Wetland Communities Research Articles

Vallisneria natans decreased CH4 fluxes in wetlands: Interactions among plant physiological status, nutrients and epiphytic bacterial community

Submerged macrophytes provide niches for epiphytic microbes (including aerobic methanotrophs) growth. However, little is known about the impacts of submerged macrophytes growth status and nutrients loadings on methanotroph community and methane release in wetlands. In the present study, methane fluxes, bacterial and methanotroph community in epiphytic biofilm, and environmental parameters were investigated during Vallisneria natans senescence in wetlands under low (VnL) and high (VnH) nutrients for seven weeks. Relative conductivity and concentration of H2O2, total chlorophyll and malondialdehyde were higher in leaves of V. natans in VnH than VnL at the same sampling time. Nutrients loading increased methane fluxes in treatments with or without (Control) macrophytes, while healthy V. natans plants reduced the methane flux and nutrients concentration in water columns. CH4 fluxes were positively correlated to temperature and COD (p < 0.05). Methane oxidation rates were 3.04–31.68 μmol methane mg−1 fresh weight of V. natans leaves - epiphytic biofilm within 1 h. Proteobacteria, Cyanobacteria, Bacteroidetes, Verrucomicrobia, Planctomycetes, Actinobacteria and Acidobacteria were dominant phylum in all epiphytic biofilms. The mean abundances of pmoA/16S rRNA were higher in VnL than VnH. According to Illumina sequencing results of pmoA gene, γ-proteobacteria and α-proteobacteria were the dominant methanotroph class in epiphytic biofilm from VnH and VnL, respectively. Among seven detected methanotrophic genera, Methylomonas was significantly higher in VnH than VnL. Network analysis revealed that there were much closer relationships between the environmental parameters and epiphytic bacterial community in VnH than in VnL. COD and MDA were negatively correlated with Methyloglobulus, Methylosarcina, Methylobacter and Methylocystis, but positively correlated with Methylomonas and Methylosinus. This study highlights that methanotrophs in epiphytic biofilm play important roles in methane-oxidizing, which can be affected by plant physiological status and environmental parameters.

Comparison of high-resolution NAIP and unmanned aerial vehicle (UAV) imagery for natural vegetation communities classification using machine learning approaches

ABSTRACT To map and manage forest vegetation including wetland communities, remote sensing technology has been shown to be a valid and widely employed technology. In this paper, two ecologically different study areas were evaluated using free and widely available high-resolution multispectral National Agriculture Imagery Program (NAIP) and ultra-high-resolution multispectral unmanned aerial vehicle (UAV) imagery located in the Upper Great Lakes Laurentian Mixed Forest. Three different machine learning algorithms, random forest (RF), support vector machine (SVM), and averaged neural network (avNNet), were evaluated to classify complex natural habitat communities as defined by the Michigan Natural Features Inventory. Accurate training sets were developed using both spectral enhancement and transformation techniques, field collected data, soil data, texture, spectral indices, and expert knowledge. The utility of the various ancillary datasets significantly improved classification results. Using the RF classifier, overall accuracies (OA) between 83.8% and 87.7% with kappa (k) values between 0.79 and 0.85 for the NAIP imagery and between 87.3% and 93.7% OA with k values between 0.83 and 0.92 for the UAV dataset were achieved. Based on the results, we concluded RF to be a robust choice for classifying complex forest vegetation including surrounding wetland communities.

Effects of Species Invasion and Inundation on the Collembola Community in Coastal Mudflat Wetland from the Perspective of Functional Traits

