Grouping tree species to estimate basal area increment in temperate multispecies forests in Durango,Mexico

Multispecies forests have received increased scientific attention,driven by the hypothesis that biodiversity improves ecological resilience.However,a greater species diversity presents challenges for forest management and research.Our study aims to develop basal area growth models for tree species cohorts.The analysis is based on a dataset of 423 permanent plots(2,500 m^(2))located in temperate forests in Durango,Mexico.First,we define tree species cohorts based on individual and neighborhood-based variables using a combination of principal component and cluster analyses.Then,we estimate the basal area increment of each cohort through the generalized additive model to describe the effect of tree size,competition,stand density and site quality.The principal component and cluster analyses assign a total of 37 tree species to eight cohorts that differed primarily with regard to the distribution of tree size and vertical position within the community.The generalized additive models provide satisfactory estimates of tree growth for the species cohorts,explaining between 19 and 53 percent of the total variation of basal area increment,and highlight the following results:i)most cohorts show a"rise-and-fall"effect of tree size on tree growth;ii)surprisingly,the competition index"basal area of larger trees"had showed a positive effect in four of the eight cohorts;iii)stand density had a negative effect on basal area increment,though the effect was minor in medium-and high-density stands,and iv)basal area growth was positively correlated with site quality except for an oak cohort.The developed species cohorts and growth models provide insight into their particular ecological features and growth patterns that may support the development of sustainable management strategies for temperate multispecies forests.

Response of phytoplankton to multispecies mariculture:a case study on the carrying capacity of shellfish in the Sanggou Bay in China

A muhispecies model for shellfish polycuhure in the Sanggou Bay in China used for large-scale long-line cultivation of the Chinese scallop Chlamysfarreri, the Pacific oyster Crassostrea gigas and the kelp Laminaria japonica is presented. The model includes key physical processes which are the transports of matter at the system boundary, and the main biological process that is the primary production and nutrients release from the bottom. By the model, the seasonal fluctuations of phytoplankton biomass and dissolved inorganic nitrogen（DIN） in 1994 are simulated. Furthermore, if the kelp culture scale is kept constant and the Chinese scallop and the Pacific oyster culture scales are adjusted, virtual shellfish farms are funded and responses of phytoplankton to the largescale shellfish culture are simulated. According to these simulated results, the room limitation, and the hypothesis that shellfish will not grow well if the phytoplankton biomass is less than 8.2 mg/m^3 , the expandable multiple of scallop culture k and that of oyster culture y are determined as k = -0.276 5y ＋4.690 5 and 0.133 3k ＋0.006 6y≤0.667 5, where, k （ or y） is equal to 1, the culture scale of scallop （ or oyster） is 8.8 x 109 individuals （or 66 ha, with a density of 59 ind./m^2 ）, and the kelp culture scale is 3 300 ha with a density of 12 ind./m^2.

Multispecies communities:interspecies interactions influence growth on saliva as sole nutritional source

Human oral bacteria live in multispecies communities in the biofilm called dental plaque. This review focuses on the interactions of seven species and the ability of each species individually and together with other species to grow on saliva as the sole source of nutrient. Community formation in biofihns in flow cells is monitored using species-specific fluorophore-conjugated immunoglobulin Gy and images are captured by confocal microscopy. Early colonizing veillonellae emerge from this review of interspecies interactions in saliva as a critical genus that guides the development of multispecies communities. Highly selective interspecies recognition is evident as initial colonizers pair with early and middle colonizers to form multispecies communities that grow on saliva.

Statistical Properties of Multispecies Competition Ecosystems Subjected to Dichotomous Noises

We investigate statistical properties of multispecies competition ecosystems subjected to both symmetric and asymmetric dichotomous noises. The expression of the stationary probability distribution function （SPDF） is analytically derived by means of mean-field approximation, and verified by stochastic simulations. The results indicate that： （i） A noise amplitude （a0）, a noise autocorrelation time （τ0） and a noise symmetry parameter （k） all can affect the SPDF; （ii） There is an optimal τ0, which makes the mean value of population density be maximal, near which a transition takes place, i.e., the stationary mean value of species density （（x）st） suddenly falls to a lower constant, （iii） As k decreases, the maximum of （x）xt and the optimal 70 increase. The parameter planes of TO -- a20 and τ0- k for the transition are plotted.

