Study Sites Research Articles

After effects of historical grassland on soil organic carbon content and plant growth in croplands in southern Germany determined using satellite data

Numerous studies have reported that grasslands harbor higher soil organic carbon (SOC) stocks compared with arable land; however, the relevant carbon dynamics and sink persistence remain unclear.Herein, arable fields characterized by historical grassland zones (h_GL; grassland use decades ago) and permanent arable land zones (h_CL) were examined. The h_GL zones were determined using historical maps. The change in land use from grassland to cropland occurred 30–50 years ago.In eight arable fields, SOC and total nitrogen (TN) stocks in the topsoil were analyzed at a high spatial resolution. Additionally, remote sensing via satellites was employed to determine the biomass yield at a high spatial resolution using the normalized difference vegetation index (NDVI). In all the fields, the mean SOC content of the h_GL zones (1.81 %, n = 97 measuring points) was higher than the mean SOC content of the h_CL zones (1.52 %, n = 220). Furthermore, the mean relative NDVI was higher in the h_GL zones than in the h_CL zones. SOC and NDVI were positively correlated (up to r = 0.79), as well as TN and NDVI (up to r = 0.72). To evaluate the first dataset, zonal soil samples were collected from the h_GL and h_CL zones from 14 arable fields to determine the SOC and TN content. The mean SOC content of the h_GL zones was 1.92 % and that of the h_CL zones was 1.39 %—a difference of absolute SOC stocks in the topsoil of 23.8 t ha−1 (bulk density: 1.5 g cm−3).The work combines the knowledge of historical soil maps, remote sensing applications and georeferenced soil sampling and shows that SOC stocks in grassland have a high persistence and can have positive impact on yields even decades after a land use change. Historical land use proved to be a major factor for spatial SOC variability at the study site.

Campylobacter jejuni and Campylobacter coli infection, determinants and antimicrobial resistance patterns among under-five children with diarrhea in Amhara National Regional State, Northwest Ethiopia.

Children with under-five year age disproportionally affected with foodborne illness. Campylobacteriosis is the most common foodborne disease next to Norovirus infection. Macrolides are commonly prescribed as the first line of treatment for Campylobacter gastroenteritis, with fluoroquinolone and tetracycline as secondary options. However, resistance to these alternatives has been reported in various regions worldwide. To determine the prevalence, associated risk-factors and antimicrobial resistance of Campylobacter jejuni and C. coli among under-five children with diarrhea. Institution-based cross-sectional study was conducted from November, 2022 to April 2023. The study sites were selected using a random sampling technique, while the study subjects were included using a convenient sampling technique. The data were collected using a structured questionnaire. Stool samples were inoculated onto modified charcoal cefoperazone deoxycholate agar and incubated for 48 hours. The suspected colonies were analyzed using matrix-assisted laser desorption ionization-time of flight mass spectrometry to confirm the species. Antimicrobial susceptibility testing was performed using a disc diffusion technique. All potential covariates (independent variables) were analyzed one by one using bivariate logistic regression model to identify candidate variables with P value < 0.25. Multivariable logistic analysis was used to identify potential associated factors using the candidate variables. A p value ≤ 0.05 at a 95% confidence interval was statistically significant. Among the 428 samples, 7.0% (CI: 4.5-9.3) were confirmed Campylobacter species. The prevalence of C. jejuni and C. coli among under-five children was 5.1% (CI: 3.0-7.0) and 1.9% (CI: 0.7-3.3), respectively. C. jejuni (73.3%) was dominant over C. coli (26.7%). The resident, contact with domestic animals, and parents/guardians education level were significantly associated with campylobacteriosis among under-five children. One-third of the Campylobacter isolates (33.3%, 10/30) were resistant to ciprofloxacin and tetracycline whereas 10.0% (3/30) were resistant to erythromycin. Furthermore, 3.3% (1/30) of the Campylobacter were found to be multidrug-resistant. The prevalence of Campylobacter species was 7.0%. The resistance rate of Campylobacter species of ciprofloxacin and tetracycline-resistance strains was 33.3%. Peri-urban residence, contact with domestic animals, and low parental educational statuses were significantly associated factors with increased risk of Campylobacter infection. Continuous surveillance on antimicrobial resistance and health education of personal and environmental hygiene should be implemented in the community.

