Search Results (132)

Vegetation is a key component of bioretention systems, significantly influencing their functionality and overall performance. The sustainability of these systems largely depends on the plant species’ ability to withstand the primary hydrological stresses induced by the infrastructure’s design, in combination with local climatic conditions. This study focuses on plant selection for bioretention applications in Sub-Mediterranean and Mediterranean regions of Italy, which are increasingly affected by extreme weather events, including intense rainfall, heat waves, and prolonged droughts. A review of scientific literature and stormwater management manuals developed for Mediterranean climates was conducted to evaluate both non-native species and Italian native species already used in international applications. The findings reveal a limited range of drought-tolerant non-native species in scientific literature, whereas such species are more prominently featured in California-based manuals. Moreover, among the relatively few native species identified, only a small number are truly suited to fully Mediterranean conditions, based on evaluations of Ellenberg index values. These results highlight a significant research gap, emphasizing the need for further studies, particularly focused on the target ecosystems of native flora in central and southern Italian regions. Full article

Mediterranean-type ecosystems (METs) occur on five continents and represent some of the most climatically constrained yet biologically rich regions on Earth. In these environments, legumes and their nitrogen-fixing rhizobial symbionts—including widely distributed genera such as Rhizobium, Bradyrhizobium, and Ensifer—play a pivotal role in sustaining plant productivity, nutrient cycling, and ecosystem resilience. This review synthesizes current knowledge on the environmental regulation of legume–Rhizobium symbiosis specifically within Mediterranean-type ecosystems, focusing on how nitrogen (N) and phosphorus (P) availability, light conditions, and carbon allocation trade-offs shape symbiotic performance across the five Mediterranean-type regions of the world (California, central Chile, the Cape Region of South Africa, southwestern Australia, and the Mediterranean Basin). By integrating physiological, ecological, and biogeochemical perspectives, we highlight how the shared features of these regions—strong seasonal drought, chronic nutrient limitation (particularly P in southwestern Australia and the Cape Region), recurrent fires, and exceptionally high plant diversity—constrain and, at the same time, favor the ecological success of symbiotic legumes. Throughout the review, we use case studies from key legume genera such as Lupinus in Chile and southwestern Australia, Virgilia and other Cape legumes in South Africa, Acacia in Australian kwongan and woodlands, and Medicago and Cytisus in the Mediterranean Basin and California to illustrate how general principles of legume–Rhizobium ecology manifest under Mediterranean-type climatic and edaphic constraints. Beyond summarizing established mechanisms, we critically examine the limitations of current metagenomic approaches, which often provide descriptive inventories of soil microbial communities without linking microbial composition to functional outcomes. We argue that advancing the field requires integrated, hypothesis-driven research that combines multi-omic tools with plant eco-physiology, soil nutrient dynamics, and temporal replication. Finally, we outline key priorities for future research, including the integration of functional ‘omics’, the study of microbiome interactions beyond rhizobia, the development of predictive models for Mediterranean-type ecosystems under climate change, and the application of symbiotic principles to restoration and agroecological management. By bridging molecular, physiological, and ecosystem perspectives, this review provides a conceptual framework for understanding and enhancing legume–Rhizobium symbiosis across five continents in a rapidly changing world. Full article

The first global goal of the 2030 Sustainable Development Agenda (SDG 1) calls for addressing poverty as a condition produced through social vulnerability and environmental risk. This paper examines the relationship between vulnerability and poverty during concurrent drought and pandemic hazards in 2021 in the American Southwest, a context less studied in sustainability research. Drawing on disaster scholarship, we conceptualize the risk of poverty as the interaction of hazard exposure and social vulnerability. We construct a county-level dataset integrating environmental, epidemiological, and social indicators across Arizona, California, Colorado, Nevada, New Mexico, and Utah, identifying income inequality and residential segregation as key dimensions of vulnerability. Using child poverty as a measurement lens, we apply spatial mapping alongside Relative and Attributable Risk metrics to assess how drought intensity, pandemic burden, and structural vulnerability contributed to spatially uneven poverty outcomes under dual hazards. Results indicate that drought had a stronger effect than COVID-19, yet pre-existing vulnerabilities were more consequential, with income inequality outweighing segregation, suggesting that hazards are most damaging where social inequalities limit resilience. Interpreting the results through the Capability Approach, we posit that sustainable poverty reduction requires not just income support and hazard mitigation, but expansion of instrumental economic, social, and political freedoms that enhance individuals’ capabilities to navigate risk and pursue long-term well-being. Full article

