Diversity of Orchids in Terms of Their Distribution, Uses and Conservation in Annapurna Conservation Area of Nepal

The Annapurna Conservation Area (ACA), the first conservation area and the largest protected area (PA) in Nepal, is incredibly rich in biodiversity. Notwithstanding this, orchids in the ACA have not been explored enough yet thus making the need for ambitious research to be carried out. Previous study only included 81 species of orchids within ACA. This study aims to update the record of species and genera richness in the ACA. In total 198 species of orchids, belonging to 67 genera (40% and 62% of the total recorded orchid species and genera in Nepal) has been recorded in ACA. This represents an increase of 144% in species and 56% in genera over the previous data. Out of the 198 species, 99 were epiphytes, 6 were holomycotrophic and 93 were terrestrial. Among the 67 genera, Bulbophyllum (17) species were dominant, followed by Dendrobium (16), Herminium (10), Coelogyne, Plantanthera (9 each), Eria, Habenaria, Oberonia (8 each), Calanthe (7), and Liparis (6). Fifty-six species were found to be ornamentally significant and 85 species medicinally significant.

Progress in systematics and biogeography of Orchidaceae

Orchidaceae are one of the largest families of angiosperms in terms of species richness.In the last decade,numerous studies have delved into reconstructing the phylogenetic framework of Orchidaceae,leveraging data from plastid,mitochondrial and nuclear sources.These studies have provided new insights into the systematics,diversification and biogeography of Orchidaceae,establishing a robust foundation for future research.Nevertheless,pronounced controversies persist regarding the precise placement of certain lineages within these phylogenetic frameworks.To address these discrepancies and deepen our understanding of the phylogenetic structure of Orchidaceae,we provide a comprehensive overview and analysis of phylogenetic studies focusing on contentious groups within Orchidaceae since 2015,delving into discussions on the underlying reasons for observed topological conflicts.We also provide a novel phylogenetic framework at the subtribal level.Furthermore,we examine the tempo and mode underlying orchid species diversity from the perspective of historical biogeography,highlighting factors contributing to extensive speciation.Ultimately,we delineate avenues for future research aimed at enhancing our understanding of Orchidaceae phylogeny and diversity.

Theoretical Analysis on Deflection and Bearing Capacity of Prestressed Bamboo-Steel Composite Beams

A theoretical analysis of upward deflection and midspan deflection of prestressed bamboo-steel composite beams is presented in this study.The deflection analysis considers the influences of interface slippage and shear deformation.Furthermore,the calculation model for flexural capacity is proposed considering the two stages of loading.The theoretical results are verified with 8 specimens considering different prestressed load levels,load schemes,and prestress schemes.The results indicate that the proposed theoretical analysis provides a feasible prediction of the deflection and bearing capacity of bamboo-steel composite beams.For deflection analysis,the method considering the slippage and shear deformation provides better accuracy.The theoretical method for bearing capacity matches well with the test results,and the relative errors in the serviceability limit state and ultimate limit state are 4.95%and 5.85%,respectively,which meet the accuracy requirements of the engineered application.

