Search Results (5,570)

This study aims to investigate the perspectives of aquaculture producers in the Western Mediterranean Region (operating in Antalya, Burdur, and Isparta provinces) on climate change, examine the impacts of climate change on regional aquaculture, and develop solution proposals. Within the scope of this objective, the socioeconomic and demographic characteristics of the aquaculture producers in the Western Mediterranean Region, along with their knowledge levels regarding climate change, were obtained through a questionnaire technique. The results indicate that producers, who are predominantly engaged in rainbow trout aquaculture, are under severe economic pressure due to high-exchange-rate-driven input costs and the abolition of government subsidies. While all participants (100%) perceived that climate change has decreased production tonnage, the most prominent impact of the climate crisis is perceived as drought and the decline of water resources, with a response rate of 37.2%. Multivariable analysis further showed that aquaculture experience and satisfaction with aquaculture income were significantly associated with producers’ future outlook, highlighting the importance of socioeconomic factors in shaping perceived sectoral vulnerability. Due to both rising costs and environmental risks, 50% of the producers view the future of the sector pessimistically and do not recommend this profession to future generations. Consequently, these results emphasize the critical need for integrated land and water resource management policies, alongside targeted climate adaptation strategies, to ensure the long-term socio-ecological sustainability of forest inland aquaculture in the region. Full article

Citrullus colocynthis (L.) Schrad., a drought-tolerant member of the Cucurbitaceae family, has been used in traditional medicine for centuries and has recently attracted increasing interest because of its potential pharmacological, agricultural, and ecological applications. This review examines current information on the plant’s distribution, ethnomedicinal uses, phytochemical composition, biological activities, applications in poultry, and ecological significance. Its bioactive constituents include cucurbitacins, flavonoids, phenolic compounds, alkaloids, glycosides, fatty acids, and tocopherols. These compounds have been associated with anticancer, antidiabetic, antimicrobial, antioxidant, anti-inflammatory, neuroprotective, hepatoprotective, and other biological activities, although most of the available evidence comes from in-vitro and preclinical studies. Initial findings also indicate that the plant may have value as a phytogenic feed additive in poultry and as a drought-tolerant species for soil stabilization, rangeland rehabilitation, and desertification control. However, the practical application of these findings is still constrained by differences in research methods, variation in phytochemical composition, limited clinical evidence, and the plant’s narrow therapeutic window and dose-dependent toxicity. Consequently, its therapeutic effectiveness and suitability for routine agricultural use cannot yet be established with certainty. Future research should focus on phytochemical standardization, quality control, thorough toxicological assessment, mechanistic studies, and well-designed clinical and animal trials using standardized preparations. Collectively, the available evidence indicates that C. colocynthis is a promising source of bioactive compounds with potential pharmaceutical, veterinary, and ecological applications, although rigorous scientific validation is required before its safe and effective utilization can be recommended. Full article

Improving the understanding of hydrological drought mechanisms is paramount for drought resistance and early warning in a changing environment. The Upper Yellow River Basin (UYRB), the primary water-producing region of the Yellow River Basin, experiences hydrological droughts that are jointly influenced by climate variability and human activities. This study systematically investigated the spatiotemporal evolution of hydrological droughts in the UYRB and elucidated their underlying mechanisms from the perspectives of sub-basin contributions, reservoir regulation, and large-scale climate drivers. We found an increasing trend in yearly drought severity from 1956 to 2010 under the natural scenario, but large reservoirs significantly reduced the severity. The headwater region, Tao River Basin, and interval region 2 were identified as the key areas in drought formation of the whole UYRB. Reservoirs generally increased monthly drought intensity in summer and autumn but decreased drought intensity in spring and winter. For drought events lasting for a longer time, reservoirs interrupted their continuity, which reduced the average severity and duration but exaggerated peak intensity, especially for extreme events. The impacts of different reservoirs on drought variations showed distinct differences due to different operation regulations. Cascade reservoir regulation weakened and altered the relationships between hydrological drought and climate indices, including PDO, AMO, NAO, and ENSO, at the 8–16 and 32–64 month timescales. This finding indicates that the effects of large-reservoir regulation should be removed using naturalized streamflow when identifying teleconnection drivers of hydrological drought and conducting drought early warning. These findings provide new insights into the mechanisms governing hydrological drought under the combined influences of climate change and reservoir regulation and offer a scientific basis for drought early warning, reservoir operation, and integrated water resources management. Full article

