Pub Date : 2026-02-17DOI: 10.1016/j.agrformet.2026.111071
Yanchen Gui, Kai Wang, Zhe Jin, Qiang Zhang, Qingyang Xiao, Philippe Ciais, Chris Huntingford, Josep Peñuelas, Shilong Piao
The seasonal cycle of atmospheric CO2 is commonly assumed to be dominated by terrestrial carbon uptake and minimally affected by fossil-fuel CO2 emissions (FF). However, the magnitude and extent of the influence of FF on the CO2 seasonal cycle remain elusive. In the first half of year 2020, the outbreak of the coronavirus disease 2019 led to large reductions in FF, providing a testbed for understanding the impact of FF on the CO2 seasonal cycle. Here, we utilized CO2 observations from the global surface network and conducted atmospheric transport simulations with daily FF data to assess the effects of FF reductions in 2020 on the CO2 seasonal cycle. We first found widespread increases of 1.10 ± 0.67 ppm in the CO2 seasonal cycle amplitude (SCA) at high-latitude sites in 2020 compared to 2018−2019, which were equal to 170 ± 11% of the inter-annual variability of detrended SCA over the previous 20 years. Further, we attribute FF reductions to 0.43 ± 0.12 ppm of the observed SCA increases at high-latitude sites in 2020. At the Barrow site, FF reductions account for 31.9% of the SCA increase in 2020. The critical impact of FF on SCA increase does not suggest a larger decline in FF at high latitudes than mid-latitudes. Rather, the FF contributes more to SCA anomalies in magnitude at mid-latitudes than high latitudes. The localized impacts of anomalies in land-atmosphere carbon exchange fluxes generally exceeded the FF impacts on SCA anomalies at mid-latitudes, inducing varying changes in SCA across different mid-latitude sites. Our study thus presents a framework that may be extended further, where the knowledge of FF for the year 2020 versus other years, enables refinement of how atmospheric CO2 concentration vary seasonally.
{"title":"COVID-19 induced reduction of fossil-fuel emissions in 2020 altered the seasonal cycle of atmospheric CO2 at high latitudes","authors":"Yanchen Gui, Kai Wang, Zhe Jin, Qiang Zhang, Qingyang Xiao, Philippe Ciais, Chris Huntingford, Josep Peñuelas, Shilong Piao","doi":"10.1016/j.agrformet.2026.111071","DOIUrl":"https://doi.org/10.1016/j.agrformet.2026.111071","url":null,"abstract":"The seasonal cycle of atmospheric CO<sub>2</sub> is commonly assumed to be dominated by terrestrial carbon uptake and minimally affected by fossil-fuel CO<sub>2</sub> emissions (FF). However, the magnitude and extent of the influence of FF on the CO<sub>2</sub> seasonal cycle remain elusive. In the first half of year 2020, the outbreak of the coronavirus disease 2019 led to large reductions in FF, providing a testbed for understanding the impact of FF on the CO<sub>2</sub> seasonal cycle. Here, we utilized CO<sub>2</sub> observations from the global surface network and conducted atmospheric transport simulations with daily FF data to assess the effects of FF reductions in 2020 on the CO<sub>2</sub> seasonal cycle. We first found widespread increases of 1.10 ± 0.67 ppm in the CO<sub>2</sub> seasonal cycle amplitude (SCA) at high-latitude sites in 2020 compared to 2018−2019, which were equal to 170 ± 11% of the inter-annual variability of detrended SCA over the previous 20 years. Further, we attribute FF reductions to 0.43 ± 0.12 ppm of the observed SCA increases at high-latitude sites in 2020. At the Barrow site, FF reductions account for 31.9% of the SCA increase in 2020. The critical impact of FF on SCA increase does not suggest a larger decline in FF at high latitudes than mid-latitudes. Rather, the FF contributes more to SCA anomalies in magnitude at mid-latitudes than high latitudes. The localized impacts