Search Results (135)

Subalpine grasslands (SGs) of the Loess Plateau in China play a crucial role in the global carbon cycle of terrestrial ecosystems. However, the distribution pattern of total carbon stores along an elevation gradient on the SG plants of the eastern plateau remains unclear. In this study, eight typical mountains with one well-developed SG being surveyed as plot for each mountain were selected along an elevation gradient from 1722 m to 2954 m on the east of the plateau. The vegetation area, hydrothermal factors, soil elements, and species composition were analyzed using methods of spatial analysis and a partial least squares structural equation model (PLS-SEM), and these were used to estimate the total carbon stores of different plant functional groups for the entire area of each SG. This study revealed the driving factors of the elevational pattern of plant carbon storage in the SGs. The entire plant carbon storage of the eight SGs was 35,880.98 Mg in total. In addition, the aboveground and belowground carbon storage values both exhibited U-shaped trends along the elevation gradient. Significant minimum values were observed at the mid-elevation regions, ranging from 2305 m to 2673 m. The plant carbon storage was predominantly allocated to the belowground portions (accounting for 72.3% of the total carbon storage), and this allocation strategy was more pronounced at both low- and high-elevation regions. The carbon storage proportion among the different plant functional groups was the largest for forbs (average in 2348.85 Mg, accounting for 52%), medium for sedges (average in 1982.81 Mg, accounting for 44%), and the smallest for grasses (average in 153.47 Mg, accounting for 4%). The plant species diversity promoted carbon accumulation in the sedges and forbs, while the soil total phosphorus exhibited an inhibitory effect. In the PLS-SEM, hydrothermal factors (total effect = −0.8107) and species diversity (total effect = 0.4969) were the primary drivers of the plant carbon storage elevational pattern in the SGs, while the soil properties (total effect = −0.3501) and biomass (total effect = 0.0697) effects did not reach statistical significances. Therefore, the plant carbon storage distribution pattern along the elevation gradient was driven by hydrothermal factors and species diversity on the SGs of the eastern plateau. The plants such as forbs and sedges might play more important roles in improving regional plant carbon storage in high-elevation grasslands, through interactions with hydrothermal factors. Full article

Microbial functional traits play a central role in regulating carbon mineralization efficiency (CME) in peatlands, yet how they respond to concurrent warming and atmospheric nitrogen deposition remains unclear. In this study, peat soils from three vegetation types (sedge, reed, and shrub) were subjected to controlled microcosm incubations simulating warming and nitrogen addition gradients. Microbial community composition and functional profiles were characterized using 16S rRNA high-throughput sequencing and Functional Annotation of Prokaryotic Taxa (FAPROTAX) functional prediction, while dissolved organic matter (DOM) composition was analyzed via excitation–emission matrix fluorescence spectroscopy with parallel factor analysis (EEM-PARAFAC) and fluorescence indices. Integrating correlation analysis, Random Forest, and partial least squares path modeling (PLS-PM) modeling, we identified microbial functional traits as key factors linking environmental changes to soil CME, with DOM serving as a substrate-mediated pathway. External nitrogen input primarily drove shifts in microbial functional composition, whereas warming modulated substrate utilization preferences and DOM turnover. The interaction between warming and nitrogen selectively reshaped microbial functional profiles, thereby jointly determining CME. Functional traits explained more variation in CME than taxonomic composition, indicating a “structure–function decoupling” under environmental change. These findings highlight the central role of microbial functional traits in peatland carbon transformation and suggest that the net response of peatland carbon emissions to future environmental change will depend critically on the balance between warming magnitude and nitrogen deposition levels. Full article

The increasing demand for energy, the finite nature of fossil fuel resources, and the necessity to reduce greenhouse gas emissions have intensified research on renewable energy sources of plant origin. Among potential energy feedstocks, herbaceous biomass has attracted growing interest due to its high productivity, rapid growth, and widespread occurrence. The aim of this study was to evaluate the energy potential of select sedge species (Carex spp.) commonly occurring in Poland as an alternative to fossil fuels. Aboveground biomass of eight sedge species was collected from natural habitats located in the Warta River valley. Cellulose, lignin, holocellulose, hemicellulose, and ash content in the biomass was determined. In addition, key energy parameters, namely net calorific value and gross calorific value, were analyzed. Differences among species were assessed using one-way analysis of variance, while similarities were explored using hierarchical clustering methods. The results revealed significant interspecific variation in both chemical composition and energy properties. Most analyzed sedge species had favorable lignocellulosic composition and energy parameters comparable to those of woody biomass, particularly willow and poplar. In contrast, Carex riparia was distinguished by a high ash content and lower calorific values, limiting its suitability for energy applications. Overall, the findings indicate that select Carex species may represent a valuable renewable feedstock for energy production, especially in the context of local and decentralized biomass-based energy systems. Full article