Background: Drought tolerance in wheat is a complex trait controlled by multiple regulatory networks, among which calcium-dependent protein kinases (CDPKs) act as important components linking stress perception with downstream cellular responses. However, the functional contribution of individual CDPK members to drought adaptation in wheat remains largely unclear. This study aimed to identify and functionally characterize drought-responsive CDPK genes associated with differential drought responses in wheat. Methods: Two wheat lines derived from the same breeding background exhibiting contrasting drought adaption, 23B1 and 23B39, were subjected to PEG6000-induced osmotic stress. Growth traits, osmotic adjustment-related metabolites, membrane damage indicators, and antioxidant enzyme activity were evaluated. Transcriptomic analysis was performed at early drought-response stages, followed by differential expression analysis, functional enrichment, CDPK family screening, and qRT-PCR validation. The role of TaCDPK22-5A was further investigated using barley stripe mosaic virus (BSMV)-mediated virus-induced gene silencing (VIGS). Results: The drought-responsive line 23B1 maintained stronger growth, accumulated higher levels of proline and soluble sugars, exhibited enhanced peroxidase activity, and showed reduced membrane lipid peroxidation compared with 23B39. Transcriptome analysis revealed extensive transcriptional reprogramming under drought stress, with differentially expressed genes mainly associated with metabolic adjustment, transport regulation, secondary metabolism, and stress-responsive pathways. Among the identified CDPK members, TaCDPK22-5A showed a strong drought-responsive expression pattern in the line exhibiting stronger drought tolerance (23B1). Virus-induced gene silencing of TaCDPK22-5A significantly impaired drought tolerance, resulting in reduced growth, biomass accumulation, and chlorophyll retention under drought conditions. Conclusions: These findings demonstrate that TaCDPK22-5A contributes positively to drought adaptation in wheat and highlight CDPK-mediated calcium signaling as an important regulatory component of drought responses. The identified gene provides a potential target for improving drought resilience in wheat breeding. Full article

Quantifying groundwater storage in karst aquifers remains challenging because of their heterogeneous structure and the scarcity of direct observations. This study proposes a pragmatic approach for characterizing storage and water availability in karst systems at the regional scale using long-term hydrographs from 16 Swiss karst springs and rivers. We distinguish between seasonal storage, associated with recharge events, and low-water storage, which sustains discharge during periods without significant recharge. Seasonal storage was estimated at approximately 30–70 mm for most investigated systems, while total storage reached up to about 140 to 180 mm at some sites, based on recharge–discharge modelling. Low-water storage was estimated to be on the order of 200 mm across most investigated systems, despite differences in hydrogeological settings. Analysis of low-water recession curves showed that most natural springs analyzed in this study followed a similar master recession curve, with low-water conditions defined as beginning at a specific transition discharge of 11.25 L s⁻¹ km⁻². This similarity provides the basis for a regional drought index that estimates the volume of remaining groundwater storage and forecasts discharge several weeks in advance. The results also support a conceptual model in which epikarstic, epiphreatic, and deeper storage compartments attenuate short-term discharge variability while sustaining low-water discharge over prolonged periods. Comparison with non-karst catchments shows that karst hydrogeological systems dampen peak flows but sustain baseflow through distinct storage reservoirs. This approach delivers quantitative indicators to assess drought, manage groundwater, and foresee water shortages in karst regions. Future work will test its validity outside the Swiss dataset. Despite discussed uncertainties in discharge measurements and catchment delineation, results demonstrate that dedicated hydrograph-based analyses can yield robust and transferable insights into karst groundwater storage at regional scales. Full article

Sustainable soil health management is a major challenge for modern agriculture, particularly under increasing water constraints and progressive soil degradation, prompting the evaluation of innovative soil conditioners such as water-soluble polymers. This study assessed the effects of the anionic copolymer SNF FLOBOND™ DI 2010 (FDI2010) on soil physical structure and microbial properties through three complementary experiments, including one lysimeter trial and two controlled microcosm incubations using contrasting agricultural soils under different moisture regimes. The results consistently showed a significant improvement in soil aggregate stability following polymer application, while effects on water retention were variable and dependent on soil type and moisture conditions, with clearer improvements observed under drought conditions and in lysimeter setups. Microbial responses were largely indirect, with increased respiration and enzymatic activities but no significant change in total microbial biomass. Under water-limited conditions, FDI2010 contributed to sustaining microbial activity, particularly for carbon and nitrogen mineralization. Overall, these findings indicate that FDI2010 primarily enhances soil structural stability and indirectly supports microbial functioning, highlighting its potential as a soil conditioner to improve soil resilience to hydric stress, although further field validation remains necessary. Full article