Carbon sequestration in a bamboo plantation:a case study in a Mediterranean area

In the Mediterranean region,despite bamboo being an alien species that can seriously alter plant and ani-mal biocoenosis,the area occupied by bamboo plantations continues to increase,especially for the purpose to seques-ter carbon(C).However,the C dynamics in the soil-plant system when bamboo is grown outside its native area are poorly understood.Here we investigated the C mitigation potential of the fast-growing Moso bamboo(Phyllostachys edulis)introduced in Italy for climate-change mitigation.We analyzed aboveground(AGB)and belowground(as root/shoot ratio)biomass,litter and soil organic C(SOC)at O-15-and 15-30-cm depths in a 4-year-old bamboo plantation in comparison with the former annual cropland on which the bamboo was established.To have an idea of the maximum C stored at an ecosystem level,a natural forest adjacent the two sites was also considered.In the plantation,C accumulation as AGB was stimulated,with 14.8±3.1 Mg C ha^(-1) stored in 3 years;because thinning was done to remove culms from the first year,the mean sequestration rate was 4.9 Mg C ha^(-1) a^(-1).The sequestration rates were high but comparable to other fast-growing tree species in Italy(e.g.,Pinus nigra).SOC was significantly higher in the bamboo plantation than in the cropland only at the 0-15 cm depth,but SOC stock did not differ.Possibly 4 years were not enough time for a clear increase in SOC,or the high nutrient uptake by bamboos might have depleted the soil nutrients,thus inhibiting the soil organic matter formation by bacteria.In comparison,the natural forest had significantly higher C levels in all the pools.For C dynamics at an ecosystem level,the bamboo plantation on the former annual cropland led to substantial C removal from the atmosphere(about 12 Mg C ha^(-1) a^(-1)).However,despite the promising C sequestration rates by bamboo,its introduction should be carefully considered due to potential ecological problems caused by this species in overexploited environments such as the Mediterranean area.

Harnessing the Market Potential of the Bamboo Industry in Central Luzon, Philippines: An Analysis of the Internal and External Environment

The bamboo industry in Central Luzon holds significant promise for economic development and environmental sustainability. This study aims to analyze the internal and external factors influencing the bamboo industry in the region through SWOT and PESTLE analyses. Based on a focus group discussion involving key industry players, the study explores the industry’s strengths, weaknesses, opportunities, and threats, as well as political, economic, social, technological, legal, and environmental factors. Findings reveal the importance of comprehensive strategies that address political stability, economic growth, consumer awareness, technological advancement, legal compliance, and environmental sustainability. Recommendations include capacity-building for production and marketing, the establishment of bamboo treatment facilities, and advocacy for supportive policies. By addressing these factors, the bamboo industry in Central Luzon can realize its potential for socio-economic development and environmental stewardship.

Free vibration and buckling analysis of polymeric composite beams reinforced by functionally graded bamboo fbers

Natural fibers have been extensively researched as reinforcement materials in polymers on account of their environmental and economic advantages in comparison with synthetic fibers in the recent years.Bamboo fibers are renowned for their good mechanical properties,abundance,and short cycle growth.As beams are one of the fundamental structural components and are susceptible to mechanical loads in engineering applications,this paper performs a study on the free vibration and buckling responses of bamboo fiber reinforced composite(BFRC)beams on the elastic foundation.Three different functionally graded(FG)layouts and a uniform one are the considered distributions for unidirectional long bamboo fibers across the thickness.The elastic properties of the composite are determined with the law of mixture.Employing Hamilton’s principle,the governing equations of motion are obtained.The generalized differential quadrature method(GDQM)is then applied to the equations to obtain the results.The achieved outcomes exhibit that the natural frequency and buckling load values vary as the fiber volume fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam change.Furthermore,a comparative study is conducted between the derived analysis outcomes for BFRC and homogenous polymer beams to examine the effectiveness of bamboo fibers as reinforcement materials,demonstrating the significant enhancements in both vibration and buckling responses,with the exception of natural frequencies for cantilever beams on the Pasternak foundation with the FG-◇fiber distribution.Eventually,the obtained analysis results of BFRC beams are also compared with those for carbon nanotube reinforced composite(CNTRC)beams found in the literature,indicating that the buckling loads and natural frequencies of BFRC beams are lower than those of CNTRC beams.

