N, P concentrations and assimilation, dark respiration rates. The canonical correlation analysis demonstrated a positive correlation (ρ = 0.57, P-value < 0.001) between leaf N, P concentrations and morphophysiology traits. The phylogenetic principal components and trait network analyses indicated that leaf and culm traits were clustered separately, with leaf assimilation and respiration rates associated with culm ground diameter.ConclusionOur study confirms the applicability of the leaf economics spectrum and the biogeochemical niche in woody bamboo taxa, improves the understanding of woody bamboo leaf and culm functional trait variations and trade-offs, and broadens the taxonomic units considered in plant functional trait studies, which contributes to our comprehensive understanding of terrestrial forest ecosystems.

Indicators sandflies and environment associated to spatial landscaping change in Chocó Biosphere Reserve UNESCO.

Sandflies are vector insects associated with terrestrial forest ecosystems; in the Ecuadorian Andes, they participate in the transmission of human cutaneous leishmaniasis. This geographical area represents an opportunity to evaluate the role of sandflies as bioindicators of the degree of intervention of tropical humid forest ecosystems (THF) associated with changes in the ecology of the local landscape. CDC-light traps were used for collecting adult sandflies in February 2020 in a humid tropical forest within the Chocó Biosphere Reserve. All species were identified using morphological keys. Analysis data about abundance, richness, species accumulation, diversity index, species composition communities, species sex proportion, spatial sandflies environmental, Renyi's Diversity Profile were performed to compare six spatial habitats in Mashpi locality, Ecuador. Sandflies were collected (n-1435); the main species are represented by Trichophoromyia reburra, Nyssomyia trapidoi, Psathyromyia aclydifera, Psychodopygus panamensis and Lutzomyia hartmanni. Only Th. reburra is associated with not intervened forest, while the other three species are associated with intervened forest within Mashpi in the Choco Biosphere Reserve. The secondary forest has major sandflies' richness, while the primary forest exhibits major abundance. Th. reburra is a sandfly restricted to the Andean Forest and is a bioindicator of the high environmental health quality of the forest, while Ny. trapidoi and Pa. aclydifera are bioindicators of environmental disturbances in the forest. Additionally, Ps. panamensis, Lu. hartmanni and Ny. trapidoi are bioindicators of human impact and the risk of leishmaniasis.

Deconstructing the mangrove carbon cycle: Gains, transformation, and losses

AbstractMangroves are one of the most carbon‐dense forests on the Earth and have been highlighted as key ecosystems for climate change mitigation and adaptation. Hundreds of studies have investigated how mangroves fix, transform, store, and export carbon. Here, we review and synthesize the previously known and emerging carbon pathways in mangroves, including gains (woody biomass accumulation, deadwood accumulation, soil carbon sequestration, root and litterfall production), transformations (food web transfer through herbivory, decomposition), and losses (respiration as CO2 and CH4, litterfall export, particulate and dissolved carbon export). We then review the technologies available to measure carbon fluxes in mangroves, their potential, and their limitations. We also synthesize and compare mangrove net ecosystem productivity (NEP) with terrestrial forests. Finally, we update global estimates of carbon fluxes with the most current values of fluxes and global mangrove area. We found that the contributions of recently investigated fluxes, such as soil respiration as CH4, are minor (&lt;1 Tg C year−1), while the contributions of deadwood accumulation, herbivory, and lateral export are significant (&gt;35 Tg C year−1). Dissolved inorganic carbon exports are an order of magnitude higher than the other processes investigated and were highly variable, highlighting the need for further studies. Gross primary productivity (GPP) and ecosystem respiration (ER) per area of mangroves were within the same order of magnitude as terrestrial forests. However, ER/GPP was lower in mangroves, explaining their higher carbon sequestration. We estimate the global mean mangrove NEP of 109.1 Tg C year−1 (7.4 Mg C ha−1 year−1) or through a budget balance, accounting for lateral losses, a global mean of 66.6 Tg C year−1 (4.5 Mg C ha−1 year−1). Overall, mangroves are highly productive, and despite losses due to respiration and tidal exchange, they are significant carbon sinks.