DMT:A model detecting multispecies of tea buds in multi-seasons

In China,tea products made from fresh leaves characterized by one leaf with one bud(1L1B)are classified as“Famous Tea”,which has better taste and higher economic value,but suffers from a labor shortage.Aiming at picking automation,existing studies focus on visual detection of 1L1B,but algorithm validation is limited to a specific variety of tea sprouting in a certain harvest season at a certain location,which limits the engineering application of developed tea picking robots working in various natural tea fields.To address this gap,a deep learning model DMT(detecting multispecies of tea)based on YOLOX-S was proposed in this paper.The DMT network takes YOLOX-S as a baseline and adds ECA-Net to the CSP Darknet and FPN of YOLOX-S.The average precision(AP),precision,and recall of DMT are 94.23%,93.39%,and 88.02%,respectively,for detecting 1L1B sprouting in spring;93.92%,93.56%,and 87.88%,respectively,for detecting 1L1Bsprouting in autumn.These experimental results are better than those of the five current object detection models.After fine-tuning the DMT network with another dataset composed of multiple tea varieties,the DMT network can detect 1L1B for different varieties of tea in multiple picking seasons.The results can promote the engineering application of picking automation of fresh tea leaves.

Advancing multispecies fishery management in China:Lessons from international experience

China’s 13th Five-Year Plan elevated the national mandate for environmental sustainability.Chinese fisheries are characterized by full retention of high diversity catch harvested using unselective gears,creating ecological risks.Therefore,China launched pilot projects in management by Total Allowable Catch(TAC)in five coastal provinces in 2017 and 2018 to build experience with output controls.Fujian province launched an important pilot in its swimming crab fishery,the first to adopt a multispecies approach.To guide Fujian and other provinces in multispecies management,a workshop in April 2018 shared international experience.The workshop considered 13 case studies spanning a wide range of underlying scientific models and types of harvest controls.Multispecies harvest controls based on simple survey-or index-based models that aggregate trends for many species are typically operationally easier for managers and fishers.However,inadequate management can cause declines of individual species,sometimes leading to adoption of species-specific models and then species-specific harvest controls.This transition often incurs economic costs through scientific and management demands,and constraints on harvest of co-occurring species.The lessons revealed by the case studies suggest multispecies TACs might be effective in the Fujian swimming crab fishery given the modest number of species with similar and productive life history traits,and the market demand for all species.Continued experimentation with different management approaches through pilot projects can enable China to maintain progress toward sustainable fisheries goals under the 14th Five-Year Plan.

A comparison of the nutritive value of perennial ryegrass,perennial ryegrass and white clover and multispecies-based farmlet systems

Background:Limited information is available regarding the nutritive value and structural characteristics of multispecies swards when rotationally grazed.Methods:Three farmlet types were investigated in terms of their nutritive value:Lolium perenne(LP);L.perenne+Trifolium repens(LP+TR);and a multispecies sward containing grasses,legumes and herbs(MSS).Farmlets were stocked with beef steers(2.5 livestock units ha−1),grazed on a 1 ha scale to 6 cm(MSS)and 4 cm(LP and LP+TR)residuals.Results:A greater ash concentration was found in MSS than LP(84 vs.75 g kg−1 DM).Both LP+TR and MSS had higher crude protein and lower neutral detergent fibre concentrations than LP.The relative ranking of water soluble carbohydrate and dry matter(DM)concentration was LP>LP+TR>MSS.Despite the leaf component of the LP farmlet contributing more to herbage DM,the organic matter digestibilities of the swards were similar.Conclusions:The MSS and LP+TR farmlets achieved similar forage quality under intensive grazing to LP.However,it is worth noting that MSS had a higher concentration of acid detergent lignin,which can negatively impact digestibility.Further investigation is needed to determine optimal grazing management practices that can minimise the effects of higher lignin concentration on digestibility in multispecies swards.