Fabrication and Characterization of Bamboo—Epoxy Reinforced Composite for Thermal Insulation

As global warming intensifies, researchers worldwide strive to develop effective ways to reduce heat transfer. Among the natural fiber composites studied extensively in recent decades, bamboo has emerged as a prime candidate for reinforcement. This woody plant offers inherent strengths, biodegradability, and abundant availability. Due to its high cellulose content, its low thermal conductivity establishes bamboo as a thermally resistant material. Its low thermal conductivity, enhanced by a NaOH solution treatment, makes it an excellent thermally resistant material. Researchers incorporated Hollow Glass Microspheres (HGM) and Kaolin fillers into the epoxy matrix to improve the insulating properties of bamboo composites. These fillers substantially enhance thermal resistance, limiting heat transfer. Various compositions, like (30% HGM + 25% Bamboo + 65% Epoxy) and (30% Kaolin + 25% Bamboo + 45% Epoxy), were compared to identify the most efficient thermal insulator. Using Vacuum Assisted Resin Transfer Molding (VARTM) ensures uniform distribution of fillers and resin, creating a structurally sound thermal barrier. These reinforced composites, evaluated using the TOPSIS method, demonstrated their potential as high-performance materials combating heat transfer, offering a promising solution in the battle against climate change.

Orchid diversity and distribution pattern in karst forests in eastern Yunnan Province,China

Global biodiversity loss and mass extinction of species have raised serious global concerns,especially in fragile ecosystems.Karst forest,a well-known fragile ecosystem,is served as a natural laboratory for biogeographical,ecological,evolutionary,and taxonomic research.However,species richness and distribution patterns in karst forests largely remain unclear.Orchidaceae has been regarded as the“flagship”group of plant diversity.In this study,we use Wanfengshan Nature Reserve in southeast Yunnan,China,as a model to determine the conservation status of orchids in the karst forest by conducting systematic field surveys in the past three years from 2019 to 2022.In total,we identified 78 orchid species in 35 genera in Wanfengshan Nature Reserve.The dominant species were Bulbophyllum andersonii,Eria coronaria,Nervilia mackinnonii and Paphiopedilum micranthum.Multiple life forms were also observed,including epiphyte(14.29%),facultative epiphyte(18.18%),lithophyte(23.38%),and terrestrial(44.15%).Orchid species richness showed a bimodal pattern varied with altitude,the higher richness was recorded at 1,500-1,600 and 1,200-1,300 m,while the minimum was below 1,100 m.Each independent hill is rich in orchid species including‘endemic’species.A total of 25(33.8%)orchid species were considered threatened by the Redlist of Chinese Vascular Plants(Qin et al.,2017),including 3 CR species,5 EN species and 17 VU species.We call for more research addressing the mechanisms of ecological adaption,mycorrhizal interactions,and pollination of orchids in karst forests,and effective ways for recovery and conservation of orchids.

Impacts of dietary supplementation of bamboo vinegar and charcoal powder on growth performance,intestinal morphology,and gut microflora of large-scale loach Paramisgurnus dabryanus

Although accumulating data demonstrate that dietary supplementation of bamboo vinegar and charcoal powder(BVC)can significantly strengthen the immunity and boost the growth of domestic animals,its application potency still awaits verification in commercial fish species such as the large-scale loach Paramisgurnus dabryanus.The impacts of 90-day dietary supplementation of 1%and 2%BVC on survival and growth performance of the loach,and on the intestinal morphological characteristics and gut microflora were analyzed.Our data show that the large-scale loach supplied with BVC at the experimental doses had significant higher survival rates and better growth performance(indicated by greater weight gain(1.13–1.14 times),higher specific growth rate(1.04 times),and lower feed conversion ratio(0.88–0.89 times))compared to that of the control(P<0.05).Histological examination revealed significant longer villus(3.22–5.54 times),deeper crypt(1.77–1.87 times),and thicker muscle(1.59–3.17 times)in the intestines of large-scale loach fed with BVC(P<0.05).Furthermore,we found that the gut microflora consisted of significantly fewer proportions of potential pathogenic bacterial species(Aeromonas veronii and Escherichia coli),but significantly greater proportions of beneficial microbes(Lactococus raffinolactis and Faecalibacterium prausnitzii).Therefore,dietary intake of BVC can promote intestinal tract development and optimize gut microflora,by which the survival and growth of large-scale loach may be improved.

