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Author(s): Ph. Ciais (corresponding author) [1]; M. Reichstein [2, 3]; N. Viovy [1]; A. Granier [4]; J. Ogée [5]; V. Allard [6]; M. Aubinet [7]; N. Buchmann [8]; Chr. Bernhofer [...]

Extreme climate events have increasingly threatened global terrestrial ecosystems in recent decades. In spring 2023, Southwest China (SWC) experienced unprecedented heatwaves and droughts. Using multiple satellite-based datasets, we found that these events led to the most significant declines in gross primary productivity (GPP) and the enhanced vegetation index (EVI) for the past two decades, with lagged effects persisting until August in the drought-affected area. Unlike the widespread and persistent drought of 2010, the record-breaking heatwaves in April and May 2023 sustained and intensified the drought stress. Elevated temperatures and suppressed precipitation, driven by anomalous atmospheric circulations, exacerbated the soil moisture (SM) shortages and increased the atmospheric vapor pressure deficit (VPD), restricting water availability and carbon uptake for vegetation photosynthesis. Our findings reveal that, during the 2023 extreme event in SWC, the decreases in forest productivity were primarily driven by low SM anomalies, while the decreases in the grassland and cropland productivity mainly resulted from abnormally high VPDs. This study highlights the combined effects of low SM and high VPD anomalies caused by a compound heatwave–drought event on vegetation growth in SWC and provides valuable insights for future assessments of regional extreme climate events on vegetation growth. [ABSTRACT FROM AUTHOR]

The article presents the results of research on the influence of moisture conditions and biopreparations on the productivity of plants of different biological characteristics of winter soft wheat varieties. The yield of winter wheat significantly depends on the genetic characteristics of the variety, moisture and nutrition conditions. Pre-sowing seed treatment and foliar fertilization of winter wheat with modern biological products increase grain yields and reduce the chemical load on agrocenoses, which is especially important in today’s market economy. The highest level of winter wheat yield under non-irrigated conditions in 2021–2023 on average was formed by the variety Duma Odeska (6.79 t/ha) in the variant with pre-sowing seed treatment with the biological product Azotophyt-r in combination with foliar fertilization with the biological product Helprost, while the lowest productivity was formed by the variety Ovid (5.63 t/ha) in the control variant (pre-sowing seed treatment with clean water without preparations). It has been established that to form a grain yield of 8.43 t/ha, it is necessary to grow a variety of soft winter wheat Duma Odeska under irrigation conditions, the seeds should be treated with the biological product Mycofriend in combination with the foliar application of the biological product Helprost before sowing. When grown under non-irrigated conditions, among the four winter wheat varieties studied, Ozerna cultivar showed the highest grain yield (6.31 t/ha). Under irrigation conditions, the highest grain yield (7.92 t/ha) was on average produced by Duma Odeska winter wheat. Thus, when grown under non-irrigated conditions, a higher yield of winter wheat grain (6.61 t/ha) was obtained by treating seeds with the biological product Azotophyt-r and foliar treatment of plants with the biological product Helprost. A higher grain yield (8.02 t/ha) under irrigation conditions, on average, was formed by winter wheat plants in the variant with pre-sowing seed treatment with the biological product Mycofriend and foliar feeding with the biological product Mycohelp. [ABSTRACT FROM AUTHOR]

Global climate change threatens ecosystem functioning worldwide. Forest ecosystems are particularly important for carbon sequestration, thereby buffering climate change and providing socio-economic services. However, recurrent stresses, such as heat waves, droughts and floods can affect forests with potential cascading effects on their carbon sink capacity, drought resilience and sustainability. Knowledge about the stress impact on the multitude of processes driving soil-plant-atmosphere interactions within these complex forest systems is widely lacking and uncertainty about future changes extremely high. Thus, forecasting forest response to climate change will require a dramatically improved process understanding of carbon and water cycling across various temporal (minutes to seasons) and spatial (leaf to ecosystem) scales covering atmosphere, biosphere, pedosphere and hydrosphere components. Many relevant processes controlling carbon and water exchange occur at small scales (e.g. rhizosphere, single leaf) with a high spatial and temporal variability, which is poorly constrained. However, interactions and feedback loops can be key players that amplify or dampen a system's response to stress. Moreover, spatial and temporal scaling rules for these non-linear processes in structurally and functionally diverse ecosystems are unknown. Legacy effects, for example, altered response after previous stress and retarded recovery of forests after climate extremes, are not captured in state-of-the-art models. Currently, we are lacking the appropriate and interconnected measurement, data assimilation and modelling tools allowing for a comprehensive, real-time quantification of key processes at high spatio-temporal coverage in heterogeneous environments. Moreover, since climate impacts are highly unpredictable with respect to timing and location, future research will require novel mobile, easily deployable and cost-efficient approaches. ECOSENSE, therefore, assembles expertise from environmental and engineering sciences, both being excellently paired at the University of Freiburg. Our interdisciplinary research project will investigate all relevant scales in a next-generation ecosystem research assessment (ECOSENSE). Our vision is to detect and forecast critical changes in ecosystem functioning, based on the understanding of hierarchical process interaction. In the first phase, ECOSENSE will explore these process interactions by investigating pools and fluxes of water and carbon, i.e. CO2 exchange, isotope discrimination and volatile organic compounds (VOC), as well as stress indicators by remotely and in situ sensed chlorophyll fluorescence. To address these research tasks, ECOSENSE will develop, implement and test a distributed, autonomous, intelligent sensor network, based on novel microsensors tailored to the specific needs in remote and harsh forest environments. They will measure the spatio-temporal dynamics of ecosystem pools and fluxes in a naturally complex structured forest system with minimal physiological impact. Measured data will be transferred in real-time into a sophisticated database, which will be explored for process analysis, conducted by Artificial Intelligence and close to real-time process-based ecosystem models for now- and forecasting applications. Thereby, ECOSENSE will: i) break new ground for integrative ecosystem research by identifying hierarchies and interactions of abiotic and physiological processes of forest carbon and water exchange, ii) provide a profound understanding of complex ecosystem responses to environmental stressors and iii) enable the prediction of process-based alterations in ecosystem functioning and sustainability. Our novel ECOSENSE toolkit, tested and validated in controlled climate extreme experiments and our ECOSENSE Forest, will open new horizons for rapid assessment in vast and remote ecosystems. Thereby, ECOSENSE will allow for a unique avenue of data acquisition and, consequently, for unprecedented scale-crossing ecosystem understanding and modelling. [ABSTRACT FROM AUTHOR]

Handling cascading reservoir systems is an important energy management optimization problem. The difficulty of these problems stems, in part, from the modeling of the hydro-production function. Data are not always easy to come by. To remedy this issue, this paper proposes and describes a realistic instance generator, building instances of varying difficulty. No specific data format for these problems is currently available in the literature. In addition, both notation and formulations tend to vary widely. Instances and case studies are poorly available or otherwise not applicable to different variants of these problems. The purpose of the generator is also a first attempt to develop a shared data format useful for different variants of hydro unit commitment problems and seeks to mediate the needs of different sectors interested in the optimization of hydropower plants. [ABSTRACT FROM AUTHOR]

