Search Results (740)

Zambia continues to experience increasingly frequent and intense droughts, with the 2023/2024 season among the most severe in recent history. These events have threatened livelihoods, strained water and food systems, and placed immense pressure on already limited national and local resources. Given the limited knowledge in the literature on drought management in Zambia, this study investigated the state of localized district efforts across the country. By using mixed methods with a total of 161 interviews, it assessed the participation of district governments and sector players across key components of drought governance, including early warning, monitoring, vulnerability and impact assessment, mitigation, and response. Although Zambia has made notable progress in establishing national institutional frameworks and climate policies, key findings reveal a pattern of limited proactive engagement, with most participation occurring only in response to extreme events like the 2023/2024 drought. This reactive posture at the district level is further compounded by inadequate resources, limited coordination, a lack of localized drought planning, and systemic bureaucratic constraints that undermine a timely and effective response. Nonetheless, numerous opportunities exist to strengthen drought management by localizing decision-making, integrating indigenous knowledge into existing early warning systems, and leveraging community-based infrastructures to maximize scarce resources and build long-term resilience. The paper concludes with recommendations for enhancing Zambia’s drought preparedness and response capacity through inclusive, risk-based, and proactive strategies; insights that can be adapted to other developing country contexts. Full article

Almonds are an essential crop for the economy of California. However, mold and mycotoxin contamination of this commodity has a serious impact on food safety and international trade. The contamination levels of molds and the aflatoxigenic potential of Aspergillus section Flavi isolates were studied on almonds collected at a processing plant in California. The mean total fungal count for 80 samples was 1.0 × 10⁴ CFU/g, while 62 samples (77.5%) had a total mold count less than 1.0 × 10⁴ CFU/g. The most common fungal contaminants were Aspergillus section Nigri (100% of samples), followed by Penicillium (57.5%) and Cladosporium (52.5%) species. Rhizopus, Fusarium and Alternaria spp. were less frequent. A total of 26 A. section Flavi strains were identified, with most strains (23) belonging to the L morphotype of A. flavus. In addition, two S morphotypes of A. flavus, and one A. tamarii strain were observed. Other Aspergillus species, including A. terreus and A. ochraceus were rare. High Performance Liquid Chromatography (HPLC) analysis revealed that 9 out of 13 isolated A. flavus strains produced aflatoxin B₁ (AFB₁) on yeast extract sucrose media. The highest levels of AFB₁ were produced by two A. flavus isolates belonging to the S morphotype (78 and 260 µg/kg). Increasing temperatures and drought conditions may change the population dynamics of toxigenic mold strains on almonds, emphasizing the need to continue monitoring these fungal populations. Full article

Plants continuously adapt to dynamic environmental conditions, which include abiotic stress such as drought, salinity, and high temperature. Translocation, availability, and uptake of essential nutrients are suggested to be disrupted, thereby impairing growth, development, and productivity of the plant. The interplay between the root architecture, membrane transporters, and hormonal regulation is suggested to have efficient nutrient acquisition. For mediating nutrient uptake and redistribution under abiotic stress conditions, transporter proteins such as nitrate (NRT), ammonium (AMT), phosphate (PHT), and potassium (HAK) families play a crucial role for the major essential elements (N, P, K). Abiotic stress triggers specific transcriptional and post-transcriptional regulation of these transporters, modulating their activity in response to external nutrient availability. Under nutrient-deficient conditions, phytohormones such as abscisic acid (ABA), cytokinin, and ethylene play a pivotal role in orchestrating plant responses. Moreover, the plant stress tolerance is suggested to be influenced by stress-induced signalling mechanisms, which are mediated by reactive oxygen species (ROS). The current review synthesizes current knowledge of nutrient dynamics under abiotic stress, focusing on the molecular mechanisms governing transporter regulation and phytohormonal crosstalk. By unravelling these complex regulatory networks, this article aims to pave the way for sustainable agricultural practices. Full article