Over the past decades, green alder (Alnus alnobetula) has spread rapidly across the Alps, expanding from moist, north-facing slopes into areas with limited water availability. Despite its growing ecological relevance in alpine environments, the species’ physiological limits under drought are largely unknown. To evaluate the species’ drought tolerance, we conducted a greenhouse experiment in which juvenile plants were subjected to drought periods of different durations, while monitoring stomatal conductance (gs) and quantum yields of photosystem II. Once the soil water potential fell below the wilting point (Θ_WP), gs declined to less than 25% of the control level. After re-irrigation, gs remained reduced for several weeks, indicating a post-drought legacy effect. Under prolonged drought, the maximum quantum yield of photosystem II (Fv/Fm) declined to 20% of control values. The correlation between effective quantum yield and radiation proved a useful indicator for moderate drought stress. During recurrent drought, plants showed an acclimation to dry conditions, and both gs and Fv/Fm declined significantly (p < 0.01) at moderate drought, indicating a short-term, drought-induced adjustment in stomatal regulation. Although green alder showed signs of acclimation under repeated drought, recurrent severe drought led to high mortality in juvenile plants, indicating vulnerability at drought-prone sites. Full article

Long-term crop rotation can improve soil function and crop performance, but it remains unclear whether rotation history can simultaneously alleviate drought-induced oxidative injury in spring wheat leaves and roots. To address this gap, we used a long-term field rotation experiment established in 2016 in the western foothills of the Greater Khingan Mountains. Four cropping systems were selected: spring wheat–potato rotation (R1), spring wheat–potato–rape rotation (R2), spring wheat–rape rotation (R3), and continuous spring wheat cropping (C1). In 2022, wheat occurred naturally in all rotation sequences, and all plots were planted with the same spring wheat cultivar (‘Longmai 36’) to enable comparison among different rotation histories. Drought stress was imposed from late jointing, and at anthesis, ROS-related levels, malondialdehyde (MDA), glutathione (GSH), and proline (Pro), as well as the activities of superoxide dismutase (SOD) and peroxidase (POD), were determined in the flag leaves and roots of spring wheat under normal-water (NC) and drought-stress (HC) conditions. Under drought stress, rotation significantly increased yield (R1 and R2 by 73.3% and 77.7% vs. C1, respectively, partly reflecting the low C1 baseline associated with continuous cropping) and reduced drought-induced accumulation of ROS-related levels and MDA, along with excessive antioxidant and osmotic responses. R1 better protected leaves, while R2 optimized root osmotic regulation. Two-way ANOVA revealed significant drought × rotation interactions for most leaf traits (p < 0.01) but not for root ROS-related levels, SOD, or POD, indicating organ-specific regulation. R1 and R2 show strong drought resilience potential, warranting multi-year, multi-site validation. Full article

Meteorological, soil, and hydrological droughts are among the most important phenomena affecting the natural environment and water management. Prolonged precipitation deficits often result in low river flows, reducing water resources and degrading aquatic ecosystems. This study evaluates the potential of meteorological drought indices as predictors of observed low flows. Long-term meteorological and hydrological data, including precipitation and river discharge records, were analyzed for the Biała Lądecka River catchment in Lower Silesia, southwestern Poland. Meteorological drought was characterized using the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) calculated for 1-, 3-, and 6-month timescales, together with corresponding one- and two-week indices. Relationships between drought index values and observed low flows were analyzed while accounting for the time lag of the catchment response. The predictive performance of individual indices was evaluated to determine their suitability for water resource monitoring and management. The results show that meteorological drought indices can effectively indicate the occurrence of low flows, although the strength of the relationships depends on the adopted timescale. Both classical and short-term indices proved useful for analyzing the development of hydrological drought and have potential applications in low-flow monitoring and early warning systems. Full article