The primary energy consumption structure of BRICS countries is dominated by fossil energy, particularly coal. Coal consumption in BRICS countries is a major driver underlying increased carbon emissions. Therefore, this study developed a spatiotemporal decoupling mode and incorporated factors related to coal consumption-induced carbon emissions into a spatiotemporal decoupling analysis method to provide differentiated and targeted policies for energy restructuring and emission reduction targets in BRICS countries. Moreover, a temporal-spatial decomposition logarithmic mean Divisia index model was developed using the spatiotemporal decoupling index method. The model is based on CO2 emissions generated by coal consumption in BRICS countries, with a primary focus on data from Brazil, Russia, South Africa, India, and China. The findings reveal distinct spatiotemporal distributions and driving effects of coal consumption and carbon dioxide emissions across various countries. Factors such as CO2 emission intensity, coal consumption intensity, economic output per capita, and population structure exerted either positive or negative effects on the distributional effect of the carbon emission-economic output per capita association in BRICS countries. Additionally, country-level heterogeneity in the influence of the distributional effects of CO2 emissions was observed within each BRICS country. Thus, different policies are needed to achieve carbon emission reduction targets in different countries. [ABSTRACT FROM AUTHOR]

The increase in the frequency and intensity of drought events expected in the coming decades in Western Europe may disturb forest biogeochemical cycles and create nutrient deficiencies in trees. One possible origin of nutrient deficiency is the disturbance of the partitioning of the green leaf pool during the leaf senescence period between resorption, foliar leaching and senesced leaves. However, the effects of drought events on this partitioning and the consequences for the maintenance of tree nutrition are poorly documented. An experiment in a beech forest in Meuse (France) was conducted to assess the effect of drought events on nutrient canopy exchanges and on the partitioning of the green leaf pool during the leaf senescence period. The aim was to identify potential nutritional consequences of droughts for trees. Monitoring nutrient dynamics, including resorption, chemistry of green and senesced leaves, foliar absorption and leaching in mature beech stands from 2012 to 2019 allowed us to compare the nutrient exchanges for three nondry and three dry years (i.e., with an intense drought event during the growing season). During dry years, we observed a decrease by almost a third of the potassium (K) partitioning to resorption (i.e. resorption efficiency), thus reducing the K reserve in trees for the next growing season. This result suggests that with the increased drought frequency and intensity expected for the coming decades, there will be a risk of potassium deficiency in trees, as already observed in a rainfall exclusion experiment on the same study site. Reduced foliar leaching and higher parititioning to the senesced leaves for K and phosphorus (P) were also observed. In addition, a slight increase in nitrogen (N) resorption efficiency occurred during dry years which is more likely to improve tree nutrition. The calcium (Ca) negative resorption decreased, with no apparent consequence in our study site. Our results show that nutrient exchanges in the canopy and the partitioning of the green leaf pool can be modified by drought events, and may have consequences on tree nutrition. [ABSTRACT FROM AUTHOR]

Heat waves, droughts, and compound drought and heat waves (CDHWs) have received extensive attention because of their disastrous impacts on agriculture, ecosystems, human health, and society. Here, we computed the heat wave magnitude index (HWMI), drought magnitude index (DMI), and compound drought and heat wave magnitude index (CDHMI) for Yangtze River Valley (YRV) from July to August during 1961–2022. We compared the large-scale atmospheric circulation characteristics of different extreme events based on these indexes. The results show that the positive center with sink motion in East Asia provides a favorable circulation background for heat wave events. Drought events are mainly affected by the zonal wave train dominated by a significant negative anomaly in Siberia and a high-pressure anomaly upstream, and a anticyclonic water vapor with strong divergence over the Yangtze River basin. During CDHW events, both anomalous systems that affect heat waves and droughts appear and strengthen simultaneously. Specifically, in the middle and upper troposphere, the positive height anomaly center in YRV expands abnormally, and the "+–+" wave train over the northern 50° N region of East Asia becomes more obvious. Therefore, the positive anomaly and water vapor anomaly brought by the two circulation patterns at different latitudes are superimposed over the YRV, leading to severe CDHWs. At the same time, the warm positive eddy center and cold negative eddy center in high latitudes exhibit more stable positive pressure features, which are conducive to the persistent development and strengthening of CDHWs. In addition, the anomalous warm sea surface temperature in western Pacific moderating the favorable circulation patterns may also promote the occurrence of CDHWs in the YRV during the same period. [ABSTRACT FROM AUTHOR]

Brazil's Pantanal wetland is one of the most threatened Brazilian ecosystems from direct anthropogenic pressures and climate change. In this study, the overarching research question is to explore whether compound drought-heat events (CDHEs) have become more recurrent, intense, and widespread over Brazil's Pantanal wetland in recent decades. For this, we purpose and tested two different approaches using validated long-term time series of monthly precipitation, temperature, and the satellite-based Vegetation Health Index (VHI) to characterize the spatiotemporal pattern of CDHEs over Pantanal. Firstly, we assessed global gridded precipitation and temperature data sets against ground measurements to choose an appropriate dataset for this study. Then, we calculated the Standardized Precipitation Index (SPI), Standardized Temperature Index (STI), and Standardized Precipitation Evapotranspiration Index (SPEI) from 1981 to 2021. The results showed that using both approaches (CDHE-M1 and CDHE-M2), the frequency of events is higher considering the moderate category, which is expected since the criteria are less restrictive. In addition, the highest frequency of CDHE events occurs between September and November (the end of the dry season). The results also indicated that CDHE events have been more recurrent and widespread since 2000 in Pantanal. Besides, considering all methods for identifying the CDHEs, the probability density function indicates a shift pattern to warmer and drier conditions in the last 40 years. The Mann–Kendall tests also confirmed the assumption that there is a significantly increasing trend in the compound drought-heat events in the Pantanal. Developing methodologies for monitoring compound climate events is crucial for assessing climate risks in a warming climate. Besides, it is expected that our results contribute to the convincing of the urgent need for environmental protection strategies and disaster risk reduction plans for the Pantanal. [ABSTRACT FROM AUTHOR]

This study invites us to reflect on our modern lives where the dramatic consequences of global warming are manifesting on a planetary scale: droughts and famines, massive migrations, oil shortages and soaring prices, economic crises and conflicts, etc. In this novel, the author pushes us to question the absurdity of our production, our dependence on the economy and our mode of consumption. It nevertheless highlights the moral values which make us capable of reaching a livable future. The story takes place at a time when all the social, climate, ecological and migrant crises that were brewing for years suddenly appear conjugate. In short, this is the great collapse. Severe heatwaves are hitting France and making daily life increasingly difficult. The resulting national power outage and fuel shortage are throwing the lives of millions of people into chaos. Among them, a wealthy couple, Stanislas and Sophie and their "eco-friendly" son Jonathan, living in Paris, will undertake a perilous journey by bike to reach the Morvan, where Stanislas had bought a farm some time earlier. When the family arrived at the farm, Patrick, the farmer, refuses to give the land to the Parisians because he did not benefit from the money received from the sale, having no longer any value. However, the two families end up learning to live together with the resources that nature offers them and thus defining the terms of a new lifestyle. This story could come out as anxietyprovoking, the author nevertheless shows confidence in human beings, believing in solidarity and resilience and adaptation. He finally calls for a reconnection between human beings and nature. [ABSTRACT FROM AUTHOR]