Bamboo Fiber Modified Asphalt Mixture Proportion Design and Road Performances Based on Response Surface Method

In order to comprehensively utilize the remaining bamboo residue of bamboo products,this paper presents a research on recycling the bamboo fibers from bamboo residue for improving the performance of the asphalt mixtures.First of all,the basic performance parameters of sinocalamus affinis fiber,phyllostachys pubescens fiber,green bamboo fiber were tested and analyzed,and the optimal content and length were put forward.Then,the mix ratio design of the bamboo fiber modified asphalt mixture was further designed through the response surface method,and was verified the rationality of the mix ratio.Finally,the mixture specimens were made according to the experimental design mix ratio,and the high temperature,low temperature performance and moisture susceptibility of the bamboo fiber modified mixtures asphalt were tested.The results showed that the high temperature performance,low temperature performance and moisture susceptibility of bamboo fiber modified asphalt mixtures were improved compared with the performance of SBS modified asphalt mixture.When the length of bamboo fiber is 7.25 mm and the content of 0.22%,the road performance of the asphalt mixture was optimal.Consequentially,the decomposition of bamboo residue into bamboo fiber and its application in asphalt pavement can improve the reuse of bamboo waste,with remarkable environmental benefits and great promotion value.

Dietary bamboo leaf flavonoids improve quality and microstructure of broiler meat by changing untargeted metabolome

Background Dietary bamboo leaf flavonoids(BLFs)are rarely used in poultry production,and it is unknown whether they influence meat texture profile,perceived color,or microstructure.Results A total of 720 one-day-old Arbor Acres broilers were supplemented with a basal diet with 20 mg bacitracin/kg,50 mg BLFs/kg,or 250 mg BLFs/kg or without additions.Data showed that the dietary BLFs significantly(P<0.05)changed growth performance and the texture profile.In particular,BLFs increased birds’average daily gain and average daily feed intake,decreased the feed:gain ratio and mortality rate,improved elasticity of breast meat,enhanced the gumminess of breast and leg meat,and decreased the hardness of breast meat.Moreover,a significant(P<0.05)increase in redness(a*)and chroma(c*)of breast meat and c*and water-holding capacity of leg meat was found in BLF-supplemented broilers compared with control broilers.In addition,BLFs supplementation significantly decreased(P<0.05)theβ-sheet ratio and serum malondialdehyde and increased theβ-turn ratio of protein secondary structure,superoxide dismutase,and glutathione peroxidase of breast meat and total antioxidant capacity and catalase of serum.Based on the analysis of untargeted metabolome,BLFs treatment considerably altered 14 metabolites of the breast meat,including flavonoids,amino acids,and organic acids,as well as phenolic and aromatic compounds.Conclusions Dietary BLFs supplementation could play a beneficial role in improving meat quality and sensory color in the poultry industry by changing protein secondary structures and modulating metabolites.

Green,Sustainable Architectural Bamboo with High Light Transmission and Excellent Electromagnetic Shielding as a Candidate for Energy-Saving Buildings

Currently,light-transmitting,energy-saving,and electromagnetic shielding materials are essential for reducing indoor energy consumption and improving the electromagnetic environment.Here,we developed a cellulose composite with excellent optical transmittance that retained the natural shape and fiber structure of bamboo.The modified whole bamboo possessed an impressive optical transmittance of approximately 60%at 6.23 mm,illuminance of 1000 luminance(lux),water absorption stability(mass change rate less than 4%),longitudinal tensile strength(46.40 MPa),and surface properties(80.2 HD).These were attributed to not only the retention of the natural circular hollow structure of the bamboo rod on the macro,but also the complete bamboo fiber skeleton template impregnated with UV resin on the micro.Moreover,a multilayered device consisting of translucent whole bamboo,transparent bamboo sheets,and electromagnetic shielding film exhibited remarkable heat insulation and heat preservation performance as well as an electromagnetic shielding performance of 46.3 dB.The impressive optical transmittance,mechanical properties,thermal performance,and electromagnetic shielding abilities combined with the renewable and sustainable nature,as well as the fast and efficient manufacturing process,make this bamboo composite material suitable for effective application in transparent,energy-saving,and electromagnetic shielding buildings.