Phylotranscriptomic discordance is best explained by incomplete lineage sorting within Allium subgenus Cyathophora and thus hemiplasy accounts for interspecific trait transition

The transition of traits between genetically related lineages is a fascinating topic that provides clues to understanding the drivers of speciation and diversification.Much can be learned about this process from phylogeny-based trait evolution.However,such inference is often plagued by genome-wide gene-tree discordance(GTD),mostly due to incomplete lineage sorting(ILS)and/or introgressive hybridization,especially when the genes underlying the traits appear discordant.Here,by collecting transcriptomes,whole chloroplast genomes(cpDNA),and population genetic datasets,we used the coalescent model to turn GTD into a source of information for ILS and employed hemiplasy to explain specific cases of apparent“phylogenetic discordance”between different morphological traits and probable species phylogeny in the Allium subg.Cyathophora.Both concatenation and coalescence methods consistently showed the same phylogenetic topology for species tree inference based on single-copy genes(SCGs),as supported by the KS distribution.However,GTD was high across the genomes of subg.Cyathophora:~27%e38.9%of the SCG trees were in conflict with the species tree.Plasmid and nuclear incongruence was also present.Our coalescent simulations indicated that such GTD was mainly a product of ILS.Our hemiplasy risk factor calculations supported that random fixation of ancient polymorphisms in different populations during successive speciation events along the subg.Cyathophora phylogeny may have caused the character transition,as well as the anomalous cpDNA tree.Our study exemplifies how phylogenetic noise can be transformed into evolutionary information for understanding character state transitions along species phylogenies.

Bioresponsive nanotherapy for preventing dental caries by inhibiting multispecies cariogenic biofilms

Early childhood caries(ECC)is a public healthcare concern that greatly reduces the quality of life of young children.As a leading factor of ECC,cariogenic biofilms are composed of acidogenic/aciduric pathogens and extracellular polysaccharides(EPSs),creating an acidic and protected microenvironment.Antimicrobial photodynamic therapy(aPDT)is a noninvasive,painless,and efficient therapeutic approach that is suitable for treating ECC.However,due to the hyperfine structure of cariogenic biofilms,most photosensitizers(PSs)could not access and penetrate deeply in biofilms,which dramatically hamper their efficiency in the clinic.Herein,bioresponsive nanoparticle loaded with chlorin e6(MPP-Ce6)is developed,which largely increases the penetration depth(by over 75%)and retention(by over 100%)of PS in the biofilm compared with free Ce6.Furthermore,MPP-Ce6-mediated aPDT not only kills the bacteria in preformed biofilms but also inhibits multispecies biofilm formation.A rampant caries model is established to mimic ECC in vivo,where the population of cariogenic bacteria is decreased to 10%after MPP-Ce6-mediated aPDT.Importantly,the number and severity of carious lesions are efficiently reduced via Keyes’scoring and micro-CT analysis.This simple but effective strategy can serve as a promising approach for daily oral hygiene in preventing ECC.

