Journal of Geophysical Research: Biogeosciences最新文献

{"title":"Mountain Peatlands and Drought: Carbon Cycling in the Pyrenees Amidst Global Climate Change","authors":"Raphael Garisoain,&nbsp;Adrien Jacotot,&nbsp;Christine Delire,&nbsp;Stéphane Binet,&nbsp;Gael Le Roux,&nbsp;Simon Gascoin,&nbsp;Thomas Rosset,&nbsp;Sébastien Gogo,&nbsp;Franck Granouillac,&nbsp;Virginie Payre-Suc,&nbsp;Laure Gandois","doi":"10.1029/2024JG008041","DOIUrl":"https://doi.org/10.1029/2024JG008041","url":null,"abstract":"<p>This study provides a multi-year (2017–2022) Net Ecosystem Carbon Balance (NECB) of a Pyrenean mountainous peatland through the integration of field data, satellite imagery, and statistical modeling. Fluvial organic carbon export was measured at 30 min frequency, while gaseous (CO₂ and CH₄) exchanges were measured monthly using closed chambers. These measurements were combined with Sentinel-2 derived chlorophyll index and in situ high frequency (1 hr) measurements of key environmental variables such as air temperature, photosynthetically active radiation, and water table level, to develop hourly gaseous carbon flux models (<i>R</i>² = 0.69 for GPP, <i>R</i>² = 0.84 for ER, <i>R</i>² = 0.59 for CH₄). Over the 2017–2022 period, modeled average GPP (610 ± 39 gC.m⁻².year⁻¹) and ER (641 ± 59 gC.m⁻².year⁻¹) showed that the peatland acted as a weak source of CO₂ to the atmosphere, releasing 31 ± 73 gC.m⁻².year⁻¹. Considering fluvial carbon export and CH₄ exchanges, the loss of carbon from the peatland increased to 55 ± 73 gC.m⁻².year⁻¹. Dissolved organic carbon constituted 8%–106% of the NECB. The estimated long-term organic accumulation rate indicated a steady carbon accumulation rate of 16.4 gC.m⁻².year⁻¹, contrasting with the contemporary NECB, suggesting a recent shift in ecosystem functioning from a carbon sink to a source. The study underscores the role of water availability and air temperature through a drought index (DI), in shaping the NECB. The DI correlated significantly with annual carbon gaseous fluxes, except for 2022, marked by an intense drought. During this year the peatland became a large source of carbon (189 gC.m⁻².year⁻¹) to the atmosphere.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008041","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141565795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal Carbon Dioxide Concentrations and Fluxes Throughout Denmark's Stream Network","authors":"Kenneth Thorø Martinsen,&nbsp;Kaj Sand-Jensen,&nbsp;Victor Bergmann,&nbsp;Tobias Skjærlund,&nbsp;Johan Emil Kjær,&nbsp;Julian Koch","doi":"10.1029/2024JG008031","DOIUrl":"https://doi.org/10.1029/2024JG008031","url":null,"abstract":"<p>Streams are important freshwater habitats in large-scale carbon budgets because of their high CO₂ fluxes which are driven by high CO₂ concentrations and surface-water turbulence. High CO₂ concentrations are promoted by terrestrial carbon inputs, groundwater flow, and internal respiration, all of which vary greatly across space and time. We used environmental monitoring data to calculate CO₂ concentrations along with a wide range of predictor variables including outputs from a national hydrological model and trained machine learning models to predict spatially distributed seasonal CO₂ concentrations in Danish streams. We found that streams were supersaturated in dissolved CO₂ (mean = 118 μM) and higher during autumn and winter than during spring and summer. The best model, a Random Forest model, scored R² = 0.46, MAE = 46.0 μM, and ⍴ = 0.72 on a test set. The most important predictor variables were catchment slope, seasonality, height above nearest drainage, and depth to groundwater, highlighting the importance of landscape morphometry and soil-groundwater-stream connectivity. Stream CO₂ fluxes determined from the predicted concentrations and gas transfer velocities estimated using empirical relationships averaged 253 mmol m⁻² d⁻¹, and the annual emissions were 513 Gg CO₂ from the national stream network (area = 139 km²). Our analysis presents a framework for modeling seasonal CO₂ concentrations and estimating fluxes at a national scale by means of large-scale hydrological model outputs. Future efforts should consider further improving the temporal resolution, direct measurements of fluxes and gas transfer velocities, and seasonal variation in stream surface area.