On the basis of Earth remote sensing data for 2000–2020, quantitative estimates of the influence of vegetation cover degradation on the summer warming in Belarus have been obtained. The average leaf area index of Belarus for this period increased by 3.3%, mainly due to forest areas, the leaf index of which increased by about 8%. The growth of the leaf area index slowed down the summer warming of forest lands in the north (above 54° N) by about half and by more than a quarter in the south of Belarus. At the same time, the leaf area index of croplands decreased by about 5%, which caused their additional warming and amplified their land surface temperature daily cycle for the summer period. Statistically significant signs of bioclimatic land degradation have been found on the territory of Belarus with a total area of about 400 000 ha, which are enhanced by high values of positive feedback between temperature, vegetation cover, and soil moisture. About of 58% of the degrading lands are agricultural lands located mainly in the southern part of the country. On these lands, the summer temperature grows twice as fast as the average for Belarus, and the leaf index decreases at a rate of about 2% per year, which indicates the insufficiency of agriculture climate mitigation in certain regions of Belarus. [ABSTRACT FROM AUTHOR]

Leaf area index (LAI) with an explicit biophysical meaning is a critical variable to characterize terrestrial ecosystems. Long-term global datasets of LAI have served as fundamental data support for monitoring vegetation dynamics and exploring its interactions with other Earth components. However, current LAI products face several limitations associated with spatiotemporal consistency. In this study, we employed the back propagation neural network (BPNN) and a data consolidation method to generate a new version of the half-month 1/12∘ Global Inventory Modeling and Mapping Studies (GIMMS) LAI product, i.e., GIMMS LAI4g, for the period 1982–2020. The significance of the GIMMS LAI4g was the use of the latest PKU GIMMS normalized difference vegetation index (NDVI) product and 3.6 million high-quality global Landsat LAI samples to remove the effects of satellite orbital drift and sensor degradation and to develop spatiotemporally consistent BPNN models. The results showed that the GIMMS LAI4g exhibited overall higher accuracy and lower underestimation than its predecessor (GIMMS LAI3g) and two mainstream LAI products (Global LAnd Surface Satellite (GLASS) LAI and Long-term Global Mapping (GLOBMAP) LAI) using field LAI measurements and Landsat LAI samples. Its validation against Landsat LAI samples revealed an R2 of 0.96, root mean square error of 0.32 m 2 m -2 , mean absolute error of 0.16 m 2 m -2 , and mean absolute percentage error of 13.6 % which meets the accuracy target proposed by the Global Climate Observation System. It outperformed other LAI products for most vegetation biomes in a majority area of the land. It efficiently eliminated the effects of satellite orbital drift and sensor degradation and presented a better temporal consistency before and after the year 2000. The consolidation with the reprocessed MODIS LAI allows the GIMMS LAI4g to extend the temporal coverage from 2015 to a recent period (2020), producing the LAI trend that maintains high consistency before and after 2000 and aligns with the reprocessed MODIS LAI trend during the MODIS era. The GIMMS LAI4g product could potentially facilitate mitigating the disagreements between studies of the long-term global vegetation changes and could also benefit the model development in earth and environmental sciences. The GIMMS LAI4g product is open access and available under Attribution 4.0 International at 10.5281/zenodo.7649107 (Cao et al., 2023). [ABSTRACT FROM AUTHOR]

Tropospheric ozone (TO) is one of the major greenhouse gases and a toxic air pollutant. It plays a key role in various chemical and photochemical processes in the troposphere. Ozone concentrations, both at the surface level and in the free troposphere, are measured by various local and remote-sensing methods. The St. Petersburg State University observational site in Peterhof (NDACC site St. Petersburg) is equipped with a Bruker IFS 125HR Fourier spectrometer used for TO measurements and the Thermo Scientific Model 49i gas analyzer for monitoring surface ozone concentrations (SOCs). The temporal variability of TO in the 0–8 km layer for the period from April 2009 to October 2022 and of SOCs for the period from 2013 to 2021 has been analyzed. The seasonal cycle of TO and SOCs is similar to that of total ozone columns, but it is shifted in time by about 1 and 1.5 months, respectively. The maximal variation of TO from the average value for the period falls on the first half of April ~+16%; a minimum of about –(12–14)% is observed from mid-October to the end of December. In the middle of summer, there is also a slight increase in the TO variation at the level of +(7–8)%. A statistically significant decrease in the TO content by 0.34 ± 0.22% per year was also obtained. A comparison of hourly averaged data on TO with synchronized data of SOC measurements revealed an increase in the correlation coefficient (CC) (up to 0.5 or more) between the two values 3–4 h after local noon in the warm season, accompanied by an increase in SOCs. The increase in correlations is in good agreement with the increase in the height of the planetary boundary layer. [ABSTRACT FROM AUTHOR]

Abstract–A seismogenic-trigger mechanism is proposed for the activation of methane emission on the Arctic shelf in the late 1970s, which caused the onset of abrupt climate warming in the Arctic and a rapid disintegration of West Antarctica's ice sheet and ice shelves in the late 20th and early 21st centuries. This process is accompanied by the release of methane from the underlying hydrate-bearing sedimentary rocks and accelerated climate warming in Antarctica. The proposed mechanism is associated with the action of deformation tectonic waves in the lithosphere–asthenosphere system, caused by strong earthquakes occurring in the subduction zones closest to the polar regions: the Aleutian, located in the northern part of the Pacific Ocean, the Chilean and Kermadec-Macquarie, located in the southeastern and southwestern parts of the Pacific lithosphere. Disturbances of the lithosphere are transmitted at an average velocity of about 100 km/yr over distances as long as 2000–4000 km, and the associated additional stresses that come to the Arctic and Antarctica several decades after earthquakes lead to the destruction of metastable gas hydrates located in the frozen rocks of the Arctic shelf or in the subglacial sedimentary rocks of Antarctica, causing the greenhouse effect and climate warming. Moreover, transmission of additional stresses causes a decrease in the adhesion of the ice sheet to the underlying rocks, its accelerated sliding and the destruction of the ice shelves in Antarctica. The considered hypothesis leads to the conclusion that in the coming decades, the processes of glacier destruction and climate warming in Antarctica will increase due to an unprecedented increase in the number of strong earthquakes in the subduction zones of the South Pacific Ocean in the late 20th and early 21st centuries. [ABSTRACT FROM AUTHOR]

The main worrying feature of climate change is its rapid evolution, in extent and variation, becoming less and less predictable. In this paper, we have reviewed the available literature and elaborated original data to outline how climate change will affect the grapevine cultivation and wine quality. We start by discussing which features of climate change will impact grapevine production most. The effects of heatwaves, air and soil temperature, extreme rainfall events, atmospheric evaporative demand, wildfires, and smoke are addressed. An increased frequency and intensity of heat waves since 2010 is shown in four grapevine production areas of Northern Italy. The focus then shifts to the impacts of the predicted increase in temperature and drought on frost risks, grapevine phenology, yield, berry quality and water needs as well as vine and vineyard carbon budgets. Climate change will challenge the achievement of current yields and wine quality as well as the ability of vineyards to sequester atmospheric carbon, but such effects will likely depend on the characteristics of the growing environments and on the varieties present. Climate change-related threats to grapevine call for a rapid implementation of adaptation strategies. [ABSTRACT FROM AUTHOR]