Background/Objectives: Eleocharis ussuriensis Zinserl. is a perennial riparian sedge widely distributed in Northeast Asia and a dominant component of freshwater vegetation in South Korea. However, the intraspecific genetic structure of this species across contrasting hydrological habitats remains insufficiently understood. This study aimed to develop novel SSR markers from whole-genome data and investigate genetic variation and population structure among E. ussuriensis populations in South Korea. Methods: Twenty-one novel simple sequence repeat (SSR) markers were developed from whole-genome sequence data and applied to analyze genetic variation in 120 individuals from 6 populations. Genetic diversity, differentiation, and gene flow were estimated using allele-frequency-based metrics, and population genetic structure was further evaluated using spatial information derived from geographic coordinates. Results: A total of 201 alleles were detected, with a mean polymorphism information content (PIC) of 0.759, indicating high marker informativeness. Mean genetic diversity across populations showed observed heterozygosity (Ho = 0.360) and expected heterozygosity (He = 0.281), while multilocus genotype ratios (G/N) ranged from 0.30 to 1.00 among populations. Genetic differentiation was substantial (F_ST = 0.373–0.669; Jost’s D = 0.540–0.997). Mantel tests revealed that genetic differentiation was significantly correlated with geographic distance (r = 0.67, p < 0.001). Both allele-frequency-based and spatially explicit approaches suggested genetic structuring among populations. Conclusions: The results suggest spatial tendencies in genetic structure among populations, reflecting patterns of allele distribution across regions. These findings provide baseline information on genetic variation in E. ussuriensis and may contribute to a better understanding of its ecological dynamics. Full article

This study has investigated the occurrence characteristics and population damage of weeds in double-cropping direct-seeded rice fields in Hunan, and has identified efficient and safe pre- and post-emergence herbicides to enhance resistance management. Field trials were conducted at two representative sites (Yiyang and Changsha) in Hunan in 2024~2025. Weed community composition and emergence patterns were systematically monitored. The inhibitory effects of weed infestations on rice growth and yield were quantified. The biological activity and field efficacy of various herbicide classes against barnyardgrass (Echinochloa crus-galli) were evaluated via greenhouse bioassays and field trials. Weed emergence lasted 3–48 days after sowing (DAS) with three distinct peaks. Grasses emerged earliest and dominated the community, with barnyardgrass peaking at 13–17 DAS (≈50% of total weeds), followed by broadleaves at 20 DAS (≈40%) and sedges at 25 DAS (<20%). Weed infestation drastically suppressed rice height (max 19% reduction) and tillering (max 50% reduction), with mixed-weed and grass-dominated plots causing the severest yield losses (92.0% and 90.5%, respectively), versus only 18.0% in broadleaf-dominated plots. Greenhouse bioassays showed that oxaziclomefone had the highest intrinsic activity against barnyardgrass (GR₉₀ = 17.70 g ai ha⁻¹). In pre-emergence applications in field trials, pretilachlor (900 g ai ha⁻¹) and mefenacet (147.6 g ai ha⁻¹) provided >96.8% control at 20 and 40 days after treatment (DAT), while oxaziclomefone (66 g ai ha⁻¹) achieved 88.2% control at 20 DAT. For post-emergence herbicides, Profoxydim showed the highest intrinsic activity (GR₉₀ = 33.01 g ai ha⁻¹), followed by feproxydim (GR₉₀ = 33.45 g ai ha⁻¹) and flusulfinam (GR₉₀ = 64.55 g ai ha⁻¹). In field trials, flusulfinam provided 100% control with superior crop safety at 20 and 40 DAT, while Florpyrauxifen-benzyl, feproxydim, and metamifop reached >93% efficacy. In conclusion, weed emergence in Hunan direct-seeded rice follows a three-peak pattern, with barnyardgrass being the most destructive species. An integrated strategy combining pretilachlor (pre-emergence) and flusulfinam (post-emergence), rotated with florpyrauxifen-benzyl and feproxydim, is recommended for effective barnyardgrass management and resistance mitigation. Full article

