Search Results (3,458)

Autonomous takeoff and landing (ATOL) remains one of the most challenging tasks for fixed-wing unmanned aerial vehicles (UAVs), particularly in environments where Global Navigation Satellite System (GNSS) signals are degraded or unavailable. This paper presents an LiDAR-assisted terrain-relative navigation framework for the autonomous takeoff and landing of a 5 kg fixed-wing UAV operating under degraded navigation conditions. The proposed architecture integrates a downward-facing LiDAR rangefinder with barometric altitude sensing, INS/GNSS navigation, optical-flow measurements, and airspeed information within a multi-sensor fusion and flight-control framework. The system combines a Pixhawk-based autopilot with a companion-computer architecture responsible for real-time sensor processing, altitude estimation, mission supervision, and MAVLink-based communication. A dedicated filtering strategy and sensor fusion approach enable reliable terrain-relative altitude estimation during critical low-altitude flight phases, while fault-tolerant command-management mechanisms improve operational robustness in the presence of temporary communication losses and sensor disturbances. The proposed framework was validated through Software-in-the-Loop (SITL), Hardware-in-the-Loop (HITL), and real-flight experiments. Experimental results demonstrated stable and repeatable autonomous landing performance. Comparative analyses showed that the LiDAR sensor provided the most accurate and responsive terrain-relative altitude measurements during takeoff, flare, and landing operations, particularly over irregular and vegetation-covered surfaces. In contrast, barometric sensing provided greater long-term stability during cruise flight, highlighting the importance of multi-sensor fusion for reliable altitude estimation throughout the mission profile. The results confirm that LiDAR-based terrain-relative sensing significantly improves autonomous takeoff and landing performance for fixed-wing UAVs operating in GNSS-degraded environments. The proposed architecture offers a practical and low-cost solution for the autonomous takeoff and landing of fixed-wing UAVs operating in GNSS-degraded environments while demonstrating the benefits of integrating LiDAR, inertial, barometric, and GNSS measurements within a unified multi-sensor autonomous flight framework. Full article

This study investigates lichen colonisation on a medieval basalt Armenian cross-stone (khachkar) in the Noratus cemetery, the largest extant concentration of memorial khachkars in Armenia, integrating fine-scale vegetation sampling, microhabitat assessment, and multivariate analysis. A preliminary survey of c. 30 cross-stones confirmed that the selected one was representative of the site. Thirty-six evenly spaced relevés of 10 cm² were recorded across the surface, with lichens identified macroscopically in situ and supported by laboratory-verified reference material from outside the protected area. Microhabitat descriptors were recorded, and ecological preferences were assessed using indicator values. The main environmental drivers at Noratus appear to be high solar irradiation, pronounced aridity and especially elevated nutrient deposition. Numerical classification and ordination revealed three main lichen communities, structured primarily by micro-scale water availability, exposure, and nutrient enrichment, which occupy different portions of the monument. The absence of endolithic lichens, together with the dry–cold climate of Noratus and the resistance of basalt to bioweathering, suggests limited structural impact. However, pronounced chromatic alteration was observed, producing a characteristic polychromy on the cross-stones. Lichen removal is likely to be problematic due to the extent of the cemetery, the prevalence of vegetative reproduction, and rapid recolonisation of nitrophilous species. This is the first study ever carried out on lichen colonisation of Armenian cross-stones, which are inscribed on the UNESCO List of the Intangible Cultural Heritage of Humanity. The results provide a baseline for future monitoring and support a conservation approach balancing material risk assessment with aesthetic considerations. Full article

Background/Objectives: School-based programmes may play an important role in promoting healthier and more sustainable dietary habits from early childhood. This study described and evaluated a community-based intervention aimed at promoting Mediterranean diet (MD) principles, improving food literacy, and raising awareness of sustainable food practices among primary school children in the Tagus Lezíria region, Portugal. Methods: The intervention was implemented in 23 schools across 11 municipalities and included two seasonal rounds of participatory educational activities focused on healthy eating, local and seasonal foods, sensory exploration, balanced meals, composting, food storage, sustainable food production, and food waste prevention. A total of 872 children participated in the intervention activities, and 370 provided paired baseline and follow-up KIDMED assessments. Results: The mean KIDMED score decreased significantly from 8.0 ± 2.2 at baseline to 7.5 ± 2.4 after the intervention. Overall, 31.6% of participants improved their score, 18.9% showed no change, and 49.5% showed a decrease. The proportion of children who did not skip breakfast increased from 79.8% to 88.6%, and avoidance of fast-food restaurants more than once weekly increased from 85.4% to 89.6%. Smaller favourable changes were observed for pastry, sweet, and fish consumption, and olive oil use, whereas fruit, vegetable, pulse, and nut consumption did not improve. Conclusions: The intervention produced heterogeneous outcomes. Although overall MD adherence decreased, almost one-third of participants improved individually, with favourable changes in breakfast and selection of less healthy behaviours. Longer programmes with stronger family involvement may be required to reinforce core MD foods and achieve broader, sustained improvements. Full article