During the years of Ukraine's independence, the provision of fodder to the livestock industry and their effective use remained a difficult and unsolved problem. The military aggression of the russian federation on the territory of Ukraine, economic, geopolitical, climatic instability, global food crisis exacerbated the pre-war problems and led to the emergence of new threats and challenges in fodder production. The purpose of the study is to assess the state and main trends of the feed market of Ukraine, the problems of the feed industry in the context of modern threats and challenges. The research uses generally accepted methods of scientific economic research, in particular: bibliometric, scientific abstraction and hypothesis, systematic and economic analysis, monographic, analysis and synthesis, complex, abstract-logical, induction and deduction, comparison and logical generalization. The main problems of Ukrainian fodder production were considered: the increase in the cost of material resources, energy resources, the increase in the cost of harvesting and storage of domestically produced fodder, the shortage of labor force due to migration and mobilization, extreme climatic conditions that affect the yield of fodder crops, the quantity and quality of fodder, non-compliance with crop rotation, low feed quality, regional redistribution of feed production and consumption, shortage of working capital, problems with reimbursement of value added tax, delays in customs clearance of imported material resources, high inflation, fixed exchange rate, problematic insurance/letter of credit instruments under export contracts, destruction of the main supply chains in Ukraine, change in the geography of exports, blockade of sea ports, high cost of created logistics chains, difficult access to the market of European countries from the point of view of import and product certification, limitation of throughput capacity of European logistics centers, etc. Attention is focused on the problems of fodder production in the de-occupied and front-line territories: a shortage of resources due to the loss of funds and property due to shelling and theft by the russian military, the destruction of crops, the inability to export products, the death of farm animals due to military actions, damage and destruction of agricultural infrastructure and equipment, the impossibility of conducting technological operations, negative consequences for the land fund as a result of mining, artillery shelling, movement of heavy equipment, etc. The main results of the research can be used for scientific developments and in the practical activities of agricultural producers, assessing the impact of risks and threats on the fodder production industry of Ukraine. [ABSTRACT FROM AUTHOR]

Droughts evolve in space and time without following borders or pre-determined temporal constraints. Here, we present a new database of drought events built with a three-dimensional density-based clustering algorithm. The chosen approach is able to identify and characterize the spatio-temporal evolution of drought events, and it was tuned with a supervised approach against a set of past global droughts characterized independently by multiple drought experts. About 200 events were detected over Europein the period 1981-2020 using SPI-3 (3-month cumulated Standardized Precipitation Index) maps derived from the ECMWF (European Centre for Medium-range Weather Forecasts) 5th generation reanalysis (ERA5) precipitation. The largest European meteorological droughts during this period occurred in 1996, 2003, 2002 and 2018. A general agreement between the major events identified by the algorithm and drought impact records was found, as well as with previous datasets based on pre-defined regions. [ABSTRACT FROM AUTHOR]

Biodiversity provides humans with abundant natural resources, but due to human activities, land use has become one of the main factors determining the loss of biodiversity. Previous research has shown that land use has different effects on different species. To illustrate this phenomenon, this study used a wide range of sets of data to determine how land use affects species diversity worldwide, and whether this effect depends on the continent. This study mainly uses linear mixed-effects models (LMM) and generalized linear mixed-effects models (GLMM) to address the questions from two aspects: abundance and species richness. The results show that the responses of both abundance and species richness differ significantly between continents, which in Europe are significantly lower than in countries with primary vegetation. However, due to the sample size for Europe being much larger than that for Asia and Oceania, this result also indicates that the level of sampling could have biased the results. [ABSTRACT FROM AUTHOR]

One of the crucial components in improving the quality of forests is post-fire vegetation regrowth monitoring. This is done by analyzing the time series of satellite data and studying the severity of forest fires to improve the ability to monitor the dynamic changes of the forest. This study investigates the regeneration process of existing vegetation types in different severities of The Rim fire in Sierra Nevada, California, using the time series of vegetation indices obtained from the MODIS sensor. The Vegetation Return Period (VRP) and the Recovery Rate (RR) after the fire were evaluated to monitor the regrowth of vegetation types. According to the results, the VRP values of the species for low, moderate, and high severity were estimated to be between 22 to 33 months, 33 to 47 months, and about 5 years, in this area. The 8-year changes in the time series of vegetation indices confirm that some vegetation types in this region have not fully recovered. In addition, spatio-temporal variations of the burned regions were examined with Landsat images at 2-year post-fire intervals until 2021. The results showed that in three 2-year periods after the fire, 16,074 hectares, 48,722 hectares, and 27,391 hectares of land were, respectively, converted into unburned areas, and until 2019, about 60% of the burned areas were recovered. Researchers and land managers can use the results of such studies to identify areas that need more attention after a fire. [ABSTRACT FROM AUTHOR]

Background: Ongoing climate change is anticipated to increase the frequency and intensity of drought events, thereby affecting forest recovery dynamics and elevating tree mortality. The drought of 2018, with its exceptional intensity and duration, had a significant adverse impact on tree species throughout Central Europe. However, our understanding of the resistance to and recovery of young trees from drought stress remains limited. Here, we examined the recovery patterns of native deciduous tree sapling species following the 2018 drought, and explored the impact of soil depth, understory vegetation, and litter cover on this recovery. Methods: A total of 1,149 saplings of seven deciduous tree species were monitored in the understory of old-growth forests in Northern Bavaria, Central Germany. The vitality of the saplings was recorded from 2018 to 2021 on 170 plots. Results: Fagus sylvatica was the most drought-resistant species, followed by Betula pendula, Acer pseudoplatanus, Quercus spp., Corylus avellana, Carpinus betulus, and Sorbus aucuparia. Although the drought conditions persisted one year later, all species recovered significantly from the 2018 drought, albeit with a slight decrease in vitality by 2021. In 2018, the drought exhibited a more pronounced adverse effect on saplings in deciduous forests compared to mixed and coniferous forests. Conversely, sapling recovery in coniferous and mixed forests exceeded that observed in deciduous forests in 2019. The pivotal factors influencing sapling resilience to drought were forest types, soil depth, and understory vegetation, whereas litter and forest canopy cover had a negative impact. Conclusion: Long-term responses of tree species to drought can be best discerned through continuous health monitoring. These findings demonstrate the natural regeneration potential of deciduous species in the context of climate change. Selective tree species planting, soil management practices, and promoting understory diversity should be considered when implementing adaptive management strategies to enhance forest resilience to drought events. [ABSTRACT FROM AUTHOR]

The objective of this study is to investigate the changes in the river flow regime under the influence of dam construction and climatic variability and disaggregate their individual effects. Daily discharge, temperature, and precipitation data were collected from Qaranqo River basin in East Azerbaijan (Iran) for the period of 1971–2017. To disaggregate the effects of climatic variability and dam construction, daily river discharge data after dam construction were simulated using an Artificial Neural Network (ANN). Then, with the use of Indicators of Hydrologic Alteration (IHA) and annual indexes, river flow regime changes were examined. Results showed that monthly flows in all months except for July, August, and September, decreased. Also, annual maximum flows (except for a maximum of 1 day) decreased and minimum flows (except for a minimum of 1 day) increased. The Julian dates of minimum and maximum flows had also preceded, in which both dam construction and climatic variability were influential. Both dam construction and climatic variability were equally effective for monthly flows, extreme flows, and Julian dates of extreme flows. However, dam construction played a greater role in the changes of high and low pulses, and fall and rise of flow hydrograph. The two indexes of relative and absolute ranges of variation of intra-annual parameters had decreased, while the non-uniformity coefficient, concentration degree, complete accommodation coefficient, and Richards-Baker index had increased, which were mainly affected by climatic variability. In the Environmental Flow Components (EFC) in the group of low monthly flows in most months, there was little difference between observed data and simulated data, which indicated the role of climatic variability in the river flow regime. By contrast, there was a significant difference in peak, duration, and time of large and small floods, which indicated the role of the dam construction in these components. Climate variability had the most role in changes of monthly low flows, extreme low flows, and high flows of river flow regime, while in small and large floods, the role of dam construction was significant. It can be concluded that the effect of climatic variability on flow regime in the Qaranqo River basin, was greater than the effect of dam construction. [ABSTRACT FROM AUTHOR]