of anomalies in land-atmosphere carbon exchange fluxes generally exceeded the FF impacts on SCA anomalies at mid-latitudes, inducing varying changes in SCA across different mid-latitude sites. Our study thus presents a framework that may be extended further, where the knowledge of FF for the year 2020 versus other years, enables refinement of how atmospheric CO<sub>2</sub> concentration vary seasonally.","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"17 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2026-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146205114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-16DOI: 10.1016/j.agrformet.2026.111070
Mahum Naseer, Marilyn Roland, Fran Lauriks, Nicola Arriga, Bert Gielen, Ivan A. Janssens, Matteo Campioli
Temperate heathlands represent an important and protected biome in Europe. Yet, their environmental regulation in terms of carbon (C) and water vapour fluxes is understudied. Using the eddy covariance (EC) technique, we analyzed the seasonal and inter-annual CO2 and water vapour fluxes of a temperate heathland (dominated by Calluna vulgaris L. ca. 45 years old) and compared them to the ones of an evergreen forest (dominated by Pinus sylvestris L. ca. 90 years old) in Flanders, Belgium, between 2021 and 2023. The year 2022 presented a severe summer drought whereas the years 2021 and 2023 presented wet summers but dry springs. The forest was a consistent CO2 sink (-216 ± 61 gC m-2 y-1) compared to the heathland which was on average a small source (29 ± 9 gC m-2 y-1). Conversely, because of the lower evapotranspiration, the heathland showed larger water drainage than the forest (519 vs. 403 mm y-1, respectively) and therefore larger ground water recharge. Despite the similar meteorology and soil, the heathland presented consistently lower soil water content than the forest and marked drought impacts such as sharp decline in CO2 uptake and in evapotranspiration. The forest was less affected by drought, likely because Scots pine trees can access deep soil water thanks to their deep root system. These conditions resulted in the water use efficiency for the growing season being higher for the forest. Overall, this study describes a unique datasets of CO2 and water vapour fluxes for the temperate heathland ecosystem. It shows that, compared to the forest, the heathland presented an expected larger water rechange, lower than expected C sequestration potential and larger than expected sensitivity of CO2 fluxes to drought.
温带荒原是欧洲重要的受保护生物群落。然而，它们在碳(C)和水蒸气通量方面的环境调节尚未得到充分研究。利用涡动相关（EC）技术，分析了比利时法兰德斯温带石南草原（45年生Calluna vulgaris L.）和常绿松林（90年生Pinus sylvestris L.） 2021 - 2023年的季节和年际CO2和水汽通量。2022年夏季严重干旱，而2021年和2023年夏季潮湿，春季干燥。森林是一个稳定的CO2汇（-216±61 gC m-2 y-1），而石南荒原的平均CO2汇（29±9 gC m-2 y-1）较小。相反，由于蒸腾量较低，石南荒原的排水量比森林大（分别为519 mm -1比403 mm -1），因此地下水补给量也较大。尽管气象和土壤条件相似，但石南荒原的土壤含水量始终低于森林，并且受到明显的干旱影响，如CO2吸收和蒸散量急剧下降。森林受干旱的影响较小，可能是因为苏格兰松树的根系较深，可以获得深层土壤水分。这些条件导致森林生长季节的水分利用效率较高。总的来说，本研究描述了温带荒原生态系统的二氧化碳和水蒸气通量的独特数据集。结果表明，与森林相比，石楠荒原表现出预期的更大的回水量、低于预期的碳固存潜力和大于预期的CO2通量对干旱的敏感性。
{"title":"Carbon dioxide and water vapour fluxes in a heathland and an evergreen forest in the temperate zone under contrasting annual and seasonal meteorological and environmental conditions","authors":"Mahum Naseer, Marilyn Roland, Fran Lauriks, Nicola Arriga, Bert Gielen, Ivan A. Janssens, Matteo Campioli","doi":"10.1016/j.agrformet.2026.111070","DOIUrl":"https://doi.org/10.1016/j.agrformet.2026.111070","url":null,"abstract":"Temperate heathlands represent an important and protected biome in Europe. Yet, their environmental regulation in terms of carbon (C) and water vapour fluxes is understudied. Using the eddy covariance (EC) technique, we analyzed the seasonal and inter-annual