Freshwater availability is one of the most pressing environmental concerns in arid ecosystems. The use of free-standing water by raptors has been little studied, and in the context of climate change has become increasingly important as extended droughts are expected to become more frequent. We analyzed digital images from camera traps captured in the freshwater springs of Sierra El Mechudo, during summer to early autumn of 2023 and 2024 in Baja California Sur, Mexico. We recorded 165 detections of four raptor species. The Turkey Vulture (Cathartes aura) was the most frequently detected (n = 55), followed by the Great Horned Owl (Bubo virginianus) (n = 50), the Red-tailed Hawk (Buteo jamaicensis) (n = 45), and the Cooper’s Hawk (Astur cooperii), which was observed only in early autumn 2024 (n = 15). The Great Horned Owl exhibited a distinct detection pattern (mainly crepuscular, with the highest peak at 6 a.m.), in contrast with the other three species, which were detected mainly at midday and in the afternoon, during the hottest hours of the day. All raptors were recorded drinking water; however, species differed in the proportion of behaviors they exhibited at the freshwater springs. The Turkey Vulture showed the highest drinking activity (76.3%), whereas both hawks exhibited the same lowest proportions (26.6%) among all species detected. The proportion of behaviors remained constant across years. The time spent at the freshwater springs did not differ across species or years. The Red-tailed Hawk, the Great Horned Owl, and the Turkey Vulture increased their detections at the springs in 2024, when a severe and prolonged drought affected the southern peninsula. The results showed that the importance of freshwater springs for raptors extends beyond their use for drinking only; the surrounding habitat as a refuge and availability of prey in the area are evidently essential for these birds of prey. Further studies should extend research into the diverse use of springs and home ranges of raptors in the southern Baja California peninsula. Full article

In January 2025, multiple wildfires erupted across the Los Angeles region, fueled by prolonged dry conditions and intense Santa Ana winds. Southern California has faced increasingly frequent and severe wildfires in recent years, driven by prolonged drought, high temperatures, and the expanding wildland–urban interface. These fires have caused major loss of life, extensive property damage, mass evacuations, and severe air-quality decline in this densely populated, high-risk region. This study integrates passive and active satellite observations to characterize the spatiotemporal and vertical distribution of wildfire emissions and assesses their impact on air quality. TROPOMI (Sentinel-5P) and the recently launched TEMPO geostationary instrument provide hourly high temporal-resolution mapping of trace gases, including nitrogen dioxide (NO₂), carbon monoxide (CO), formaldehyde (HCHO), and aerosols. Vertical column densities of NO₂ and HCHO reached 40 and 25 Pmolec/cm², respectively, representing more than a 250% increase compared to background climatological levels in fire-affected zones. TEMPO’s unique high-frequency observations captured strong diurnal variability and secondary photochemical production, offering unprecedented insights into plume evolution on sub-daily scales. ATLID (EarthCARE) lidar profiling identified smoke layers concentrated between 1 and 3 km altitude, with optical properties characteristic of fresh biomass burning and depolarization ratios indicating mixed particle morphology. Vertical profiling capability was critical for distinguishing transported smoke from boundary-layer pollution and assessing radiative impacts. These findings highlight the value of combined passive–active satellite measurements in capturing wildfire plumes and the need for integrated monitoring as wildfire risk grows under climate change. Full article