Continuous urban land development is causing environmental changes. The most visible effects are a decline in biodiversity, an increase in urban temperatures, and changes in the water balance. Recently, very intense and sudden rainfall events have been observed, and existing drainage systems are not effective enough. Urban surfaces tend to be impermeable with low retention, so there is no way to respond to both the rainy periods and the drought periods that often follow. A good remedy for these factors is urban greening, which can be achieved through the design of green roofs and living walls. The substrate used for this type of construction should be light, permeable, and retentive. This study aimed to produce artificial aggregate granules with various additives that modify the structure to create open mesopores and facilitate better rainwater management. Through suitable sintering, materials with water absorption of more than 40%, retention in simulated rainfall of over 35% and a bulk density of ~0.70 g/cm³ were obtained. Detailed microstructural analyses were carried out using various microscopic techniques. Strength tests and simple vegetation tests were also carried out. Full article

Under global warming, the frequency and intensity of extreme climate events have markedly increased. As one of the most climate-sensitive and ecologically fragile regions in the world, the Tibetan Plateau faces mounting environmental and demographic challenges. This study integrates multi-model ensemble simulations from the Coupled Model Intercomparison Project Phase 6 (CMIP6) with population projection data from the Shared Socioeconomic Pathways (SSPs) under the high-emission scenario (SSP5-8.5). Three extreme climate indices—very wet days precipitation (R95p), warm days (TX90p), and consecutive dry days (CDDs)—were analyzed to assess future changes in climate extremes (2021–2100) and their relationships with demographic dynamics across Tibetan ethnic areas. The results indicate that, under high-emission conditions, both R95p and TX90p increase significantly, while CDDs slightly decreases, though drought risks remain pronounced in central regions. Over the same period, the total population is projected to decline by nearly 60%, with substantial differences in climate risk exposure across groups: working-age adults and less-educated individuals experience the highest exposure before mid-century, followed by a decline, whereas the elderly and highly educated populations will show continuously increasing exposure, stabilizing by the end of the century. The transformation of population patterns is reshaping socio-cultural structures, highlighting the need for culturally adaptive governance to ensure the sustainability of Tibetan ethnic communities. These findings enhance our understanding of the coupled interactions among climate change, population dynamics, and cultural transitions, providing a scientific basis for integrated adaptation strategies to promote sustainable development across the Tibetan Plateau. Full article

In semi-arid regions of Morocco, where the majority of water withdrawals are devoted to irrigation, optimizing irrigation practices in agriculture is a national priority in the face of recurring droughts and growing pressure on groundwater resources. However, the hydrological impacts of different drip-irrigation systems in the soil–plant–atmosphere continuum remain insufficiently understood. We monitored the stable isotope composition (δ²H, δ¹⁸O) across the two agricultural plots in Marrakech (Morocco) with surface drip and subsurface drip irrigation treatments for a complete hydrologic year (June 2022 to June 2023). Weekly to daily samples of rainfall, irrigation water, groundwater, and soil at various depths (5–50 cm) were sampled, and water from branch xylem was extracted using the cryogenic vacuum distillation method. We found that the subsurface irrigation treatment, which delivered water directly to the root zone, maintained narrow isotopic ranges in water of soils beyond 30 cm, as well as in branch xylem and leaf water. By contrast, surface irrigation treatment plots showed pronounced evaporative isotopic enrichment: summer topsoil water δ¹⁸O peaked at −1.1‰ (vs. −8.7‰ in subsurface irrigation treatment), and leaf water reached +13‰ (vs. +8‰ in subsurface). Despite this larger isotopic heterogeneity in surface irrigation site, branch xylem water δ¹⁸O remained within −6 to 2.5‰ across all soil depth, similar to subsurface irrigation treatment, which ranged between −5 and 0‰. This suggests that olive roots accessed soil water uniformly from the upper 50 cm under both irrigation treatments. Seasonal xylem isotopic enrichment in spring and midsummer mirrored shifts towards shallow, evaporatively altered soil water under surface irrigation, but not under the subsurface. The results suggest that subsurface drip irrigation can significantly improve drought resilience and water-use efficiency in the expanding olive sector of the Maghreb, while continuous isotope monitoring serves as a practical approach to enhance sustainable and adaptive water management in water-limited regions. Full article