Summary: European beech (Fagus sylvatica) was among the most affected tree species during the severe 2018 European drought. It not only suffered from instant physiological stress but also showed severe symptoms of defoliation and canopy decline in the following year.To explore the underlying mechanisms, we used the Swiss‐Canopy‐Crane II site and studied in branches of healthy and symptomatic trees the repair of hydraulic function and concentration of carbohydrates during the 2018 drought and in 2019.We found loss of hydraulic conductance in 2018, which did not recover in 2019 in trees that developed defoliation symptoms in the year after drought. Reduced branch foliation in symptomatic trees was associated with a gradual decline in wood starch concentration throughout summer 2019. Visualization of water transport in healthy and symptomatic branches in the year after the drought confirmed the close relationship between xylem functionality and supported branch leaf area.Our findings showed that embolized xylem does not regain function in the season following a drought and that sustained branch hydraulic dysfunction is counterbalanced by the reduction in supported leaf area. It suggests acclimation of leaf development after drought to mitigate disturbances in canopy hydraulic function. [ABSTRACT FROM AUTHOR]

Summary: Understanding the effects of temperature and moisture on radial growth is vital for assessing the impacts of climate change on carbon and water cycles. However, studies observing growth at sub‐daily temporal scales remain scarce.We analysed sub‐daily growth dynamics and its climatic drivers recorded by point dendrometers for 35 trees of three temperate broadleaved species during the years 2015–2020. We isolated irreversible growth driven by cambial activity from the dendrometer records. Next, we compared the intra‐annual growth patterns among species and delimited their climatic optima.The growth of all species peaked at air temperatures between 12 and 16°C and vapour pressure deficit (VPD) below 0.1 kPa. Acer pseudoplatanus and Fagus sylvatica, both diffuse‐porous, sustained growth under suboptimal VPD. Ring‐porous Quercus robur experienced a steep decline of growth rates with reduced air humidity. This resulted in multiple irregular growth peaks of Q. robur during the year. By contrast, the growth patterns of the diffuse‐porous species were always right‐skewed unimodal with a peak in June between day of the year 150–170.Intra‐annual growth patterns are shaped more by VPD than temperature. The different sensitivity of radial growth to VPD is responsible for unimodal growth patterns in both diffuse‐porous species and multimodal growth pattern in Q. robur. [ABSTRACT FROM AUTHOR]

Estimates suggest that a swarm of desert locusts can consume food grains sufficient to feed up to 35,000 people. Despite the potential disaster that these migratory pests can bring about, there is no credible economic estimate of the actual damage caused by locust upsurges to agricultural production. This article takes advantage of plausibly exogenous variation generated by the timing of locust upsurges and geographic variation due to their migration patterns to estimate the impact of an upsurge on crop yields using a large district level panel dataset from India covering more than 200 districts over 45 years. I find that locust upsurges have no impact on rice yields but can lead to a decline of up to 0.2 tons of wheat production per hectare. Given that locusts attack India from the western side and majority of the rice is produced in the east and south, such findings are not surprising. There are two ways to interpret the estimated effect size in terms of how hard the locust upsurges can sting the economy. First, in terms of the economic costs, the magnitude of the effects are around 12% compared to mean per‐hectare production of wheat. Second, in terms of accounting costs, back of the envelope calculations suggest losses up to US$3 billion. Policy implications include recognizing locust upsurges as natural disasters and providing demand‐based market instruments such as locust insurance to help farmers hedge against this risk. Related Content: Monopsonists, Disruptive Innovation and Food Security: The Case of High-Value Commodity [ABSTRACT FROM AUTHOR]

From hampering the ability of water utilities to fill their reservoirs to leaving forests parched and ready to burn, drought is a unique natural hazard that impacts many human and natural systems. A great deal of research and synthesis to date has been devoted to understanding how drought conditions harm agricultural operations, leaving other drought‐vulnerable sectors relatively under‐served. This review aims to fill in such gaps by synthesizing literature from a diverse array of scientific fields to detail how drought impacts nonagricultural sectors of the economy: public water supply, recreation and tourism, forest resources, and public health. We focus on the Intermountain West region of the United States, where the decadal scale recurrence of severe drought provides a basis for understanding the causal linkages between drought conditions and impacts. This article is categorized under:Human Water > Value of WaterScience of Water > Water Extremes [ABSTRACT FROM AUTHOR]

Seasonal droughts are a common feature of the Iberian (Mediterranean) climate. They can have severe impacts on both natural and human life - especially, when recurring in consecutive years. In this study, we investigate the potential impacts of climate change on recurrent drought events in the Iberian Peninsula (IP). With this aim, we use the new set of indices introduced in Moemken and Pinto (2022): the Recurrent Dry Year Index (RDYI) and the Consecutive Drought Year (CDY) Index. These are applied to a large EURO-CORDEX multi-model ensemble consisting of 25 different global-toregional model (GCM-RCM) chains that follow the RCP8.5 scenario with 12 km horizontal resolution. A drizzle correction and a simple multiplicative approach are used to biasadjust the daily precipitation sums. Results reveal a general tendency towards more severe drought conditions in IP under different global warming levels (GWLs). Moreover, recurrent drought events are projected to occur more frequent and last longer. While the ensemble mean responses are only moderate for a GWL of +2°C (compared to the pre-industrial average), recurrent drought conditions are strongly enhanced for the +3°C GWL. The magnitude of projected changes shows some sensitivity on the choice of index and model. Typically, changes are more pronounced for indices based on the effective drought index (EDI) and show a larger spread for the individual GCMs than for the various RCMs. Nevertheless, the climate change signals are robust for most of IP and all indices, with a larger model agreement for the +3°C GWL. We conclude that the Iberian Peninsula is confronted with an increased risk of recurrent drought events in future decades. If global warming should exceed the +3°C threshold, the majority of models projects an almost permanent state of drought - which could result in severe implications for the Iberian population and ecosystems. [ABSTRACT FROM AUTHOR]

Seasonal drought is a typical feature of the Mediterranean climate that may lead to strong socioeconomic and ecological impacts. We investigate the occurrence and intensity of historical extreme drought events over the Iberian Peninsula (IP) for the past decades, with special focus on recurrent drought events. With this aim, we introduce and apply a new set of indices: The Recurrent Dry Year Index (RDYI) and the Consecutive Drought Year (CDY) Index. Additionally, three drought indices are considered for individual events: A simple Drought Index (DI) based on precipitation deficits and the number of affected grid points, the Effective Drought Index (EDI), and the Standardized Precipitation Index (SPI). Different gridded observational (E-OBS V20e, IBERIA01) and reanalysis datasets (ERA5) are analysed at several spatial resolutions, ranging roughly between 10km and 25km. Results show that extreme droughts are a common feature in the IP, with roughly three individual events per decade. Especially the southern and central parts of IP are exposed to recurrent events. These events typically last two to three years, but may reach a length of six consecutive years. Sensitivity in the number of drought years is found regarding the spatial resolution. Moreover, drought is identified more often with EDI, leading to an enhanced number of recurrent droughts. (Recurrent) Droughts in IP are driven by precipitation deficits in winter (rainiest season) as there is hardly any precipitation during summer over most of IP. Still, deficits in spring and autumn may also be decisive, and some sensitivity is identified regarding the choice of index and the affected region. We conclude that the new indices are suitable for the detection and analysis of recurrent drought events. They are a first step towards a systematic worldwide evaluation of recurrent drought events under present and future climate conditions. [ABSTRACT FROM AUTHOR]