Florpyrauxifen-benzyl (FPB) is an auxin-mimic herbicide that controls selected grasses, sedges, and broadleaves in rice cropping systems. Field experiments were conducted in 2023 and 2024 to characterize the effects of FPB on crop safety and weed control when applied alone or in combination with other herbicides, and to assess whether FPB can provide season-long, effective weed management. Base treatments of benzobicyclon (BBC)/halosulfuron-methyl (HSM), clomazone (CLM), or thiobencarb (TBC) were applied on the day of seeding (DOS) or within the 2-leaf stage (LS) rice and followed by foliar treatments of FPB alone or in a mixture with bispyribac-sodium (BPS), penoxsulam (PNX)/cyhalofop-butyl (CHB), or propanil (PPL). Additionally, FPB was applied alone with no prior base treatment, in combination with a mixture partner, and as a sequential treatment, 14 days apart, with the first application made to 4- to 5-LS rice; in contrast, the second application was made to mid-tillering rice. The FPB applied alone or in sequential application showed results for more than 98% of watergrasses and 100% of ricefield bulrush, smallflower umbrella sedge, ducksalad, redstems, and all other broadleaves control at 56 days after treatment (DAT). When applied after the base treatments, the weed control increased to 100% for all weed species at 14 DAT. The sequential application of FPB achieved the highest yields of 7683 kg ha⁻¹ in 2023 and 11,249 kg ha⁻¹ in 2024, resulting in 3.6- and 6.4-fold increases in rice yield over the nontreated control. Owing to its excellent sedge and broadleaf weed control and good activity on troublesome grasses, such as barnyardgrass, FPB could be an essential part of the weed management programs in rice production systems. Full article

Current climatic conditions are drying peatland ecosystems, compromising carbon storage through increased decomposition and vegetation shifts. Large-scale monitoring is essential to quantify climate change impacts on vegetation and hydrology. PlanetScope high-resolution imagery (3 m pixel) over seven years (2017–2023) served as proof-of-concept for a central European peatland (Rzecin, Poland). The enhanced vegetation index (EVI) was selected based on ground validation (R = 0.9 vs. 0.8 for NDVI-normalised vegetation index). Phenological metrics (SOS—start of the season; EOS—end of the season; LOS—length of the season; POS—peak of the season; EVImax; amplitude; area) were derived via DATimeS from snow-free EVI time series. Trends were analysed using pixel-wise slopes, change-point detection (break ~2020–2021), paired correlations, subarea (P1–P4) behaviour, and PCA, alongside air temperature (Tair), precipitation, and water table depth (WTD). Results revealed LOS and peak EVI increased until 2020, a 2021 break, and a 2022–2023 recovery, signalling nonlinear vegetation reorganisation. Transitional mire floating mats (Sphagnum spp.–Carex spp.–Vaccinium oxycoccus) showed the longest seasons/highest greenness but weakest hydrometeorological links, implying rising internal dynamics. Phragmites mats, fern–sedge edges, and riparian willow differed in tolerance or sensitivity to WTD and precipitation oscillations. Tair dominated EVI seasonality across types, while WTD and precipitation controlled phenology and greenness in edges, showing better results with phase-aligned means. Vascular plants outpaced mosses in peak EVI and persistence, with patch-specific shifts. Full article

Although the central focus of ecology has long been the relationship between biodiversity and ecosystem functioning, this relationship has rarely been explored in species-poor communities such as salt marshes, which have the potential to shed new light on this debate. We conducted two microcosm experiments, each testing a different environmental variable (salinity or disturbance) and its interaction with the plant community’s richness and species composition, using all possible combinations of the three sedge species found in the pioneer plant community in the Yangtze River Estuary. The relationships between diversity and productivity were weak and non-significant, possibly due to intense competition among the sedges. Species composition played a more important role in determining productivity. Moreover, biodiversity effects were found to be environment-dependent. Salinity stress increased the selection effect, while disturbance tended to increase both selection and complementarity effects. Interestingly, the correlation between biodiversity and stability was non-linear and presented different patterns in the salinity and disturbance experiments. Our results show that species-poor systems with low functional group diversity may exhibit weak relationships between biodiversity and ecosystem functioning during the establishment phase under controlled experimental conditions. In this ecosystem, species richness rarely impacted biomass, which was instead primarily driven by species composition and environmental conditions. Full article

This study examines a long-term dataset where 16 passerine species, classified as long-distance migrants, short-distance migrants, and residents were monitored at the Santo André National Ringing Station (Portugal) from 1997 to 2024. Using standardized capture data from 16 passerines species collected during the autumn migration period, we evaluated trends in population abundance over a 27-year time span. Our analyses revealed pronounced and statistically robust declines in all long-distance migratory species, particularly savi’s warbler, grasshopper warbler, and sedge warbler, which are now almost locally extinct. In contrast, short-distance migrants and resident species exhibited more heterogeneous patterns depending on their ecological specialization, yet all strictly insectivorous taxa, except for the chiffchaff, showed marked population declines, particularly the bluethroat and the sardinian warbler. The parallel decline in insectivorous species across migratory strategies points to a widespread trophic effect, likely linked to the global depletion of insect populations, driven by habitat destruction, pesticide use, pollution, and climate change. Collectively, these findings emphasize the urgent need for regionally adapted, long-term monitoring programs to inform effective conservation strategies in the face of accelerating climate and land-use change. Full article