Soil surfactants are essential tools for enhancing irrigation water efficiency and improving the quality and functionality of amenity turfgrass. They play a crucial role in sports turf management by reducing soil water repellency, which helps prevent dry spots, ensures even moisture distribution, and supports water conservation efforts. Most research on soil surfactants and amenity turfgrasses focuses on their effects on soil moisture, infiltration, and addressing localized dry spots during drought conditions, with limited studies on their impact under wet or saturated conditions. This study aimed to evaluate the impact of soil surfactants on the quality and health of turfgrass under wet conditions. Field studies were conducted over a span of five years, beginning in the USA in 2019 and continuing in Ireland from 2020 to 2023. The research in Ireland was conducted at three locations, each featuring different rootzones: a “push-up” green with loam soil, USGA-specification sand, and natural link sand. The site in the USA was a native loam soil. The study compared a commercial soil surfactant (ProWet Evolve; PWE) and a non-treated control (NT) in a randomized complete block design with four replications, with sequential applications starting in June and continuing until mid-September each year. The rootzone volumetric water content (VWC%), turfgrass quality, and normalized difference vegetation index (NDVI) were measured bi-weekly. Environmental conditions, with above-average precipitation each year, significantly influenced results. Although there were no significant or consistent differences in VWC% between the soil surfactant and NT-treated plots, turfgrass quality was significantly enhanced in the soil surfactant-treated plots and supported by higher NDVI values. Even in prolonged wet conditions with high VWC%, improved turfgrass quality was consistently observed in soil surfactant-treated plots across multiple locations in both countries over the five-year study period. Full article

The Amazon hosts one of the richest diversities of mosquitoes in the family Culicidae, which are key both as arbovirus vectors and as environmental bioindicators. However, the state of Amapá remains poorly studied regarding its mosquito fauna. This study aimed to characterize the diversity and seasonal composition of Culicidae in the municipality of Mazagão, Eastern Amazon, within a rural landscape influenced by human activity and extreme climatic events. Three sampling campaigns were conducted between 2023 and 2024, covering rainy, intermediary, and dry periods. Mosquitoes were collected using Protected Human Attraction (PHA) and CDC light traps at both ground and canopy strata. A total of 3500 specimens were obtained, representing 38 species across 15 genera. The intermediary period yielded the highest abundance and richness, whereas the dry season presented very low diversity, probably because of severe drought and forest fires. Dominant species included Coquillettidia (Rhy.) venezuelensis, Cq. albicosta, and Mansonia titillans. There were significant differences in community diversity between dry and wetter periods, underscoring the strong role of seasonality in shaping mosquito populations. These findings represent the entomofaunistic survey of the region, contributing to biodiversity knowledge and highlighting potential public health risks, thus reinforcing the need for continuous entomological monitoring. Full article

Soil respiration (Rs), the second largest carbon flux in terrestrial ecosystems, critically regulates the turnover of soil carbon pools. However, its seasonal and annual responses to extreme events in monsoon forests remain unclear. This study used a continuous multichannel automated chamber system to monitor Rs over three years of drought (2019–2021) in an Asian monsoon forest in Taiwan. We assessed seasonal and annual Rs patterns and examined how drought influenced autotrophic (Rr) and heterotrophic (Rh) respiration through changes in soil temperature and moisture. Results showed Rs declined from 5.20 ± 2.08 to 3.86 ± 1.20 μmol CO₂ m⁻² s⁻¹, and Rh from 3.36 ± 1.21 to 3.15 ± 0.98 μmol CO₂ m⁻² s⁻¹ over the study period. Spring Rr values dropped significantly—by 29.3% in 2020 and 62.2% in 2021 compared to 2019 (p < 0.05), while Rh remained unchanged (p > 0.05). These results suggest that spring drought strongly suppresses autotrophic respiration but has minimal effect on Rh. Incorporating these dynamics into carbon models could improve predictions of carbon cycling under climate change. Our findings demonstrate that spring drought exerts a strong influence on soil carbon fluxes in Asian monsoon forests. Full article