Construction of new seawater reverse osmosis desalination (SWRO) plants in the state of California (USA) requires environmental permits containing rather strict conditions. The California Ocean Plan requires the use of subsurface intake systems (SSIs) unless they are deemed to be not feasible. The Governor of California requested that the State Water Resources Control Board (State Board) study the issue of accelerating the desalination plant permitting process and making it more efficient. The State Board formed an independent scientific Panel to study the issue of SSI feasibility and to submit a report. The Panel recommendations included the following: the feasibility assessment (FA) for SSIs should be streamlined for completion within a maximum of three years, and this requirement should be added to the Ocean Plan; applicants need to perform a financial feasibility study before pursuing SSI capacities exceeding 38,000 m³/d (10 MGD) for wells or 100,000 m³/d (25 MGD) for galleries because project financing may be denied for such larger capacity systems; the mitigation options for each site–SSI combination in the screening process should be addressed by both the project proponent and regulatory agencies as early as practicable in the overall permitting process; and the impacts of SSIs on local aquifers and associated wetland systems must be assessed during the analyses conducted during the FA and during post-construction monitoring. The Panel further concluded that the design and evaluation of SSI–site combinations are highly site-specific, involving technically complex issues, which require both the applicant and the reviewing state agencies to have the expertise to design and review the applications. Economic feasibility must consider cost to the consumer and the engineering risk that can preclude project financing. Projected capacities exceeding the above noted limits may not by financed due to risks of failure or could require government guarantees to lenders. The current permitting system in California is likely to preclude construction of large seawater desalination facilities that can provide another source of potable water for coastal communities in California during severe droughts. Without seawater desalination, the potable water supply in California would suffer a greater sustainability and resilience risk during future periods of extended drought. Full article

Sustaining irrigated agriculture under drought conditions with alternative water sources such as saline groundwater requires understanding their effects on salt-tolerant crops like pistachio. During recent California droughts, pistachio trees planted in 2002, 2009, and 2011 were irrigated with high-saline water containing traces of boron (B) and selenium (Se). In 2018, irrigation was divided so that half of the trees received low-saline water, while the others continued under high-saline irrigation. Three years later, nuts were harvested to evaluate how irrigation quality affected seed coats, the main storage site of phenolic antioxidants. Sixty seed coat extracts from both irrigation treatments were analyzed for antioxidant capacity (ABTS, DPPH, FRAP and Folin–Ciocalteu assays). Nuts from the oldest trees (planted in 2002) had the highest antioxidant capacity. High-performance liquid chromatography (HPLC) identified gallic acid and nine flavonoids. Catechin, procyanidin B1, cyanidin-3-O-galactoside, and eriodictyol were most abundant in the oldest trees. Irrigation salinity significantly affected gallic acid, quercetin, and isoquercetin, with higher concentrations detected in seed coats from trees receiving continued high-saline irrigation. These compound-specific shifts, together with strong age-dependent patterns, provide insight into how long-term salinity exposure influences phenolic composition in pistachio seed coats. Full article

Santa Ana winds are extreme meteorological events that strongly affect the U.S.–Mexico border region, often associated with droughts, high fire risk, and hydrological imbalance. Understanding the temporal behavior of key atmospheric variables during these events is crucial for integrated water resource management in semi-arid regions such as the Guadalupe Basin in northern Baja California. In this study, we explored the predictive capability of several hybrid deep learning architectures—Long Short-Term Memory (LSTM), Convolutional Neural Network combined with LSTM (CNN–LSTM), and Bidirectional LSTM with Attention (BiLSTM–Attention)—to model the temporal evolution of wind speed, wind direction, temperature, relative humidity, and atmospheric pressure using Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) reanalysis data from 1980 to 2020. Model performance was evaluated using RMSE, MAE, and R² metrics and compared against persistence and climatology baselines. The BiLSTM–Attention model achieved the best overall performance, showing particularly high accuracy for temperature (R² = 0.95) and relative humidity (R² = 0.76), while maintaining angular errors below 35° for wind direction. The results demonstrate the potential of hybrid deep learning models to capture nonlinear temporal dependencies in meteorological time series and provide a methodological framework to enhance hydrometeorological understanding and water resource management in the Guadalupe Basin under Santa Ana wind conditions. Full article

