Search Results (111)

Litter accumulation and small mammal disturbances create specific fine-scale microhabitats in grasslands. These microhabitats serve as safe sites and regeneration niches for subordinate plant species and are important in diversity maintenance. Previous experiments manipulating litter and disturbance and studying their effects on diversity revealed complex relationships. However, little is known about the realized net effects of these mechanisms in different types of grasslands. We conducted a long-term observational study exploring these patterns and their effects in successional and mature grasslands. We applied a specific mapping technique: the presences of litter, disturbance, and living plant species were recorded in 5 cm × 5 cm contiguous microquadrats along 52 m permanent transects. Sampling was repeated annually over 10 years. Spatial dynamics and associations with subordinate grassland specialists were evaluated using information theory models. Analyses were performed at increasing spatial and temporal scales. Varying associations were found across years. Negative associations dominated the relationships between litter and local diversity hotspots, while the relationships with disturbances were mainly neutral. When analyses were repeated at longer time scales, consistent negative associations were detected between litter and diversity hotspots. Long-term relationships between disturbance and diversity were negative in old-fields and positive in the natural grassland. To collect more representative and reliable data on the role of plant litter accumulation and small mammal disturbances, we recommend long-term annual monitoring and the application of temporal scaling based on cumulative diversity. Full article

Soil organic carbon (SOC) is a key component of terrestrial carbon stocks, yet its spatial variability, recovery potential, and dominant controls across tropical forest succession remain insufficiently quantified. We combined field measurements from 40 natural forest plots on Hainan Island, China, with laboratory analyses and multi-source environmental data to assess topsoil SOC (0–20 cm) distribution, recovery potential, and regulatory drivers. In natural forests on Hainan Island, topsoil SOC stocks ranged from 33.06 to 62.60 Mg · C · ha⁻¹. Using the median (Q0.5) SOC of old-growth forests as the reference level, recovery potential ranged from 12.60 to 42.14 Mg · C · ha⁻¹. Topsoil SOC exhibited clear spatial heterogeneity across the island, with higher values in more continuous forest areas. Secondary forests generally exhibited lower current SOC but greater recovery potential, whereas old-growth forests showed higher and more stable stocks. Multivariate analyses revealed a clear successional shift in dominant controls: total phosphorus (TP) was the primary predictor in secondary forests, while total nitrogen (TN) dominated across the full gradient, particularly in old-growth forests. These findings highlight stage-dependent SOC regulation and the critical role of soil nutrient status in shaping tropical forest carbon recovery. Full article

The Muški bunar old-growth forest on Mount Psunj represents one of the rare preserved mixed ecosystems of sessile oak (Quercus petraea (Matt.) Liebl.) and European beech (Fagus sylvatica L.) in Southeastern Europe, providing an important reference for understanding natural forest dynamics. This study aimed to analyse stand structure, age distribution, growth dynamics, and disturbance regime based on repeated field surveys conducted in 1979 and 2021. The results revealed pronounced structural heterogeneity and clear interspecific differences. European beech dominates smaller- and medium-diameter classes, as well as a wider range of age classes, whereas sessile oak is primarily present in older and larger diameter classes. A very high growing stock (1155.81 m³ ha⁻¹) indicates exceptional stand productivity, with maximum cambial ages of 295 years for oak and 253 years for beech. Basal area increment analysis showed that both species maintain substantial growth at advanced ages. However, recent decades show divergence, with increasing growth in beech and stagnation or decline in oak. Importantly, growth releases in sessile oak were not accompanied by successful regeneration, indicating a decoupling between growth response and recruitment. Stand dynamics are mainly driven by low-intensity disturbances. These findings highlight the importance of old-growth forests as reference systems and improve understanding of species-specific responses to disturbance. Full article