Evaluating multispecies survey designs using a joint species distribution model

Survey designs should be efficient as marine survey programs are usually expensive and time-consuming;however,surveys have rarely been evaluated for multiple species.In the present study,we evaluated multispecies fisheries surveys with respect to three influential factors,i.e.,sampling methods,estimation methods and sample size.A joint species distribution model(JSDM)developed in north Yellow Sea,China was used as the operating model to simulate the spatial distribution of multiple species simultaneously.We examined the precision of multispecies abundance estimation using diverse sampling methods[random sampling(RDS),systematic sampling(SYS),stratified random sampling(SRS),generalized random-tessellation stratified sampling(GRT)and spatial coverage sampling(SPC)],estimation methods[arithmetic mean(Arm),universal kriging(Ukr),multivariate distribution model(Mvd),and boral model(Brm)],and a range of sample sizes(from 30 to 300).The results showed significant differences in estimation among sampling methods,where GRT and SYS yielded less relative absolute bias(RAB)over all and RDS showed the least precision.Regarding estimation methods,Mvd and Arm showed the best performances and Brm yielded the least precision.Significant interactions existed between sampling and estimation methods.Arm worked best with GRT,likewise Mvd with SYS and Ukr with SPC.SPC and Mvd showed the best performances for a small sample size(N=30),and all sampling and estimation methods provided similar results for a large sample size(N=300).Generally,doubling sample size resulted in a decrease of RAB by 0.097 on average,a rate depending on species,sampling and estimation methods.This study contributed to an integrative framework for evaluating designs of multispecies fisheries surveys.

Influence of Static Low Electromagnetic Field on Copper Corrosion in the Presence of Multispecies Aerobic Bacteria

The effects of low electromagnetic field (EMF)(B = 2 mT) on the corrosion of pure copper in the absence and presence of multispecies marine aerobic bacteria were investigated in this work. The results showed that EMF has an inhibitory effect on copper metals and decreases the corrosion rate of copper metals in sterile artificial seawater. However, microbiologically influenced corrosion of Cu was increased in the presence of electromagnetic field due to its effect on the biofilm morphology and structure. EMF reduced the growth rate of bacteria and decreased bacterial attachment, thereby forming a heterogeneous and non-stable biofilm on the Cu surface in the presence of EMF. Moreover, the biofilm was dispersed throughout the surface after 7 days, whereas the scattered bacteria were observed on the surface after 10 days. Confocal laser scanning microscopy images showed large and deep pits on the surface in the presence of EMF and confirmed the acceleration of Cu corrosion in the presence of EMF and multispecies bacteria. Furthermore, XPS and FTIR results demonstrated that the corrosion products and metabolic by-products were significantly changed in the presence of EMF.

Exponential Runge-Kutta Methods for the Multispecies Boltzmann Equation

This paper generalizes the exponential Runge-Kutta asymptotic preserving(AP)method developed in[G.Dimarco and L.Pareschi,SIAM Numer.Anal.,49(2011),pp.2057–2077]to compute the multi-species Boltzmann equation.Compared to the single species Boltzmann equation that the method was originally applied on,this set of equation presents a new difficulty that comes from the lack of local conservation laws due to the interaction between different species.Hence extra stiff nonlinear source terms need to be treated properly to maintain the accuracy and the AP property.The method we propose does not contain any nonlinear nonlocal implicit solver,and can capture the hydrodynamic limit with time step and mesh size independent of the Knudsen number.We prove the positivity and strong AP properties of the scheme,which are verified by two numerical examples.

Multivalent network modifier upregulates bioactivity of multispecies biofilm-resistant polyalkenoate cement

Polyalkenoate cement(PAC)is a promising material for regenerative hard tissue therapy.The ionically rich glass component of PAC encourages bioactive interaction via.the release of essential ions.However,PAC bioactivity is restricted owing to(i)structurally inherent cationic network formers and(ii)surface bacterial biofilm formation.These two factors cause a deficiency in ion release,further complicated by secondary infections and premature therapeutic failure.Here,a multivalent zwitterionic network modifier(mZM)is presented for upregulation of ionic exchange and bioactivity enhancement.By introducing a non-zero charged mZM into PACs,an increase in the proportion of non-bridging oxygen occurs.The network modification promotes ion channel formation,causing a multiple-fold increase in ion release and surface deposition of hydroxy-carbonate apatite(ca.74%).Experiments ex vivo and animal models also demonstrate the efficient remineralization ability of the mZM.Furthermore,divalent cationic interaction results in bacterial biofilm reduction(ca.68%)while also influencing a shift in the biofilm species composition,which favors commensal growth.Therefore,PAC modification with mZM offers a promising solution for upregulation of bioactivity,even aiding in customization by targeting site-specific regenerative therapy in future applications.

