Detrended Correspondence Analysis Research Articles

Dry grasslands and thorn-cushion communities of Armenia: a first syntaxonomic classification

Aim: To provide the first syntaxonomic, plot-based classification of the dry grasslands and thorn-cushion communities in Armenia. Study area: Armenia. Methods: We sampled 111 vegetation plots (10 m2) and recorded environmental and structural parameters. We collected additional 487 relevés from surrounding countries for a broad-scale comparison. We used modified TWINSPAN to derive a syntaxonomic classification system, whose units were then compared among each other regarding species composition, structure, site conditions and distribution. Results: The classification of Armenian vegetation plots resulted in a 12-cluster solution. Unsupervised classification of the broad-scale dataset yielded five main groups, which were used for the high-level syntaxonomic assignments of the Armenian data. We assigned about half of the plots of the Armenian dataset to the Festuco-Brometea, while the remaining represented a potential new class, preliminarily called “Ziziphora tenuior-Stipa arabica grasslands”. Most of the syntaxa below class level are new to science, therefore we provide formal descriptions of three orders (Plantagini atratae-Bromopsietalia variegatae, Onobrychido transcaucasicae-Stipetalia pulcherrimae, Cousinio brachypterae-Stipetalia arabicae), four alliances (Acantholimono caryophyllacei-Stipion holosericeae, Artemision fragrantis, Onobrychido michauxii-Stipion capillatae, Onobrychido transcaucasicae-Stipion pulcherrimae) and six associations. We found significant differences in the topographic, climatic and soil characteristics, and structural parameters, species life forms and distribution range types between the grassland types at different syntaxonomic levels. The mean species richness was 47.3 (vascular plants: 46.8, bryophytes: 0.4, lichens: 0.1). Conclusions: We found remarkable differences of the Armenian dry grasslands from the previously known units and described most of the higher syntaxa and all the associations as new to science. Our study provides arguments for a potential new class of Ziziphora tenuior-Stipa arabica grasslands separate both from the Euro-Siberian Festuco-Brometea and the Anatolian Astragalo-Brometea. Finally, we found plot scale richness of vascular plants clearly above the Palaearctic average of dry grasslands and that of non-vascular plants clearly below, which calls for further biodiversity analyses. Taxonomic reference: Euro+Med (2023) for vascular plants, Hodgetts et al. (2020) for bryophytes, Nimis et al. (2018) for lichens except for Xanthoparmelia camtschadalis (Ach.) Hale. Abbreviations: EDGG = Eurasian Dry Grassland Group; DCA = detrended correspondence analysis; ICPN = International Code of Phytosociological Nomenclature (Theurillat et al. 2021); TWINSPAN = two-way indicator species analysis.

Response of vulnerable karst forest ecosystems under different fire severities in the Northern Dinaric Karst mountains (Slovenia)

BackgroundThis study deals with wildfires in marginal areas of the Mediterranean climatic and biogeographical regions (Northern Mediterranean) where fires were not common. The aim of the research was to determine the differences in floristic composition and traits at different intensities of fire damage and to analyze the changes in forest ecosystems during the wildfires that took place in the summer of 2022. The study included both the zonal forests and non-native black pine (Pinus nigra) forests. Remote sensing techniques linked to the vegetation data sampled in the field during the 2023 vegetation season, the very first season after the fires, were also used in the fire assessment.ResultsThe study confirmed that satellite data analysis, orthophoto interpretation, and on-site vegetation sampling provide equivalent information on fire severity, opening up the possibility of transferring knowledge to similar post-fire sites without field sampling in the future. TWINSPAN classification analysis divided the sampled plots into clusters based on tree species prevalence and fire severity. The diagnostic species of the clusters were calculated using a fidelity measure. Ordination revealed that the first axis on the detrended correspondence analysis (DCA) correlated with wildfire severity. Ecological conditions and strategies, life forms, chorotypes, seed dispersal classes, and regeneration traits were analyzed along this gradient. We found that post-fire sites became warmer, drier, and lighter, which favored the growth of ruderal, theropytic, cosmopolitan, anemochorous and post-fire emergent species. After the fire, a “wave” of annual ruderal species was observed.ConclusionsThe results indicate that post-fire recovery can be left to natural processes without human intervention, except in the case of non-native pine stands where planting or seeding may be necessary. Otherwise, it is essential to control the possible occurrence of invasive species. Isolated adaptations of species to fire have also been observed, such as heat-stimulated germination. Such adaptations could develop in regions exposed to frequent fires and where fires act as an evolutionary factor.