Wetlands characterized by the presence of rare and endangered reed plant communities are seriously threatened by hydrological changes and pollution caused by human activity, e.g., drainage, river regulation, and conversion to agricultural land. Despite numerous studies of wetland communities, the “volume of ecological niche” based on Ellenberg indices, i.e., the ecological preferences of vascular plant species, has rarely been analyzed at the level of entire plant communities. Properly defined indicators of microclimatic and habitat factors (ranges of environmental conditions), appropriate for individual rush and sedge communities (specific communities), are very important for the sustainable management of ecosystems and potential restoration processes in renaturation activities. Therefore, a comprehensive floristic and habitat assessment of wetland communities of the Phragmitetea class was conducted in a Natura 2000 site in southeastern Poland (name and number of the Natura 2000 site—Wolica Valley PLH060058), located within the East European Lowland. The communities were analyzed in the context of the variability of individual Ellenberg indices and designated ecological hypervolumes. These were typical rush communities occurring in wet and fertile soils with a neutral or alkaline pH. The microclimatic conditions were typical for these habitats. The studied communities differ in terms of the variability of Ellenberg ecological indices. Some of them are characterized by low ecological niches, while others are characterized by larger ones. The volume of determined multidimensional hypervolumes allowed us to distinguish two communities (Phragmitetum australis and Caricetum rostratae) to have greater generality compared to the others. They can occur in a greater variety of environmental conditions than other communities that require more specific conditions. Other phytocenoses with low hypervolume values (hypervolumes more than 10 times smaller than mentioned before) were distinguished by high habitat specialization. In turn, the analysis of the overlapping of hypervolumes allowed us to group communities into four clusters with similar ranges of Ellenberg indices’ values: (1) Caricetum distichae and Caricetum gracilis; (2) Glycerietum maximae, Iridetum pseudoacori, Caricetum appropinquatae, and Phalaridetum arundinaceae; (3) Phragmitetum australis and Caricetum rostratae; and (4) Caricetum acutiformis, Caricetum vesicariae, and Caricetum elatae. Full article

During the pre-hydrotreatment process, the hydrogen sulfide and ammonia present in the reaction atmosphere affect the conversion rate of bicyclic aromatics and the retention rate of monocyclic aromatic hydrocarbons (RRMA). In this study, 1-Methylnaphthalene (1-MN) is used to investigate hydrogenation behavior on Ni-Mo-S active sites. The results indicate that at low conversion rates, 1-MN is preferentially converted to 5-methyltetrahydronaphthalene (5-MTHN) on the S-edge, and can be simultaneously converted to 1-methyltetrahydronaphthalene (1-MTHN) and 5- MTHN on the Mo-edge. Additionally, the H₂S in the reaction atmosphere significantly competes with 1-MN for adsorption on the S-edge, limiting the hydrogenation selectivity of 5-MTHN, whereas NH₃ preferentially competes with 1-MN on the Mo-edge. At a high1-MN conversion rate, the competitive adsorption of 1-MN and MTHN is concentrated on the S-edge. Conversely, at a low bicyclic aromatic conversion rate, H₂S increases the RRMA, whereas NH₃ significantly lowers it. Full article

Alpine grasslands on the Qinghai–Tibet Plateau are highly sensitive to climate change and human disturbances, and their degradation poses serious threats to ecosystem stability and soil conservation. Belowground bud banks form the foundation of vegetative regeneration, yet their variation along degradation gradients and the soil factors regulating these changes remain insufficiently understood. In this study, we investigated the density and composition of belowground buds in grasses, sedges, and forbs across four degradation levels during the peak growing season and examined the soil controls shaping these responses. The results showed that moderate degradation significantly increased total bud density, indicating enhanced clonal renewal capacity, whereas severe degradation markedly reduced bud-bank potential. Bud types from different functional groups responded differently to soil conditions: rhizome buds of grasses were mainly driven by soil fertility, while tiller buds were more sensitive to soil compaction and carbon–nitrogen availability; rhizome buds of sedges could still develop in compact, nutrient-poor soils; and bud types of forbs were more responsive to variations in soil nutrient status or soil structure. Structural equation modeling further revealed that the formation of the belowground bud is primarily influenced by soil physico-chemical properties, particularly soil nutrients, which regulate regenerative capacity under degraded alpine grasslands. This study reveals the variation patterns of belowground bud banks along degradation gradients in alpine grasslands on the Qinghai–Tibet Plateau and their responses to soil factors, and it elucidates the pathways through which degradation mediates belowground bud bank dynamics via soil physico-chemical properties, particularly soil nutrients, thereby providing a scientific basis for understanding the regeneration potential of alpine grasslands and for the sustainable management and ecological restoration of degraded alpine grasslands. Full article