CO<ce:inf loc=\"post\">2</ce:inf> and water vapour fluxes of a temperate heathland (dominated by <ce:italic>Calluna vulgaris</ce:italic> L. ca. 45 years old) and compared them to the ones of an evergreen forest (dominated by <ce:italic>Pinus sylvestris</ce:italic> L. ca. 90 years old) in Flanders, Belgium, between 2021 and 2023. The year 2022 presented a severe summer drought whereas the years 2021 and 2023 presented wet summers but dry springs. The forest was a consistent CO<ce:inf loc=\"post\">2</ce:inf> sink (-216 ± 61 gC m<ce:sup loc=\"post\">-2</ce:sup> y<ce:sup loc=\"post\">-1</ce:sup>) compared to the heathland which was on average a small source (29 ± 9 gC m<ce:sup loc=\"post\">-2</ce:sup> y<ce:sup loc=\"post\">-1</ce:sup>). Conversely, because of the lower evapotranspiration, the heathland showed larger water drainage than the forest (519 vs. 403 mm y<ce:sup loc=\"post\">-1</ce:sup>, respectively) and therefore larger ground water recharge. Despite the similar meteorology and soil, the heathland presented consistently lower soil water content than the forest and marked drought impacts such as sharp decline in CO<ce:inf loc=\"post\">2</ce:inf> uptake and in evapotranspiration. The forest was less affected by drought, likely because Scots pine trees can access deep soil water thanks to their deep root system. These conditions resulted in the water use efficiency for the growing season being higher for the forest. Overall, this study describes a unique datasets of CO<ce:inf loc=\"post\">2</ce:inf> and water vapour fluxes for the temperate heathland ecosystem. It shows that, compared to the forest, the heathland presented an expected larger water rechange, lower than expected C sequestration potential and larger than expected sensitivity of CO<ce:inf loc=\"post\">2</ce:inf> fluxes to drought.","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"45 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146209246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-15DOI: 10.1016/j.agrformet.2026.111048
Qiaoli Wu, Xinyang Zhang, Shaoyuan Chen, Trevor F. Keenan, Wei He, Li Wang, Jie Jiang
Gross primary production (GPP) has increased substantially across the China’s Loess Plateau (LP) over the past two decades, a trend widely attributed to vegetation greening driven by land use and land cover change (LUCC), particularly the Grain to Green Program (GGP). However, most existing studies rely on statistical or machine learning approaches, limiting mechanistic understanding. Here, we combined a process-based ecosystem model with Shapley value attribution and multi-source observations to quantify the drivers of GPP dynamics in the LP from 2001 to 2019. We found that 84% of the LP exhibited significant greening without LUCC, indicating that climate and other environmental changes-rather than LUCC or the GGP alone-dominanted regional greening. The combined effects of climate change and CO2 fertilization explained ∼79% of the GPP increase, through both direct enhancement of photosynthetic rate (∼1.28 Tg C yr-2) and indirect increase in leaf area index (∼5.07 Tg C yr-2). Notably, in contrast to previous studies, we detected a small but spatially widespread negative impact of TEMP on GPP, whereas declining vapor pressure deficit exerted a positive influence. The GGP contributed ∼11.3% of the GPP increase (∼0.95 Tg C yr-2), primarily by altering vegetation structure across ∼9.5% of the LP’s area, while other LUCC events accounting for the remaining ∼9.7% of the GPP increase. These findings offer new insights into the relative roles of climatic and anthropogenic drivers of ecosystem productivity and provide mechanistic evidence to inform future ecological restoration and land management strategies.