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008031","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141556645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Divergent Roles of UV Exposure and Microclimatic Conditions in the Decomposition of Standing and Soil Surface Litter in a Semi-Arid Steppe","authors":"Sen Yang,&nbsp;Jing Wang,&nbsp;Jiao Su,&nbsp;Ziyang Peng,&nbsp;Lulu Guo,&nbsp;Yuntao Wu,&nbsp;Pengfei Chang,&nbsp;Yi Wang,&nbsp;Junsheng Huang,&nbsp;Lingli Liu","doi":"10.1029/2023JG007934","DOIUrl":"https://doi.org/10.1029/2023JG007934","url":null,"abstract":"<p>Recent studies have highlighted the crucial role of abiotic processes, such as photodegradation and microclimatic fluctuation, in accelerating dryland litter decomposition. In grasslands, substantial amounts of dead plant material persist upright above the soil surface after senescence, experiencing distinct microclimatic conditions compared to surface litter. However, our understanding of how ultraviolet (UV) exposure and microclimatic conditions influence their decomposition is limited. To address this knowledge gap, we conducted a field experiment manipulating UV radiation for both soil surface litter and standing litter and monitored their microclimatic conditions in a semi-arid grassland. Our findings indicate that UV exposure enhanced the decomposition of soil surface litter by alleviating the constraint of lignin on litter decomposition, while having no significant influence on standing litter. Although the mean levels of thermal-hydric conditions were lower, more intense fluctuation of temperature and air humidity was detected in standing litter. These higher-level microclimatic fluctuations facilitated the release of dissolved organic carbon, potentially increasing the availability of labile substrates to microbes. Meanwhile, standing litter released more photo-sensitive phenols, leading to decreased sensitivity to UV exposure. Consequently, while UV exposure initially increased standing litter decomposition during the early stage, its influence eventually diminished. These findings underscore the critical yet differing roles of microclimatic conditions and UV exposure in the decomposition of standing and surface litter. Relying solely on knowledges derived from surface litter decomposition and microclimate conditions may not accurately capture the patterns of grassland litter degradation.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141536898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Autotrophic Respiration Is More Sensitive to Nitrogen and Phosphorus Supply Than Heterotrophic Respiration in Semiarid Grassland","authors":"Junjie Zhou,&nbsp;Zhifei Chen,&nbsp;Chunxia Jian,&nbsp;Yang Luo,&nbsp;Furong Niu,&nbsp;Jairo A. Palta,&nbsp;Bingcheng Xu","doi":"10.1029/2024JG008230","DOIUrl":"https://doi.org/10.1029/2024JG008230","url":null,"abstract":"<p>Quantification of autotrophic (Ra) and heterotrophic (Rh) components of soil respiration (Rs) could greatly improve our understanding of terrestrial carbon cycling. Here, we investigated the effect of nitrogen (N) and phosphorus (P) supply on soil respiration rates and its components, and seasonal cumulative soil CO₂ efflux in a semiarid grassland. A two-factor experiment of N (0, 50 and 100 kg N ha⁻¹ yr⁻¹) and P (0, 18 and 36 kg P ha⁻¹ yr⁻¹) supply was conducted on the Loess Plateau in 2018–2021. Our results indicated that the promoting effect of combination of N and P supply on soil respiration and its components was greater than that of N/P supply alone. N and/or P supply increased the cumulative soil CO₂ efflux in both non-growing and growing seasons, and the non-growing season CO₂ efflux accounted for ∼25% of the growing season CO₂ efflux. The increase of cumulative CO₂ efflux from Ra in response to N and/or P supply was significantly greater than that of Rh in 2018 and 2019, while it shifted to the opposite, that is, a greater increase in Rh than in Ra in 2020 and 2021. Our results suggest that 100 kg N ha⁻¹ yr⁻¹ supply alone is an optimum fertilization scheme to trade-off grassland productivity and soil CO₂ emissions. Our results highlighted that the promoting effects of N and P fertilization on different soil CO₂ efflux components could be reversed in a relatively short period (4 years), and this should be considered when nutrient addition is adapted to restore degraded grasslands.