Integrating SAR and Optical Data for Aboveground Biomass Estimation of Coastal Wetlands Using Machine Learning: Multi-Scale Approach

Coastal wetlands encompass diverse ecosystems such as tidal marshes, mangroves, and seagrasses, which harbor substantial amounts of carbon (C) within their vegetation and soils. Despite their relatively small global extent, these wetlands exhibit carbon sequestration rates on par with those observed in terrestrial forests. The application of remote sensing technologies offers a promising means of monitoring aboveground biomass (AGB) in wetland environments. However, the scarcity of field data poses a significant challenge to the utilization of spaceborne data for accurate estimation of AGB in coastal wetlands. To address this limitation, this study presents a novel multi-scale approach that integrates field data, aerial imaging, and satellite platforms to generate high-quality biomass maps across varying scales. At the fine scale level, the AVIRIS-NG hyperspectral data were employed to develop a model for estimating AGB with an exceptional spatial resolution of 5 m. Subsequently, at a broader scale, large-scale and multitemporal models were constructed using spaceborne Sentinel-1 and Sentinel-2 data collected in 2021. The Random Forest (RF) algorithm was utilized to train spring, fall and multi-temporal models using 70% of the available reference data. Using the remaining 30% of untouched data for model validation, Root Mean Square Errors (RMSE) of 0.97, 0.98, and 1.61 Mg ha−1 was achieved for the spring, fall, and multi-temporal models, respectively. The highest R-squared value of 0.65 was achieved for the multi-temporal model. Additionally, the analysis highlighted the importance of various features in biomass estimation, indicating the contribution of different bands and indices. By leveraging the wetland inventory classification map, a comprehensive temporal analysis was conducted to examine the average and total AGB dynamics across various wetland classes. This analysis elucidated the patterns and fluctuations in AGB over time, providing valuable insights into the temporal dynamics of these wetland ecosystems.

Two new species of Rhodoveronaea (Rhamphoriales, Ascomycota) from terrestrial habitats in China

During a microfungi investigation carried out in a terrestrial forest in Guizhou Province in China, hyphomycetes on a decaying wood log in a terrestrial habitat were collected. Morphological characteristics and phylogenetic analyses of combined ITS, LSU, SSU, tef1-α, and rpb2 sequence data revealed that the collected hyphomycetes represent two distinct new species in Rhodoveronaea. The two new species introduced in this paper are Rhodoveronaea hyalina and R. lignicola. Full descriptions, illustrations, and a phylogenetic tree to show the placement of the two new species are provided.

Carbon stock estimation of Sonneratia alba in mangrove restoration area in Pasar Rawa, Langkat North Sumatera

Mangrove forests must be protected because they are an important ecosystem for climate mitigation. Mangrove forests are one of the “blue carbon” ecosystems capable of absorbing significantly more carbon than terrestrial forests. Mangrove restoration is being carried out in various regions as part of an effort to rehabilitate damaged ecosystems, one of which being Pasar Rawa Village in Langkat Regency. Sonneratia alba is a native plant that is employed in restoration activities. The purpose of this study is to investigate carbon stock in the S. alba monoculture restoration area in Pasar Rawa Village, Langkat Regency, North Sumatra Province. Purposive sampling was employed in this study, with plots distributed evenly around the research area. Carbon stock estimation is performed non-destructively by estimating carbon estimates based on diameter at breast height (DBH) and total height of trees. According to the research findings, the total carbon stored in the Sonneratia alba restoration area is quite low, at 60.89 ton.ha−1. S. alba produced 192.13 ton.ha−1 of absorbed carbon with CO2 absorption of 19212.84 g/m2 and so was classified as low.

Indicators sand flies and environment associated to spatial landscaping change in Choco Biosphere Reserve UNESCO.