Patterns of avian tree usage in the primeval temperate forests of Białowieża National Park.

Species distribution and resource utilization are a fundamental aspect of ecology. By analyzing the tree space usage by birds and determining the species composition of birds across different parts of trees, our study could shed light on the mechanisms shaping co-occurrence patterns in bird communities. Therefore, our study aimed to determine the species composition of birds across different parts of trees. We investigated whether species richness differs between positions on a tree and how these positions influence the probability of occurrence of the 10 most frequently observed bird species. To achieve this, we observed birds within permanent plots in Białowieża National Park (BNP) and analyzed the distribution patterns of birds within six vertical and three horizontal sectors of trees. The compositional dissimilarity between tree sectors was assessed using detrended correspondence analysis. We employed generalized linear mixed-effects models to examine differences in species richness. The majority of the BNP bird community was associated with the branches, while other birds occupied the tree crown trunks and the understory trunks. Species richness was the highest on branches in the crown part of trees, followed by lower species richness on trunks associated with crowns, and the lowest richness was observed on branches and trunks in the understory. These results indicate that branches in the middle and lower parts of the crown serve as avian diversity hotspots on trees, likely due to the abundance of various food sources. The differing patterns of tree usage by specific bird species may suggest the avoidance of interspecific competition for resources. The study results of tree usage by bird species obtained in the primeval forest provides a reference point for studies conducted in human-altered woods.

Identification of clinical characteristics biomarkers for rheumatoid arthritis through targeted DNA methylation sequencing

ObjectivesRheumatoid arthritis (RA) is a complex disease with a challenging diagnosis, especially in seronegative patients. The aim of this study is to investigate whether the methylation sites associated with the overall immune response in RA can assist in clinical diagnosis, using targeted methylation sequencing technology on peripheral venous blood samples. MethodsThe study enrolled 241 RA patients, 30 osteoarthritis patients (OA), and 30 healthy volunteers control (HC). Fifty significant cytosine guanine (CG) sites between undifferentiated arthritis and RA were selected and analyzed using targeted DNA methylation sequencing. Logistic regression models were used to establish diagnostic models for different clinical features of RA, and six machine learning methods (logit model, random forest, support vector machine, adaboost, naive bayes, and learning vector quantization) were used to construct clinical diagnostic models for different subtypes of RA. Least absolute shrinkage and selection operator regression and detrended correspondence analysis were utilized to screen for important CGs. Spearman correlation was used to calculate the correlation coefficient. ResultsThe study identified 16 important CG sites, including tumor necrosis factort receptor associated factor 5 (TRAF5) (chr1:211500151), mothers against decapentaplegic homolog 3 (SMAD3) (chr15:67357339), tumor endothelial marker 1 (CD248) (chr11:66083766), lysosomal trafficking regulator (LYST) (chr1:235998714), PR domain zinc finger protein 16 (PRDM16) (chr1:3307069), A-kinase anchoring protein 10 (AKAP10) (chr17:19850460), G protein subunit gamma 7 (GNG7) (chr19:2546620), yes1 associated transcriptional regulator (YAP1) (chr11:101980632), PRDM16 (chr1:3163969), histone deacetylase complex subunit sin3a (SIN3A) (chr15:75747445), prenylated rab acceptor protein 2 (ARL6IP5) (chr3:69134502), mitogen-activated protein kinase kinase kinase 4 (MAP3K4) (chr6:161412392), wnt family member 7A (WNT7A) (chr3:13895991), inhibin subunit beta B (INHBB) (chr2:121107018), deoxyribonucleic acid replication helicase/nuclease 2 (DNA2) (chr10:70231628) and chromosome 14 open reading frame 180 (C14orf180) (chr14:105055171). Seven CG sites showed abnormal changes between the three groups (P < 0.05), and 16 CG sites were significantly correlated with common clinical indicators (P < 0.05). Diagnostic models constructed using different CG sites had an area under the receiver operating characteristic curve (AUC) range of 0.64–0.78 for high-level clinical indicators of high clinical value, with specificity ranging from 0.42 to 0.77 and sensitivity ranging from 0.57 to 0.88. The AUC range for low-level clinical indicators of high clinical value was 0.63–0.72, with specificity ranging from 0.48 to 0.74 and sensitivity ranging from 0.72 to 0.88. Diagnostic models constructed using different CG sites showed good overall diagnostic accuracy for the four subtypes of RA, with an accuracy range of 0.61–0.96, a balanced accuracy range of 0.46–0.94, and an AUC range of 0.46–0.94. ConclusionsThis study identified potential clinical diagnostic biomarkers for RA and provided novel insights into the diagnosis and subtyping of RA. The use of targeted deoxyribonucleic acid (DNA) methylation sequencing and machine learning methods for establishing diagnostic models for different clinical features and subtypes of RA is innovative and can improve the accuracy and efficiency of RA diagnosis.

