Search Results (173)

Drought is one of the most complex natural hazards, characterized by its slow onset, persistent nature, diverse sectoral impacts (e.g., agriculture, water resources, ecosystems), and dependence on meteorological, hydrological, and socioeconomic factors. Over the years, significant scientific effort has been devoted to developing methodologies that address its multifaceted nature, reflecting the interdisciplinary challenges of drought analysis. However, previous reviews have typically focused on individual methods, while this study presents a unified, multidisciplinary framework that integrates multiple drought analysis methods and links them to key factors guiding method selection. To address this gap, five widely used methods—index-based, remote sensing, threshold-level methods (TLM), impact-based methods, and the storyline approach—are critically evaluated from a multidisciplinary perspective. In addition, the study examines spatial and temporal trends in scientific publications, illustrating how the application of these methods has evolved over time and across regions. The primary objective of this review is twofold: (1) to provide a holistic, state-of-the-art synthesis of these methods, their applications, and their limitations; and (2) to evaluate and prioritize the critical decision-making factors, including drought type, data type/availability, study scale, and management objectives that influence method selection. By bridging this gap, the paper offers a conceptual decision-support framework for selecting context-appropriate drought analysis methods. However, challenges remain, including the vast diversity of methods beyond the scope of this review and the limited consideration of less influential factors such as user expertise, computational resources, and policy context. The paper concludes with insights and recommendations for optimizing method selection under varying circumstances, aiming to support both drought research and effective policy implementation. Full article

Seeds in soil are often exposed to cycles of hydration and dehydration, which can prime them by triggering physiological activation without leading to germination. While this phenomenon has been scarcely studied in wild species, it may play a critical role in enhancing drought resilience and maintaining seed viability under the warmer conditions predicted by climate change. In this study, I investigated the effects of hydration–dehydration cycles on germination response under water stress in eight Cistus species typical of Mediterranean shrublands. First, seeds were exposed to a heat shock to break physical dormancy, simulating fire conditions. Subsequently, they underwent one of two hydration–dehydration treatments (24 or 48 h) and were germinated under a range of water potentials (0, –0.2, –0.4, –0.6, and –0.8 MPa). Six out of eight species showed enhanced germination responses following hydration–dehydration treatments, including higher final germination percentages, earlier germination onset (T₀), or increased tolerance to water stress. These findings highlight the role of water availability as a key factor regulating germination in Cistus species and evidence a hydration memory mechanism that may contribute in different ways to post-fire regeneration in Mediterranean ecosystems. Full article

Climate models forecast warmer winter conditions, which could lead to an earlier spring xylem phenology in trees. Localized stem heat experiments mimic this situation and have shown that stem warming leads to an earlier cambial resumption in evergreen conifers. However, there are still few comprehensive studies comparing the responses to stem heating in coexisting conifers and hardwoods, particularly in drought-prone regions where temperatures are rising. We addressed this issue by comparing the responses (xylem phenology, wood anatomy, growth, and sapwood concentrations of non-structural carbohydrates—NSCs) of two pines (the Eurosiberian Pinus sylvestris L., and the Mediterranean Pinus pinaster Ait.) and a ring-porous oak (Quercus pyrenaica Willd.) to stem heating. We used the Vaganov-Shashkin growth model (VS model) to simulate growth phenology considering several emission scenarios and warming rates. Stem heating in winter advanced cambial phenology in P. pinaster and Q. pyrenaica and enhanced radial growth of the three species 1–2 years after the treatment, but reduced the transversal lumen area of earlywood conduits. P. sylvestris showed a rapid and high growth enhancement, whereas the oak responded with a 1-year delay. Heated P. pinaster and Q. pyrenaica trees showed lower sapwood starch concentrations than non-heated trees. These results partially agree with projections of the VS model, which forecasts earlier growth onset, particularly in P. pinaster, as climate warms. Climate-growth correlations show that growth may be enhanced by warm conditions in late winter but also reduced if this is followed by dry-warm growing seasons. Therefore, forecasted advancements of xylem onset in spring in response to warmer winters may not necessarily translate into enhanced growth if warming reduces the hydraulic conductivity and growing seasons become drier. Full article