Seasonal variations in nutritive and botanical composition properties of multispecies grazing swards over an entire dairy grazing season

Background Recently,there has been increasing interest in the use of multispecies(MS)swards in dairy grazing systems.Methods A plot grazing study was established to investigate the potential contribution of different sward species(perennial ryegrass,legumes and herbs)sown in grazing pastures.Ten sward mixtures were sown,ranging in complexity from a perennial ryegrass(PRG)monoculture to binary mixtures including either forage legumes or herbs to a five-species mixture;four different nitrogen(N)application rates of 0,100,150 and 200 kg N ha−1 were applied to each sward.Results Species abundance for all sward species components was associated with the interaction of time point and sward mixture;species abundance for all sward components,except PRG,was associated with the interaction of N application and sward mixture.The interactions of time point and sward mixture,and time point and N application rate,were associated with all analysed sward chemical components,except for sward digestibility.Conclusions Increased N application rates reduced the level of clover in all sward mixtures.Increased levels of white clover led to increased sward crude protein levels;the inclusion of ribwort plantain led to some seasonal variation in the nutritive value of swards.

Systematics of the avian family Alaudidae using multilocus and genomic data

The family Alaudidae,larks,comprises 93-100 species(depending on taxonomy)that are widely distributed across Africa and Eurasia,with single species extending their ranges to North and northernmost South America and Australia.A decade-old molecular phylogeny,comprising~80%of the species,revealed multiple cases of parallel evolution and large variation in rates of morphological evolution,which had misled taxonomists into creating many non-monophyletic genera.Here,we reconstruct the phylogeny of the larks,using a dataset covering one mitochondrial and 16 nuclear loci and comprising all except one of the currently recognised species as well as several recently proposed new species(in total 133 taxa;not all loci available for all species).We provide additional support using genome-wide markers to infer a genus-level phylogeny based on near-complete generic sampling(in total 51 samples of 44 taxa across 40 species).Our results confirm the previous findings of rampant morphological convergence and divergence,and reveal new cases of paraphyletic genera.We propose a new subfamily classification,and also that the genus Mirafra is divided into four genera to produce a more balanced generic classification of the Alaudidae.Our study supports recently proposed species splits as well as some recent lumps,while also questioning some of the latter.This comprehensive phylogeny will form an important basis for future studies,such as comparative studies of lark natural history,ecology,evolution and conservation.

Hybrid Multipopulation Cellular Genetic Algorithm and Its Performance

The selection pressure of genetic algorithm reveals the degree of balance between the global exploration and local optimization.A novel algorithm called the hybrid multi-population cellular genetic algorithm(HCGA)is proposed,which combines population segmentation with particle swarm optimization(PSO).The control parameters are the number of individuals in the population and the number of subpopulations.By varying these control parameters,changes in selection pressure can be investigated.Population division is found to reduce the selection pressure.In particular,low selection pressure emerges in small and highly divided populations.Besides,slight or mild selection pressure reduces the convergence speed,and thus a new mutation operator accelerates the system.HPCGA is tested in the optimization of four typical functions and the results are compared with those of the conventional cellular genetic algorithm.HPCGA is found to significantly improve global convergence rate,convergence speed and stability.Population diversity is also investigated by HPCGA.Appropriate numbers of subpopulations not only achieve a better tradeoff between global exploration and local exploitation,but also greatly improve the optimization performance of HPCGA.It is concluded that HPCGA can elucidate the scientific basis for selecting the efficient numbers of subpopulations.