Lightning-ignited wildfires represent a dominant natural disturbance agent in the Greater Khingan Mountains of northeastern China; however, the relationship between their occurrence and lightning characteristics remains insufficiently quantified. This study analyzed cloud-to-ground (CG) lightning data (2019–2024) and 417 lightning-ignited wildfires (2019–2024) using a full-waveform lightning detection network and spatial matching based on the Minimum Distance Method. Lightning activity shows pronounced spatiotemporal clustering, with more than 93% of flashes occurring in summer and a diurnal peak at 15:00. About 74.6% of wildfires ignited within 1 km of a lightning strike, and the holdover time exhibited clear seasonality, peaking in August (≈317 h). Negative CG (−CG) flashes dominated ignition events (56.5% multiple-stroke, average multiplicity = 2.60), and igniting flashes were concentrated within the −10 to −30 kA peak-current range, suggesting a key threshold for ignition. Vegetation type strongly influenced ignition efficiency: cold temperate and temperate coniferous forests recorded the highest lightning and fire counts, while alpine grasslands and sedge meadows showed the highest lightning ignition efficiency (LIE). These findings clarify how lightning electrical properties and vegetation conditions jointly determine ignition probability and provide a scientific basis for improving lightning-ignited wildfire risk monitoring and early-warning systems in boreal forest regions. Full article

Peatlands, as globally important carbon sinks, are highly sensitive to human disturbances. The direct discharge or use of domestic sewage with different treatment gradients as peatland replenishment water affects plant communities, but how the plant community structure and biomass change and what drives these changes remain unclear. This study simulated domestic sewage input to a sedge-dominated peatland in the Changbai Mountain region of Northeast China, explored changes in plant community structure and aboveground biomass and revealed the key factors influencing these plant characteristics. The results revealed the following: (1) Reclaimed water treatment (Z) had little effect on the plant community structure; treatments with 50% tap water and 50% domestic sewage (H) and domestic sewage (W) caused rapid expansion of Poaceae plants, with Echinochloa crus-galli (L.) P. Beauv. occupying dominance. (2) Domestic sewage input increases plant diversity, which is driven jointly by soil nutrients and aboveground plant nutrients. (3) The H and W treatments significantly altered aboveground biomass, which was positively correlated with soil nutrients, aboveground plant nutrients, and diversity, whereas the Z treatment had little effect. This research provides scientific support for the control of domestic sewage discharge and whether reclaimed water can be used for ecological water replenishment in peatlands. It holds significant practical value for the scientific management of peatlands, the maintenance of carbon sink functions, and the mitigation of climate change. Full article

Cyperus esculentus L., commonly known as Yellow Nutsedge or Tiger Nut, belongs to the Sedge family (Cyperaceae), which is widely distributed in tropical and temperate regions around the world. The species is particularly noted for its underground tuber, which is rich in starch and oil, and can be used for both food and industrial purposes. However, cultivated C. esculentus rarely flowers in the field, and when it does, flowering is often accompanied by sterility, significantly hindering the development of superior varieties through sexual hybridization. Our investigation into the causes of pollen abortion in C. esculentus yielded several key findings. Initially, we observed pollen abortion within the anthers using Alexander’s red staining and starch-iodide staining techniques. Further examination through semi-thin sections of the anthers revealed that, although the pollen appeared normal during the pachytene stage, the pollen failed to stain blue in later developmental stages, indicating abnormal development. This was followed by vacuolation, collapse, and degradation of the pollen, ultimately resulting in abortion. Additionally, we monitored chromosome behavior throughout meiosis and observed premature chromosome separation during metaphase II, leading to disarray in the subsequent pseudomonad phase. Chromosomal karyotype analysis and ploidy predictions suggested that the triploid nature of C. esculentus contributes to meiotic disorders, which may explain the phenomenon of pollen abortion. These findings provide valuable insights into the reproductive challenges faced by this species and may inform future breeding efforts aimed at overcoming its sterility. Full article