Sand flies are insects vector associated with terrestrial forest ecosystems; in the Ecuadorian Andes, they participate in the transmission of human cutaneous leishmaniasis. This geographical area is an opportunity to evaluate the role of sand flies as bioindicators od the degree of intervention of a tropical humid forest ecosystems (THF) associated with changes in the ecology of the local landscape. CDC-light traps were used for collecting adults' sand flies in February 2020 in a humid tropical forest within Choco Biosphere Reserve. All species were identified using morphological keys. Analysis data about abundance, richness, species accumulation, diversity index, species composition communities, species sex proportion, spatial sand flies environmental, Renyi's Diversity Profile were performed to compare six spatial habitats in Mashpi locality, Ecuador. Sand flies were collected (n-1435); the main species are represented by Th. reburra Ny. trapidoi, Pa. aclydifera, Py. panamensis and Lu. hartmanni. Only Th. reburra is associated with not intervened forest, while the other 3 species are associated with intervened forest within Mashpi in the Choco Biosphere Reserve. The secondary forest has the major sandflies' richness, while the primary forest exhibits the major abundance. The results indicated that Th. reburra is a sandfly restricted to the Andean Forest and is a bioindicator of the high environmental health quality of the forest, while Ny. trapidoi and Pa. aclydifera are bioindicators of environmental disturbances in the forest. Additionally, Ps. panamensis, Lu. hartmanni and Ny. trapidoi are bioindicators of human impact and the risk of leishmaniasis.

Blue carbon accounting to monitor coastal blue carbon ecosystems

In the global context, countries must reduce carbon dioxide emissions to "net zero" by 2050 to limit global warming to 1.5 °C above pre-industrial levels. China's Nationally Determined Contributions (NDCs) are to peak carbon dioxide emissions by 2030 and achieve the carbon neutrality target by 2060. To monitor the achievements of the NDCs, establishing an annual-based accounting mechanism is necessary to record the carbon stocks in China, especially for Blue Carbon. The paper aims to present China's first national-scale systematic Blue Carbon accounting for mangroves, salt marshes, and seagrasses, covering the accounting subjects of physical and monetary assets, as well as relevant indicators for investors. It focuses on the design of the accounting method and system, the selection of data categories applied to this system, and the application of China's Blue Carbon accounting based on this accounting system. Taking Blue Carbon accounting as a starting point, this paper analyses the restoration prospects of these ecosystems and their application potential for NDCs in China compared with the terrestrial ecosystems. The results indicate that mangroves are the most cost-effective type of ecosystem, even compared to terrestrial forests. Thus, the paper provides policymakers with a new perspective on the decision-making of carbon sequestration relevant decisions, aiming to promote the monitoring, restoration, and expansion of China's coastal blue carbon ecosystem through the establishment of a sound Blue Carbon accounting system, and to help achieve the carbon neutrality goal in China's NDCs through regular and systematic monitoring of its national Blue Carbon inventories.

Stronger increases but greater variability in global mangrove productivity compared to that of adjacent terrestrial forests.

Mangrove forests are a highly productive ecosystem with important potential to offset anthropogenic greenhouse gas emissions. Mangroves are expected to respond differently to climate change compared to terrestrial forests owing to their location in the tidal environment and unique ecophysiological characteristics, but the magnitude of difference remains uncertain at the global scale. Here we use satellite observations to examine mean trends and interannual variability in the productivity of global mangrove forests and nearby terrestrial evergreen broadleaf forests from 2001 to 2020. Although both types of ecosystem experienced significant recent increases in productivity, mangroves exhibited a stronger increasing trend and greater interannual variability in productivity than evergreen broadleaf forests on three-quarters of their co-occurring coasts. The difference in productivity trends is attributed to the stronger CO2 fertilization effect on mangrove photosynthesis, while the discrepancy in interannual variability is attributed to the higher sensitivities to variations in precipitation and sea level. Our results indicate that mangroves will have a faster increase in productivity than terrestrial forests in a CO2-rich future but may suffer more from deficits in water availability, highlighting a key difference between terrestrial and tidal ecosystems in their responses to climate change.