Given the growing impact of climate change, this study examines the flowering phenology of Rosa rugosa Thunb. in Kupinovo (Vojvodina, Serbia). Data collected over 18 years (2007–2024) were analyzed to assess changes in primary flowering, while secondary flowering was monitored from 2022 to 2025. Phenological stages were recorded every other day, and dates were converted into day-of-year (DOY) values. Heat accumulation (GDD) was calculated using daily max/min temperatures and thresholds. In 2024, R. rugosa exhibited a 37-day earlier onset and a 50.4-day later completion of primary flowering compared to previous years. The variability of key phenological events of primary flowering was observed in the interaction with climatic parameters, with regular fruiting. The species proved tolerant to heat and drought, suggesting potential range expansion. Optimal temperatures for secondary flowering were identified: abundant flowering occurred at 13.6 °C max and 4.9 °C min, while moderate flowering occurred at 9.0 °C max and 4.2 °C min. Regression analysis confirmed the positive effect of rising temperatures on flowering intensity. While freezing halted secondary flowering and damaged open buds, unopened buds remained unaffected. These findings highlight R. rugosa as a resilient, ornamental species, relevant to climate adaptation strategies, nature-based solutions, and the preservation of ecosystem services under global warming scenarios. Full article

Climate change refers to a significant and measurable alteration in the climate’s state, evident through shifts in the average and variability of key climate factors. Although the onset of climate change spans several decades, recent studies reveal a concerning intensification that is increasingly driven by anthropogenic activities, with the construction sector emerging as a significant contributor. The present paper investigates climate-conscious innovations within Romania’s construction industry, with a specific focus on the implementation of adaptive strategies. Through a narrative review methodology, this study synthesizes diverse sources, including scientific literature, technical reports, urban policy documents and relevant websites, to map the integration of sustainable construction practices in response to climate pressures. The findings highlight a range of local approaches, including passive design, green infrastructure, and reversible architecture, reflecting Romania’s gradual alignment with broader European environmental objectives. Despite Romania’s relatively low green contribution on a global scale, the country faces significant climate risks, including heatwaves, intense rainfall, and droughts. This evolving climate context necessitates a comprehensive adaptation of architectural practices, construction processes, material selection, and design strategies to mitigate environmental impact and enhance resilience. However, the narrative review approach has inherent limitations, including the potential for selection bias and limited replicability, which constrain the generalizability of the findings. Future research should employ quantitative and empirical methods to validate the effectiveness of climate-adaptive measures in structural engineering. Key areas include the integration of climate-resilient materials, structural performance under climate-induced stressors, and lifecycle carbon assessments of building components. Additionally, further investigation is needed into the development of predictive simulation models that assess the long-term structural impacts of evolving climate scenarios specific to Romania’s geographic and climatic conditions. Full article

Nostoc flagelliforme, a filamentous cyanobacterium inhabiting desert biological soil crusts (BSCs), has developed exceptional strategies to endure extreme environmental stresses, including severe desiccation, intense ultraviolet (UV) radiation, and drastic temperature fluctuations. These organisms must effectively sense and predict environmental changes, particularly the onset of desiccation. This review explores recent advancements in the molecular mechanisms that enable N. flagelliforme to survive under such harsh conditions, with a focus on stress signal sensing, transduction pathways, and photosynthetic adjustments. Key molecular adaptations include the production of extracellular polysaccharide (EPS) sheaths for water retention, the accumulation of compatible solutes like trehalose, and the synthesis of UV-absorbing compounds such as scytonemin and mycosporine-like amino acids (MAAs). Furthermore, N. flagelliforme utilizes a complex signal transduction network, including light-sensing pathways, to regulate responses to rehydration and desiccation cycles. This review emphasizes the integrative nature of N. flagelliforme’s adaptive mechanisms and highlights their potential for biotechnological applications, such as enhancing drought tolerance in crops and advancing ecological restoration in arid regions. Full article

Flash droughts are rapidly evolving drought events, primarily affecting agriculture, with an onset ranging from 5 days to 8 weeks. Previous research has highlighted the significant impact of flash droughts on agriculture and ecosystems, posing unique challenges for drought monitoring and mitigation. Various indicators have been used to identify the regions and occurrences of flash droughts. However, studies indicate that a single unique indicator does not serve the purpose of identifying/monitoring flash droughts in the United States. This study aims to identify flash droughts using indicators, including the Evaporative Stress Index (ESI), Soil Moisture (SM), and Normalized Difference Vegetation Index (NDVI), complemented by data from the United States Drought Monitor (USDM), which is used as a reference. The research examines flash droughts across Florida, Georgia, and Louisiana from 2000 to 2023, incorporating case studies of recent events. The findings indicate that the SM indicator demonstrates the highest consistency (91%) with the USDM, followed by SESI (64%) and NDVI (52%). Seasonally, flash droughts were most frequent in Florida and Georgia during May and October, whereas Louisiana experienced the highest occurrences between June and October. These indicators effectively reflect flash drought impacts, as documented by crop progress and condition reports from the United States Department of Agriculture (USDA). Finally, to enhance understanding and management of flash droughts, the study proposes a Driver-Impact-Response (DRI) conceptual framework is proposed to connect the drivers, impacts, and responses. The DRI framework identifies the drivers initiating flash droughts, evaluates their impacts, and develops mitigation strategies. The DRI framework is specifically of support and management use for planners to summarize the information for decision-making. Full article