Wild edible plants play a crucial role in supporting rural livelihoods, yet knowledge about their use remains under documented, particularly among younger generations and across gender lines. This study examined the distribution of ethnobotanical knowledge of wild edible plants across age and gender groups in four municipalities of the Vhembe District, South Africa. Data were collected through semi-structured interviews conducted with 160 participants, primarily in the Venda region. Gendered patterns emerged, where women were more familiar with wild vegetables, while men demonstrated greater knowledge of wild fruits. Promisingly, some female youth demonstrated greater knowledge than older women and male participants. Voucher specimens of the cited plants were verified at the University of Venda Herbarium, and data were analysed using qualitative methods and generalised linear models. Results of this study suggest the need to document and conserve Indigenous knowledge, promote intergenerational knowledge transfer, and empower women and youth in traditional food systems to enhance food security and cultural heritage. The study further provides a foundation for future research on knowledge transmission pathways and supports the development of targeted, community-based conservation and educational initiatives to enhance food security and cultural heritage. Full article

Kazakhstan’s Ili River delta nourishes a unique wetland ecosystem in arid Central Asia. The delta is dominated by common reed [Phragmites australis (Cav.) Trin. ex Steud.], an ecologically and economically significant species that is sensitive to water levels. We used machine learning methods, including the Random Forest algorithm, to classify common reed-containing wetland vegetation and water surfaces in the delta based on satellite data from 2000 to 2023. The remote sensing results were integrated with field-based geobotanical studies conducted between 2017 and 2019. These studies, which facilitated identification of three classes of vegetation: meadow, marsh and aquatic, also revealed a good correspondence between predicted and measured common reed biomass per unit area. The long-term dynamics of four wetland communities with a common reed content of ≥25% were analyzed with respect to significant interannual variability in the flow of the Ili River. The highest water inflows and water surface areas in the delta were recorded in 2002, 2010 and 2016, and in each case, a statistically significant expansion of common reed was observed one year later. Common reed areas subsequently declined—rapidly or after a lag of several years. Temporal expansion and contraction of these areas following pulses of water differed substantially from that of overall wetland vegetation as measured previously. The identified patterns have important scientific and practical significance for assessing the stability of the surrounding wetlands, preservation of the delta environment, and sustainable use of common reed. Full article

Litter and understory are key components of forest ecosystems, playing vital roles in soil carbon inputs and microhabitat regulation. Their removal is a common forest management practice: litter removal (L) reduces fire and pest risks while promoting nutrient cycling, whereas understory removal (U) alleviates nutrient competition between understory plants and trees. However, the combined effects and underlying mechanisms of litter removal (L) and understory removal (U) on soil nematode communities remain unclear. This study investigated the individual and interactive effects of L and U on soil nematode communities in a coniferous–broadleaved mixed forest in a subtropical–warm temperate transition zone. The results showed that L significantly reduced soil nematode abundance by 18.1%, increased the relative abundance of bacterivores and omnivores-predators by 21.1% and 103.3%, respectively. U significantly elevated the relative abundance of fungivores by 30.8%, while both L and U reduced the relative abundance of plant-parasitic nematodes. Significant interactive effects between L and U were observed on soil nematode abundance, relative abundances of fungivores, plant-parasites, maturity index, and plant parasite index. Litter plus understory removal (LU) alleviated soil nematode resource limitation through synergistic regulation of resource pulses and microhabitat modification. Faunal analysis based on structure and enrichment indices indicated that LU enhanced food web structural complexity and resource-use efficiency. Redundancy analysis identified microbial biomass carbon, microbial biomass nitrogen, and soil total carbon as key drivers of nematode community differentiation. This study reveals the synergistic regulatory patterns of litter and understory vegetation on soil nematode communities, providing a theoretical reference for understanding the responses of soil nematodes to understory disturbance during the growing season in climate transitional forests, and offering basic data for long-term monitoring and forest soil management. Full article