The quantitative assessment of acoustic rain enhancement technology is highly significant for improving the ecological environment. A scientific and accurate evaluation of its operational effects provides an important basis for continued government and public support and investment in artificial weather modification activities. To effectively analyze the effects of acoustic rain enhancement on the vegetation of grassland ecosystems in arid and semi-arid areas and to clarify its mechanism, this study constructed eight vegetation indices based on Sentinel-2 satellite data. A comprehensive assessment of the changes in vegetation within the grassland ecosystem of the experimental zone was conducted by analyzing spatiotemporal distribution patterns, double-ratio analysis, and difference value comparisons. The results showed that (1) following the acoustic rain enhancement experiment, vegetation growth improved significantly. The mean values of all eight vegetation indices increased more substantially than before the experiment, with kNDVI showing the most notable gain. The proportion of the zone with kNDVI values greater than 0.417 increased from 52.62% to 71.59%, representing a relative increase of 36.05%. (2) The rain enhancement experiment significantly raised the values of eight vegetation indices: kNDVI increased by 0.042 (18.68%), ARVI by 0.043 (18.67%), and the remaining indices also increased to varying degrees (9.51–12.34%). (3) Vegetation improvement was more pronounced in areas closer to the acoustic rain enhancement site. Under consistent climate conditions, vegetation growth in the experimental zone showed significant enhancement. This study demonstrates that acoustic rain enhancement technology can mitigate drought and low rainfall, improve grassland ecosystem services, and provide a valuable foundation for ecological restoration and aerial water resource utilization in arid and semi-arid regions. Full article

Drought-induced forest mortality threatens biodiversity globally, particularly in arid, and semi-arid woodlands. The continual development of remote sensing approaches enables enhanced monitoring of forest health. Herein, we investigate the ability of a limited ground-truthed canopy dieback dataset and satellite image derived Normalised Difference Vegetation Index (NDVI) to make inferences about forest health as temporal and spatial extent from its collection increases. We used ground-truthed observations of relative canopy mortality from the Pinus edulis-Juniperus osteosperma woodlands of southeastern Utah, United States of America, collected after the 2017–2018 drought, and PlanetScope satellite imagery. Through assessing different modelling approaches, we found that NDVI is significantly associated with sitewide mean canopy dieback, with beta regression being the most optimal modelling framework due to the bounded nature of the variable relative canopy dieback. Model performance was further improved by incorporating the proportion of J. osteosperma as an interaction term, matching the reports of species-specific differential dieback. A time-series analysis revealed that NDVI retained its predictive power for our whole testing period; four years after the initial ground-truthing, thus enabling retrospective inference of defoliation and regreening. A spatial random forest model trained on our ground-truthed observations accurately predicted dieback across the broader landscape. These findings demonstrate that modest field campaigns combined with high-resolution satellite data can generate reliable, scalable insights into forest health, offering a cost-effective method for monitoring drought-impacted ecosystems under climate change. Full article

Using Landsat series imagery and the deep learning model CITNet, this study conducted high-accuracy classification and spatiotemporal change analysis of wetlands on Chongming Island from 2000–2020 and explored the driving mechanisms by integrating climatic and anthropogenic factors. The results demonstrate that the total wetland area decreased by approximately 125.5 km² over the two decades. Among natural wetlands, tidal mudflats and shallow seawater zones continuously shrank, while herbaceous marshes exhibited a “decline recovery” trajectory. Artificial wetlands expanded before 2005 but contracted significantly thereafter, mainly due to aquaculture pond reduction. Wetland transformation was dominated by wetland-to-non-wetland conversions, peaking during 2005–2010. Driving factor analysis revealed a “human pressure dominated, climate modulated” pattern: nighttime light index (NTL) and GDP demonstrated strong negative correlations with wetland extent, while minimum temperature and the Palmer Drought Severity Index (PDSI) promoted herbaceous marsh expansion and accelerated artificial wetland contraction, respectively. The findings indicate that wetland changes on Chongming Island result from the combined effects of policy, economic growth, and ecological processes. Sustainable management should focus on restricting urban expansion in ecologically sensitive zones, optimizing water resource allocation under drought conditions, and incorporating climate adaptation and invasive species control into restoration programs to maintain both the extent and ecological quality of wetlands. Full article