The warming climate and increasing extreme weather events are transforming ecological backgrounds, which is bringing new challenges to herders’ livelihood in grassland areas. To understand the practical ecological risks and the current resilience situations of herders’ behaviors and government correspondence measures, we built a conceptual framework of community resilience in pastoral areas, selected different kinds of steppes along the ecological gradient (desert steppe, typical steppe and meadow steppe) and took household surveys to recognize the difference in ecological risks and enhancing strategies in different grassland types. The results show that: (1) Herders in desert steppe, with the lowest precipitation and the worst grassland condition, turn out to have more experience in perceiving droughts and mitigating loss from disaster, but received the most attention from government assistance (28.0%) to getting through drought; (2) Typical steppe, with traditionally better pastural husbandry environment, suffered most broadly through droughts (85.7%) and have worst household livestock loss (26.7%) through snow storms; (3) Meadow steppe has the highest catastrophic snow storm ratio (65.0%) and affected ratio (95.0%), but the least assistance from the government (22.22%). The results revealed that originally high ecological vulnerability gradually encouraged herder’s livelihood adaptive capability. However, the government assistance and attention are more inclined to the local original ecological vulnerability. In addition, the increasing extreme climate events are bringing new challenges to adaptive knowledge systems of indigenous herders under good ecological condition. There is a clear need to combine the efforts of local pastoralists, policymakers and scientific community together to construct a more resilient socio-ecological pastoral systems under the global climate change. This research provides an in-depth understanding of community resilience in pastoral areas along the ecological gradient while facing the slow-onset climate change impacts. Practical recommendations on climate risk management and adaptation in pastoral areas are discussed. Full article

Water stress is one of the foremost global abiotic stressors limiting agricultural productivity. Biostimulants and bioactive compounds are emerging as promising tools to enhance crop stress tolerance. This study investigates the effects of Cytolan^® Stress, a novel seaweed-derived biostimulant, on the water stress tolerance of lettuce plants. Three application strategies were evaluated: priming, where the biostimulant is applied before the onset of stress to prepare the plants for adverse conditions; buffering, involving application at the onset of stress to mitigate its immediate effects; and detoxifying, where the biostimulant is applied after stress to aid in plant recovery. Biomass, stress-related parameters, antioxidant activity, osmoprotectant levels, and photosynthesis-related metrics were analyzed to elucidate its potential mechanisms of action. The results demonstrated that Cytolan^® Stress in priming and buffering applications significantly improved water stress tolerance, reducing biomass loss from 45% to only 25%. Moreover, the detoxifying treatment was the most effective, as plants showed biomass values similar to those of the control plants. The biostimulant reduced oxidative stress indicators while enhancing antioxidant defenses, including ascorbate (AsA)-glutathione (GSH) cycle, antioxidant compounds, and enzyme activities. In addition, Cytolan^® Stress preserved photosynthesis performance under water stress conditions. These findings highlight the potential of Cytolan^® Stress to mitigate drought stress effects in lettuce, offering broader implications for crop tolerance and resilience under water-limited conditions. Further studies are recommended to explore its efficacy across different crops and stress scenarios. Full article

Point-of-care (PoC) devices offer a promising solution for fast, portable, and easy-to-use diagnostics. These characteristics are particularly relevant in agrifood fields like viticulture where the early detection of plant stresses is crucial to crop yield. Microfluidics, with its low reagent volume requirements, is well-suited for such applications. Self-driven microfluidic devices, which rely on capillary forces for fluid motion, offer an attractive alternative by eliminating the need for external pumps and complex fluid control systems. However, traditional microfluidic prototyping materials like polydimethylsiloxane (PDMS) present challenges due to their hydrophobic nature. This paper presents the development of a reusable, portable, capillary-driven microfluidic platform based on a PDMS-PEG (polyethylene glycol) copolymer designed for the rapid low-cost detection of abscisic acid (ABA), a key biomarker for the onset of ripening of non-climacteric fruits and drought stress in vines. By employing passive fluid transport mechanisms, such as capillary-driven sequential flow, this platform enables precise biological and chemical screenings while maintaining portability and ease of use. A simplified field-ready sample processing method is used to prepare the grapes for analysis. Full article