近20年来，中国黄土高原（LP）的初级生产总值（GPP）大幅增加，这一趋势被广泛归因于土地利用和土地覆盖变化（LUCC），特别是粮食退耕还林计划（GGP）推动的植被绿化。然而，大多数现有研究依赖于统计或机器学习方法，限制了机制理解。在此，我们将基于过程的生态系统模型与Shapley值归因和多源观测相结合，量化了2001 - 2019年LP中GPP动态的驱动因素。研究发现，在没有土地利用/土地覆盖变化的情况下，84%的低海拔地区出现了显著的绿化，这表明气候和其他环境变化——而不是单纯的土地利用/土地覆盖变化或GGP——主导了区域绿化。通过直接提高光合速率（~ 1.28 Tg C /年-2）和间接增加叶面积指数（~ 5.07 Tg C /年-2），气候变化和CO2施肥的综合效应解释了GPP增加的~ 79%。值得注意的是，与以往的研究相比，我们发现温度对GPP的负面影响很小，但在空间上广泛存在，而蒸汽压赤字的下降对GPP产生了积极影响。GGP贡献了GPP增加的~ 11.3% (~ 0.95 Tg C -年-2)，主要是通过改变LP面积的~ 9.5%的植被结构，而其他LUCC事件占GPP增加的其余~ 9.7%。这些发现为了解气候和人为驱动因素对生态系统生产力的相对作用提供了新的见解，并为未来的生态恢复和土地管理策略提供了机制证据。
{"title":"Reevaluating the contribution of grain for green program to GPP in the Loess Plateau: Insights from a process-based model","authors":"Qiaoli Wu, Xinyang Zhang, Shaoyuan Chen, Trevor F. Keenan, Wei He, Li Wang, Jie Jiang","doi":"10.1016/j.agrformet.2026.111048","DOIUrl":"https://doi.org/10.1016/j.agrformet.2026.111048","url":null,"abstract":"Gross primary production (GPP) has increased substantially across the China’s Loess Plateau (LP) over the past two decades, a trend widely attributed to vegetation greening driven by land use and land cover change (LUCC), particularly the Grain to Green Program (GGP). However, most existing studies rely on statistical or machine learning approaches, limiting mechanistic understanding. Here, we combined a process-based ecosystem model with Shapley value attribution and multi-source observations to quantify the drivers of GPP dynamics in the LP from 2001 to 2019. We found that 84% of the LP exhibited significant greening without LUCC, indicating that climate and other environmental changes-rather than LUCC or the GGP alone-dominanted regional greening. The combined effects of climate change and CO<ce:inf loc=\"post\">2</ce:inf> fertilization explained ∼79% of the GPP increase, through both direct enhancement of photosynthetic rate (∼1.28 Tg C yr<ce:sup loc=\"post\">-2</ce:sup>) and indirect increase in leaf area index (∼5.07 Tg C yr<ce:sup loc=\"post\">-2</ce:sup>). Notably, in contrast to previous studies, we detected a small but spatially widespread negative impact of TEMP on GPP, whereas declining vapor pressure deficit exerted a positive influence. The GGP contributed ∼11.3% of the GPP increase (∼0.95 Tg C yr<ce:sup loc=\"post\">-2</ce:sup>), primarily by altering vegetation structure across ∼9.5% of the LP’s area, while other LUCC events accounting for the remaining ∼9.7% of the GPP increase. These findings offer new insights into the relative roles of climatic and anthropogenic drivers of ecosystem productivity and provide mechanistic evidence to inform future ecological restoration and land management strategies.","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"64 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2026-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146209247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-14DOI: 10.1016/j.agrformet.2026.111057
Junjie Dai, Xianhui Tang, Wen Lin, Xin Song
Nocturnal sap flow (Qn) is an integral component of plant physiological processes and ecosystem water cycling. However, global patterns in the relative contribution of nocturnal to total daily sap flux (Qn%) remain poorly understood, limiting our ability to predict plant and ecosystem water use under climate change. To address this gap, we leveraged a global sap flow network (SAPFLUXNET) to assemble a dataset of Qn% comprising 1,366 woody individuals from 79 species across 121 sites worldwide. We used this dataset to examine Qn% variations and associated drivers at the global scale. Across geographic gradients, Qn% exhibited a hump-shaped relationship with latitude, averaging 12.6% across all woody plants. Gymnosperms exhibited significantly higher Qn% values than angiosperms, highlighting the role of plant functional strategies. Qn% also varied among biomes—being highest in desert regions and lowest in tropical and boreal forests. Partitioning nocturnal sap flow using the forecasted refilling method revealed that Qn was globally dominated by stem water refilling, which accounted for 82% of Qn. Under arid conditions, however, the relative contribution of nocturnal transpiration to Qn increased, and the sensitivity of Qn% to short-term water stress was amplified. Further, using a linear mixed effects model, we identified two previously under-appreciated factors—species identity and nighttime length—as crucial drivers of the Qn% variation at the global scale. Together, these findings enhance our understanding of nocturnal sap fluxes and offer key insights for modeling spatiotemporal patterns of plant water relations and ecohydrological dynamics in a changing environment.