To mitigate the impact of north–south strip errors inherent in Gravity Recovery and Climate Experiment (GRACE) spherical harmonic coefficient solutions, this research develops a state-space model to generate a more robust solution. The efficacy of the state-space model is demonstrated by comparing its performance with that of conventional filtering methods and hydrological modeling schemes. The method is subsequently applied to estimate the GRACE Groundwater Drought Index in the California Central Valley basin, a region significantly affected by drought during the GRACE observation period. This analysis quantifies the severity of droughts and floods while investigating the direct influences of precipitation, runoff, evaporation, and anthropogenic activities. By incorporating the El Niño–Southern Oscillation (ENSO) and the Pacific Decadal Oscillation, the study offers a detailed causal analysis and proposes a novel methodology for water resource management and disaster early warning. The results indicate that a moderate-duration flood event in 2006 resulted in a recharge of 19.81 km³ of water resources in the California Central Valley basin, whereas prolonged droughts in 2008 and 2013, lasting over 15 months, led to groundwater depletion of 41.53 km³ and 91.45 km³, respectively. Precipitation and runoff are identified as the primary determinants of local drought and flood conditions. The occurrence of ENSO events correlates with sustained precipitation variations over the subsequent 2–3 months, resulting in corresponding changes in groundwater storage. 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

Drought stress is a critical abiotic constraint on agricultural productivity, particularly affecting crops like pepper (Capsicum annuum L.), which are highly susceptible to water deficits due to their physiological characteristics. The present study investigated the impact of a 40% reduction in irrigation on yield, macronutrient concentrations, and fruit quality across several pepper genotypes. The cultivars evaluated included two landraces, namely ‘JO109’ and ‘JO204’ (Capsicum annuum var. grossum), as well as the California cultivar ‘Yolo Wonder’ and the commercial F1 hybrid ‘Sammy RZ’, which served as controls. The experiment was conducted at the greenhouse facilities of the Laboratory of Vegetable Production, Agricultural University of Athens. Under reduced irrigation, most of the cultivars studied exhibited a decline in yield, which was attributed to a decrease in fruit number in ‘Yolo Wonder’ and a reduction in fruit weight in both ‘JO204’ and ‘Sammy’. In contrast, the landrace ‘JO109’ exhibited consistent yields under both growing conditions, a response likely attributed to elevated K concentration in the leaves and lower Na accumulation in the fruit, indicating enhanced tolerance to water deficit. A decline in leaf K concentration was observed in response to drought stress, while concomitantly increased concentrations of Na, Ca and Mg were recorded. Among fruit macronutrients, only Ca showed a significant decrease under reduced irrigation. Furthermore, fruit firmness (FF), titratable acidity (TA) and total soluble solids content (TSSC) exhibited higher levels under drought stress, particularly in ‘JO109’, while TA remained unaltered. These findings highlight the potential of landraces such as ‘JO109’ to be utilized in breeding programs aimed at enhancing resilience, while maintaining pepper fruit quality under limited water availability. Full article

Gazania is a genus of herbaceous plants from the Asteraceae (daisy) family. Native to southern Africa, several species of this genus have been introduced to different countries as ornamental garden plants due to their beautiful flowers. In the wild, Gazania species have been observed with flowers of different shades of pink, red, yellow, orange and combination of these colours. Some species of Gazania have escaped the gardens and become highly invasive weeds in their introduced range. Invasive, drought-tolerant and prolific seed-producing Gazania plants are found in Australia, New Zealand, Algeria, Egypt, Europe and California. In particular, two perennial species, Gazania linearis and Gazania rigens, commonly known as gazania, have become a major problem in Australia. They have naturalized and are widespread in a range of environments, such as roadsides, pasture/grassland systems, coastal sand dunes, and natural and managed ecosystems. Their seeds and underground reproductive structures are carried along roadsides by slashers, machinery, wind and water, and spread into native vegetation, pastures, horticultural crops and broadacre agronomic crop production systems. Gazania causes significant environmental, production and economic losses in the infested ecosystems. While limited research has been conducted on their biology and invasion ecology, anecdotal evidence suggests that the ability of gazania plants to produce a large number of seeds form thick, dense populations, and tolerate harsh environments, including drought, heat and sub-optimal soil pH, making them persistent, problematic weed species. In addition, perennial growth habit, high genetic diversity and allelopathic potential have also been suggested to facilitate their invasion success, but no research has been conducted on these aspects. Gazania is very difficult to manage, and currently, there are no effective control options available, including chemical herbicides. The lack of knowledge on their biology, invasion pathways and management is hindering the effective management of gazanias. This review compiles and synthesizes currently available information on the distribution, biology, ecology and management of weedy gazania species, with a particular focus on Australia. We also highlight the key knowledge gaps for future research. We believe this information provides researchers and practitioners with an up-to-date account on the weedy aspects of these popular ornamental plants and will help improve management efforts. Full article