Mangrove browning trends in the semiarid southern Caribbean: spatial context matters

Mangroves are tropical coastal ecosystems threatened mainly by land cover change due to commodities. The effect of urbanization has been overlooked due to the low percentage of area loss globally, but it can be a significant driver of mangrove loss locally. Moreover, highly fragmented mangrove areas dominated by small patches might be more sensitive to natural and anthropogenic stressors as in terrestrial forests, especially in highly modified systems such as cities. However, little is known about the interactive effects of these drivers on mangrove loss and degradation, namely urbanization and fragmentation. Our objective is to analyze the mangrove ecosystem’s response in terms of the greenness trend to urbanization and patch fragmentation in the semiarid Colombian Caribbean. Specifically, we aim to: (1) calculate the greenness trend from 2017 to 2023 during the dry season by analyzing the Normalized Difference Vegetation Index (NDVI) derived from Sentinel-2 satellite images; (2) correlate the greenness trend in mangrove patches with fragmentation metrics at the patch level; (3) evaluate the patch greenness trend along an urban-to-rural gradient. Our analysis revealed that 89.5% of the area showed no significant trend, while 5.2% exhibited greenness trends and 5.3% showed browning trends, mainly concentrated along the Canal del Dique and the Sinú River delta. Patch shape and isolation did not seem to affect patch greenness trends. In-patch greenness trends variability followed a U-shaped pattern along the urban to rural gradient. These findings highlight the importance of spatial context on vegetation condition and suggest opportunities for remote monitoring of mangrove degradation.

Marsh sediments chronically exposed to nitrogen enrichment contain degraded organic matter that is less vulnerable to decomposition via nitrate reduction

Blue carbon habitats, including salt marshes, can sequester carbon at rates that are an order of magnitude greater than terrestrial forests. This ecosystem service may be under threat from nitrate (NO3−) enrichment, which can shift the microbial community and stimulate decomposition of organic matter. Despite efforts to mitigate nitrogen loading, salt marshes continue to experience chronic NO3− enrichment, however, the long-term consequence of this enrichment on carbon storage remains unclear. To investigate the effect of chronic NO3− exposure on salt marsh organic matter decomposition, we collected sediments from three sites across a range of prior NO3− exposure: a relatively pristine marsh, a marsh enriched to ~70 μmol L−1 NO3− in the flooding seawater for 13 years, and a marsh enriched between 100 and 1000 μmol L−1 for 40 years from wastewater treatment effluent. We collected sediments from 20 to 25 cm depth and determined that sediments from the most chronically enriched site had less bioavailable organic matter and a distinct assemblage of active microbial taxa compared to the other two sites. We also performed a controlled anaerobic decomposition experiment to test whether the legacy of NO3− exposure influenced the functional response to additional NO3−. We found significant changes to microbial community composition resulting from experimental NO3− addition. Experimental NO3− addition also increased microbial respiration in sediments collected from all sites. However, sediments from the most chronically enriched site exhibited the smallest increase, the lowest rates of total NO3− reduction by dissimilatory nitrate reduction to ammonium (DNRA), and the highest DNF:DNRA ratios. Our results suggest that chronic exposure to elevated NO3− may lead to residual pools of organic matter that are less biologically available for decomposition. Thus, it is important to consider the legacy of nutrient exposure when examining the carbon cycle of salt marsh sediments.

A dataset of soil moisture in Xishuangbanna tropical seasonal rain forests (2009–2017)

As the carrier of material circulation and energy flow, soil moisture plays an important role in terrestrial forest ecosystems. Observing soil moisture is beneficial for unveiling the hydrological characteristics, water conservation capacity and ecosystem service function of forest ecosystems. The tropical rain forest is among the most biodiverse ecosystems. There are large areas of tropical rain forests in Xishuangbanna, where the tropical seasonal rain forest represents a prominent vegetation type. Conducting continuous, long-term and high-quality ecological monitoring is one of the main tasks of China Ecosystem Research Network (CERN). Soil moisture content is an important indicator in the long-term site-specific water environment observations within the terrestrial ecosystems monitored by CERN. This dataset comprises soil moisture content data collected from January 2009 to December 2017 at the Xishuangbanna Station for Tropical Rainforest Ecosystem Studies of the Chinese Academy Sciences (also known as National Forest Ecosystem Research Station at Xishuangbanna, BNF for short), with a total of 2,879 entries. The determination method used for this dataset is fixed-point continuous observation using Time Domain Reflectometry (TDR) instruments; observations were conducted at multiple, ranging from 0–10 cm, 10–20 cm, 20–30 cm, 30–40 cm, 40–50 cm, 50–70 cm, 70–90 cm and 90–110 cm. The observation frequency consists of 3 times per month, respectively at the beginning, middle and end of each month. The observations were conducted strictly according to the CERN observation and quality control protocols. The dataset is readily available for online sharing and serves as essential foundational data for conducting research on tropical forest hydrology under the global climate change and different vegetation environments.