Nonalcoholic Fatty Liver Disease: Changes in Gut Microbiota and Blood Lipids.

The global prevalence of nonalcoholic fatty liver disease (NAFLD) is 25%. This study aimed to explore differences in the gut microbial community and blood lipids between normal livers and those affected by NAFLD using 16S ribosomal deoxyribonucleic acid sequencing. Gut microbiome profiles of 40 NAFLD and 20 non-NAFLD controls were analyzed. Information about four blood lipids and 13 other clinical features was collected. Patients were divided into three groups by ultrasound and FibroScan, those with a normal liver, mild FL (FL1), and moderate-to-severe FL (FL2). FL1 and FL2 patients were divided into two groups, those with either hyperlipidemia or non-hyperlipidemia based on their blood lipids. Potential keystone species within the groups were identified using univariate analysis and a specificity-occupancy plot. Significant difference in biochemical parameters ion NAFLD patients and healthy individuals were identified by detrended correspondence analysis and canonical correspondence analysis. Decreased gut bacterial diversity was found in patients with NAFLD. Firmicutes/Bacteroidetes decreased as NAFLD progressed. Faecalibacterium and Ruminococcus 2 were the most representative fatty-related bacteria. Glutamate pyruvic transaminase, aspartate aminotransferase, and white blood cell count were selected as the most significant biochemical indexes. Calculation of areas under the curve identified two microbiomes combined with the three biochemical indexes that identified normal liver and FL2 very well but performed poorly in diagnosing FL1. Faecalibacterium and Ruminococcus 2, combined with glutamate pyruvic transaminase, aspartate aminotransferase, and white blood cell count distinguished NAFLD. We speculate that regulating the health of gut microbiota may release NAFLD, in addition to providing new targets for clinicians to treat NAFLD.

Reef Fish in the Vitória-Trindade Seamount Chain of the Southwestern Atlantic: Biogeographical Corridors and Impact of Fishing

This paper aimed to study the community structure of large reef fish off the central coast of Brazil by defining the spatial distribution patterns of 34 species in the outer shelf (50 to 100 m) between 13 and 22ºS, including sea banks, seamounts and the Trindade Island, seeking further to interpret these patterns in light of biogeographic knowledge. In addition, this study attempted to estimate the impact of fishing on the community in different regions using mean weight and size distribution data. The data were obtained in four exploratory fishing surveys of demersal resources employing a bottom longline with steel wire under the aegis of the REVIZEE Program between 1996 and 1998. The numerical abundances were standardised in catch-per-unit-effort (CPUE) in number, and species matrices per station were subjected to detrended correspondence analysis (DCA) and cluster analysis. Reef fauna in the southwestern Atlantic can be divided, in its continental margin, into a tropical component and a subtropical component from latitude 19ºS, which corresponds to the Southern limit of the Abrolhos Bank. North of 19ºS, four distribution patterns were identified (North, Abrolhos, Banks and Trindade). The similarity between the last three enabled the definition of an “Abrolhos-Trindade faunal complex”. Evidence of the impact of commercial fishing on the structure of reef communities was found through differences in the sizes of species studied, which may have occurred differently in each one of the regions of the Abrolhos-Trindade complex. The results also reinforce the importance of the need for conservation measures in these areas.

Fragmentation and biodiversity change in urban vegetation: A case study of tram lines