Cashew (Anacardium occidentale L.), a vital tropical cash crop, may face yield declines in old plantations due to unexplored risks of autotoxicity. This study investigated the allelopathic and autotoxic potential of cashew plant under laboratory and greenhouse conditions. The laboratory bioassays with leaf and stem bark (10–200 mg) demonstrated a strong allelopathic effect, reducing lettuce radicle elongation to 7–46.0% and 9–79% of the control, respectively. Aqueous leaf extract (50 mg/mL) completely inhibited (0%) lettuce seed germination and reduced pepper germination to 42%. However, the root exudate of cashew seedlings did not have any inhibitory effect on the test plants. Greenhouse experiments simulating field litter fall revealed significant autotoxicity in cashew. Cashew seedlings grown in growth media amended with 10% cashew leaf powder exhibited severe growth suppression after 13 weeks, including a reduction in plant height by 58.2% compared to controls. Chlorophyll content, stem girth, and leaf number were also significantly reduced. This study concludes that cashew possesses significant allelopathic properties and a clear potential for autotoxicity, as directly evidenced by the suppressed growth of its own seedlings following the incorporation of leaf powder. These findings identify autotoxicity, mediated through leaf litter decomposition, as a critical risk factor for the replanting success and long-term sustainability of cashew orchards, necessitating further investigation into management strategies. Full article

Argania spinosa L. Skeels is an ecological pillar of the arid zones of South-West Morocco, currently threatened by the drastic climate change. This study investigates the effect of the combined application of compost (C) and subsurface water retention technology (SWRT) on field performances of one-(1Y) and two-year-old (2Y) argan seedlings. A randomized field trial was performed with four treatments: Control, C, SWRT, and C + SWRT. We evaluated soil properties, growth, and physiology, alongside biochemical parameters including stress markers, compatible solutes, antioxidant enzyme activities, and secondary metabolites. The results reveal the significant effect of C and/or SWRT on argan seedlings performances, particularly in 1Y subjects. The C + SWRT strongly stimulated stem elongation (246% vs. 163%), stomatal conductance (75% vs. 99%), photosynthetic efficiency (18% vs. 11%), and chlorophyll a content (80% vs. 65%) in 1Y and 2Y seedlings, respectively, compared to their corresponding controls. Under the same treatment, malondialdehyde levels were significantly reduced by 37% in 1Y seedlings and 23% in 2Y seedlings. In addition, catalase activity and soluble sugar, protein, and polyphenol content increased by 38, 43, 26, and 21%, respectively, in the younger seedlings and by 53, 51, 18, and 19%, respectively, in the elder seedlings. In terms of soil health, C + SWRT significantly enhanced total organic carbon and matter, available phosphorus, and reduced electrical conductivity. In summary, the C + SWRT application significantly improved argan plant performances, with a particularly marked effect on 1Y seedlings, which makes this combination an alternative solution to enhance the resilience of the argan tree in the era of climate change and promote the success of the reforestation program. Full article

This study was carried out to investigate stand structure, growth dynamics, and carbon fluxes in Pinus rigida plantations of varying ages in South Korea. Field measurements across four mountain sites quantified diameter-class distributions, net primary productivity (NPP), soil respiration, and net ecosystem production (NEP). P. rigida exhibited normally distributed diameter structures in larger classes, whereas Quercus spp. showed reverse J-shaped patterns, indicating active regeneration and ongoing succession toward mixed broadleaved stands. Individual NPP was highest in P. densiflora (4.77 kg yr⁻¹) and P. rigida (4.31 kg yr⁻¹), while Quercus spp. displayed lower growth due to light limitation. Stand-level NPP peaked in 20–40-year-old stands (4.27–4.88 ton C ha⁻¹ yr⁻¹) and declined with age (2.30 ton C ha⁻¹ yr⁻¹). Soil respiration averaged 1.0 ton C ha⁻¹ yr⁻¹ and was strongly temperature dependent (R² = 0.56; Q₁₀ = 2.70). NEP on Mt. Galmi reached 4.38 ton C ha⁻¹ yr⁻¹, demonstrating substantial carbon sink capacity. These findings indicate that aging P. rigida plantations maintain ecosystem-level carbon uptake through successional compensation. Policy efforts should prioritize adaptive thinning, assisted natural regeneration, and long-term monitoring frameworks to accelerate the transition toward climate-resilient mixed forests and to strengthen national forest carbon neutrality strategies. Future research should integrate long-term carbon flux observations, species interaction modeling, and assessments of climate-driven disturbance regimes to refine management pathways for resilient mixed-forest landscapes. Full article