{"title":"Global patterns and biophysical drivers of the contribution of nocturnal to daily sap flow in woody plants","authors":"Junjie Dai, Xianhui Tang, Wen Lin, Xin Song","doi":"10.1016/j.agrformet.2026.111057","DOIUrl":"https://doi.org/10.1016/j.agrformet.2026.111057","url":null,"abstract":"Nocturnal sap flow (<ce:italic>Q</ce:italic><ce:inf loc=\"post\">n</ce:inf>) is an integral component of plant physiological processes and ecosystem water cycling. However, global patterns in the relative contribution of nocturnal to total daily sap flux (<ce:italic>Q</ce:italic><ce:inf loc=\"post\">n</ce:inf>%) remain poorly understood, limiting our ability to predict plant and ecosystem water use under climate change. To address this gap, we leveraged a global sap flow network (SAPFLUXNET) to assemble a dataset of <ce:italic>Q</ce:italic><ce:inf loc=\"post\">n</ce:inf>% comprising 1,366 woody individuals from 79 species across 121 sites worldwide. We used this dataset to examine <ce:italic>Q</ce:italic><ce:inf loc=\"post\">n</ce:inf>% variations and associated drivers at the global scale. Across geographic gradients, <ce:italic>Q</ce:italic><ce:inf loc=\"post\">n</ce:inf>% exhibited a hump-shaped relationship with latitude, averaging 12.6% across all woody plants. Gymnosperms exhibited significantly higher <ce:italic>Q</ce:italic><ce:inf loc=\"post\">n</ce:inf>% values than angiosperms, highlighting the role of plant functional strategies. <ce:italic>Q</ce:italic><ce:inf loc=\"post\">n</ce:inf>% also varied among biomes—being highest in desert regions and lowest in tropical and boreal forests. Partitioning nocturnal sap flow using the forecasted refilling method revealed that <ce:italic>Q</ce:italic><ce:inf loc=\"post\">n</ce:inf> was globally dominated by stem water refilling, which accounted for 82% of <ce:italic>Q</ce:italic><ce:inf loc=\"post\">n</ce:inf>. Under arid conditions, however, the relative contribution of nocturnal transpiration to <ce:italic>Q</ce:italic><ce:inf loc=\"post\">n</ce:inf> increased, and the sensitivity of <ce:italic>Q</ce:italic><ce:inf loc=\"post\">n</ce:inf>% to short-term water stress was amplified. Further, using a linear mixed effects model, we identified two previously under-appreciated factors—species identity and nighttime length—as crucial drivers of the <ce:italic>Q</ce:italic><ce:inf loc=\"post\">n</ce:inf>% variation at the global scale. Together, these findings enhance our understanding of nocturnal sap fluxes and offer key insights for modeling spatiotemporal patterns of plant water relations and ecohydrological dynamics in a changing environment.","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"49 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2026-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146209252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-14DOI: 10.1016/j.agrformet.2026.111080
Yu Bai, Fangyue Zhang, Menghang Liu, Zheng Fu
Changes in precipitation patterns are intensifying soil drying dynamics, profoundly affecting ecosystem carbon and water cycling. However, how photosynthesis changes during short-term soil moisture (SM) decline at daily scales following moisture pulses remain poorly understood across terrestrial ecosystems. Using global flux tower measurements, we identified soil dry-down events following moisture pulses and analyzed daily gross primary production (GPP) responses across dryland and non-dryland ecosystems. We found that drylands exhibited a stronger and more pronounced positive response relative to the first day of dry-down due to moisture replenishment, whereas non-drylands showed more variable patterns, with GPP increases during dry-down more common in drylands. Across all sites, daily GPP was primarily driven by precipitation, radiation, and pre-pulse SM. Furthermore, the timing of dry-down events strongly influenced GPP changes, with events occurring during phases of pronounced GPP rise or decline contributing substantially to total carbon uptake. These findings highlight distinct ecosystem-specific GPP response to moisture pulse during soil dry-down and emphasize the need to represent such dynamics in carbon–climate models under changing precipitation patterns.