AbstractThis study explores the vegetation composition along various tram line sections in Bydgoszcz, Poland, with a focus on understanding the impact of usage, maintenance, and historical development on urban vegetation dynamics. This study addresses this knowledge gap by investigating how these factors influence plant species composition, leading to variations in the prevalence of native and non‐native species. The aim of this study is to contribute to urban ecological knowledge and inform vegetation management strategies. The investigation centers on five tram line sites representing different usage and maintenance scenarios: Unused line, New line, Loop rec, Loop old, and Old line. Through phytocoenological relevés conducted in 2020 and 2021, we measured the plant taxa coverage. Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA) revealed relationships between plant species and tram line sites. The results indicated the presence of 107 plant taxa, with graphical representations highlighting the prevalent species on each tram line section. Older sections showed a higher representation of non‐native plant species, whereas new sections exhibited native species dominance. Moisture‐indicative values suggest an affinity for soils with average moisture content. CCA provides insights into the relationships between plant taxa and site variants and offers valuable implications for urban vegetation management and conservation strategies. The novelty of this study lies in its holistic approach for understanding how multiple factors interact to shape urban vegetation. By illuminating urban ecological dynamics and informing decision‐making processes, this study contributes to urban planning, ecology, and biodiversity conservation. Additionally, this study fills a knowledge gap by providing insights into the unique ecological dynamics and species composition of tram lines in urban environments. Unlike previous research in Central European countries focusing on planted vegetation, this study explored the spontaneous spread of plants and successional patterns along tram lines, enhancing our understanding of the environmental conditions created by tram lines that influence vegetation composition and development.

Environmental filtering is the primary driver of community assembly in forest–grassland mosaics: A case study based on CSR strategies

AbstractAimsEcological strategies can provide information about plant community assembly and its main drivers. Our aim was to reveal the dominant strategies of the vegetation types of forest–grassland mosaics and to deduce the assembly processes responsible for their species composition.LocationHungary.MethodsWe investigated eight vegetation types of Hungarian forest–steppes. The trade‐off between three key traits related to leaf size and economics was used to calculate Grime's competitive–stress tolerance–ruderal (CSR) value for each species, based on which the mean value for each vegetation type was determined. Detrended correspondence analysis (DCA) ordination was used to reveal the compositional differences among the vegetation types under study. To analyze how ecological strategies correlate with the compositional gradient, we used linear regression between plot ordination scores (the first DCA scores) and each strategy (C, S, and R). Linear mixed‐effect models were used to evaluate the differences between the vegetation types regarding each strategy (C, S, and R).ResultsEach vegetation type was dominated by the stress‐tolerator strategy, indicating the prominent role of environmental filtering in community assembly. However, ecological strategies differed significantly among the communities. The importance of the stress‐tolerator strategy decreased toward the less harsh end of the gradient (i.e., from grasslands to forests), while the competitor strategy showed a reverse pattern. The ruderal strategy was weakly correlated with the gradient, although its proportion increased toward the harsh end of the gradient.ConclusionsWith ongoing climate change, an increasing importance of environmental filtering is expected in the assembly of the vegetation types in the studied forest–grassland mosaics. We suggest that CSR strategies offer a useful tool for studying plant‐community assembly rules along environmental gradients.

Ecological and statistical models to configure flow regime for environment benefit in highly engineered rivers: a case study in the MacKenzie River, Southeast Australia.

Ecological and statistical models were developed using freshwater algal assemblages to assess water quality and ecological health of a regulated river. These models were used to inform configuration of flows to maintain or improve environmental conditions of the waterway whilst meeting consumptive water supply commitments. The flow regime of the MacKenzie River, western Victoria, Australia, has been substantially modified since the construction of a water supply reservoir on its upper reach in 1887. Water is withdrawn at several locations downstream of the reservoir, creating a substantially modified flow regime, impacting key environmental values of the river. To assess the impact of the different flow regimes on river health and ecosystem function, ten sites were repeatedly sampled along the river between February 2012 and April 2014. Physical and chemical characteristics of water, including pH, temperature, turbidity, electrical conductivity, dissolved oxygen, total nitrogen, total phosphorous, cations, and anions, were measured. Biological properties of the algal periphyton communities, including dry mass, ash-free dry mass, chlorophyll-a concentration, and species composition, were also measured. Exploration of the algal assemblage and water chemistry data using the computationally unconstrained ordination technique such as principal component analysis principal component analysis (PCA), correspondence analysis (CA), detrended correspondence analysis (DCA), and canonical correspondence analysis (CCA) indicated two strong gradients in the data sets. Furthermore, the quantitative ecosystem response models have been developed as the prototype tool to assist in the future configuration of flows in this river. The empirical data and models showed the lower reaches of the river to be in poor condition under low flows, but this condition improved under flows of 35 ML/day, as indicated by the reduction in green algae and cyanobacteria and improvement. Finally, the results are presented to tailor discharge and duration of water volume by amalgamation of consumptive and environmental flows to improve the condition of the stream thereby supplementing the flows dedicated to environmental outcomes.

Vegetation response to forest ditch reconstruction: Promoting a potential habitat for insect-pollinated plant species?