Spatial heterogeneity of species distributions modulates local interactions and dynamics, playing a key role in the development of diversity and ecosystem functioning during secondary succession. Here, we tested the cycling heterogeneity hypothesis, which predicts fluctuating spatial beta diversity, i.e., alternating periods of high and low heterogeneity during succession, driven by the changes in the abundance of dominant species. We analyzed long-term monitoring data collected annually along 52 m long permanent transects over 15 years in abandoned fields. Recovery of grassland vegetation was fast due to the humus-rich chernozem soil, the rich species pool, and the fast colonization of native grassland species from adjacent natural meadow steppe. Heterogeneity was quantified by spatial beta diversity as the mean pairwise dissimilarity among sampling units. Incidence-based (Jaccard) and abundance-based (Bray–Curtis) indices were used. We found large temporal fluctuations in spatial heterogeneity, with amplitudes reaching 80–100% of the total beta diversity range across the successional gradient. Two major beta diversity peaks were identified: maximum heterogeneity occurred during transitions between successional phases, whereas periods of minimum heterogeneity coincided with the sequential dominance of a few particular species. Bromus sterilis and Festuca valesiaca were the most important species driving heterogeneity. Similar patterns were recorded at two monitoring sites. Changing the sampling unit size computationally, varying the dissimilarity indices, or excluding dominant species had little influence on the results. Using null models, we removed the effects of species richness and abundance and found an increasing degree of spatial dependence as succession progressed. However, the corresponding beta deviations also showed non-linear, fluctuating patterns. Our results support the cycling heterogeneity hypothesis in secondary grassland succession. Increasing understanding of heterogeneity patterns provides new opportunities to optimize the temporal and spatial design of grassland restoration measures. Full article

Background: Catheter ablation of atrial fibrillation (AF) is now a Class I recommendation therapy. However, the standard inferior vena cava (IVC) approach of catheter ablation is not feasible in all patients. Case presentation: We report a case of a 64-year-old woman in whom guidewire passage was hindered by prior left iliac vein stent placement and with symptomatic recurrent paroxysmal AF who underwent successful pulmonary vein isolation with a pulsed-field ablation system by superior vena cava (SVC) access from the right internal jugular vein. Conclusions: PFA administered via the SVC provides an effective and efficient treatment strategy for patients with paroxysmal AF ineligible for standard IVC catheter ablation. Full article

Foot-and-mouth disease (FMD), a vesicular disease, causes lesions in the mouth, nose, teats, and feet of cloven-hoofed animals. Vaccination remains the most effective method to prevent FMD outbreaks. Since 2010, South Korea has implemented nationwide vaccination and developed multiple domestic vaccine strains to achieve vaccine self-sufficiency. Here, we aimed to construct an infectious clone using the A/SKR/Yeoncheon/2017 virus, which exhibits the highest antigen productivity among previously developed vaccine strains. An infectious clone was constructed based on the A/Yeoncheon/SKR/2017 virus isolated during an FMD outbreak in Korea in 2017. The viral genome was amplified in two fragments and assembled into a full-length clone, from which infectious recombinant virus was successfully rescued. The rescued virus was confirmed via serotyping and transmission electron microscopy to exhibit canonical 25–30 nm icosahedral morphology. Under optimized culture conditions using suspension-adapted BHK-21 cells (multiplicity of infection 0.001; 12 h post-infection), the recombinant virus achieved titers of 10⁸ TCID₅₀/mL and produced 6.2 μg/mL of 146S antigen, comparable to its parental counterpart. The experimental vaccine formulated with the rescued virus (15 μg/dose), 1% saponin, 1% aluminum hydroxide gel, and ISA 206 VG, induced protective immunity in eight-week-old pigs, with vaccinated animals exhibiting no clinical signs following homologous challenge. To our knowledge, this study represents the first successful construction of an infectious clone derived from a field-isolated serotype A FMDV in South Korea. In the future, this A/SKR/Yeoncheon/2017 infectious clone can serve as a platform backbone for the rapid development of next-generation, high-yield vaccine seed strains through targeted epitope exchange. Full article