Glyphosate contamination: implications for honeybee Apis mellifera and consumers in Southeastern Mexico

In a study conducted from June 2021 to May 2022 in two apiaries in southeastern Mexico, levels of glyphosate residues in pollen collected by bee Apis mellifera were analyzed to assess potential risks to both bees and humans. The analysis used an immunoassay method after residue extraction using the QUECHERS method. The results revealed the presence of glyphosate in all samples, with concentrations ranging between 3.71 and 7.29 μg/kg. However, risk analysis, as indicated by the pollen hazard quotient, suggested that these quantities did not pose a serious threat to bees or humans. The levels were within acceptable limits of the acceptable daily intake (ADI), acute reference dose (ARfD) and acceptable operator exposure level (AOEL). In conclusion, although this study did not find any significant association between glyphosate and potential risks for both humans and bees, its persistence in the environment is demonstrated. Glyphosate levels at the study site were low, suggesting minimal risk to both species. However, the wide distribution of glyphosato in the region makes it necessary to emphasize long-term studies to understand the possible chronic effects of the pesticide on all species in the area.

Morphological identification and characterization of the formation of floral primordium in Vanilla planifolia (Orchidaceae)

Objective: To morphologically identify and characterize the formation of floral primordium and the individual flower development in Vanilla planifolia Jacks Ex. Andrews. Design/Methodology/Approach: Inflorescence primordia and young inflorescences in different development stages were sampled from the stem internodes of the following positions: basal (11-15), middle (6-10), and distal (1-5). Four samples were taken from each stem position from February to May, with five repetitions per sampling date. Observations and characterization were made with a stereo microscope. The study site was located at Rancho Xanathtlan, in Barriles, municipality of Gutiérrez Zamora, Veracruz. Results: The development of the V. planifolia raceme is described in seven phases: (I) differentiated meristem of the floral inflorescence; (II) appearance of the third bract; (III) initiation of the racemes formation; (IV) elongation of the floral primordium; (V) development and growth of the individual floral primordium in the acropetal direction, (VI) anthesis of the inflorescence in the acropetal direction; and (VII) complete flowering of the raceme. The development of the buds in the raceme is described in five stages from the appearance of the third bract in the acropetal direction. Study Limitations/Implications: The biochemical processes and the interaction of environmental aspects on the floral development of V. planifolia pose questions that remain unanswered. Findings/Conclusions: The first aspects of floral formation within the inflorescence of Vanilla planifolia were determined, along with its floral phenology.

The geosemiotics of urban transnationalism: a case study of Vietnamese commercial landscapes in Prague

This study analyzes the discursive social position of Vietnamese migrants represented by three types of Vietnamese commercial places: a large wholesale complex, Vietnamese-run grocery shops on local streets, and stylish chain restaurants in commercial centers. Guided by the notions of semiotic landscapes and geosemiotics, this study analyzes the semiotic dynamic among the spatial structures, visual images, and human activities in and around the study sites. The analysis demonstrates that the spatial representations of Vietnamese in Prague are associated with the spatial-visual discourses of the globalized city. The walled wholesale complex, situated on the margin of the city, serves to discursively segregate the diasporic community from the mainstream society. Ubiquitous grocery stores on local streets paradoxically signify the inconspicuousness of Vietnamese in Czech society. On the other hand, stylish Vietnamese restaurants in commercial centers add sophisticated cultural tastes and are included in the cosmopolitan dynamic of Prague. This geosemiotic study illustrates how geographical centrality and marginality are intertwined with migrants’ commercial practices, reflecting their multilayered positions in the socioeconomic strata of society. In transnational urban spaces, understanding the discursively associated ethnic markers and their urban locations provides important insights into the inclusive and exclusive dynamics of globalized cities.

Urinary polycyclic aromatic hydrocarbon (PAH) metabolite concentrations in three pregnancy cohorts from 7 U.S. study sites.

Prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) is associated with adverse birth and developmental outcomes in children. We aimed to describe prenatal PAH exposures in a large, multisite U.S. consortium. We measured 12 mono-hydroxylated metabolites (OH-PAHs) of 7 PAHs (naphthalene, fluorene, phenanthrene, pyrene, benzo(c)phenanthrene, chrysene, benz(a)anthracene) in mid-pregnancy urine of 1,892 pregnant individuals from the ECHO PATHWAYS consortium cohorts: CANDLE (n = 988; Memphis), TIDES (n = 664; Minneapolis, Rochester, San Francisco, Seattle) and GAPPS (n = 240; Seattle and Yakima, WA). We described concentrations of 8 OH-PAHs of non-smoking participants (n = 1,695) by site, socioeconomic characteristics, and pregnancy stage (we report intraclass correlation coefficients (ICC) for n = 677 TIDES participants). Exposure to the selected PAHs was ubiquitous at all sites. 2-hydroxynaphthalene had the highest average concentrations at all sites. CANDLE had the highest average concentrations of most metabolites. Among non-smoking participants, we observed some patterns by income, education, and race but these were not consistent and varied by site and metabolite. ICCs of repeated OH-PAH measures from TIDES participants were ≤ 0.51. In this geographically-diverse descriptive analysis of U.S. pregnancies, we observed ubiquitous exposure to low molecular weight PAHs, highlighting the importance of better understanding PAH sources and their pediatric health outcomes attributed to early life PAH exposure.

Assessing the key concerns in snow storage: a case study for China

Abstract. Snow security plays a crucial role in ensuring the success of winter sports events and supporting the ski industry. One effective approach to enhancing snow reliability is through snow storage. Despite its potential benefits, investigations of snow storage in China have been limited. To address this gap, we implemented snow storage covered with geotextiles at two venues, namely the Big Air Shougang (BAS) in Beijing for the Beijing 2022 Winter Olympic Games and the National Biathlon Center (NBC) in Chongli for the Beijing 2022 Winter Paralympic Games, in response to possible extreme meteorological conditions. To assess the key concerns associated with snow storage, ablation (the process of snow loss) and snow properties, we introduced a fine-snow-pile monitoring system and the SNOWPACK model. Our observations revealed that, by 18 February, the snow pile at BAS had lost 158.6 m3 of snow (equivalent to 6.7 % of the initial volume). Subsequently, the accelerated ablation was influenced by meteorological conditions and a thin geotextile layer. Between 16 January and 15 April, the snow pile at BAS experienced a total loss of 1242.9 m3 of snow (corresponding to 52.7 % of the original volume). Regarding snow properties, no significant variations were modeled at the study sites, except for the upper part of the snow piles. Notably, the evaporation of the geotextiles contributed to slowing the ablation process. Consequently, we discourage the use of impermeable coverage schemes for snow storage. Instead, the thickness of the cover played a vital role in preserving the snow pile. At Beijing and Chongli, the 0.7 and 0.4 m thick cover layers, respectively, were found to protect approximately half of the snow pile height over the summer season. Importantly, the evolution of snow properties was consistent across the different cover thicknesses. The findings of our study have implications for the ski industry in China, as they provide valuable insights into snow storage techniques and their impact on snow reliability.

Body mass, diet, foraging strata and foraging behaviour predict variation in the propensity to join mixed‐species flocks across birds

Mixed‐species flocking is common in birds and is associated with increased foraging efficiency and reduced predation pressure. The propensity to join mixed‐species flocks within a community varies across species, possibly reflecting species‐specific needs for increased protection from predators, opportunities to increase foraging efficiency or both. Previous studies on predictors of mixed‐species flocking propensity across species have typically focused on local communities, with or without accounting for phylogenetic relatedness. Here, we examined predictors of mixed‐species flocking propensity across the published literature using a phylogenetic linear mixed model framework. We obtained 724 mixed‐species flocking propensity estimates from 31 different study sites located primarily in South America and East Asia. Flocking propensity was associated with diet, foraging strata and foraging behaviour, and was inversely related to body mass. Controlling for phylogeny and body mass, flocking propensity was significantly lower for nectarivores than for species with other diets, lower for species foraging on the ground than in higher strata, and lower for sallying species than for bark and near‐perch foragers. These results suggest that variation across species in the tendency to join mixed‐species flocks can be predicted from knowledge about various species‐specific ecological traits in birds.