Abstract In a managed forest landscape, the high degree of human intervention has caused significant shifts in natural processes, and preservation of remaining natural ecosystem features is crucial to safeguard ecosystem functioning and support ecosystem services. While drainage ditches, subject to regular maintenance, are anthropogenically created and maintained infrastructure elements, they may still support diverse environmental conditions and provide habitats for a variety of plant species, including flowering plants important for pollinators. We assessed vegetation composition changes on recently reconstructed and unmanaged forest ditches and ditch edges in a commercial forest in Central Latvia in two surveys (one and five years after the ditch reconstruction). We used generalized linear mixed-effects models to analyze the impact of environmental variables on species richness and detrended correspondence analysis to analyze plant species composition. We found higher total plant species richness and insect-pollinated plant species richness along recently reconstructed ditches. The differences were mainly explained by better light availability beside reconstructed ditches. Anthropogenically created and managed ecosystems may support biodiversity and directly and indirectly contribute to the provision of different ecosystem services, including pollination.

Quantitative Characteristics and Environmental Interpretation of Vegetation Restoration in Burned Areas of the Dry Valleys of Southwest China

Fire is a common natural disturbance in forest ecosystems and plays an important role in subsequent vegetation patterns. Based on the spatial sequence method, adopted as an alternative to the time successional sequence method, we selected burned areas in different locations in the Anning River Basin, which encompasses typical dry valleys. Quadrat surveys and quantitative classification were used to identify and classify the vegetation and distribution pattern and to carry out environmental interpretation during the natural restoration process after a forest fire. The results showed the following: (1) in the early stage of natural recovery after a forest fire disturbance, the vegetation community could be divided into seven community types, and Quercus guyavaefolia H. Leveille (Qg) was the dominant species in the community; (2) the vegetation samples could be divided into five ecological types, and the classification and distribution pattern of community types in this region changed most notably with altitude; and (3) a detrended correspondence analysis could be used to accurately classify vegetation community types, while a detrended canonical correspondence analysis could reveal the relationships between species and environmental factors. This study provides a scientific basis for guiding the restoration of ecosystem structural stability and biodiversity in burned areas.

Cedar vascular flora of Djebel Maadid. Floristic analysis – Conservation

The study region belongs to Cedrus atlantica Manetti formation, which is a North Africa endemic species. It is situated at Djebel Maadid, southern Bordj-Bou-Arreridj province, Algeria. To preserve this community, a flora inventory is important. We adopted a systematic-subjective non-probability sampling method in 30 surveys. The results revealed 108 species distributed among 91 genera and belonging to 34 botanical families. The analysis, including similarity and detrended correspondence analysis, identified various groups of plants-samples that demonstrate different environmental states linked to distinct stationarity. The species richness in particular sites can play a local role in the in-situ conservation of plants and habitats and must be registered for an urgent awareness situation.

Birds Species on Vertical Stratification of Mangrove Vegetation Nusa Lembongan, Bali Indonesia

This study aims to determine the use of vertical stratification of mangrove vegetation by bird species in the mangrove ecosystem of Nusa Lembongan. The study was conducted at seven mangrove ecosystem sites, in April-July 2021. Observation of the number of birds in each vegetation strata was carried out using the point count method. The association of the use of vegetation strata by bird species was carried out by Detrended correspondence analysis (DCA) statistical test. The results showed that total of 32 species are found in the mangrove ecosystem of Nusa Lembongan which belong to 26 families. There is a strong association between bird species and the vertical strata of vegetation. The species of birds associated with pure mangrove vegetation are; strata I, namely Amaurornis phoenicurus (Pennant,1769), Ardea purpurea Linnaeus, 1766, Sterna bergii M.H.K.Lichtenstein, 1823, Passer domesticus (Linnaeus, 1758), and Pycnonotus aurigaster (Vieillot, 1818); strata II are Todiramphus chloris (Boddaert, 1783), Todirhamphus sanctus (Vigors and Horsfield, 1827), Alcedo coerulescens Vieillot, 1818 and Butorides striata (Linnaeus, 1758); strata III are Hypothymis azurea (Boddaert, 1783), Lanius schach Linnaeus, 1758, Merops philippinus Linnaeus, 1767, Nectarinia jugularis Linnaeus, 1766 and Gerygone sulphurea Wallace, 1864; strata IV are Collocalia linchi Horsfield &amp; F.Moore,1854, Oriolus chinensis Linnaeus, 1766, Hirundo tahitica Gmelin,1789 and Pycnonotus goiaver (Scopoli, 1786). The bird species associated with mixed mangrove and dryland vegetation are strata I, namely species Turnix suscitator (J.F.Gmelin, 1789), Acridotheres javanicus Cabanis, 1851, Anthreptes malacensis (Scopoli, 1786), Passer domesticus (Linnaeus,1758), Pycnonotus aurigaster (Vieillot, 1818), Spilopelia chinensis (Scopoli, 1786) and Geopelia striata (Linnaeus, 1766); strata II, namely Alcedo coerulescens Vieillot, 1818, Zosterops chloris Bonaparte, 1850, Todirhamphus sanctus (Vigors and Horsfield,1827) and Todiramphus chloris (Boddaert, 1783); strata III, namely Anthreptes malacensis (Scopoli,1786), Cacomantis merulinus (Scopoli,1786), Hypothymis azurea (Boddaert,1783), Copsychus saularis (Linnaeus,1758), Nectarinia jugularis Linnaeus, 1766, Gerygone sulphurea Wallace, 1864 and Merops philippinus Linnaeus,1767; strata IV, namely Collocalia linchi Horsfield &amp; F.Moore,1854, Hirundo tahitica Gmelin,1789 and Corvus sp. Factors influencing strata preference by birds are resources, both food and space, as well as the bioecological characteristics of the birds themselves.