The global challenge of climate change demands innovative, inclusive, and experiential education that fosters ecological literacy, behavioral change, and climate advocacy. This study explores a cross-cultural collaboration between two undergraduate ecology courses—one at the University of La Verne (ULV) in California and the other at the Universidad Centroamericana José Simeón Cañas (UCA) in El Salvador—that employed 360° virtual reality (VR) photosphere photographs to investigate climate change impacts. Students documented local ecological phenomena, such as drought and habitat loss, and shared insights with international peers, facilitating a rich exchange of perspectives across biomes. Generative AI tools like ChatGPT were utilized to overcome language barriers, enabling equitable participation and enhancing cross-cultural communication. The findings highlight VR’s transformative role in helping students visualize and communicate complex ecological concepts while fostering empathy, emotional engagement, and agency as climate advocates. Institutional and curricular factors shaping the integration of VR-based approaches are discussed, along with their potential to drive behavioral shifts and promote global engagement. This study demonstrates that immersive technologies, combined with collaborative learning, provide a powerful framework for bridging geographic and cultural divides, equipping students with the tools and perspectives needed to address the critical global challenges posed by climate change. Full article

Drought poses a significant challenge to cowpea growth and productivity, necessitating the development of drought-tolerant cultivars through detailed morpho-physiological and molecular analyses. This study evaluated drought stress responses in cowpea cultivars using polypropylene plastic boxes under greenhouse conditions. RT-qPCR was conducted to assess the relative expression of five photosynthetic and abiotic stress-related genes in a subset of seven contrasting cultivars at 7-, 14-, and 28-days post-treatment initiation (DPTI) and 24 h post-rewatering. Drought-stressed plants showed progressive wilting and a declining chlorophyll content, with plant greenness scores ranging from 2.2 (TVu11987) to 4.7 (TVu2428). California Blackeye (72.2%) and TVu11987 (69.4%) had the highest recovery rates, indicating greater drought tolerance, while TVu2428 had the lowest (2.8%). Gene expression analyses revealed significant drought-induced variation across cultivars and time points. Transcript levels were notably higher in drought-tolerant cultivars, particularly at 14 DPTI and 24 h post-rewatering, aligning with the morpho-physiological screening results. However, gene expression declined as the drought severity increased. These results suggest that California Blackeye, TVu11987, Lobia-I-Sefade, K929, and Aloomba were more drought tolerant compared to Mississippi Silver and TVu2428. Future research using transcriptomic profiling could unravel the complex molecular mechanisms of drought responses in cowpeas, providing valuable insights for breeding genotypes with improved resiliency to drought. Full article

Seasonally dry mature and old-growth (MOG) forests in the western USA face increasing threats from catastrophic wildfire and drought due to historical fire exclusion and climate change. The Emerald Point forest at Lake Tahoe in the Sierra Nevada of California, one of the last remaining old-growth stands at lake level, is at high risk due to elevated fuels and tree densities. The stand supports huge trees and the highest tree diversity in the Lake Tahoe Basin and protects important raptor habitat. In this study, we simulate forest response to vegetation management and wildfire to assess the impacts of four fuel-reduction scenarios on fire behavior and stand resilience at Emerald Point. Results: Our results demonstrate that restorative forest management can greatly improve an MOG forest’s resistance to catastrophic fire. Thinning to the natural range of variation for density, basal area, and fuel loads, followed by a prescribed burn, was most effective at reducing large-tree mortality, maintaining basal area, and retaining live tree carbon post-wildfire, while reducing secondary impacts. Conclusions: Our findings highlight the value of proactive management in protecting old-growth forests in seasonally dry regions from severe fire events, while also enhancing their ecological integrity and biodiversity. Full article