Increased water limitations due to climate change will pose severe challenges to forest ecosystems in Europe. We investigated the response of potted saplings of Fagus sylvatica L., one of the major European tree species, to a spring and a summer water-withholding period with control–control (C-C), control–drought (C-D), drought–control (D-C) and drought–drought (D-D) treatments. We focused on recovery capacity and phenological and growth traits and questioned the extent to which an earlier drought influenced the response to a second drought in the same growing season. To examine the impact of the level of drought stress, a distinction was made between saplings with less or more than half of their leaves desiccated due to the spring drought (D<50 and D>50). The timing of the drought influenced the immediate post-drought response: saplings severely affected by the spring drought (D>50) resprouted, whereas saplings severely affected by the summer drought (C-D and D<50-D) did not. The spring treatment influenced the onset of visual symptoms in the summer drought, with saplings less affected in the spring drought (D<50-D) developing symptoms three days later than the saplings not subjected to drought in the spring (C-D), whereas severely affected saplings (D>50-D) had not yet display symptoms seventeen days after the first visual symptoms in the spring control saplings (C-D). The timing of autumnal leaf senescence displayed the legacies of the spring treatment. The saplings heavily affected by the spring drought showed a slower decrease in relative chlorophyll content and delayed leaf senescence (D>50-C and D>50-D), which may enable the repair of damaged tissues. The saplings that were less affected by the spring drought (D<50-C) showed earlier autumnal leaf senescence, which is likely an acclimation response. Interestingly, a larger diameter increment in autumn for all of the saplings that experienced the summer drought (C-D, D<50-D and D>50-D) may indicate the recovery of hydraulic capacity by new xylem growth. Our results underline the plasticity of young F. sylvatica saplings in response to (repeated) drought. Full article

The rainfed cereal growing regions of Northern Kazakhstan experience significant yield fluctuations due to dependence on weather conditions. Early detection and monitoring of droughts is crucial for effective mitigation strategies in this region. This study emphasises the following objectives: (1) description of the current vegetation condition with a possible separation of short-term weather effects and (2) analysing trends of changes with their directionality and quantification. Terra MODIS satellite images from 2000 to 2023 are used. Differential indices—Normalised Difference Vegetation Index (NDVI) and Vegetation Condition Index (VCI)—are used to determine the characteristics of each current season. A key component is the comparison of the current NDVI values with historical maximum, minimum, and average values to identify early indicators of drought. NDVI deviations from multiyear norms and VCI values below 0.3 visually reflect changing vegetation conditions influenced by seasonal weather patterns. The results show that the algorithm effectively detects early signs of drought through observed deviations in NDVI values, showing a trend towards increasing drought frequency and intensity in Northern Kazakhstan. The algorithm was particularly effective in detecting severe drought seasons in advance, as was the case in June 2010 and May 2012, thus supporting early recognition of drought onset. The Integrated Vegetation Index (IVI) and Integrated Vegetation Condition Index (IVCI) time series are used for integrated multiyear assessments, in analysing temporal changes in vegetation cover, determining trends in these changes, and ranking the weather conditions of each growing season in the multiyear series. Areas with high probability of drought based on low IVCI values are mapped. The present study emphasises the value of remote sensing as a tool for drought monitoring, offering timely and spatially detailed information on vulnerable areas. This approach provides critical information for agricultural planning, environmental management and policy making, especially in arid and semi-arid regions. The study emphasises the importance of multiyear data series for accurate drought forecasting and suggests that this methodology can be adapted to other drought-sensitive regions. Emphasising the socio-economic benefits, this study suggests that the early detection of drought using satellite data can reduce material losses and facilitate targeted responses. Full article