High-density rodent populations cause severe habitat degradation and ecological imbalance in natural grasslands through intense foraging and burrowing activities. However, dynamically monitoring these small mammals and assessing their large-scale damage using traditional ground surveys alone is challenging. In this study, we evaluated rodent damage severity in alpine meadows and typical steppe by proposing an integrated framework that combines ground, unmanned aerial vehicle (UAV), and satellite data. Using data from 36 plots per grassland type, we extracted a suite of ecological parameters, including aboveground biomass, vegetation cover, community height, rodent burrow density, and plant diversity metrics, to construct a plot-scale Rodent Damage Index ($RDI$). This $RDI$ was then linked with a satellite-derived Remote Sensing Ecological Index ($RSEI$) to model and map damage severity at the regional scale. Separate linear regression models were developed for the two grassland types. The alpine meadow model exhibited better model fit and predictive performance (fitting $R^2$ = 0.762, RMSE = 0.136; LOOCV $R^2$ = 0.729, RMSE = 0.145, 95% CI: 0.580–0.886) than the typical steppe model (fitting $R^2$ = 0.574, RMSE = 0.198; LOOCV $R^2$ = 0.478, RMSE = 0.214, 95% CI: 0.279–0.787), highlighting that the predictive relationship model performance differs significantly between grassland types. Our findings demonstrate that integrating multi-source, cross-scale spatial data is an effective approach for assessing rodent damage. Furthermore, these results indicate that rodent damage assessment should be grassland-type-specific to ensure accuracy and support targeted rodent damage management planning. Full article

Mangrove sediments harbor complex bacterial communities that play critical roles in ecosystem functioning. In this study, we investigated the spatial patterns and environmental drivers of sediment bacterial communities across intertidal flats and vegetated zones in five representative mangrove habitats spanning the Northern Beibu Gulf, South China. Utilizing high-throughput 16S rRNA gene amplicon sequencing, we analyzed bacterial composition and diversity from sediments collected in Qinzhou, Fangchenggang, and Beihai. Results indicated that bacterial communities were dominated by Proteobacteria (37–45%), followed by Bacteroidota and Acidobacteriota; however, a considerable proportion of taxa remained unclassified, particularly in intertidal flats. Bacterial richness and diversity were generally higher in vegetated zones, where sediments were more acidic and nutrient-rich, whereas intertidal sediments were more alkaline and contained higher chlorophyll-a (Chl-a) concentrations. Beta-diversity analysis revealed distinct differences in community structures between zones and regions, which were shaped by both deterministic environmental filtering and stochastic processes. Redundancy analysis (RDA) indicated that bacterial communities assembly driven by niche differentiation influences salinity (Sal), pH, biogenic silica (BSi), total phosphorus (TP), and total nitrogen (TN), as these factors vary across sites due to differing environmental filtering intensities. These findings highlight the distinct differences in mangrove sediment bacterial communities between intertidal flats and vegetated zones, which are shaped by local sediment physicochemical conditions and regional environmental gradients. They provide critical insights for the conservation and restoration of mangrove ecosystems. Full article

Anemia among adolescent girls remains a persistent public health challenge in Indonesia, driven by limited nutritional knowledge, poor dietary practices, and suboptimal adherence to iron supplementation programs. This study is grounded in the Social–Ecological Model (SEM), which frames health behaviors as shaped by individual, interpersonal, institutional, and community-level factors. This study aimed to explore students’ knowledge and dietary behaviors related to anemia, assess perceptions of existing supplementation programs, and examine teachers’ and students’ perspectives on school-based digital education for anemia prevention in Denpasar, Bali. A qualitative descriptive design was employed across eight public junior high schools. Participants included eight teachers and 40 female students (aged 13–15 years) selected via purposive sampling. Data were collected through semi-structured in-depth interviews, non-participant observations, and document analysis. Thematic analysis was conducted using Atlas.ti version 23, with trustworthiness ensured through triangulation, member checking, peer debriefing, and iterative saturation assessment. Four inter-related themes emerged: (1) students held superficial, menstruation-centric conceptualizations of anemia with limited understanding of iron deficiency as an underlying cause; (2) dietary patterns were dominated by low-iron foods with poor vegetable consumption; (3) adherence to the Weekly Iron and Folic Acid Supplementation (WIFAS) program was inconsistent, hindered by side effects, forgetfulness, and low perceived benefit; and (4) both teachers and students expressed strong interest in digital education tools while identifying infrastructure and training gaps as barriers. Anemia prevention in school settings requires a multi-level approach integrating knowledge improvement, dietary behavior support, and institutional reinforcement. School-based digital education represents a contextually appropriate, youth-aligned innovation with strong potential to bridge the gap between health information and sustained behavioral change. Full article