Integrating genomic and morphological data into bamboo taxonomicand evolutionary studies

The Bambusoideae (bamboos),with over 1700 described species,is the third largest subfamily of the Poaceae (grasses),native to all continents except Antarctica and Europe (Clark et al.,2015;Soreng et al.,2022).Within the Bambusoideae,three tribes representing the three major lineages are recognized.The Olyreae comprise the ca.130 species of herbaceous bamboos,which are smaller and much less lignified than their woody cousins.

基于NECP-Bamboo程序的商用压水堆乏燃料组件核素成分分析

乏燃料组件核素成分的精确计算是乏燃料临界安全分析等工作的输入条件,放射性源项计算是乏燃料组件核素成分分析的典型应用。国内现有程序由于存在数据库中核素种类不全、辐照过程无法完全模拟等弊端,限制了乏燃料后处理安全分析的可靠性和经济性。本文基于完全自主化的压水堆堆芯分析软件NECP-Bamboo,研发了商用压水堆乏燃料组件核素成分计算程序Bamboo-SFuel,利用辐照后实验(PIE)实测数据对核素成分进行了定量验证与分析,通过与Scale程序包计算结果进行对比验证了程序源项计算的精度,还探究了不同燃耗数据库对核素成分和源项计算结果的影响。数值结果表明,Bamboo-SFuel能精确分析不同辐照条件下商用压水堆乏燃料组件的核素成分和放射性源项,使用NECP-Bamboo程序中不同核素数目的燃耗数据库对重要核素成分计算结果影响不大,但对总的放射性源项计算结果影响较大;基于内置的包含1547种核素的燃耗数据库,该程序可同时给出可靠的乏燃料临界安全分析和辐射安全分析关注的重要核素成分。

Moso bamboo expansion decreased soil heterotrophic respiration but increased arbuscular mycorrhizal mycelial respiration in a subtropical broadleaved forest

Moso bamboo(Phyllostachys Pubescens)expansion into adjacent forests has been widely reported to affect plant diversity and its association with mycorrhizal fungi in subtropical China,which will likely have significant impacts on soil respiration.However,there is still limited information on how Moso bamboo expansion changes soil respiration components and their linkage with microbial community composition and activity.Based on a mesh exclusion method,soil respirations derived from roots,arbuscular mycorrhizal(AM)mycelium,and free-living microbes were investigated in a pure Moso bamboo forest(expanded),an adjacent broadleaved forest(nonexpanded),and a mixed bamboo-broadleaved forest(expanding).Our results showed that bamboo expansion decreased the cumulative CO_(2)effluxes from total soil respiration,root respiration and soil heterotrophic respiration(by 19.01%,30.34%,and 29.92%on average),whereas increased those from AM mycelium(by 78.67%in comparison with the broadleaved forests).Bamboo expansion significantly decreased soil organic carbon(C)content,bacterial and fungal abundances,and enzyme activities involved in C,N and P cycling whereas enhanced the interactive relationships among bacterial communities.In contrast,the ingrowth of AM mycelium increased the activities ofβ-glucosidase and N-acetyl-β-glucosaminidase and decreased the interactive relationships among bacterial communities.Changes in soil heterotrophic respiration and AM mycelium respiration had positive correlations with soil enzyme activities and fungal abundances.In summary,our findings suggest that bamboo expansion decreased soil heterotrophic respiration by decreasing soil microbial activity but increased the contribution of AM mycelial respiration to soil C efflux,which may potentially increase soil C loss from AM mycelial pathway.