Physiological response mechanism of European birch (Betula pendula Roth) to PEG-induced drought stress and hydration.

Drought stress is also one of the important abiotic factors limiting plant growth and development, and the global temperature is rising year by year, resulting in a dry environment in most terrestrial forests, which will continue to affect the growth, development and reproduction of tree species in forests. European birch(Betula pendula Roth.) native to Europe, introduced to the mountains of eastern Liaoning in 1981 (annual precipitation of about 800mm), European birch relative to downy birch (B. pubescens)has strong adaptability and drought tolerance and cold tolerance, can grow normally in eastern Liaoning, but it is easy to be affected by drought at the seedling stage and cause death, many arid and semi-arid areas have no introduction and practical application of European birch, and there is less research on the drought resistance of European birch. This study used different concentrations of PEG-6000 treatment to simulate drought stress and clarify the changes of various growth physiological parameters and photosynthetic characteristics of European birch seedlings under drought stress, in order to investigate the physiological response mechanism of European birch under drought stress . This study used different concentrations of PEG-6000 treatment to simulate drought stress and clarify the changes of various growth physiological parameters and photosynthetic characteristics of European birch seedlings under drought stress, in order to investigate the physiological response mechanism of European birch under drought stress. The findings demonstrated that stress duration and increasing PEG concentration had a highly significant impact on the growth traits of European birch seedlings (p<0.01); With increasing stress concentration and stress time, antioxidant enzyme activity, membrane lipid peroxidation, and osmoregulatory substance concentrations increased significantly (p<0.01); With increasing stress concentration and duration, photosynthetic parameters and pigments decreased highly significantly (p<0.01); Under different PEG concentration treatments, the anatomical structure of seedling leaves changed more noticeably; there was a significant effect (p <0.05) on the change in mean stomatal length and a highly significant effect (p<0.01) on the change in mean stomatal structure. The study's findings serve as a foundation for the selection and breeding of new drought-tolerant European birch species, as well as a theoretical underpinning for the use of this species in landscaping and the promotion of new drought-tolerant species in China.

Functional vegetation community responses to soil and topographic factors in the Loess Plateau of China

AbstractGiven the developmental program outlined in United Nations Sustainable Development Goal 15 (Life on Land) and the to effectively address the challenge of biodiversity decline while mitigating the adverse effects of climate change, particularly drought, on terrestrial forest ecosystems, a fundamental reorientation of global forest restoration paradigms is warranted. It is imperative to move beyond a narrow emphasis on expanding forest area and instead prioritize the enhancement of biodiversity and functional attributes within these ecosystems. However, the differential response mechanisms of forest ecosystem functional communities and main plant functional types (PFTs) to environmental factors, especially soil and topography, remains unclear, especially at plant level. Here, we divided the functional communities of 93 sites in the study area into seven groups through Two‐way indicator species analysis (TWINSPAN), and studied the different functional communities, namely dynamic succession, species richness, and PFT compositional differences. We also analyzed the various PFTs and functional community response mechanisms to soil and topographic factors using canonical correspondence analysis (CCA). The main results were as follows: (1) With the successional stages of PFTs, vegetation diversity across multiple functional communities inceased, tree and shrub proportions and importance increased, while herbs decreased. (2) From the arid and barren areas (i.e., G2), to the humid and fertile areas (i.e., G6 and G7), various compositional PFT differences, and their responses to soil and topographic factors, were found, namely, xerophytic, annual and biennial species gradually changed to mesophytic, hygrophytic, and perennial species (richness increased 6.94 ~ 27.33%, important value (IV) increased 8.73 ~ 29.45%) for shrubs and herbs. (3) Functional communities in various successional stages display distinct sensitivities to soil and topographic factors, as evidenced by a notable increase in the richness and IV of deciduous broad‐leaved tree species, rendering their communities more responsive to SOC and AS, whereas evergreen coniferous trees (e.g., Pinus tabuliformis Carr.) were sensitive to altitude (AL) and exhibited a tendency to transition from plantations to natural secondary forests predominantly at higher altitudes (above 1200 m). Our findings suggest that site conditions influence scenarios, and that different PFT responses and adjustments to soil and topography factors affect whole functional community dynamic succession processes, which can profoundly impact forest ecosystem function predictions based on PFT changes in the Loess Plateau of China.