Classification of forest and shrubland vegetation in central and eastern Euxine Turkey and SW Georgia

AbstractQuestionsWhat are the main vegetation types of forest and shrubland vegetation in central and eastern Euxine Turkey and SW Georgia? What are the main environmental factors affecting their diversity? What is their syntaxonomic position? Can we integrate them into the European vegetation classification system?LocationCentral and eastern Euxine Turkey and SW Georgia.MethodsWe collected 3104 vegetation plots of forest and shrubland vegetation in the study region and performed Two‐Way Indicator Species Analysis (TWINSPAN) classification. We described vegetation types based on the classification results, expert knowledge and information from literature sources. We defined diagnostic species and prepared distribution maps for each vegetation type. To determine the most significant environmental variables on floristic differentiation, we used canonical correspondence analysis. Detrended correspondence analysis with passive projection of most significant environmental variables was run to interpret the environmental variation of vegetation types.ResultsThe studied vegetation was divided into 29 vegetation types related to seven main vegetation groups: relict Mediterranean forests and shrubland (mainly along the coastline, beside some inland localities), lowland to submontane forests, central Euxine mountain forests, eastern Euxine (Colchic) mountain forests, subeuxine forests, azonal riparian forests and subalpine and alpine shrubland. Elevation is the most important factor causing the differentiation in vegetation. It is followed by longitude and latitude. Among climatic variables, temperature seasonality, annual precipitation and precipitation of the wettest quarter are the most significant factors for vegetation differentiation. These factors correlate with the reduction of maritime climate and geomorphological features.ConclusionsVegetation types mostly correspond to the syntaxa accepted in the EuroVegChecklist. However, some of them do not appear in the EuroVegChecklist since they appear only beyond Europe. We described three syntaxa as new: Abietion equi‐trojani, Querco cerridis‐Carpinion orientalis and Piceo orientalis‐Fagenion orientalis. The study revealed high vegetation diversity of the region that should be taken into consideration in ecosystem management and used as a reference in restoration and mitigation of the effects of global changes.

Tracing last millennium cycles of Río de la Plata Plume Water input into the Southwestern Atlantic Ocean

Recent studies established a strong connection between instrumental hydroclimatic changes in the Río de la Plata (RdlP) watershed and the influx of continental terrigenous material and productivity changes. This correspondence was further validated for the last millennium. Here, we identified centennial, multi-decadal, and interannual changes in diatom composition, as a proxy for La Plata Plume Water (PPW) discharge into the inner shelf. Core GeoB13813-4 diatom data were revisited, and grouped into freshwater, marine, and brackish categories for multivariate, timeseries, and correlation analyses. Such record exhibits a noteworthy resemblance to paleoclimatic and paleoceanographic variations throughout the past millennium. A Detrended Correspondence Analysis (DCA) on the dominant taxa, and Axis-1 revealed a salinity gradient over the past millennium. DCA1-scores exhibited significant correlation with reconstructions of El Niño Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), and the Atlantic Multidecadal Oscillation (AMO) over the same period.By plotting DCA1-scores, we inferred time intervals with varying levels of PPW influence. During ∼936–1500 CE, the PPW influence was weak, as the record was dominated by marine taxa, indicating lateral transport from the Brazilian upwelled water and a stronger influence of the Subtropical Shelf Water. After 1500 CE, a well-developed plume was inferred, with the highest influence occurring after 1800 CE, as evidenced by an increased presence of freshwater/brackish taxa. This increased PPW influence after 1500 CE can be attributed to the onset of more humid conditions and associated increased river discharge, particularly under El Niño conditions, with further ENSO intensification after 1800 CE. We identified significant centennial (250 years) and multidecadal cycles (25–50 years) in diatom community composition. These cycles are related to solar forcing, PDO, and AMO. During the 20th Century, cycles of 2 to 7 years were associated with interannual ENSO variability, while 40-year cycles were linked to AMO and PDO variability.