Effects of habitat biotic features on hymenopteran diversity in East Africa

Abstract Purpose Originally, the coastal region of East Africa was largely covered with coastal forest. With the human settlement, the majority of these forests have been transformed into agricultural land for subsistence farming. Today, only small and geographically isolated forest remnants exist and form a mosaic of different habitat types, including natural, semi-natural and anthropogenic ones. The forest remnants may still represent valuable habitats for typical forest plant and animal species. Methods In this study, we surveyed hymenopteran diversity and community composition in different habitat types in southern Kenya. Hereby we considered a small remnant of East African coastal forest, adjoining orchards, shrublands, tree plantations, agricultural fields, and settlements. Hymenoptera represent a large variety of taxa and provide relevant ecosystem services such as pollination to the local people. Hymenoptera were collected with coloured pan traps, identified to family or genus level, and sorted to morphospecies. Habitat parameters such as dead wood, leaf litter, vegetation structure, and the availability of flowers has been assessed for each study site. Results In total, we found 419 Hymenoptera individuals of 153 morphospecies. The different habitat types showed distinct species communities of Hymenoptera. Increasing shrub layer and increasing herb cover had a negative effect on hymenopteran species richness and abundance. Flowers, trees, leave litter, and deadwood showed no significant effect on hymenopteran diversity. Conclusion Our results underline that small-scale habitat diversity lead to high overall diversity of Hymenoptera. Implications for insect conservation: The coastal forest remnant still holds a unique hymenopteran community with 20 Hymenoptera species exclusively found in this habitat type. It is thus of very high conservation value.

Perceived Soundscape Experiences and Human Emotions in Urban Green Spaces: Application of Russell’s Circumplex Model of Affect

Humans perceive their surrounding environments largely through their experiences of sight and hearing. The perceived environmental information then brings on neurophysiological changes, so as to influence human emotions. These mutually influenced relations have been widely utilized by many environmental psychologists to explore potential avenues for improving human emotions through design interventions. However, to date, no efficient and accurate way has been established to describe these relationships. Inspired by Russell’s model of emotion, this study aims to develop an efficient process that uses coordinate mapping and can intuitively describe the impact of visual-aural perceptive attributes on human emotions. Taking typical urban green spaces (UGSs) in Chengdu as examples, this study first measured the visual and aural characteristics of study sites perceived by people and their emotional responses. The study then established the use of emotional status on a coordinate axis, allowing each visual-aural attribute corresponding to each emotional response to be projected onto the coordinates. Results suggested that the dataset composed of 279 evaluations could be classified into three distinct types of visual-aural settings and the distribution of emotions is evidently varied in different settings. It was found that aesthetic and order of visual aspects as well as eventful and harmonious soundscape in environments are more likely to make people feel pleasure, while openness and layering of the visual landscape can easily arouse people’s positive status. The research outcome broadens the practical path of soundscape research, centring on human emotions, experiences and feelings, such as the pleasantness and arousal raised in Russell’s theory of emotion. The study also makes an empirical contribution to the design of UGSs based on multi-sensory perception and serves the purpose of improving people’s environmental experiences.

Indigenous people doing citizen science to assess water quality using the BMWP in rivers of an arid semi-arid biosphere reserve in Mexico

Arid and semi-arid areas are among the most threatened ecosystems on the planet. The Tehuacán-Cuicatlán Biosphere Reserve (TCBR), in southeastern Mexico, is an arid and semi-arid area with high biological diversity and human settlements of eight ethnic groups. Two rivers drain the reserve, Río Grande (RG) and Río Salado (RS), which are not subject to water quality monitoring by government agencies; however, measures of water quality of these rivers are needed to focus conservation actions on this resource. This work aimed to test the effectiveness of participatory water quality monitoring with the participation of three actors: Reserve management leaders, local communities, and academics, to monitoring water quality in the rivers of the TCBR. Ninety-two residents were trained to carry out water quality biomonitoring using the Biological Monitoring Working Party (BMWP) index calibrated for the reserve. The BMWP uses macroinvertebrate families to display numerical and categorical water quality scores. Additionally, the Water Quality Index (WQI) was assessed and the Normalized Difference Vegetation Index (NDVI) of the riparian zones was estimated in each study site. The mean WQI scores were 69.24 for RS (no treatment necessary for most crops and necessary treatment for public water supply) and 75.16 for RG (minor purification for crops requiring high-quality water and necessary treatment for public water supply). The BMWP showed five water quality categories (Excellent, Very Good, Good, Fair, and Poor), showing higher water quality scores in the upper portion of the basins and capable of discriminating study sites with lower scores close to human settlements. At one study site, data from participatory monitoring impelled actions taken to address a pollution source and influenced policy focus, reaching the maximum level of participatory-based monitoring. This led to avoid the discharge of wastewater into the river to conserve and protect the water resource. WQI is closely related to BMWP; however, the latter was far more sensitive to detecting areas affected by domestic water discharges. The NDVI presented low values for the TCBR, being lower in RS (the driest area). Although the NDVI showed a weak relationship with BMWP values, areas with higher NDVI values generally achieved higher BMWP values. The results of this study highlight the high sensitivity of the BMWP to detect several water quality conditions in the rivers running through the TCBR when compared to WQI. In addition, the usefulness of biomonitoring using the BMWP index was evident, as well as the importance of the participation of local inhabitants contributing to the knowledge of water quality in biosphere reserves and carrying out timely measures that allow the rivers in these reserves to be maintained in good condition.