Copyright of Cuadernos de Investigación Geográfica is the property of Universidad de la Rioja, Servicio de Publicaciones and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Summary: The frequency and severity of heatwave events are increasing, exposing species to conditions beyond their physiological limits. Species respond to heatwaves in different ways, however it remains unclear if plants have the adaptive capacity to successfully respond to hotter and more frequent heatwaves.We exposed eight tree populations from two climate regions grown under cool and warm temperatures to repeated heatwave events of moderate (40°C) and extreme (46°C) severity to assess adaptive capacity to heatwaves.Leaf damage and maximum quantum efficiency of photosystem II (Fv/Fm) were significantly impacted by heatwave severity and growth temperatures, respectively; populations from a warm‐origin avoided damage under moderate heatwaves compared to those from a cool‐origin, indicating a degree of local adaptation. We found that plasticity to heatwave severity and repeated heatwaves contributed to enhanced thermal tolerance and lower leaf temperatures, leading to greater thermal safety margins (thermal tolerance minus leaf temperature) in a second heatwave.Notably, while we show that adaptation and physiological plasticity are important factors affecting plant adaptive capacity to thermal stress, plasticity of thermal tolerances and thermal safety margins provides the opportunity for trees to persist among fluctuating heatwave exposures. [ABSTRACT FROM AUTHOR]

Ectomycorrhizal fungi (EMF) can enhance drought resistance of host plants by increasing nutrient and water absorption. Calcium (Ca) plays a central role in drought stress adaptation, yet it remains unclear how EMF influence Ca uptake of plants under drought stress. We carried out a pot experiment in which Quercus acutissima seedlings were inoculated with or without the ectomycorrhizal (EM) fungus Xerocomus chrysenteron under control and water stress soil moisture conditions in order to investigate how soil Ca availability and plant Ca uptake are modulated by EMF and how this may contribute to drought resistance of the seedlings. We found that soil water-extractable Ca was significantly reduced by drought in non-ectomycorrhizal treatment, while EM treatment significantly increased soil Ca availability and Ca uptake of Quercus acutissima seedlings under drought conditions. Furthermore, seedling water use efficiency (WUE) was positively correlated with soil Ca availability and plant Ca content. Calcium uptake promotion seems to be involved in the mechanisms of drought tolerance enhancement by EMF. [ABSTRACT FROM AUTHOR]

We have revealed the dependence of current soil-forming processes in laylands on the period of theirs overgrowing, landform, and cultivation intensity. The main object of research is represented by regraded agrosoddy-podzolic soils (Albic Glossic Retisols (Loamic, Aric, Cutanic, Ochric)), differing in the overgrowing period, cultivation rate, and texture, and located on transit and accumulative elements of the landscape. The soils have been studied during soil-ecological surveys in the Udmurt Republic and in a long-term field experiment. It has been revealed that all major changes in layland soils occur in the former plowed layer, which is subdivided into two sublayers. Humus formation is intensive in the upper 10-cm-thick part of the plow layer, which results in higher humus content, total exchangeable bases, and structure coefficient. The zonal podzolization process is activated in the lower part of the plow layer (from 10- to 20-cm-thick) and results in lower content of humus and exchangeable basis, and in higher acidity. After the 40-year-long period of overgrowing, the properties of these sublayers become similar to those of the AY (gray-humus) and EL (eluvial) horizons of virgin soils, respectively. The changes of all the parameters during layland overgrowing are stepwise. Differentiation of the formed plow layer is the most intensive in soils on transit elements of the catena. More favorable moisture conditions of the accumulative positions in catena result in higher productivity of biocenoses and more intensive humus formation. Differentiation of the former plow layer is more intensive in soils of the increased and high cultivation rate. [ABSTRACT FROM AUTHOR]

Relationships between stem growth and climatic and edaphic factors, notably air temperatures and soil moisture for different slopes, are not completely understood. Stem radial variations were monitored at the bottom and top slope positions in a Larix principis-rupprechtii plantation during the 2017 and 2018 growing seasons. Total precipitation during the growing season in 2017 and 2018 was 566 mm and 728 mm, respectively. Stem contractions typically occurred after mid-morning followed by swelling in the late afternoon in both plots, reflecting the diurnal cycle of water uptake and loss. Trees at the two locations showed the same growth initiation (mid-May) because of the small differences in air and soil temperatures. There were no significant differences in cumulative stem radial growth between the bottom plot (1.57 ± 0.34 mm) and the top plot (1.55 ± 0.26 mm) in 2018. However, in 2017, the main growth period of the bottom plot ceased 17 days earlier than in the top plot, while cumulative seasonal growth of the bottom plot (1.08 ± 0.25 mm) was significantly less than the top plot (1.54 ± 0.43 mm). Maximum daily stem shrinkage was positively correlated with air and soil temperatures, solar radiation, vapor pressure deficits, and negatively correlated with volumetric soil moisture content. The maximum daily shrinkage reflected transpiration rates as affected by environmental factors. Daily radial stem increment was correlated with precipitation and volumetric soil moisture in both years, but with air temperatures only in 2017. The seasonal growth of L. principis-rupprechtii Mayr thus shows interannual dynamics, while precipitation constitutes a key driving factor. [ABSTRACT FROM AUTHOR]

Summary: Hydraulic failure of the plant vascular system is a principal cause of forest die‐off under drought. Accurate quantification of this process is essential to our understanding of the physiological mechanisms underpinning plant mortality. Imaging techniques increasingly are applied to estimate xylem cavitation resistance. These techniques allow for in situ measurement of embolism formation in real time, although the benefits and trade‐offs associated with different techniques have not been evaluated in detail.Here we compare two imaging methods, microcomputed tomography (microCT) and optical vulnerability (OV), to standard hydraulic methods for measurement of cavitation resistance in seven woody species representing a diversity of major phylogenetic and xylem anatomical groups.Across the seven species, there was strong agreement between cavitation resistance values (P50) estimated from visualization techniques (microCT and OV) and between visual techniques and hydraulic techniques.The results indicate that visual techniques provide accurate estimates of cavitation resistance and the degree to which xylem hydraulic function is impacted by embolism. Results are discussed in the context of trade‐offs associated with each technique and possible causes of discrepancy between estimates of cavitation resistance provided by visual and hydraulic techniques. [ABSTRACT FROM AUTHOR]