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141536673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Satellite Derived Trait Data Slightly Improves Tropical Forest Biomass, NPP and GPP Estimates","authors":"Christopher E. Doughty,&nbsp;Camille Gaillard,&nbsp;Patrick Burns,&nbsp;Yadvinder Malhi,&nbsp;Alexander Shenkin,&nbsp;David Minor,&nbsp;Laura Duncanson,&nbsp;Jesús Aguirre-Gutiérrez,&nbsp;Scott Goetz,&nbsp;Hao Tang","doi":"10.1029/2024JG008108","DOIUrl":"https://doi.org/10.1029/2024JG008108","url":null,"abstract":"<p>Improving tropical forest current biomass estimates can help more accurately evaluate ecosystem services in tropical forests. The Global Ecosystem Dynamics Investigation (GEDI) lidar provides detailed 3D forest structure and height data, which can be used to improve above-ground biomass estimates. However, there is still debate on how best to predict tropical forest biomass using GEDI data. Here we compare stand biomass predicted by GEDI data with the observed data of 2,102 inventory plots in tropical forests and find that adding a remotely sensed (RS) trait map of leaf mass area (LMA) significantly (<i>P</i> &lt; 0.001) improves field biomass predictions, but by only a small amount (<i>r</i>² = 0.01). However, it may also help reduce the bias of the residuals because there was a negative relationship between both LMA (<i>r</i>² of 0.34) and percentage of phosphorus (%P, <i>r</i>² = 0.31) and residuals. Leaf spectral data (400–1,075 nm) from 523 individual trees along a Peruvian tropical forest elevation gradient predicted Diameter at Breast height (DBH) (the critical measurement underlying plot biomass) with an <i>r</i>² = 0.01 and LMA predicts DBH with an <i>r</i>² = 0.04. Other data sets may offer further improvements and max temperature (<i>T</i>_max) predicts Amazonian biomass residuals with an <i>r</i>² of 0.76 (<i>N</i> = 66). Finally, for a network of net primary production (NPP) and gross primary production (GPP) plots (<i>N</i> = 21), leaf traits predicted with remote sensing are better at predicting fluxes than structure variables. Overall, trait maps, especially future improved ones produced by Surface Biology Geology, may improve biomass and carbon flux predictions by a small but significant amount.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141536603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deep-Marine Brine Seeps Stimulate Microbial Nitrogen Cycling: Implications for the Formation of Sediment-Hosted Ore Deposits","authors":"Eva E. Stüeken,&nbsp;Annabel Long,&nbsp;Nathan Rochelle-Bates,&nbsp;Andreas Teske","doi":"10.1029/2024JG008189","DOIUrl":"https://doi.org/10.1029/2024JG008189","url":null,"abstract":"<p>Deep-marine brine seeps in the modern ocean are considered analogs for settings that favored the formation of sedimentary-exhalative zinc and lead deposits in deep time. Microbial activity plays an important role in the accumulation of ore minerals, meaning that the extent of mineralization is at least indirectly dependent on nutrient fluxes. Here, we investigated the biogeochemical nitrogen cycle in shallow (15–50 cm) sediment cores from the Orca Basin brine pool and surrounding sites, as well as from an active brine seep area near Dead Crab Lake in the Gulf of Mexico, with the aim of constraining the effect of brine seepage on this bio-essential element. We find high porewater ammonium concentrations in the millimolar range, paired with elevated ratios of organic carbon to nitrogen in sediments, which confirm previous hypotheses that the brine recycles ammonium from sedimentary strata back into the water column. Within Orca Basin, we note tentative evidence of microbial ammonium utilization. At the active seep, ammonium is mixed into the overlying water column and likely undergoes oxidation. Isotopic data from sediments and dissolved ammonium, paired with previously published genomic data, suggest the presence of dissimilatory nitrate reduction to ammonium at the brine-seawater interface. We conclude that brine seeps can stimulate biological nitrogen metabolisms in multiple ways. Our results may help calibrate studies of biogeochemical cycles around brine seeps that are archived in the rock record.