Elevational changes in soil properties shaping fungal community assemblages in terrestrial forest

Environmental variables shifted by climate change act as driving factors in determining plant-associated microbial communities in terrestrial ecosystems. However, how elevation-induced changes in soil properties shape the microbial community in forest ecosystems remains less understood. Thus, the Pinus tabuliformis forests at elevations of 1500 m, 1900 m, and 2300 m above sea level were investigated to explore the effect of environmental factors on microbial assemblage. Significant changes in the soil physicochemical properties were found across the investigated elevations, such as soil moisture, temperature, pH, nitrogen (N), and phosphorus (P). Soil enzymatic activities, including soil sucrase, phosphatase, and dehydrogenase, were significantly affected by elevation, and sucrase showed a linear correlation with soil organic matter. Furthermore, the richness of fungal communities in the rhizosphere was decreased as elevation increased, while a humpback pattern was found for roots. Certain core microbiota members, such as Agaricomycetes, Leotiomycetes, and Pezizomycetes, were crucial in maintaining a stable ecological niche in both the root and rhizosphere. We also found that shifting of fungal communities in the rhizosphere were more related to physical properties (e.g., pH, soil moisture, and soil temperature), while changes in root fungal communities along elevation gradient were related mostly to soil nutrients (e.g., soil N and P). Overall, this study demonstrates that the assemblage of the root and rhizosphere fungal communities in P. tabuliformis forest primarily depends on elevation-induced changes in environmental variables and highlights the importance of predicting fungal responses to future climate change.

Sedimentary Organic Facies Division and Hydrocarbon-Generation Potential of Source Rocks in Coal-Bearing Strata-A Case Study of the Upper Paleozoic in Huanghua Depression, Bohai Basin, China.

Sedimentary organic facies cover the formation, evolution, and spatial distribution characteristics of organic matter, and they are effective tools for oil and gas resource evaluation and basin prospect prediction. According to the basic organic rock composition of the sedimentary organic facies, combined with the sedimentary facies and organic matter geochemical characteristics of Carboniferous-Permian strata, the characteristics of organic facies and hydrocarbon-generation potential of Upper Paleozoic source rocks in Huanghua Depression are being discussed. The results show that source rocks of Taiyuan and Shanxi Formations in the study area were oil-prone, and the oil-generation potential of mudstone is greater than that of carbonaceous mudstone and coal. The organic facies in the study area can be divided into six types: (1) terrestrial forest organic facies; (2) shallow swamp forest organic facies; (3) deep swamp forest organic facies; (4) deep swamp reed organic facies; (5) flowing water swamp organic facies; and (6) open water organic facies. The Taiyuan Formation is mainly composed of flowing water swamp, deep swamp forest, and shallow swamp forest with a strong hydrocarbon-generation capacity, while the Shanxi Formation chiefly includes organic facies of the deep swamp forest and shallow swamp forest. The deep swamp reed sedimentary organic facies had the highest hydrocarbon-generation potential, while the terrestrial forest sedimentary organic facies had the worst hydrocarbon-generation potential. Coal had a certain oil-generating capacity but was weaker than that of mudstone. Compared with mudstone, coal had a stronger gas-generating capacity.