The purpose of this study was to identify barriers to the development of medicinal plants in Nahavand in 2019. The sample size was 11 experts and 5 farmers who were selected through targeted snowball sampling. Semi-structured interviews were conducted to collect data using the thematic analysis approach. The results were 22 main themes which were determined by MAXQDA10 quality software. The main topics in this study were "supportive-supervisory barriers" and "managerial barriers". The results of this study showed that insufficient conversion and complementary industries, farmers' lack of knowledge of the market, the inability of farmers to package and sell, and lack of planning for crop development are among the obstacles to the development of medicinal plants in Nahavand. A comprehensive (financial-information) support system can be effective in reducing barriers and developing cultivation. This system can have public, information and financial parts. In the "Personal Information" section of this system, all personal and economic details of cultivation applicants can be registered. In the "Specific Information" section, all areas prone to cultivating different types of medicinal plants and how to plant and harvest them can be identified. In the "Communication Channels" section, all relevant experts can be introduced. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Mediterranean holm oak forests are subjected to chronic seasonal droughts coinciding with the warmest conditions during the summer. Importantly, climate change projections support increased frequency and intensity of droughts in the future. In order to evaluate whether thinning practices can be used as efficient adaptation strategies to climate change, we measured canopy cover as a surrogate of defoliation in 49 Quercus ilex L. subsp. ilex individual genets subjected to experimental ramet thinning. Canopy cover measurements were obtained before, during and after the exceptionally intense and prolonged drought of 2016. Our results show that intensity of basal area reduction determined higher resistance, but not resilience, to this intense-long drought period. Independently of shoot thinning intensity, every holm oak exhibited crown defoliation during the dry period but most of them recovered their leaves the next spring. Holm oaks subjected to thinning with more than over 50% of basal area removed, were less vulnerable to severe drought, however, and supported more leaves later on. Additionally, our results highlight the positive influence of canopy shading from neighbouring trees preventing defoliation after drought events. A greater canopy shading per stool led to a higher resistance in holm oak trees exposed to severe drought. These findings suggest that, in order to cope with concomitant climate change and to optimize genet-level stress tolerance, coppice selection should be done by removing shoots with fewer leaves per unit area, preferably those unexposed to shading from neighbouring trees until a reduction around 50% of basal area per stool is achieved. [ABSTRACT FROM AUTHOR]

The climate change on the impact of grain production potential has significant regional differences. Researchers have studied the grain production potential of various crop combinations or focused on single crop types in a typical area; however, the regional differences of the climate change on the impact of grain production potential were neglected. This paper used the Global Agro-Ecological Zone (GAEZ 3.0) model to focus on the analysis what is the climate change on the impact of grain production potential in different geographic units (Northern Shaanxi Plateau, Guanzhong Basin, Qinba Mountain) in Shaanxi Province of China. The case showed that the precipitation (Pre) what made changes of grain production potential was the most important factor in different geographic units. The increase of Pre had a positive impact on the grain production potential in Northern Shaanxi Plateau and Guanzhong Basin. However, in Qinba Mountain, due to excessive Pre in the Qinba Mountains, the decrease of Pre had a certain positive impact on the grain production potential. The precipitation was less in the Northern Shaanxi Plateau; therefore, its major factors leading to changes of crop production were precipitation and rainfall days. The increase of the mean maximum temperature (Tmx) and the mean minimum temperature (Tmn) had a positive impact of the grain production potential in the Northern Shaanxi Plateau and Guanzhong Basin. The higher temperature had a negative impact on the grain production potential. In Qinba Mountain, the increase of the temperature has a certain negative impact on the grain production potential. It has more influence of Tmx in the Guanzhong Basin and Qinba Mountain rather than that in the Northern Shaanxi Plateau. Generally speaking, the major climatic factors leading grain production potential were Pre and Tmx in Guanzhong Basin and Qinba Mountain. [ABSTRACT FROM AUTHOR]

Extreme climatic events, such as flooding and drought, can abruptly modify the amplitude of the river level of a river, promoting new environmental conditions and impacting aquatic communities. Furthermore, an increasing frequency of extreme droughts in dammed rivers is expected because dams homogenize the flood pulse and decrease the river level. In this study, we evaluated the effects of extreme river-level oscillations on the benthic macroinvertebrate communities in a floodplain river. We analysed 47 years of river-level data and 17 years of benthic macroinvertebrate data. Our findings indicated that (1) extreme river-level oscillations promoted environmental conditions that were distinct from the regular oscillation; moreover, environmental characteristics were more heterogeneous in extreme oscillations than regular oscillations; (2) extreme oscillations were associated with a decreased richness, density, and diversity of benthic macroinvertebrates, promoting the dominance of tolerant taxa. Furthermore, in the studied river, a large hydroelectric power plant was built 19 years ago, which (3) decreased the river-level downstream, accentuating the occurrence of extreme drought, which has become more common after damming. We emphasize the importance of long-term biological monitoring considering the more frequent occurrence of extreme river-level oscillations in response to factors such as dam building and climate change. [ABSTRACT FROM AUTHOR]

Global, fast and accessible monitoring of biodiversity is one of the main pillars of the efforts undertaken in order to revert it loss. The Group on Earth Observations Biodiversity Observation Network (GEO-BON) provided an expert-based definition of the biological properties that should be monitored, the Essential Biodiversity Variables (EBVs). Initiatives to provide indicators for EBVs rely on global, freely available remote sensing (RS) products in combination with empirical models and field data, and are invaluable for decision making. In this study, we provide alternatives for the expansion and improvement of the EBV indicators, by suggesting current and future data from the European Space Agencýs COPERNICUS and explore the potential of RS-integrated Dynamic Global Vegetation Models (DGVMs) for the estimation of EBVs. Our review found that mainly due to the inclusion of the Sentinel constellation, Copernicus products have similar or superior potential for EBV indicator estimation in relation to their NASA counterparts. DGVMs simulate the ecosystem level EBVs (ecosystem function and structure), and when integrated with remote sensing data have great potential to not only offer improved estimation of current states but to provide projection of ecosystem impacts. We suggest that focus on producing EBV relevant outputs should be a priority within the research community, to support biodiversity preservation efforts. [ABSTRACT FROM AUTHOR]

In the work dedicated to the 50th anniversary of the V.E. Zuev Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences (IAO SB RAS), experimental studies are reviewed in a certain chronology that have been milestones in the development of an integrated study of aerosol life in the atmosphere. We discuss briefly the main results from the series of expedition studies of the optical and microphysical properties of aerosol of marine coastal hazes, arid zones, and different geographic regions of the World Ocean. The modern set of methods and instrumentation that we use to measure the aerosol characteristics in the monitoring mode at the network of IAO SB RAS stations is described. The results of multiyear studies of tropospheric aerosol using aircraft laboratories are presented. [ABSTRACT FROM AUTHOR]

Two important threats to the sustainable functioning of seminatural grasslands in temperate zones are (1) nutrient loading due to agricultural fertilization and pollution, and (2) the increase of extreme drought events due to climate change. These threats may cause substantial shifts in species diversity and abundance and considerably affect the carbon and water balance of ecosystems. The synergistic effects between those two threats, however, can be complex and are poorly understood. Here, we experimentally investigated the effects of nitrogen addition and extreme drought (separately and in combination) on a seminatural temperate grassland, located in Freiburg (South Germany). To study the grassland response, we combined eddy-covariance techniques with open gas exchange systems. Open gas exchange chambers were connected to an infrared gas analyzer and water isotope spectrometer, which allowed the partitioning of net ecosystem exchange and evapotranspiration. Vegetation parameters were described by species richness, species abundance, and leaf area index. Our results suggest that grassland communities, strongly weakened in their stress response by nitrogen loading, can substantially lose their carbon sink function during drought. While nitrogen addition caused a significant loss in forb species (−25%), precipitation reduction promoted a strong dominance of grass species at season start. Consequently, the grass-dominated and species-poor community suffered from a strong above-ground dieback during the dry summer months, likely caused by lower water use efficiency and weaker drought adaptations of the species community. Over the growing season (April-September), the carbon sequestration of the studied grassland was reduced by more than 60% as a consequence of nitrogen addition. Nitrogen addition in combination with precipitation reduction decreased carbon sequestration by 73%. Eutrophication can severely threaten the resilient functioning of grasslands, in particular when drought periods will increase as predicted by future climate scenarios. Our findings emphasize the importance of preserving high diversity of grasslands to strengthen their resistance against extreme events such as droughts. [ABSTRACT FROM AUTHOR]