This study evaluates the effects of Eucalyptus camaldulensis stands established within the ramblas of the Tabernas Desert (SE Spain) on ant communities used as ecological bioindicators. Ants were sampled using pitfall traps in four eucalyptus stands and adjacent areas of natural vegetation between 2017 and 2024. Diversity indices, species accumulation curves, non-metric multidimensional scaling (NMDS), PERMANOVA, and indicator species analyses were conducted. The results show that, although the total number of species is similar in both environments, eucalyptus ecosystems present significantly higher diversity and evenness, also harboring a notable presence of the specialist genus Temnothorax, which is typical of structured habitats. In the context of extreme aridity, these tree formations act as hybrid ecosystems that increase landscape heterogeneity, providing refuge and microclimatic regulation. Therefore, from a sustainable management perspective, the study advises against the drastic eradication or clear-cutting of this non-native species, as this could destabilize the soil and worsen habitat degradation. Instead, it is recommended to use their current structure transitorily as an “ecological bridge,” applying selective thinning to facilitate the progressive and safe recovery of native flora and fauna. Full article

The vertical structure of fen vegetation has received little attention, despite its obvious relevance to interactions between herbaceous plants and bryophytes. The main objective of this study was to determine relationships among the vertical herbaceous-rich-fen vegetation structure and the overall cover and species diversity of bryophytes. The study was conducted in eight fens in Lithuania and covered 210 subplots (0.5 m × 0.5 m). Within each subplot, the total and individual percentages of bryophyte and vascular plant cover, and of each visually distinct vertical vegetation layer, were estimated. In vertical vegetation structure, five distinct structural groups were identified, ranging from a simple two-layer group to a four-layer group. Vertical structural differences in herb cover were primarily associated with water level and microrelief. Our results revealed that an open structure is favourable for entire bryophyte cover; shading does not necessarily lead to a decline in total bryophyte cover but rather drives a structural rearrangement of the bryophyte community. The abundant development of higher vegetation layers in highly hummocky areas negatively affects the bryophyte cover. Monitoring visually distinct vertical structures can help predict negative trends in plant community structure, including shifts in bryophyte diversity and cover. Full article

Fruit and vegetable wastes can be recycled into value-added fermentation broths (FBs) through anaerobic fermentation, but the characteristics of FBs and the effects on soil ecological processes remain insufficiently understood. This study analyzed FBs produced from 14 wastes and selected five FBs (garlic, tomato, sweet potato, apple, and lettuce) for pot experiments. The results showed significant differences among the FBs in nutrients, enzymes, and microbial communities. Garlic FB had the highest concentrations of ammonium nitrogen (309.81 mg/L), total phosphorus (327.73 mg/L), total potassium (1365.8 mg/L), and organic matter (28.99 g/L), along with the highest activity of acid phosphatase, urease, protease, and catalase (p < 0.05). FB application improved soil nutrient availability and enzyme activities, with garlic FB showing the strongest effects, increasing catalase, urease, acid phosphatase, and β-glucosidase by 83.34%, 180.72%, 112.34%, and 21.95%, respectively. Metagenomic analysis revealed that the soil treated with garlic FB contained beneficial taxa, including Saprospiraceae, Chitinophagaceae, Azotobacter, and Sphingomonas, which are associated with enzyme production and organic matter decomposition. Furthermore, the application of FBs reduced the incidence of downy mildew and leaf spot and promoted the growth of Brassica chinensis. Though chemical fertilizer produced the highest biomass due to immediate nutrient availability, the FB treatments, especially garlic FB, showed advantages concerning soil health, disease suppression, and sustainability, highlighting their potential for organic waste recycling and sustainable agriculture. Full article