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008189","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141536801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatio-Temporal Variations of Habitat Quality Under 8 SSP-RCP Scenarios in China","authors":"Yuke Feng,&nbsp;Shiyan Zhai,&nbsp;Genxin Song,&nbsp;Hongquan Song,&nbsp;Guanpeng Dong,&nbsp;Xintong Jiang,&nbsp;Changchang Dong,&nbsp;H. B. T. P. Jayathilaka","doi":"10.1029/2024JG008030","DOIUrl":"https://doi.org/10.1029/2024JG008030","url":null,"abstract":"<p>Habitat quality is a key expression of ecosystem ability and the basis for effective species conservation and regional ecological environment improvement. However, most studies have focused on assessing habitat quality over historical periods, ignoring the influence of coupled future development paths and climate change. The present study addresses this issue by developing a spatial-temporal variation analysis framework for assessing habitat quality in China, which integrates the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model with eight Earth system coupled scenarios (SSP-RCP). The results showed that from 2020 to 2100, and under five scenarios (SSP2-4.5, SSP3-7.0, SSP4-6.0, SSP5-3.4, and SSP5-8.5), habitat quality was generally stable and high, while under three scenarios (SSP1-1.9, SSP1-2.6, and SSP4-3.4), it decreased. The SSP2-4.5 scenario was significantly better than the SSP4-3.4 scenario. In all scenarios, the influences of different development patterns on China's ecologically fragile areas were obvious and serious. In 2030 and 2060, the spatial distribution patterns of habitat degradation and habitat quality had similar characteristics. High habitat degradation values were mostly distributed east of the Heihe-Tengchong Line, while low values were mainly distributed in the arid zone. The mean habitat degradation ranged between 0.0226 and 0.0302, and the degradation degree was relatively light. The habitat quality index mean was 0.5120–0.5376, indicating that the overall habitat quality was at the medium level. This study provides a potential ecological protection baseline for China based on habitat protection and provides an important reference for China's sustainable development.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141489037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shifting Sources and Fates of Carbon With Increasing Hydrologic Presses and Pulses in Coastal Wetlands","authors":"Kenneth J. Anderson,&nbsp;John S. Kominoski,&nbsp;Christopher L. Osburn,&nbsp;Matthew A. Smith","doi":"10.1029/2023JG007903","DOIUrl":"https://doi.org/10.1029/2023JG007903","url":null,"abstract":"<p>Coastal ecosystems are rapidly shifting due to changes in hydrologic presses (e.g., sea-level rise) and pulses (e.g., seasonal hydrology, disturbances, and restoration of degraded wetlands). Changing water levels and sources are master variables in coastal wetlands that can alter carbon concentrations, sources, processing, and export. Yet, how long-term increases in water levels from marine and freshwater sources influence dissolved organic carbon (DOC) concentrations and dissolved organic matter (DOM) composition is uncertain. We quantified how long-term changes in water levels are affecting DOC concentration (2001–2021) and DOM composition (2011–2021) differently across the Florida Everglades. DOC concentrations decreased with high water depths in peat marshes and increased with high water levels in marl marshes and across mangroves, and these relationships were reproduced in freshwater peat marshes and shrub mangroves. In the highly productive riverine mangroves, cross-wavelet analysis highlighted variable relationships between DOC and water level were largely modulated by hurricane disturbances. By comparing relationships between water level and DOC concentrations with carbon sources from DOM fluorescence indices, we found that changing water sources between the dry and wet season shift DOM from algal to detrital sources in freshwater marshes, from detrital marsh to detrital mangrove sources in the brackish water ecotone, and from detrital mangrove to algal marine sources in downstream mangroves. As climate change and anthropogenic drivers continue to alter water levels in coastal wetlands, integrating spatial and temporal measurements of DOC concentrations and DOM compositions is essential to better constrain the transformation and export of carbon across these coastal ecosystems.