Gyrfalcon Disease Ecology: A Survey Across Western Alaska

ABSTRACT The Gyrfalcon (Falco rusticolus) is a top avian predator, an Arctic specialist, and among the bird species most vulnerable to climate change. This vulnerability is driven by their narrow ecological niche, limited or lack of southward migration, and circumpolar distribution where the most rapid climatic changes are occurring. Climatic and habitat changes may alter Gyrfalcon disease ecology due to changes in vector distributions, host ranges, and pathogen life cycles. Warmer Arctic temperatures and accompanying landscape changes may also alter the Gyrfalcon’s prey base, and dietary habits can influence transmission of pathogens. To better understand disease ecology in Gyrfalcons, we compared pathogen prevalence across varying time periods at three study sites in Alaska—the Seward Peninsula (2014–2022), the Alaska Peninsula (2021–2022), and the Yukon–Kuskokwim Delta (2008–2013). We collected Gyrfalcon whole blood, thin blood films, cloacal swabs, and fecal samples for serology, haemoparasite assays, microbiological cultures, and fecal tests for parasites. An aliquot of whole blood preserved on filter paper or in Longmire solution was kept for molecular diagnosis of haemoparasites. Serology revealed high exposure to Salmonella (77%), low seroprevalence of avian influenza antibodies (1.5%), exposure to falcon adenovirus type 1 in hatch-year Gyrfalcons (1.3%), and the first report of a Leucocytozoon spp. blood parasite in a Gyrfalcon. We found no antibodies indicative of prior exposure to avian paramyxovirus, West Nile virus, or Chlamydia. One nestling and one hatch-year bird sampled (2 of 12) on the Seward Peninsula exhibited oral plaques from capillarids (Eucoelus spp.) in contrast to those trapped in the Izembek National Wildlife Refuge on the Alaska Peninsula (0 of 6).

Insights into the pathophysiology and response of persistent spinal pain syndrome type 2 to spinal cord stimulation: a human genome-wide association study

BackgroundSpinal cord stimulation (SCS) provides pain relief for some patients with persistent spinal pain syndrome type 2 (PSPS 2), but the precise mechanisms of action and prognostic factors for a...

Application of remote sensing to understand the role of Galician feral horses in the biomass reduction of a shrub-grassland-dominated landscape

Galician forests in northwestern Spain are subject to frequent wildfires with high environmental and economic costs. In addition, due to the consequences of climate change, these fires are becoming more virulent, occurring throughout the year, and taking place in populated areas, in some cases involving the loss of human life. Therefore, forest fire prevention is even more relevant than mitigating its consequences. Given the costs involved in forestry work, alternative measures to reduce fuel load and create vegetation gaps are needed. One involves grazing by an endemic species of feral horses (Equus ferus atlanticus) that feed on thicket-forming gorse (Ulex europaeus). In a 100-ha forest fenced study area stocked with 11 horses, four 50 m2 enclosed plots prevented the access of these wild animals to the vegetation, with the aim of manipulating their impact on the reduction of forest biomass. The measurement of biomass volumes is an important method that can describe the assessment of wildfire risks, unfortunately, high-resolution data collection at the regional scale is very time-consuming. The best result can be using drones (unmanned aerial vehicles - UAVs) as a method of collecting remotely sensed data at low cost. From September 2018 to November 2020, we collected information about aboveground biomass from these four enclosed plots and their surrounding areas available for horses to forage, via UAV. These data, together with environmental variables from the study site, were used as input for a fire model to assess the differences in the surface rate of spread (SROS) among grazed and ungrazed areas. Our results indicated a consistent but small reduction in the SROS between 0.55 and 3.10 m/min in the ungrazed enclosured plots in comparison to their grazed surrounding areas (which have an SROS between 15 and 25 m/min). The research showed that radar remote sensing (UAV) can be used to map forest aboveground biomass, and emphasized the importance and role of feral horses in Galicia as a prevention tool against wildfires in gorse-dominated landscapes.