Large-scale mining of rare earth resources has caused a series of ecological and environmental problems in mining areas, including soil structural degradation, nutrient depletion, acidification, and rare earth element (REE) accumulation. Conventional physicochemical remediation technologies are often limited by high costs, strong disturbance, and insufficient long-term stability. To compare the effects of different vegetation types on ecological restoration of ion-adsorption REE tailing soils, this study was conducted in an abandoned REE tailing area in Changfeng’ao, Ganxian District, Ganzhou City, Jiangxi Province. A small-scale field restoration experiment was established with three treatments: unrestored tailings (CK), slash pine (PE), and broadleaf paspalum (CS). Soil physicochemical properties, REE concentrations, bacterial and fungal community structures, and untargeted metabolomic profiles were comprehensively analyzed. Compared with CK, both PE and CS increased soil organic matter, alkali-hydrolyzable nitrogen, and available potassium and were associated with lower concentrations of several REEs, including Dy, Nd, Er, Y, and Yb, whereas the response of Ce differed between vegetation types. The two vegetation treatments exerted inconsistent effects on microbial communities: PE significantly increased bacterial richness and Shannon index and increased fungal richness, but decreased fungal Pielou evenness and Shannon index; in contrast, CS did not markedly enhance bacterial alpha diversity. Community composition analysis showed that vegetation treatments altered the relative abundances of dominant bacterial and fungal taxa, which were closely associated with changes in pH, soil organic matter, nitrogen, phosphorus and potassium nutrients, and REEs. Metabolomic analysis indicated that fatty acyls, organooxygen compounds, and carboxylic acids and derivatives were the major classes of differential metabolites. Pathways such as ABC transporters, nicotinate and nicotinamide metabolism, purine metabolism, and secondary metabolite biosynthesis may participate in soil metabolic reshaping under vegetation restoration. Overall, this study indicates that broadleaf paspalum and slash pine have differentiated ecological effects in REE tailing restoration and provides preliminary field evidence for vegetation recovery and soil microecological reconstruction in REE mining areas of southern Jiangxi. Full article

Background: In the coming decades, the agricultural system will increasingly rely on organic amendments to sustain crop production, maintain soil health and ensure long-term food security. While inorganic fertilizers remain widely used for vegetable production due to their rapid nutrient availability, their prolonged application has been shown to degrade soil quality, disrupt microbial communities and limit the nutritional quality of harvested produce. Consequently, there is a growing need to explore organic alternatives such as biochar and poultry manure that can enhance both crop productivity and functional quality. Objective: This study aimed to determine the influence of different application rates of biochar (5/T₁, 10/T₂, and 20/T₃ t/ha), poultry manure (10/T₁, 20/T₂, 30/T₃ t/ha), and NPK (2:3:4) as control on the metabolomic profile of tomato fruit. Methods: The metabolomic profile was determined using 1H-nuclear magnetic resonance (NMR). Results: Common metabolites across biochar rates included allantoin, asparagine and betaine, while rate-specific released metabolites such as inosine (T₁), epicatechin (T₂) and kynurenine (T₃) were also identified. Similarly, poultry manure showed an array of metabolites at the highest application rate, with metabolites such as cellobiose, creatinine and maltose, while histamine (T₁) and ADP (T₃) were also detected as distinct metabolites. Full article

As high-density cities face severe conflicts between urban expansion and limited ecological space, exploring the potential drivers of carbon sequestration within urban green spaces is crucial. The overarching aim of this study is to establish an interpretable, model-based analytical framework for assessing the Annual Carbon Fixation Rate (ACFR). To address the limitations of linear models and “black-box” machine learning algorithms, this study analyzed 149 urban parks in Nanjing by coupling Sentinel-2 high-resolution data with a Random Forest algorithm and the SHAP framework to model Annual Carbon Fixation Rate. The model achieved high predictive reliability (R² = 0.9690). This study quantitatively identified critical nonlinear thresholds: an impervious surface proportion exceeding 30% is associated with a structural decline in carbon sinks, while the optimal Leaf Area Index interval for maximum efficiency is 2.5–3.5. Moreover, the present research identified a potential model-derived ecological compensation effect; optimizing vegetation community structures under high anthropogenic disturbance showed a 23.9% higher modeled marginal ACFR response compared to low-disturbance habitats. This explainable framework attempts to translate complex model-derived biophysical associations into referenced quantitative thresholds. Importantly, the ACFR and derived thresholds represent remote sensing-based model estimates rather than field-measured ecological causality, serving as exploratory planning references. These findings challenge the assumption that greening is inefficient in degraded environments and provide concrete control indicators for targeted micro-renewal and sustainable urban regeneration. Full article