With the characteristic of “decentralized distribution and local power supply”, small hydropower (SHP) in China has become a core means of solving the problem of insufficient power supply in rural and remote mountainous areas, effectively promoting the improvement of local livelihoods. However, for a long time, SHP has had many problems, such as irrational development, old equipment, and poor economic efficiency, resulting in some rivers with connectivity loss and reduced biodiversity, etc. The Chishui River Watershed is an ecologically valuable river in the upper reaches of the Yangtze River. As an important habitat for rare fish in the upper reaches of the Yangtze River and the only large-scale tributary that maintains a natural flow pattern, the SHP plants’ dismantling and ecological restoration practices in the Chishui River Watershed can set a model for regional sustainable development. This paper adopts the methods of literature review, field research, and case study analysis, combined with the comparison of ecological conditions before and after the dismantling, to systematically analyze the effectiveness and challenges of SHP rectification in the Chishui River Watershed. The study found that after dismantling 88.2% of SHP plants in ecologically sensitive areas, the number of fish species upstream and downstream of the original dam site increased by about 6.67% and 70%, respectively; the natural hydrological connectivity has been restored to the downstream of the Tongzi River, the Gulin River and other rivers, but there are short-term problems such as sediment underflow, increased economic pressure, and the gap of alternative energy sources; the retained power stations have achieved the success and challenges of power generation and ecological management ecological flow control and comprehensive utilization, achieving a balance between power generation and ecological protection. Based on the above findings, the author proposes dynamic monitoring and interdisciplinary tracking research to fill the gap of systematic data support and long-term effect research in the SHP exit mechanism, and the results can provide a reference for the green transition of SHP. Full article

Mandibular reconstruction with the fibula free flap is the gold standard for large defects, with virtual surgical planning becoming integral to the process. The localization and dissection of critical vessels, such as the recipient vessels in the neck and the perforating vessels of the fibula flap, are demanding steps that directly impact surgical success. Augmented reality (AR) offers a solution by overlaying three-dimensional virtual models directly onto the surgeon’s view of the operative field. We report the first case in Latin America utilizing a low-cost, commercially available holographic navigation system for complex microsurgical mandibular reconstruction. A 26-year-old female presented with a large, destructive osteoblastoma of the left mandible, requiring wide resection and reconstruction. Preoperative surgical planning was conducted using DICOM data from the patient’s CT scans to generate 3D holographic models with the Medicalholodeck^® software. Intraoperatively, the primary surgeon used the AR system to superimpose the holographic models onto the patient. The system provided real-time, immersive guidance for identifying the facial artery, which was anatomically displaced by the tumor mass, as well as for localizing the peroneal artery perforators for donor flap harvest. A free fibula flap was harvested and transferred. During the early postoperative course and after 3-months of follow-up, the patient presented with an absence of any clinical complications. This case demonstrates the successful application and feasibility of using a low-cost, consumer-grade holographic navigation system. Full article

The conservation of plant species requires detailed knowledge of their reproductive behaviour and population demographic structure. This is particularly important for species such as Cardamine bulbifera, which depend on old-growth forest habitats and rely predominantly or entirely on vegetative reproduction through axillary bulbils. Although C. bulbifera has a wide native range, little is known about its population structure and dynamics. The aim of this study was to assess the demographic composition, density and main traits of C. bulbifera individuals in six populations occurring in three types of forest habitats in southern Lithuania: Fennoscandian hemiboreal natural old broadleaved deciduous forests, Fennoscandian herb-rich forests with Picea abies and Galio-Carpinetum oak–hornbeam forests. Field studies were conducted in 2023, during which a total of 20 sampling plots (each 1 m²) were analysed in each population, arranged in a transect. The study revealed an absolute dominance of young (juvenile and immature) individuals in the populations (89.2%), whereas mature individuals comprised only a small fraction (10.8%). The proportion of mature individuals was significantly larger in hornbeam forests than in the other two forest types. The highest density of individuals was recorded in broadleaved forest, while the lowest density was found in spruce forest habitat. Mature C. bulbifera individuals in hornbeam habitats were significantly taller and had longer inflorescences than those in other habitats. The highest mean number of bulbils was produced by individuals of the studied species in spruce habitats, while bulbil production was lowest in hornbeam habitats. The strongest negative contribution to the number of C. bulbifera individuals was the area of bare soil in the sampling plot, whereas herb cover had the strongest positive effect. These results highlight habitat-specific differences in C. bulbifera population structure and suggest that the long-term viability of its populations is closely associated with forest type, as well as stability of the habitat and plant community. The optimum habitat conditions for C. bulbifera are found in old broadleaved forests, and habitats with natural succession are the most favourable for its growth and conservation. Full article