Retrieving chlorophyll content and equivalent water thickness of Moso bamboo(Phyllostachys pubescens) forests under Pantana phyllostachysae Chao-induced stress from Sentinel-2A/B images in a multiple LUTs-based PROSAIL framework

Biochemical components of Moso bamboo(Phyllostachys pubescens)are critical to physiological and ecological processes and play an important role in the material and energy cycles of the ecosystem.The coupled PROSPECT with SAIL(PROSAIL)radiative transfer model is widely used for vegetation biochemical component content inversion.However,the presence of leaf-eating pests,such as Pantana phyllostachysae Chao(PPC),weakens the performance of the model for estimating biochemical components of Moso bamboo and thus must be considered.Therefore,this study considered pest-induced stress signals associated with Sentinel-2A/B images and field data and established multiple sets of biochemical canopy reflectance look-up tables(LUTs)based on the PROSAIL framework by setting different parameter ranges according to infestation levels.Quantitative inversions of leaf area index(LAI),leaf chlorophyll content(LCC),and leaf equivalent water thickness(LEWT)were derived.The scale conversions from LCC to canopy chlorophyll content(CCC)and LEWT to canopy equivalent water thickness(CEWT)were calculated.The results showed that LAI,CCC,and CEWT were inversely related with PPC-induced stress.When applying multiple LUTs,the p-values were<0.01;the R2 values for LAI,CCC,and CEWT were 0.71,0.68,and 0.65 with root mean square error(RMSE)(normalized RMSE,NRMSE)values of 0.38(0.16),17.56μg cm-2(0.20),and 0.02 cm(0.51),respectively.Compared to the values obtained for the traditional PROSAIL model,for October,R2 values increased by 0.05 and 0.10 and NRMSE decreased by 0.09 and 0.02 for CCC and CEWT,respectively and RMSE decreased by 0.35μg cm-2 for CCC.The feasibility of the inverse strategy for integrating pest-induced stress factors into the PROSAIL model,while establishing multiple LUTs under different pest-induced damage levels,was successfully demonstrated and can potentially enhance future vegetation parameter inversion and monitoring of bamboo forest health and ecosystems.

Determination of Inorganic Elements Content and Distribution in Bamboo Shoots by Microwave Digestion and ICP-MS

Microwave digestion and inductively coupled plasma mass spectrometry (ICP-MS) method was used to determine the contents of 25 inorganic elements in basal part, meat and shell of bamboo shoots. It could be concluded that the method could be applied to determine 25 inorganic elements in bamboo shoots. The elements with a dry basis content higher than 10 mg/kg were listed in the order of content decrease as follows, basal part of bamboo shoots: K > Ca > Mg > Mn > P > Al > Fe > Zn > Na;bamboo shoots meat: K > P > Ca > Mg > Mn > Fe > Al > Zn > Na > Ba > Sr;bamboo shoots shell: K > P > Mg > Ca > Mn > Al > Fe > Na > Zn;B, Pb, Cu, Cr ranged from 1.0 - 10 mg/kg;Ga, As, Se, Cd, Sn, Sb, V, Co, Ni were lower than 0.80 mg/kg. The harmful elements Cd, As, Cr, Hg, Pb were commonly monitored in feeds. The wet basis content (mg/kg) of Cd, As, Cr was lower than: 0.028, 0.022 and 0.42 respectively;no Hg was found;the content of Pb(mg/kg) in basal part, meat and shell of bamboo shoots was 0.82, 0.35 and 0.41 respectively. The results provide basic data for the development of bamboo shoots and its byproduct.