Peatlands, critical global carbon sinks, are facing increasing threats from climate change-driven heatwaves and droughts. These threats can cause a midday depression in carbon uptake through photosynthetic inhibition. Using high-temporal-resolution solar-induced chlorophyll fluorescence (SIF; ~30 s) and chamber-based CO₂ flux measurements, we investigated the coupling between SIF and gross primary production (GPP) during extreme events (air temperature > 25 °C and vapour pressure deficit > 15 hPa) in a northern peatland. Our results show that SIF tracks GPP closely under non-stress conditions (daily R² = 0.86–0.96). However, during combined heat and drought stress, midday correlations collapsed (Case A: R² = 0.04 on 27 June; Case B: R² = 0.15 and 0.01 on 29 and 30 June, respectively), indicating severe decoupling. Importantly, we discovered legacy effects from multi-day heat exposure: on 26 June, vegetation with prior cumulative stress (Case A) showed weak morning coupling (R² = 0.07), while vegetation without prior stress history (Case B) maintained strong coupling (R² = 0.93). This suggests that cumulative stress alters baseline physiology and can exacerbate midday mismatches; therefore, not just current condition controls photosynthetic regulation. These findings highlight limitations of SIF-based GPP estimation at sub-daily timescales during stress, particularly in heterogeneous peatland systems where canopy composition and physiological responses could vary among plant functional types. Full article

Extreme drought events have become increasingly frequent under ongoing climatic change, thereby constraining vegetation growth and altering ecosystem processes. Vegetation recovery time following drought plays a crucial role in ecosystem stability, and extensive studies have been conducted to quantify vegetation recovery. However, most studies estimate vegetation recovery time using a single vegetation index, which does not adequately reflect how vegetation responds to drought conditions, since different vegetation indicators reflect different facets of vegetation dynamics. In this study, multiple vegetation indicators, including Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), Leaf Area Index (LAI), Gross Primary Productivity (GPP), and Solar-Induced Chlorophyll Fluorescence (SIF), were applied to investigate post-drought vegetation recovery in the Yangtze River Basin (YRB). The findings reveal that: (1) most vegetation recovered within four months after drought, with one-month recovery being the most prevalent, followed by four-month recovery; (2) the average recovery times derived from EVI, LAI, NDVI, GPP, and SIF were 2.23, 1.62, 2.45, 2.79, and 2.00 months respectively; (3) forests exhibited the fastest recovery rates, whereas shrublands recovered the slowest. This study assesses post-drought vegetation status via the recovery duration, offers theoretical basis for water resource allocation optimization, and provides important reference for coping with future ecological risks. Full article

Drought is a natural hazard characterized by gradual onset and prolonged precipitation deficit. With climate change intensifying precipitation variability, accurate drought assessment is critical for effective water resource management and mitigation. Focusing on Maryland in the Mid-Atlantic region of the United States, this study computes and analyzes drought indices to assess both near (2021–2060) and late (2061–2100) drought conditions, in the context of climate variability. We employed three distinct objectives to enhance drought assessment and monitoring capabilities under projected climate scenarios: (1) calculation of the Standardized Precipitation Index (SPI) reflecting meteorological conditions using precipitation data from seven GCMs across three SSPs for two future periods (2021–2060 and 2061–2100); (2) integration of both precipitation and temperature projections in the Palmer Drought Severity Index (PDSI) (implemented here as a simplified PDSI based on a standardized Z-index) to reflect combined hydrological and thermal influences (i.e., Hydrological indices); and (3) a Low Precipitation Duration–Frequency Analysis (LPDF) as indicator of both meteorological and hydrological conditions to quantify and compare the frequency and severity of low precipitation events across different SSPs. These objectives were achieved by fitting a gamma distribution for SPI and an Extreme Value Type I distribution for LPDF, and applying Z-index (i.e., long-term moisture abnormalities) and weighting factors representing the ratio of precipitation to evapotranspiration. Results reveal notable variability in SPI values, with a general trend toward increased extreme wet conditions, especially under high emission scenarios (i.e., SSP585) in the latter half of the century (2061–2100). Meanwhile, PDSI analysis indicated a subtle shift toward drier conditions despite increases in precipitation, particularly under SSP126 and SSP245, suggesting that temperature rises may offset precipitation gains. In addition, LPDF values indicated a reduced frequency of prolonged low-precipitation events under SSP585 compared to SSP126 and SSP245; this reflects higher total precipitation and should not be interpreted as resilience to drought, since the concurrent rise in temperature-driven evaporative demand can still intensify hydrological and agricultural drought stress. These results highlight the importance of incorporating climatic variables in drought assessments to understand future meteorological and hydrological scenarios under climate change projections. The study can help water resource managers and illustrates how such integrations can enhance our understanding of future drought scenarios under different climate change projections. Full article