{"title":"Observed daily photosynthesis responses following moisture pulses in terrestrial ecosystems","authors":"Yu Bai, Fangyue Zhang, Menghang Liu, Zheng Fu","doi":"10.1016/j.agrformet.2026.111080","DOIUrl":"https://doi.org/10.1016/j.agrformet.2026.111080","url":null,"abstract":"Changes in precipitation patterns are intensifying soil drying dynamics, profoundly affecting ecosystem carbon and water cycling. However, how photosynthesis changes during short-term soil moisture (SM) decline at daily scales following moisture pulses remain poorly understood across terrestrial ecosystems. Using global flux tower measurements, we identified soil dry-down events following moisture pulses and analyzed daily gross primary production (GPP) responses across dryland and non-dryland ecosystems. We found that drylands exhibited a stronger and more pronounced positive response relative to the first day of dry-down due to moisture replenishment, whereas non-drylands showed more variable patterns, with GPP increases during dry-down more common in drylands. Across all sites, daily GPP was primarily driven by precipitation, radiation, and pre-pulse SM. Furthermore, the timing of dry-down events strongly influenced GPP changes, with events occurring during phases of pronounced GPP rise or decline contributing substantially to total carbon uptake. These findings highlight distinct ecosystem-specific GPP response to moisture pulse during soil dry-down and emphasize the need to represent such dynamics in carbon–climate models under changing precipitation patterns.","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"42 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2026-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146209248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-13DOI: 10.1016/j.agrformet.2026.111059
Frank Thomas Ndjomatchoua, Christopher Aidan Gilligan
The sap-feeding cassava whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a serious pest in tropical agro-ecosystems. Its capacity to spread cassava mosaic virus and cassava brown streak virus, which negatively impact agricultural production, poses a global biosecurity threat. Environmental niche modelling has revealed the potential for additional range expansions of the whitefly complex, particularly into Australia, America, and Europe. To enhance biosecurity readiness for vulnerable African farmers, research is needed on the likely seasonal life-history dynamics of this pest in its invasive range, to inform monitoring programs. Here we develop a mechanistic model incorporating eco-physiological data on the growth life stages, fertility and survival of cassava-African-specific whitefly, and crop host phenology, expressed over different temperature ranges. The model was tested against published field observational data during two cropping seasons in Tanzania. The annual numbers of whitefly generations were then mapped using gridded meteorological data throughout sub-Saharan Africa, highlighting regional vulnerabilities. By leveraging these findings to inform life-history projections across its invasive range, policymakers can make informed, science-based biosecurity decisions and focus preparedness efforts.
{"title":"Modelling and geospatial mapping of whitefly Bemisia tabaci population dynamics in cassava-growing areas of Sub-Saharan Africa in response to climate change","authors":"Frank Thomas Ndjomatchoua, Christopher Aidan Gilligan","doi":"10.1016/j.agrformet.2026.111059","DOIUrl":"https://doi.org/10.1016/j.agrformet.2026.111059","url":null,"abstract":"The sap-feeding cassava whitefly, <em>Bemisia tabaci</em> (Gennadius) (Hemiptera: Aleyrodidae) is a serious pest in tropical agro-ecosystems. Its capacity to spread cassava mosaic virus and cassava brown streak virus, which negatively impact agricultural production, poses a global biosecurity threat. Environmental niche modelling has revealed the potential for additional range expansions of the whitefly complex, particularly into Australia, America, and Europe. To enhance biosecurity readiness for vulnerable African farmers, research is needed on the likely seasonal life-history dynamics of this pest in its invasive range, to inform monitoring programs. Here we develop a mechanistic model incorporating eco-physiological data on the growth life stages, fertility and survival of cassava-African-specific whitefly, and crop host phenology, expressed over different temperature ranges. The model was tested against published field observational data during two cropping seasons in Tanzania. The annual numbers of whitefly generations were then mapped using gridded meteorological data throughout sub-Saharan Africa, highlighting regional vulnerabilities. By leveraging these findings to inform life-history projections across its invasive range, policymakers can make informed, science-based biosecurity decisions and focus preparedness efforts.","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"8 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146198602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-13DOI: 10.1016/j.agrformet.2026.111066