Healthcare Providers' and Frontline Workers' Experiences of an Ebola Vaccine Trial in the Boende Health District of the Democratic Republic of the Congo.

This study explored the experiences of healthcare providers (HCPs) and frontline workers who were involved in an Ebola vaccine trial in the Democratic Republic of the Congo. The researchers interviewed a total of 99 participants (HCPs and frontline workers) living and working in the Boende health district during the period of the study, from February to March 2022. These individuals included a mix of trial participants and non-trial participants (staff of the trial, local health authorities, and head nurses of health centers). In-depth individual interviews, as well as focus group discussions (FGDs), were used to understand interviewees' experiences and perceptions. The data were analyzed to identify the main themes. The findings unveiled a multitude of positive experiences among interviewees/FGD participants. The commitment of the trial investigators to improve the study site and to equip the volunteers with necessary skills and knowledge greatly contributed to a positive trial experience. However, some interviewees felt that the reimbursement for time and travel expenses during their trial visits was insufficient in comparison with their expectations. Additionally, there were expressions of worry about the frequency of blood draws during scheduled trial visits. Our findings emphasize the critical importance of addressing and continuously considering the perspectives and concerns of trial participants before designing and implementing vaccine trials. By actively incorporating their inputs, researchers can mitigate concerns and tailor communication strategies, potentially enhancing the overall success and impact of the vaccine trial.

Culex quinquefasciatus Mosquitoes Resist Acquisition of Methicillin-Resistant Staphylococcus aureus: Insights from Field and Laboratory Studies

The emergence of antimicrobial resistance (AMR) in pathogens and their spillover into the environment have become a global public health menace. Insects can acquire these pathogens from the environment and would serve as mechanical and biological vectors. The current study assessed the ability of Culex quinquefasciatus mosquitoes to acquire methicillin-resistant Staphylococcus aureus (MRSA) through the exposure of the mosquitoes to the pathogen via rearing water, blood feed, or a feeding membrane under laboratory conditions. In addition, mosquito immatures collected from their habitat in the vicinity of hospitals, veterinary dispensaries, and butcher shops at 15 study sites in Puducherry were screened for MRSA infection. All samples were subjected to the culture-based isolation of S. aureus from the surface and homogenate. The presence of the S. aureus-specific nuc gene and the genes that confer resistance to methicillin (mecA and mecC) were screened using PCR tests. MRSA was not evident either on the external surface or in the homogenate of the mosquitoes emerging from the larvae reared in the MRSA-spiked water or those fed with MRSA through blood or smeared membranes. Furthermore, the presence of MRSA was not evident in any of the field-caught mosquitoes. Hence, we conclude that C. quinquefasciatus mosquitoes are impervious to MRSA colonization.

Advancing clinical trial equity through integration of telehealth and decentralized treatment.

Innovative strategies to increase clinical trial accessibility and equity are needed. We conducted a retrospective review of a phase II investigator-initiated trial to determine whether the modification of clinical trial design to decentralize study treatment can improve trial accessibility among underrepresented groups. Sociodemographic characteristics, including area deprivation indices, as well as study site travel distance, time, and costs were compared between enrolled participants who received chemotherapy locally and participants who did not. Participants who received chemotherapy locally lived substantially farther from the study site (median = 95.90 vs 25.20 miles, P = .004), faced a greater time burden traveling to the study site (median = 115.00 vs 34.00 minutes, P = .002), and had higher travel-related costs for a single trip to the study site (median = $62.81 vs $16.51, P = .004). This study highlights opportunities for alleviating financial and time burdens associated with clinical trial participation, promoting equity in clinical research. Trial Registration: ClinicalTrials.gov identifier: NCT04380337.