Although drought is recognized as one of the major hydroclimatic hazards affecting the Mediterranean Basin, local-scale assessments to support planning for its agricultural, hydrological, and food security impacts remain limited. This study investigates historical and future drought dynamics in Manisa (Western Türkiye) using a multi-scale framework integrating the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) with CMIP6 climate projections. A comprehensive dataset including ERA5-Land, CHIRPS, TerraClimate, and station observations was evaluated, revealing strong agreement in temperature but higher uncertainty in precipitation. SPI results indicate recurrent short-term droughts with extreme events reaching −2.5 in 2007–2008, alongside intensified long-term hydrological droughts since the early 1990s, while SPEI reveals a stronger temperature-driven drought signal, peaking near −2.0 during 2020–2024 as the most severe cumulative drought period in the past 40 years. Rapid wet–dry transitions have increased since 2000, indicating a more unstable hydroclimatic regime. Future projections (2025–2100) under a high-emission scenario suggest a progressive intensification of thermally driven drought conditions, with SPEI trends declining more steeply than SPI, indicating that evapotranspiration-driven water deficits may increasingly outweigh precipitation deficits as a driver of future drought risk. These findings offer localized, data-driven evidence relevant to climate adaptation and water resource planning in semi-arid Mediterranean agricultural regions. Full article

Rice farmers in Chiang Rai are increasingly exposed to recurrent drought under climate change. Although previous studies have applied Knowledge–Attitude–Practice (KAP) frameworks to drought adaptation, evidence on ageing farming populations and the interaction between behavioral and institutional factors remains limited. This study aimed to identify behavioral and institutional factors associated with drought adaptation practices among rice-farming households. A cross-sectional study was conducted among 180 rice-farming households. Quantitative data were collected using a structured questionnaire validated through expert review (IOC) and pilot testing to assess socio-demographic characteristics and drought-related perception, knowledge, attitudes, and practices (KAP). Pearson correlation and binary logistic regression were applied to examine relationships and factors associated with higher drought adaptation practices. Qualitative data from open-ended questionnaire responses regarding government support and drought management recommendations were analyzed thematically to provide contextual insights into farmers’ experiences and adaptation challenges. Farmers demonstrated high drought perception (M = 4.86 ± 1.05/5) but only moderate knowledge (16.75 ± 3.36/25), attitudes (2.77 ± 1.33/5), and practices (22.57 ± 6.04/35). Knowledge was positively associated with adaptation practices (r = 0.224, p < 0.01), whereas perception showed no significant direct association, indicating a gap between awareness and adaptive action. Regression analysis showed that higher drought-related knowledge (aOR = 4.60, p = 0.003) and prior water scarcity experience (aOR = 4.45, p = 0.002) were significantly associated with higher drought adaptation practices. In contrast, older age, male gender, and off-farm employment were significant constraints. Qualitative findings highlighted persistent concerns regarding the adequacy, timeliness, and equity of government support, suggesting that institutional barriers limited farmers’ ability to translate awareness into adaptive action. These findings indicate that both behavioral and structural factors shape drought adaptation practices. While drought-related knowledge represents an important component of adaptive capacity, effective adaptation also depends on institutional support and resource accessibility. Strengthening agricultural extension services and improving the responsiveness and equity of government support may enhance the adaptive capacity and resilience of smallholder rice farmers in drought-prone regions. Full article

Melatonin (MT), a potent antioxidant, can mitigate abiotic stress. The objective of this study was to determine if foliar spraying of MT can alleviate the stress of Trichosanthes kirilowii seedlings under drought conditions. The results showed that drought stress significantly inhibited the growth of T. kirilowii seedlings, whereas exogenous MT alleviated this inhibition. Compared with the treatment with drought stress alone, the addition of MT significantly increased the stem length, net photosynthetic rate, chlorophyll content, maximum photochemical efficiency, and relative leaf water content of T. kirilowii seedlings after 20 days of drought stress. Under drought stress, the addition of MT significantly reduced the levels of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂), and reduced electrolyte leakage (EL) in the leaves of T. kirilowii seedlings. Compared with the control group, the antioxidant enzyme activity was significantly enhanced under drought stress, and the contents of soluble sugars (SSs) and proline (Pro) increased significantly. The antioxidant enzyme activity was strongest in the group treated with MT, and the SS and Pro contents were the highest in this group. The results indicate that the addition of MT can maintain the relative water content (RWC) of the leaves of T. kirilowii seedlings under drought stress, significantly enhance antioxidant capacity, reduce drought-induced damage, maintain the stability of the photosynthetic system, and promote the growth of T. kirilowii seedlings. Full article