FERNS RICHNESS ALONG ENVIRONMENTAL GRADIENTS IN AYER HITAM FOREST, PENINSULAR MALAYSIA

Fern species richness was assessed to ascertain the distributional pattern of the ferns as influenced by the environmental gradients in Ayer Hitam forest reserve, Peninsular Malaysia. The ferns were collected using a preferential non-random sampling technique. Temperature, humidity, light intensity and elevation data were obtained at each point of collection of the ferns. The influence of these environmental gradients on the distribution of the species was determined using Detrended Correspondence Analysis (DCA) and general linear model (GLM). A total of 67 ferns were identified at all the study sites. Two ferns namely Asplenium antiquum and Pteris longipinnula were first recorded in this study. In all the sites, light intensity ranges from 337.9 – 8098 lux, temperature ranges from 28.5 - 33oC, humidity ranges from 66.24 - 88.80%, and elevation ranges from 14–33m. Tectaria singaporeana and Nephrolepis biserrata are the only species that are widely distributed across all the study sites. The DCA revealed that the light intensity influences the distribution of the ferns species in this forest. However, the GLM showed that temperature had a positive influence on the distribution of the ferns while light intensity had a negative influence on them.

Trouble in the rice field: Distribution ecology and indicator value of weed species in the rice fields of Himalayan region

Field-based evaluation of indicator weed species in agriculture systems is effective for developing site-specific weed management. Because of anthropogenic activities and climate change, new weeds are invading agricultural fields. The current study examined the weed species in agricultural fields with a focus on diversity, distribution ecological patterns, and identification of indicator species, all of which might help in effective weed management practices. Following the calculation of the Importance Value Index for each weed species, ordination, and indicator species analysis were conducted. We collected vegetation data through random sampling, and the current study recorded 47 species, taxonomically distributed across 41 genera and 19 families. Asteraceae with 13% of species was the leading family followed by Poaceae, and Brassicaceae (11% each). Annual weed species with 49% were the dominant life span category. The phytogeographical analysis revealed that the highest number (28 species) recorded from the study area were native, while 19 species were alien. Of the total alien species, 4 were invasive, and 14 were naturalised and one species Bassia scoparia was casual. The diversity indices show significant differences (p ≤ 0.05) in weeds in rice fields recorded from the study area. Detrended correspondence analysis grouped the species Geranium rotundifolium, Sisymbrium loeselii, Mentha longifolia, Rumex dentatus, Amaranthus viridis on the extreme left side suggest a low score on axis 1 and a high score on axis 2. The analysis of indicator species revealed a significant difference (p ≤ 0.05) in agriculture fields across the sampled sites. According to the indicator species analysis, Poa annua, Persicaria hydropiper, Ranunculus sceleratus, and Echinochloa colona were the key weed species found in the study area. This investigation might aid weed management strategies to minimize crop losses and increase of rice production to fulfill the current food requirement.

Toward Sustainable Development Trajectories? Estimating Urban Footprints from High-Resolution Copernicus Layers in Athens, Greece

Land imperviousness reflects settlement growth and urban sprawl. Grounded on a comparative approach, a set of multidimensional statistical techniques were adopted here to quantify the evolution of land imperviousness from Copernicus High-Resolution Layers (HRLs) in a representative case study of Southern Europe (Athens, Greece). A two-way data matrix reporting the percent share of the surface land exposed to different sealing levels (101 classes ranging continuously from 0% to 100%) in the total municipal area was computed for two years (2006 and 2018) individually for 115 municipalities in metropolitan Athens. This matrix represented the information base needed to derive place-specific urban footprints and a comprehensive (global) profile of land imperviousness. Results of a Detrended Correspondence Analysis (DCA) delineated a metropolitan structure still organized along the density gradient, moving from dense settlements in central locations with dominant land classes sealed for more than 90% of their surface area to completely pervious land (0%) typical of rural locations. While the density gradient became less steep between 2006 and 2018, it continued to aliment a socioeconomic polarization in urban and rural districts with distinctive profiles of land imperviousness. Intermediate locations had more mixed imperviousness profiles as a result of urban sprawl. Differential profiles reflect place-specific urban footprints with distinctive land take rates.