Drought recurrence is increasing in arid and semi-arid regions, and its effects are becoming more complicated due to climate change. Despite the increasing frequency of drought events, the sensitivity of natural vegetation to different levels of drought frequency and severity is not fully understood. Here, we aim to characterize the regional spatio-temporal patterns of drought frequency and severity and the response of vegetation across Iran at a high spatial resolution (5 km × 5 km). We examined the responses of three natural vegetation types (forest, grassland, and shrubland) to drought conditions across Iran using the Normalized Difference Vegetation Index (NDVI) and the Standardized Precipitation Evapotranspiration Index (SPEI) at different time scales and temporal lags from 2001 to 2022. Our results showed that drought severity increased in 15%, decreased in 1%, and remained stable in 84% of the study area. The severity and frequency of drought showed spatial patterns across Iran (i.e., increased from northwest to southeast and central Iran). The correlation between the monthly NDVI anomaly and SPEI varied across vegetation types, SPEI accumulation period (SPEI-1-3-6-9-12), and temporal lags, revealing different sensitivities of vegetation to drought in Iran. All natural vegetation types showed the strongest responses two months after drought events. Forests, mostly located in northern Iran, showed lower sensitivity to drought onset and responded slower to drought severity than other vegetation classes (i.e., grasslands and shrublands). These findings highlight the importance of analyzing the sensitivity of natural vegetation at different levels of drought severity and frequency for land use planning and mitigation efforts. Full article

The dendrochronological parameters of 97 pedunculate oak (Quercus robur L.) trees including 20 plus trees (142-year-old on average) and four half-sib families for four of them were analyzed considering also specifically years of the most severe droughts that were identified using average monthly air temperature and precipitation data. The tree-ring width (TRW) was mostly affected by air temperature that had the largest cross-dating indices (CDI), up to 78% maximum. However, the 32-year Brückner–Egeson–Lockyer cycle (a climatic cycle of approximately 30–40 years that correlates with sunspot activity) was more reflected in the TRW dynamics in plus trees than precipitation and air temperature. A high-frequency of abnormal TRW was clearly observed during drought periods and in the following 2–3 years. Tree radial-growth reduction due to drought stress varied significantly between families. The resistance to drought based on TRW was higher in the maternal plus oak trees than in progeny. Drought resulted in reduced growth during the subsequent year(s); hence, the minimum growth occurred after the actual climate event. Autumn–winter precipitation and weather conditions were of the greatest importance at the onset of active vegetation in April and May. The influence of air temperature on oak growth was the largest in March (r = 0.39, p < 0.05). The strongest positive correlation between precipitation and growth (with r up to 0.38) was observed in May 2023. Plus trees had a high adaptive potential due to the stability of radial growth during drought with high resistance (Rt = 1.29) and resilience (Rs = 1.09) indexes. The offspring of families 1 (Rt = 0.89, Rs = 0.89) and 2 (Rt = 1.04, Rs = 0.87) had similar resistance and resilience, but the recovery indices (Rc) for offspring in families 1, 2 and 3 exceeded the recovery values for plus trees. For offspring in families 3 and 4, the index values were lower. The revealed responses of wood growth of plus trees to climatic parameters estimated as resistance (Rt), resilience (Rs) and recovery (Rc) indexes and similar responses in their progeny can be used in breeding pedunculate oak for wood growth productivity and drought resistance. Full article

Flash droughts, characterized by their rapid onset and severe impacts, have critical implications for the ecological environment and water resource security. However, inconsistent definitions of flash droughts have hindered scientific assessments of drought severity, limiting efforts in disaster prevention and mitigation. In this study, we propose a new method for explicitly characterizing flash drought events, with particular emphasis on the process of soil moisture recovery. The temporal and spatial evolution of flash droughts over the Yangtze River Basin was analyzed, and the severity of the extreme flash drought in 2022 was assessed by comparing its characteristics and impacts with those of three typical dry years. Additionally, the driving factors of the 2022 flash drought were evaluated from multiple perspectives. Results indicate that the new identification method for flash droughts is reasonable and reliable. In recent years, the frequency and duration of flash droughts have significantly increased, with the Dongting Lake and Poyang Lake basins being particularly affected. Spring and summer were identified as peak seasons for flash droughts, with the middle reaches most affected in spring, while summer droughts tend to impact the entire basin. Compared to 2006, 2011, and 2013, the flash drought in 2022 affected the largest area, with the highest number of grids experiencing two flash drought events and a development rate exceeding 15%. Moreover, the summer heat in 2022 was more extreme than in the other three years, extending from spring to fall, especially during July–August. Its evolution was driven by the Western Pacific Subtropical High, which suppressed precipitation and elevated temperatures. The divergence of water vapor flux intensified water shortages, while anomalies in latent and sensible heat fluxes increased surface evaporation and heat transfer, further disturbing the regional water cycle. This study provides valuable insights for flash drought monitoring and early warning in the context of a changing climate. Full article