Despite the progress to understand drought tolerance worldwide, the response of urban trees to the increased frequency and severity of droughts, particularly in tropical regions, remains unclear. Such an evaluation is essential for predicting future urban forest dynamics. The leaf turgor loss point (π_TLP), leaf safety margins (SMs) and their relationship with functional traits were measured in ten native tree species during wet and dry seasons in a tropical urban environment. We detected interspecific variation in tree responses related to desiccation tolerance and desiccation avoidance as strategies to resist drought. Desiccation avoidance was linked to lower adjustment of midday water potentials and water-conservative traits such as high wood density, low specific leaf area (SLA), and high leaf dry matter content, while species with more negative π_TLP maintained stomatal conductance and growth despite decreasing leaf water potentials. Although the differences between predawn and midday potentials during the dry season suggest that severe drought does not occur, some species showed negative safety margins. This indicates that while some urban trees can tolerate or avoid current dry periods, continued climate change may push certain species beyond their safe operating range, making species selection for urban planning increasingly critical. Full article

Extreme drought events may become more frequent with climate change. Understanding the impact of extreme drought on grassland ecosystems is therefore crucial for the long-term sustainability of ecosystems. Here, we identified extreme drought events in the Inner Mongolia grasslands of China using long-term standardized precipitation evapotranspiration index (SPEI) data and evaluated drought resistance of the vegetation under extreme drought based on net primary production (NPP). The impact of consecutive extreme drought events and multiple discontinuous one-year extreme drought events on grasslands were further analyzed to investigate the response strategies of different grassland types to different drought conditions. We found that the frequency and area of extreme drought in 2000–2011 were significantly higher than those in 2012–2020, and the Xilingol League region showed the highest frequency of extreme drought events. Under extreme drought, vegetation resistance was positively correlated, where annual precipitation > 300 mm. The mean resistance of different grassland types followed the order: upland meadow (UM) > lowland meadow (LM) > temperate meadow steppe (TMS) > temperate desert (TD) > temperate steppe (TS) > temperate steppe desert (TSD) > temperate desert steppe (TDS). In the analysis of two cases of consecutive two-year extreme drought, all grassland types except TSD and TD showed obvious decreased resistance in the final drought year, with the highest reduction (0.16) in LM during 2010–2011, implying the widespread and significant inhibition of grassland growth by continuous drought. However, under the multiple discontinuous extreme drought events, the resistance of all grassland types showed a fluctuating but an overall increasing trend, suggesting the adaptability of grassland to drought. The results emphasize that management departments should pay more attention to regions with low resistance and enhance the stability of grassland production by increasing the proportion of drought-resistant plants in reaction to future extreme drought scenarios. Full article

The present work focuses on seven megaliths sampled for the first time as a continuation of our studies on the biodiversity of algae on megaliths in Bulgaria. A total of 55 species from four divisions were identified (Chlorophyta was the richest with 31 species), of which 14 species are new for Bulgaria. Two species were of conservation concern, but six were potential toxin producers that could affect the health of visitors to the megaliths. Despite the general granitic character and relatively close location of the studied sites, their floristic similarity was low, with most algae (51 species) being rarely distributed (except Stichococcus bacillaris and Mychonastes homosphaera). The largest cult complex Paleokastro, furthest from populated areas, had the highest species diversity (22 species), while the lowest (8 species) was found in the highly exposed Kalinkin Kamuk, located in a village. The NMDS analysis tool showed the existence of four distinct ecological groups and that temperature and light are the most important drivers for the distribution of the epilithic algae on the investigated megaliths. Correlations with temperatures estimated to identify potential indicators or future survivors under global warming conditions were low, except for the Streptophyta. It was represented by four species of the genus Klebsormidium, which is known for its high ecological tolerance and drought resistance. Extending the studies on lithophytic algae to megaliths is important for a better knowledge of their biodiversity and ecology, but also for the protection of megaliths and for understanding the impact of climate change on these fragile monuments. Full article