Tetiana Vovk, Maciej Kryza, Małgorzata Werner, Szymon Tomczyk, Małgorzata Malkiewicz, Dorota Myszkowska, Monika Ziemianin, Beata Bosiacka, Agnieszka Grinn-Gofroń, Barbara Majkowska-Wojciechowska
Airborne allergenic birch (Betula) and grass (Poaceae) pollen poses significant public health challenges, as high concentrations can trigger allergic rhinitis and exacerbate asthma for millions of people globally. Accurate forecasts of pollen concentrations enable vulnerable individuals to take preventive measures and support healthcare planning. In this study, we developed a spatially transferable forecasting methodology based on weighted ensemble machine learning models to predict daily birch and grass pollen concentrations up to five days ahead. Historical daily pollen measurements (2006–2022) from a Hirst-type trap in Wrocław, Poland, were combined with Weather Research & Forecasting (WRF) meteorological outputs (e.g., temperature, humidity, wind speed, precipitation), phenological indices (e.g., growing degree days), calendar features (e.g., day of year, week), and lagged pollen predictors. Four decision tree-based base learners – Random Forest, ExtraTrees, XGBoost, and LightGBM – were tuned within nested leave‐year‐out cross-validation and combined via a weighted‐average ensemble. Separate ensembles were trained for lead times from +1 to +5 days for both taxa. Variable importance analysis revealed that lagged pollen predictors dominated short‐term forecasts, while phenological and meteorological variables gained prominence at longer lead times. Independent testing on 2023–2024 data covered Wrocław and three other Polish cities, with two scenarios: (A) using local lagged pollen inputs and (B) replacing local inputs with non-local data from Wrocław (applied only to external sites). Successful spatial transferability was demonstrated in both scenarios. Ensemble models consistently outperformed individual algorithms, achieving test coefficients of determination (R²) of ∼0.77 (birch) and ∼0.72 (grass) at +1 day, declining to ∼0.55 and ∼0.66 at +5 days (scenario A).The findings illustrate that a weighted ensemble can produce reliable short‐ and medium‐term pollen forecasts in data‐scarce regions even if only a single well‐monitored site is available. The approach is readily adaptable for operational implementation and may improve allergy prevention and public‐health interventions in regions with limited pollen monitoring.
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Pub Date : 2026-02-13DOI: 10.1016/j.agrformet.2026.111065
Anne C.S. Mendonça, Cléo Quaresma Dias-Júnior, Maurício Ilha de Oliveira, Rafael Maroneze, Luis G. Nogueira Martins, Daniel Magnabosco Marra, Flávio A. Farias D’Oliveira, Felipe Denardin Costa, Gilberto Fisch, Denisi H. Hall, Raíssa S. de Oliveira, Bruno T.T. Portela, Otávio C. Acevedo
Low-Level Jets (LLJs) influence the dynamics of the Nocturnal Boundary Layer (NBL) by enhancing mechanical turbulence below the jet nose through vertical wind shear. In this study, we have evaluated whether the jet nose height (<span><span style=""></span><span data-mathml='<math xmlns="http://www.w3.org/1998/Math/MathML"><msub is="true"><mrow is="true"><mi is="true">h</mi></mrow><mrow is="true"><mi mathvariant="normal" is="true">Njet</mi></mrow></msub></math>' role="presentation" style="font-size: 90%; display: inline-block; position: relative;" tabindex="0"><svg aria-hidden="true" focusable="false" height="2.548ex" role="img" style="vertical-align: -0.812ex;" viewbox="0 -747.2 2013.6 1096.9" width="4.677ex" xmlns:xlink="http://www.w3.org/1999/xlink"><g fill="currentColor" stroke="currentColor" stroke-width="0" transform="matrix(1 0 0 -1 0 0)"><g is="true"><g is="true"><g is="true"><use xlink:href="#MJMATHI-68"></use></g></g><g is="true" transform="translate(576,-150)"><g is="true"><use transform="scale(0.707)" xlink:href="#MJMAIN-4E"></use><use transform="scale(0.707)" x="750" xlink:href="#MJMAIN-6A" y="0"></use><use transform="scale(0.707)" x="1057" xlink:href="#MJMAIN-65" y="0"></use><use transform="scale(0.707)" x="1501" xlink:href="#MJMAIN-74" y="0"></use></g></g></g></g></svg><span role="presentation"><math xmlns="http://www.w3.org/1998/Math/MathML"><msub is="true"><mrow is="true"><mi is="true">h</mi></mrow><mrow is="true"><mi is="true" mathvariant="normal">Njet</mi></mrow></msub></math></span></span><script type="math/mml"><math><msub is="true"><mrow is="true"><mi is="true">h</mi></mrow><mrow is="true"><mi mathvariant="normal" is="true">Njet</mi></mrow></msub></math></script></span>) can serve as a reliable proxy for estimating the NBL height (<span><span style=""></span><span data-mathml='<math xmlns="http://www.w3.org/1998/Math/MathML"><msub is="true"><mrow is="true"><mi is="true">h</mi></mrow><mrow is="true"><mi