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JG007903","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141489038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Changes in Soil Carbon and Nitrogen Along a 3-m Vertical Profile and Environmental Regulation in Alpine Grassland on the Tibetan Plateau","authors":"Ruojun Sun,&nbsp;Kuo Sun,&nbsp;Leren Liu,&nbsp;Wenjuan Wu,&nbsp;Zhenzhu Xu","doi":"10.1029/2023JG007579","DOIUrl":"https://doi.org/10.1029/2023JG007579","url":null,"abstract":"<p>Much attention has been given to the distribution of soil organic carbon and nitrogen in alpine grasslands, but the important role of the deep soil layers has been understudied. In this study, the soil organic carbon and nitrogen contents in the shallow (0–30 cm), middle (30–100 cm) and deep (100–300 cm) layers were examined, and the effects of climatic, soil and vegetation factors were investigated along a climatic gradient on the Tibetan Plateau. We found that although soil organic carbon and nitrogen on the Tibetan Plateau declined logarithmically with depth, the total soil organic carbon and nitrogen in the middle and deep layers accounted for more than two-thirds of the total carbon and nitrogen in the 3-m depth soil profile. Carbon to nitrogen ratio increased with soil depth in 1 m soil, but it remained consistent in 1–3 m soil. The surface carbon and nitrogen contents were positively correlated with precipitation. The comprehensive research has revealed that soil carbon and nitrogen contents are mainly influenced by the local humid climate, vegetation productivity, and soil properties, which strongly depend on soil depth. Therefore, more attention should be given to the changes in carbon and nitrogen in deep soils in alpine regions.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141488964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impacts of Natural Environmental Factors and Anthropogenic Activities on the Distribution of Threatened Orchid Species in China","authors":"Weixuan Shang,&nbsp;Lingfeng Mao,&nbsp;Lu Miao,&nbsp;Yuehong Yan,&nbsp;Shicheng Li,&nbsp;Gang Feng","doi":"10.1029/2023JG007681","DOIUrl":"https://doi.org/10.1029/2023JG007681","url":null,"abstract":"<p>Natural environmental factors and anthropogenic activities could have strong impacts on threatened species distribution. Based on Random Forest modeling and ordinary least squares models, we tested the correlations between natural environmental factors (mean annual temperature (MAT), mean annual precipitation (MAP) and elevation range), anthropogenic activities (changes in cropland area, population density and pasture area) over different periods (between 1700 and 1800, between 1800 and 1900, and between 1900 and 2000) and ratio of threatened orchids in China. The results showed that threatened orchids were concentrated in Southwest China, Central China and Northeast China. The ratio of threatened orchids was positively correlated with MAT and MAP, but negatively correlated with elevation range. In addition, the three anthropogenic activity variables most correlated with threatened orchids ratio were changes of cropland area between 1900 and 2000, population density between 1700 and 1800, and between 1800 and 1900. These correlations were positive, indicating that areas with more anthropogenic activities had more threatened orchids. Moreover, MAP and changes of cropland area between 1900 and 2000 together were more correlated with threatened orchids ratio than other variables. These findings suggest important roles of contemporary climate and anthropogenic activities in shaping the distribution of threatened orchid species in China.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JG007681","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141488544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}