Dominant species form species-specific fine-scale vegetation matrices in grasslands that regulate community dynamics, diversity and ecosystem functioning. The structure of these dynamic microscale landscapes was analyzed and compared between primary and secondary plant communities. We explored fine-scale monitoring data along permanent transects over seven consecutive years. Spatial and temporal patterns of dominant grass species (Festuca valesiaca, Alopecurus pratensis and Poa angustifolia) were analyzed using information theory models. These matrix-forming species showed high spatiotemporal variability in all grasslands. However, consistent differences were found between primary and secondary grasslands in the spatial and temporal organization of the vegetation matrix. Alopecurus pratensis and Poa angustifolia had coarse-scale patchiness with stronger aggregation in secondary grasslands. The spatial patterns of Festuca valesiaca were nearly random in both types of grasslands. Strong associations were observed among the spatial patterns of each species across years, with a stronger dependence in secondary grasslands. In contrast, the rate of fine-scale dynamics was higher in primary grasslands. The complexity of microhabitats within the matrix was higher in primary grasslands, often involving two to three dominant species, while, in secondary grasslands, patches formed by a single dominant species were more frequent. In the spatial variability of small-scale subordinate species richness, significant, temporally consistent differences were found. Higher variability in secondary grasslands suggests stronger and more spatially variable microhabitat filtering. We recommend that grassland management and restoration practices be guided by preliminary information on the spatial organization of primary grasslands. Enhancing the complexity of the matrix formed by dominant species can further improve the condition of secondary grasslands. Full article

Cryptosporidium is a genus of protozoa that infects the gastrointestinal and respiratory epithelium of various host species. The aim of this study was to perform experimental infection in conventional mice with three Cryptosporidium species isolated from humans. The three Cryptosporidium species, namely Cryptosporidium canis, Cryptosporidium parvum, and Cryptosporidium ryanae, were obtained from fecal samples collected from patients hospitalized in an infectious disease hospital. The mice, from 10-day-old litters kept with their mother, were divided into three groups and orally infected with one of the Cryptosporidium species. The first oocysts were identified in the feces of the mice four days post-infection. The infection was successful with all three Cryptosporidium species, but the infection level (expressed as the number of oocysts per microscopic field) was low. The infection was detected using a rapid immunochromatographic test 40 days post-infection. Furthermore, starting on the 17th day after infection, the mothers also tested positive on the rapid immunochromatographic test, having been negative until that point. It was concluded that mice could represent a source of infection for the three Cryptosporidium species in other susceptible species, including humans. No behavioral changes or diarrhea were observed in any of the experimental cases. Full article

Regenerating sweet potato from field-derived plant material requires careful management of several critical factors, including the effectiveness of the disinfectant, the age of the explant, and the genotype used. In this context, establishing a reliable aseptic protocol is essential for successful in vitro culture. This study aimed to assess the effects of two disinfectants (sodium hypochlorite and mercuric chloride), three sweet potato genotypes (Nakabo, Boyapleu, and Irene), and three explant ages (2, 3, and 4 weeks) on clean culture establishment and regeneration efficiency from nodal explants. The findings revealed that regeneration success is significantly influenced by the type and concentration of disinfectant, explant age, and genotype. Treatment with 10% sodium hypochlorite markedly reduced contamination, achieving clean culture and regeneration rates of 75.72 ± 3.36% and 86.83 ± 3.02%, respectively, regardless of explant age. In contrast, higher concentrations of mercuric chloride induced necrosis in the explants. The highest clean culture rate (93.82 ± 1.16%) was observed in 3-week-old explants, which also showed a regeneration rate of 54.93 ± 3.19%. Furthermore, the Boyapleu and Irene genotypes demonstrated good suitability for in vitro culture, whereas the Nakabo genotype performed poorly under the tested conditions. Full article