mathvariant="normal" is="true">N</mi></mrow></msub></math>' role="presentation" style="font-size: 90%; display: inline-block; position: relative;" tabindex="0"><svg aria-hidden="true" focusable="false" height="2.317ex" role="img" style="vertical-align: -0.582ex;" viewbox="0 -747.2 1207.2 997.6" width="2.804ex" xmlns:xlink="http://www.w3.org/1999/xlink"><g fill="currentColor" stroke="currentColor" stroke-width="0" transform="matrix(1 0 0 -1 0 0)"><g is="true"><g is="true"><g is="true"><use xlink:href="#MJMATHI-68"></use></g></g><g is="true" transform="translate(576,-150)"><g is="true"><use transform="scale(0.707)" xlink:href="#MJMAIN-4E"></use></g></g></g></g></svg><span role="presentation"><math xmlns="http://www.w3.org/1998/Math/MathML"><msub is="true"><mrow is="true"><mi is="true">h</mi></mrow><mrow is="true"><mi is="true" mathvariant="normal">N</mi></mrow></msub></math></span></span>
Pub Date : 2026-02-13DOI: 10.1016/j.agrformet.2026.111068
Pratima Pahadi, Uri Hochberg, Jay Wason, Yong-Jiang Zhang
The drought response mechanisms of shrubs such as blueberry plants remain poorly understood. Crucial gaps exist in the mechanistic understanding of shrub drought response strategies, the threshold for irreversible declines in physiological function, and their recovery potential. As drought events intensify in the northeastern U.S., it is increasingly important to understand the drought response of blueberry plants in this region. Here, we investigated the response of key plant physiological processes such as turgor loss, stomatal conductance, photosynthesis, xylem embolism, and phytochemistry in one highbush and one lowbush blueberry species. We found a coordinated decline in stomatal conductance, photosynthesis, transpiration, and plant hydraulic conductance before reaching the turgor loss point (TLP) of -2.0 MPa. At water potentials beyond the TLP, there was a progressive decline of phytochemistry as well as an increase in xylem embolism, leaf browning and leaf shedding, supporting TLP as a critical threshold beyond which drought-induced embolism and subsequent branch mortality occur in blueberries. We also revealed novel mechanisms regarding their high recovery potential: lowbush blueberries resprouted from belowground stems while highbush blueberries generated new branches from the basal stem, even following severe drought stress with 100 % loss of xylem hydraulic conductivity and total branch dieback. Our results thus provide new insights into the drought resistance and recovery mechanisms of these shrub species. The protection of belowground or stem base tissues during drought may have played a key role in enabling post-drought resprouting in blueberries and other shrubs.
{"title":"Drought response strategies of blueberry shrubs: Stomatal regulation, xylem embolism, and leaf dropping protect remaining tissues for resprouting","authors":"Pratima Pahadi, Uri Hochberg, Jay Wason, Yong-Jiang Zhang","doi":"10.1016/j.agrformet.2026.111068","DOIUrl":"https://doi.org/10.1016/j.agrformet.2026.111068","url":null,"abstract":"The drought response mechanisms of shrubs such as blueberry plants remain poorly understood. Crucial gaps exist in the mechanistic understanding of shrub drought response strategies, the threshold for irreversible declines in physiological function, and their recovery potential. As drought events intensify in the northeastern U.S., it is increasingly important to understand the drought response of blueberry plants in this region. Here, we investigated the response of key plant physiological processes such as turgor loss, stomatal conductance, photosynthesis, xylem embolism, and phytochemistry in one highbush and one lowbush blueberry species. We found a coordinated decline in stomatal conductance, photosynthesis, transpiration, and plant hydraulic conductance before reaching the turgor loss point (TLP) of -2.0 MPa. At water potentials beyond the TLP, there was a progressive decline of phytochemistry as well as an increase in xylem embolism, leaf browning and leaf shedding, supporting TLP as a critical threshold beyond which drought-induced embolism and subsequent branch mortality occur in blueberries. We also revealed novel mechanisms regarding their high recovery potential: lowbush blueberries resprouted from belowground stems while highbush blueberries generated new branches from the basal stem, even following severe drought stress with 100 % loss of xylem hydraulic conductivity and total branch dieback. Our results thus provide new insights into the drought resistance and recovery mechanisms of these shrub species. The protection of belowground or stem base tissues during drought may have played a key role in enabling post-drought resprouting in blueberries and other shrubs.","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"10 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146198604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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