Exploring the InSAR signature associated with river-sourced recharge in California’s San Joaquin Valley

Recharge is a critical component for understanding aquifer systems and the sustainable management of groundwater resources, yet this process is challenging to measure at policy-relevant spatiotemporal scales. Building upon previous research, we tested the hypothesis that InSAR can be used to observe river-sourced recharge if the underlying recharge pathways are associated with sufficient clay content. Our analysis leveraged the decomposition of InSAR time series with interpretations of 3D resistivity models derived from airborne electromagnetic (AEM) surveys. We focused our analysis on two study sites where high density AEM data were available and river-sourced recharge is determined to have occurred during wet years: (1) near Fresno, California and (2) near Visalia, California. Sediment type and hydrogeological structure from AEM supported our hypothesis with the InSAR signature attributed to river-sourced recharge occurring only in the study site with semi-confined to confined conditions and relatively high fraction of interbedded clay within recharge pathways. The timing to peak amplitude, the key feature we wanted to isolate in the InSAR data, near Visalia was interpreted as a pressure pulse front associated with river-sourced recharge propagating into the San Joaquin Valley. This study further validated the potential of InSAR, coupled with AEM data, to map and monitor river-sourced recharge in aquifer systems. As InSAR data become more accessible, this approach holds promise for broader applications in groundwater science and management worldwide.

Vegetation composition and organic carbon content along right-of-ways on Interstate Highway 35 in Bexar County, Texas

Roadside habitat through major urban areas may offer remnant examples of natural grasslands. These habitats may be subjected to frequent as mowing and exposure to automobile emissions and runoff. This study was conducted on interstate highway right-of-ways in San Antonio, Texas, U.S.A. We compared the vegetation species and diversity, and the organic carbon of leaf litter, plants, and soils. Two non-native grasses accounted for 50.9% cover, while all native forbs and grasses accounted for only 9.8% cover. The mean biomass of non-native grasses was 4.5 times greater than that of all native species. Organic carbon content of leaf litter, plants, and soils was variable among the study sites, possibly due to management practices and a drought that occurred during the study. The mean organic carbon content in the upper 20 cm soil was 5.0 kg·C/m2 and organic carbon content was greater in the upper 10 cm than organic carbon in the 10.1 to 20 cm portion. Cynodon dactylon and Bouteloua curtipendula exhibited the greatest photosynthesis efficiency indicating these grasses are more adaptable to hot summer temperatures found in Central Texas. The organic carbon content along a major interstate was 13793 kg·C/ha for leaf litter, vegetation, and the upper 20 cm of the soil. We conclude that interstate highways provide habitat for some native species, but the vegetation along right-of-ways is dominated by two non-native grasses. It appears unlikely that roadside habitat can be restored to resemble native grasslands without large scale and costly restoration efforts.

Integrating rainfall index-based insurance with optimal crop management strategies can reduce financial risks for Australian dryland cotton farmers

Drought undermines the financial sustainability of farmers. While farmers have adopted various strategies to mitigate some drought impacts, they remain exposed to substantial drought risk. Insurance could be useful in managing climatic risks and for encouraging farmers to take sensible risks (e.g., changing their sowing date to increase yield), but it can be costly. Here, we tested whether the integration of a change in sowing date with rainfall index-based insurance could improve farmer profitability and income stability. We used the Agricultural Production Systems Simulator (APSIM)-Cotton model to simulate cotton lint yields for various sowing dates, taking into account different management strategies, across three dry-land cotton research farm sites – Dalby, Goondiwindi, and Theodore – from 1940 to 2022. We designed the index-based insurance payout when the average rainfall received during the growing season falls below a predefined level, such as the 5th, 10th, or 20th percentile of rainfall. Our study, which involved 3.9 million cotton lint simulations and 3,000 rainfall index-based insurance products, showed that combining a shift in sowing date with insurance can lead to an income improvement of up to 21.5% at some study sites. Additionally, in drought years, the income improvement for farmers who combined optimal sowing dates with rainfall index-based insurance was up to 48.0%. The framework developed in this study could aid in devising financial strategies to enhance farming resilience during climate extremes.