Single-cell transcriptome atlas reveals spatiotemporal developmental trajectories in the basal roots of moso bamboo (Phyllostachys edulis)

Roots are essential for plant growth and development.Bamboo is a large Poaceae perennial with 1642 species worldwide.However,little is known about the transcriptional atlas that underpins root cell-type differentiation.Here,we set up a modified protocol for protoplast preparation and report single-cell transcriptomes of 14279 filtered single cells derived from the basal root tips of moso bamboo.We identified four cell types and defined new cell-type-specific marker genes for the basal root.We reconstructed the developmental trajectories of the root cap,epidermis,and ground tissues and elucidated critical factors regulating cell fate determination.According to in situ hybridization and pseudotime trajectory analysis,the root cap and epidermis originated from a common initial cell lineage,revealing the particularity of bamboo basal root development.We further identified key regulatory factors for the differentiation of these cells and indicated divergent root developmental pathways between moso bamboo and rice.Additionally,PheWOX13a and PheWOX13b ectopically expressed in Arabidopsis inhibited primary root and lateral root growth and regulated the growth and development of the root cap,which was different from WOX13 orthologs in Arabidopsis.Taken together,our results offer an important resource for investigating the mechanism of root cell differentiation and root system architecture in perennial woody species of Bambusoideae.

Uncovering the miRNA-mediated regulatory network involved in Ma bamboo(Dendrocalamus latiflorus)de novo shoot organogenesis

Bamboo is an important non-timber forest product and is well-known for its reluctance to regenerate.Recently we have established a de novo shoot organogenesis(DNSO)protocol in Ma bamboo(Dendrocalamus latiflorus)and revealed the transcriptomic dynamics during Ma bamboo regeneration,which suggested the potential roles of Ma bamboo microRNAs(DlamiRNAs)in this process.However,how DlamiRNAs regulate bamboo DNSO is poorly understood.Here we performed integrated analysis with sRNAome,degradome,and transcriptome sequencing by using samples covering the four stages of the bamboo DNSO process.A total of 727 DlamiRNAs showed differential expression during the bamboo DNSO process,and the core DlamiRNA-DlamRNA-mediated regulatory networks for bamboo DNSO were constructed.Based on the results,DlamiR156 was selected for further functional characterization of its potential roles in bamboo DNSO.Transgenic bamboos with increased DlamiR156 levels exhibited an enhancement in their regeneration efficiency.Conversely,when DlamiR156 levels were downregulated,the regeneration efficiencies of transgenic bamboos decreased.Our findings show that the DlamiRNA-mediated regulatory pathways are significant in the process of bamboo regeneration and will contribute to our understanding of the molecular mechanisms governing plant organogenesis in a more comprehensive manner.

Dramatical hydro-sedimentary changes induced by bamboo fences over mangrove tidal flat of the largest delta in Beibu Gulf, southwestern China

Mangrove forest is one of the most important ecological and environmental resources by effectively promoting tidal flat deposition and preventing the coastal region from typhoon.However,there have been mass loss of mangrove forests due to anthropogenic activities.It is an urgent need to explore an effective way for mangrove restoration.Here,three rows of bamboo fences with hydro-sedimentary observation set over Aegiceras corniculatum mangrove tidal flat of the Nanliu Delta,the largest delta of Beibu Gulf,China,were conducted to analyze the hydro-sedimentary variations induced by bamboo fences.Results identified that the mean horizontal velocity Um per burst(20 min)decreased by as much as 71%and 40%in comparison with those without bamboo fences in March and November,respectively,when the tidal current entering the bamboo area during flood.The maximum of mean horizontal flow velocity Um-max at bamboo area was 50%–75%of that without bamboo fences during ebb tide.The suspended sediment concentration of bamboo area suggested a maximum reduction of 57%relative to bare flat during flood,and was 80%lower than bare flat at ebb peak.Moreover,the turbulent kinetic dissipationεat flood tide was significantly higher than that at ebb tide,while the bamboo fences greatly increased the turbulent kinetic dissipationεby 2 to 5 times relative to bare flat,resulting in an increase of the bed elevation by inhibiting the sediment incipient motion and intercepting suspended sediment.The siltation rate at the bamboo area was 140%and 29.3%higher than that at the bare flat and the region covered with A.corniculatum,respectively.These results highlight that bamboo fences can effectively attenuate tidal current and thus promote siltation over mangrove flat,which contribute great benefit to mangrove survival.