Different species have different sensitivity to heat waves; therefore, interspecific competition may affect the crop response to heat waves. We investigated the effects of heat waves on spring barley (Hordeum vulgare L.) grown with and without wild mustard (Sinapis arvensis L.) as well as the recovery of barleys from stress. The plants were exposed to a 7‐day 35/28ºC (day/night) heat wave at ambient CO2 (400 μmol/mol) and elevated CO2 (800 μmol/mol). All seedlings were rehydrated and returned to control conditions (21/14ºC, CO2 400 μmol/mol) after the cease of heat wave and grown for a 7‐day period of recovery. Heat wave had more pronounced negative effect on the barley's aboveground biomass under competition with mustard, whereas the response of root biomass was not influenced by the presence of weeds. The heat wave induced reductions in barley's photosynthetic rate, stomatal conductance and water use efficiency under interspecific competition were higher compared to monocultured conditions. Interspecific competition impaired and delayed the recovery of barley's biomass production and leaf gas exchange parameters after heat wave. Elevated CO2 slightly mitigated negative heat wave impact on the growth and leaf gas exchange parameters but had no effect during the recovery period. [ABSTRACT FROM AUTHOR]

Greenhouse gas (GHG) inventories at national or provincial levels include the total emissions as well as the emissions for many categories of human activity, but there is a need for spatially explicit GHG emission inventories. Hence, the aim of this research was to outline a methodology for producing a high-resolution spatially explicit emission inventory, demonstrated for Poland. GHG emission sources were classified into point, line, and area types and then combined to calculate the total emissions. We created vector maps of all sources for all categories of economic activity covered by the IPCC guidelines, using official information about companies, the administrative maps, Corine Land Cover, and other available data. We created the algorithms for the disaggregation of these data to the level of elementary objects such as emission sources. The algorithms used depend on the categories of economic activity under investigation. We calculated the emissions of carbon, nitrogen sulfure and other GHG compounds (e.g., CO2, CH4, N2O, SO2, NMVOC) as well as total emissions in the CO2-equivalent. Gridded data were only created in the final stage to present the summarized emissions of very diverse sources from all categories. In our approach, information on the administrative assignment of corresponding emission sources is retained, which makes it possible to aggregate the final results to different administrative levels including municipalities, which is not possible using a traditional gridded emission approach. We demonstrate that any grid size can be chosen to match the aim of the spatial inventory, but not less than 100 m in this example, which corresponds to the coarsest resolution of the input datasets. We then considered the uncertainties in the statistical data, the calorific values, and the emission factors, with symmetric and asymmetric (lognormal) distributions. Using the Monte Carlo method, uncertainties, expressed using 95% confidence intervals, were estimated for high point-type emission sources, the provinces, and the subsectors. Such an approach is flexible, provided the data are available, and can be applied to other countries. [ABSTRACT FROM AUTHOR]

Aims: Long-duration drought can alter ecosystem plant species composition with subsequent effects on carbon cycling. We conducted a rainfall manipulation field experiment to address the question: how does drought-induced vegetation change, specifically shrub encroachment into grasslands, regulate impacts of subsequent drought on soil CO2 efflux (Rs) and its components (autotrophic and heterotrophic, Ra and Rh)? Methods: We conducted a two-year experiment in Inner Mongolia plateau, China, using constructed steppe communities including graminoids, shrubs and their mixture (graminoid + shrub) to test the effects of extreme-duration drought (60-yr return time) on Rs, Rh and Ra. Results: Our results indicated that extreme-duration drought reduced net primary production, with subsequent effects on Rs, Rh and Ra in all three vegetation communities. There was a larger relative decline in Ra (35–54%) than Rs (30–37%) and Rh (28–35%). Interestingly, we found Rs in graminoids is higher than in shrubs under extreme drought. Meanwhile, Rh declines were largest in the shrub community. Although Ra and Rh both decreased rapidly during drought treatment, Rh recovered quickly after the drought, while Ra did not, limiting the Rs recovery. Conclusions: This study suggests that plant species composition regulates several aspects of soil CO2 efflux response to climate extremes. This regulation may be limited by above- and below-ground net primary production depending on soil water availability. The results of this experiment address a critical knowledge gap in the relationship between soil respiration and plant species composition. With shrub encroachment into grasslands, total soil respiration is reduced and can partly offset the effect of reduction in productivity under drought stress. [ABSTRACT FROM AUTHOR]

Heatwaves, with increases in day and night time temperatures, are predicted to increase in frequency. We investigated the response of forbs, shrubs, grasses and non‐grass monocotyledons from warm temperate environments in Australia to repeated heatwaves to determine if responses differed with growth form and whether the addition of hot night temperatures influenced the ability of species to grow and acclimate. Plants were subjected to 3, 3‐day heatwaves comprising either hot days and nights or hot days and cool nights, with control plants maintained under cool days and nights. All species were thermotolerant to repeated heatwaves, although two species showed lower biomass under heat treatments, indicating repeated heatwaves influenced function in some, but not all species. While there was evidence of photosynthetic damage in some species, these recovered by the end of the experiment. While grasses and one herb showed some evidence of photosystem acclimation, increases in the threshold temperatures for membrane breakdown only occurred in one shrub. Leaf sacrifice in grasses was significantly increased after repeated heatwaves suggesting that fuel loads in grass communities will increase in the future. These results indicate high resilience for these Australian native warm temperate plants although lower growth rates in some species after heatwaves may result in changes to community composition. [ABSTRACT FROM AUTHOR]

We describe the current state and technical characteristics of Tropospheric Ozone Research (TOR) station, created 25 years ago to monitor atmospheric composition, basic meteorological variables, and other parameters. The multiyear observations showed that the air quality on the territory of Akademgorodok in Tomsk has been substantially degraded since the creation and development of the Special Economic Zone on its territory. [ABSTRACT FROM AUTHOR]

Recent experimental evidence suggests that during heat extremes, wooded ecosystems may decouple photosynthesis and transpiration, reducing photosynthesis to near zero but increasing transpiration into the boundary layer. This feedback may act to dampen, rather than amplify, heat extremes in wooded ecosystems. We examined eddy covariance databases (OzFlux and FLUXNET2015) to identify whether there was field-based evidence to support these experimental findings. We focused on two types of heat extremes: (i) the 3 days leading up to a temperature extreme, defined as including a daily maximum temperature >37 ∘ C (similar to the widely used TXx metric), and (ii) heatwaves, defined as 3 or more consecutive days above 35 ∘ C. When focusing on (i), we found some evidence of reduced photosynthesis and sustained or increased latent heat fluxes at seven Australian evergreen wooded flux sites. However, when considering the role of vapour pressure deficit and focusing on (ii), we were unable to conclusively disentangle the decoupling between photosynthesis and latent heat flux from the effect of increasing the vapour pressure deficit. Outside of Australia, the Tier-1 FLUXNET2015 database provided limited scope to tackle this issue as it does not sample sufficient high temperature events with which to probe the physiological response of trees to extreme heat. Thus, further work is required to determine whether this photosynthetic decoupling occurs widely, ideally by matching experimental species with those found at eddy covariance tower sites. Such measurements would allow this decoupling mechanism to be probed experimentally and at the ecosystem scale. Transpiration during heatwaves remains a key issue to resolve, as no land surface model includes a decoupling mechanism, and any potential dampening of the land–atmosphere amplification is thus not included in climate model projections. [ABSTRACT FROM AUTHOR]