Whole genome phylogeny of Gallus: introgression and data-type effects

Background: Previous phylogenetic studies that include the four recognized species of Gallus have resulted in a number of distinct topologies, with little agreement. Several factors could lead to the failure to converge on a consistent topology, including introgression, incomplete lineage sorting, different data types, or insufficient data.Methods: We generated three novel whole genome assemblies for Gallus species, which we combined with data from the published genomes of Gallus gallus and Bambusicola thoracicus(a member of the sister genus to Gallus). To determine why previous studies have failed to converge on a single topology, we extracted large numbers of orthologous exons, introns, ultra-conserved elements, and conserved non-exonic elements from the genome assemblies. This provided more than 32 million base pairs of data that we used for concatenated maximum likelihood and multispecies coalescent analyses of Gallus.Results: All of our analyses, regardless of data type, yielded a single, well-supported topology. We found some evidence for ancient introgression involving specific Gallus lineages as well as modest data type effects that had an impact on support and branch length estimates in specific analyses. However, the estimated gene tree spectra for all data types had a relatively good fit to their expectation given the multispecies coalescent.Conclusions: Overall, our data suggest that conflicts among previous studies probably reflect the use of smaller datasets(both in terms of number of sites and of loci) in those analyses. Our results demonstrate the importance of sampling large numbers of loci, each of which has a sufficient number of sites to provide robust estimates of gene trees. Low-coverage whole genome sequencing, as we did here, represents a cost-effective means to generate the very large data sets that include multiple data types that enabled us to obtain a robust estimate of Gallus phylogeny.

Production and Biochemestry-Molecular Analysis of Microbial Community Fermenting Whey as a Potential Probiotic for Use Animals

The aims of this work were: To achieve a simple and low cost propagation of potential probiotic agents using plain whey as a culture medium, study the diversity of the members of the bacterial community (MC) in plain whey and to evaluate the probiotic capacity of this MC. After a systematic selection of agents according to their growing capacity in whey, the constituted MC was considered as a unit. Biochemical characterization of the lactic acid bacteria were performed using the API system. Molecular characterization of the lactic acid bacteria was realized using AFLPTM DNA-fingerprinting, partial 16S rDNA sequence analysis and PCR-denaturing gradient gel electrophoresis (PCR-DGGE). The physiological characterization of yeast was determined with the automated microplate method Allev/Biolomics and using yeast characterization system based on standard taxonomic criteria. The identification molecular was realized by PCR-fingerprinting. The resistance of MC to pH and bile salts were evaluated. The MC was composed of agents from different separated Dominium like Bacteria (Lactobacillum) and Eukaria (yeast). They are multispecies and also multistrain assuring high biodiversity. The MC grew at low pH and different concentrations bile salts.

Open Mass Cultures of Marine Microalgae for Biodiesel Production: Laboratory Approach to Study Species Competition in Mixed Cultures

Since the interspecific competition represents a critical issue for biodiesel production in open mass cultures of microalgae, laboratory studies aimed to select competitive species receive significant interest. In this work, a laboratory approach based on the method of multisizing cell counting was developed to monitor the competition course of single algal species grown in mixed cultures. Two marine microalgae, Dunaliella tertiolecta and Phaeodactylum tricornutum, were used to set-up an induced-contamination assay, with the aim to test their competitive capabilities. The evaluation of the oil production by dried biomass extraction was coupled to the growth assay to investigate the effect of competition on oil yield. The adopted experimental approach revealed effective as a method to selectively measure the algal growth of single species in mixed cultures, enabling to evaluate the competitive properties of Dunaliella outgrowing the contaminant species Phaeodactylum. At the end of the experiment the dominant species contributed more than 90% to the total biomass, while no loss of oil production was observed, the oil yield in the mixed being even higher than in the unialgal culture (3.15 vs. 2.28 mg). The outcomes of the induced competition suggest the use of Dunaliella as a competitive oil-producer species and especially support the potential of the experimental approach to be used for preliminary screening to drive species selection for open mass cultures.

Calogero Model with Different Masses

We study a multispecies one-dimensional Calogero model with two- and three-body interactions. Here, we factorize the ground stateout of the Hamiltonian H in order to get the new operatorwhich preserves some spaces of polynomialsin the case of equal masses, i.e. (the usual Calogero model) and in the case with different masses. The spectrum of these both cases is found easily.