Ecological and structural differentiation of the Sudanian woodlands in the Biosphere Reserve of Pendjari, Benin

Aims: This study aims to: i) differentiate the plant associations in the Biosphere Reserve of Pendjari (BRP), ii) determine the ecological characteristics of their habitats and iii) present distribution maps on different soil types. Study area: The BRP, located in the Sudanian Zone of Benin. Methods: 202 phytosociological relevés were sampled according to the Braun-Blanquet method within the BRP. Ordination was performed using Detrended Correspondence Analysis to evaluate vegetation patterns. Soil parameters were used to characterize the vegetation types. Results: The numerical analysis of 202 plots and 249 plant species showed two major floristic groups that correlated with a moisture gradient: drylands versus wetlands. The dryland group was a mixture of woodland and shrub savanna, the dominant ecosystems of the study area. The wetland group encompassed species primarily from riparian forest, tree savanna and grass savanna on floodplains. Syntaxonomical analysis of the dryland group showed rocky and gravelly soil associations (Burkeo africanae-Detarietum microcarpi) and soils associated with or without fine gravels (Andropogono gayani-Terminalietum avicennioidis, Andropogono gayani-Senegalietum dudgeonii and Terminalietum leiocarpae). Syntaxonomical analysis of the wetland group showed riparian forest associations on sandy-clay soil (Coletum laurifoliae, Borassetum aethiopi and Hyparrhenio glabriusculae-Mitragynetum inermis) and floodplain associations on silt-clay soil (Terminalio macropterae-Mitragynetum inermis, Brachiario jubatae-Terminalietum macropterae, Sorghastro bipennati-Vachellietum hockii). Conclusions: Eleven new associations were identified in this study. If the distribution of plant associations was determined by different soil properties, the soil humidity would be one of the main ecological factors determining the establishment of plant species and thus plant association development. Taxonomic reference: Akoègninou et al. (2006), Angiosperm Phylogeny Group classification for the orders and families of flowering plants (APG IV, 2016). Abbreviations: BRP = Biosphere Reserve of Pendjari; CBD = Convention on Biological Diversity; CCA = Constrained Correspondence Analysis; DCA = Detrended Correspondence Analysis; GPS UTM = Global Positioning System Universal Transverse Mercator.

A Ferroptosis-Related lncRNAs Signature Predicts Prognosis of Colon Adenocarcinoma.

(1) Ferroptosis is a type of cellular death caused by lipid-dependent iron peroxide, which plays a major role in cancer. Long noncoding RNAs (lncRNAs) are increasingly recognized as key regulating substances in ferroptosis; (2) RNA sequencing expressions and clinical data of 519 patients with colon adenocarcinoma (COAD) were downloaded from The Cancer Genome Atlas (TCGA) database. The expression levels of lncRNAs related to ferroptosis were screened with Pearson correlation analysis. Differential genes were enriched with Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. LncRNAs related to ferroptosis were determined with univariate Cox regression and multivariate Cox regression analyses, and patients with COAD were classified into high- and low-risk subgroups according to their median risk score. The prognostic value was further examined, and the association between ferroptosis-related lncRNAs (frlncRNAs) and survival in patients with high and low risks of COAD was validated. A TCGA-COAD data set was used for receiver operating characteristic (ROC) analysis and detrended correspondence analysis (DCA) to assess prediction accuracy. Finally, a nomogram was constructed to predict survival probability; (3) We obtained a model consisting of a five-frlncRNAs signature comprising AP003555.1, AP001469.3, ITGB1-DT, AC129492.1, and AC010973.2 for determining the overall survival (OS) of patients with COAD. The survival analysis and ROC curves showed that the model had good robustness and predictive performance on the TCGA training set; (4) We found that a five-frlncRNAs signature may play a potential role in anti-COAD immunity. Risk characteristics based on frlncRNAs can accurately predict the prognosis and immunotherapy response of patients with COAD.