Carbon sequestration and climate change mitigation using macroalgae: a state of knowledge review.

The conservation, restoration, and improved management of terrestrial forests significantly contributes to mitigate climate change and its impacts, as well as providing numerous co-benefits. The pressing need to reduce emissions and increase carbon removal from the atmosphere is now also leading to the development of natural climate solutions in the ocean. Interest in the carbon sequestration potential of underwater macroalgal forests is growing rapidly among policy, conservation, and corporate sectors. Yet, our understanding of whether carbon sequestration from macroalgal forests can lead to tangible climate change mitigation remains severely limited, hampering their inclusion in international policy or carbon finance frameworks. Here, we examine the results of over 180 publications to synthesise evidence regarding macroalgal forest carbon sequestration potential. We show that research efforts on macroalgae carbon sequestration are heavily skewed towards particulate organic carbon (POC) pathways (77% of data publications), and that carbon fixation is the most studied flux (55%). Fluxes leading directly to carbon sequestration (e.g. carbon export or burial in marine sediments) remain poorly resolved, likely hindering regional or country-level assessments of carbon sequestration potential, which are only available from 17 of the 150 countries where macroalgal forests occur. To solve this issue, we present a framework to categorize coastlines according to their carbon sequestration potential. Finally, we review the multiple avenues through which this sequestration can translate into climate change mitigation capacity, which largely depends on whether management interventions can increase carbon removal above a natural baseline or avoid further carbon emissions. We find that conservation, restoration and afforestation interventions on macroalgal forests can potentially lead to carbon removal in the order of 10's of Tg C globally. Although this is lower than current estimates of natural sequestration value of all macroalgal habitats (61-268 Tg C year-1 ), it suggests that macroalgal forests could add to the total mitigation potential of coastal blue carbon ecosystems, and offer valuable mitigation opportunities in polar and temperate areas where blue carbon mitigation is currently low. Operationalizing that potential will necessitate the development of models that reliably estimate the proportion of production sequestered, improvements in macroalgae carbon fingerprinting techniques, and a rethinking of carbon accounting methodologies. The ocean provides major opportunities to mitigate and adapt to climate change, and the largest coastal vegetated habitat on Earth should not be ignored simply because it does not fit into existing frameworks.

Changes in air dose rates due to soil moisture content in the Fukushima prefecture forests

Radionuclides released and deposited because of the 2011 Fukushima Dai-ichi Nuclear Power Plant accident caused an increase in air dose rates in Fukushima Prefecture forests. Although an increase in air dose rates during rainfall was previously reported, the air dose rates in the Fukushima forests decreased during rainfall. This study aimed to develop a method to estimate rainfall-related changes in air dose rates, even in the absence of soil moisture data, in Namie-Town and Kawauchi-Village, Futaba-gun, Fukushima Prefecture. Moreover, we examined the relationship between preceding rainfall (Rw) and soil moisture content. The air dose rate was estimated by calculating the Rw in Namie-Town from May to July 2020. We found that the air dose rates decreased with increasing soil moisture content. The soil moisture content was estimated from Rw by combining short-term and long-term effective rainfall using half-live values of 2 h and 7 d and considering the hysteresis of water absorption and drainage processes. Furthermore, the soil moisture content and air dose rate estimations showed a good agreement with coefficient of determination (R2) scores >0.70 and >0.65, respectively. The same method was tested to estimate the air dose rates in Kawauchi-Village from May to July 2019. At the Kawauchi site, variation in estimated value is relatively large due to the presence of water repellency in dry conditions, and the amount of 137Cs inventory was low, so estimating air dose from rainfall remained a challenge. In conclusion, rainfall data were successfully used to estimate soil moisture and air dose rates in areas with high 137Cs inventories. This leads to the possibility of removing the influence of rainfall on measured air dose rate data and could contribute to the improvement of methods currently used to estimate the external air dose rates for humans, animals, and terrestrial forest plants.