The group of soil arthropods known as Collembola is characterized by its abundance and sensitivity to environmental changes. They are ideal an species for soil indicators. In order to clarify the effects of species invasion and inundation on the Collembola community in coastal mudflat wetlands, the correlation between the collembolan functional traits and environmental factors was studied in Shanghai Jiuduansha Wetland National Nature Reserve for the first time. Five sample plots, including three vegetations-Spartina alterniflora (an invasive species), Phragmites australis, and Zizania latifolia-were set up following the differences in vegetation types and between high and low tidal flats. Data on the diversity of the Collembolan species and their functional traits were collected and combined with the soil physicochemical properties and vegetation environment factors in different tidal flats. The key findings and conclusions of the study are as follows: a total of 18 species, four families, and three orders make up the obtained Collembola, two species of Proisotoma are dominant species that account for 49.59% and 24.91% of the total, respectively. The maintenance of the species diversity of Collembola is disturbed by the higher conversion efficiency of Spartina alterniflora rather than Phragmites australis with lower organic carbon (C) content and higher total nitrogen (N) content. The primary environmental variables influencing species distribution were the C/N ratio, total N, and bulk soil density. The bulk density of the soil impacts the movement and dispersal of the functional traits. The depth of the soil layer is related to the functional traits of the sensory ability. The analysis of the functional traits and environment is fairly helpful in exploring how species respond to their environment and offers a better explanation for the habitat selection of Collembola.

Benthic macroinvertebrate communities and water quality assessment in high Andean Wetlands Callali-Oscollo, Arequipa-Cusco, Peru

High Andean wetlands are fragile systems, vulnerable to human activity and climate change. In the Arequipa region (Peru), there are high Andean lotic and lentic systems currently affected by livestock raising, fish farming, and dams. The aim of the study was to evaluate the aquatic invertebrate community in the Callalli-Oscollo wetlands and the possible impact of human activities. Samples were taken from November 2017 to October 2018 at 4 sampling stations in lotic environments and 2 in lentic environments. Macroinvertebrates were identified to the family level. The following were determined to evaluate community structure: richness, relative abundance, Shannon-Wiener diversity, Simpson dominance, Pielou evenness, and true diversity. The indices ABI, BMWP/Bol and nPeBMWP were applied to evaluate the ecological quality of the environments sampled. Thirty families were recorded in lotic environments, the most abundant being Chironomidae, Naididae, Limnesiidae, Elmidae, Baetidae and Lumbriculidae. The ecological quality was good, except at the station associated to the dam, where it was doubtful. Twenty-six families were recorded in lentic environments, the most abundant being Cyprididae, Naididae and Corixidae. The macroinvertebrate communities in high Andean environments reflect ecosystem conditions. Environments associated to human activity have lower ecological quality.

The influence of the taphonomically active zone on peat formation: Establishing modern peat analogs to decipher mangrove sub-habitats from historical peats

Mangroves create unique and highly productive wetland communities in intertidal zones of tropical and subtropical coastlines. Despite their many ecosystem services, such as carbon sequestration, mangroves remain threatened by climate change, sea-level rise, and human development. The inclusion of conservation paleobiology and long-term perspectives on how these ecosystems have responded to past environmental change can inform current policy and lead to more effective conservation and restoration management strategies for modern mangrove communities. In South Florida, humified plant debris, or peat, in mangroves provides this historical record. Our research takes a novel paleobiological approach by using plant organ- and taxon-based measures to describe the influence of the taphonomically active zone (TAZ: the zone near the surface of the substrate where taphonomic processes actively formation and degrade accumulated detritus) on the decomposition of mangrove peat with depth. This allows us to understand the taphonomic biases imposed on mangrove peat as it is sequestered into the sedimentological record and provides us with the paleoecological context to better interpret preserved peats and reconstruct past mangrove sub-habitats from peat cores. Accordingly, we collected modern surficial peat cores from two contrasting mangrove sub-habitats in Barnes Sound, FL. These surficial cores were characterized and compared to historical, deep cores from other South Florida mangrove peat deposits. By comparing the proportional abundance of mangrove peat constituents in these samples, we established modern analogs needed to interpret changes in the depositional environment of historical mangrove peats found in sediment cores, which is critical for understanding shoreline responses of mangroves to sea-level rise and anthropogenic change. We demonstrate that (1) leaf mat thickness may be a relative indicator of surficial peat decomposition rates because it correlates with the degree of tidal activity and detritivore access to the leaf litter layer; (2) root percentages are valid tools to differentiate between peats at depth, and can be used as relative indicators for the distance of in situ peat from shorelines; and (3) organismal signals, such as foraminifera and insect parts, provide a means for deciphering precursor mangrove sub-habitats from sequestered peats.

Functional insights into succession in a phyllospheric microbial community across a full period of aquatic plant litter decomposition

Phyllosphere microbes are essential in the mediation of plant–soil biogeochemical recycling during the decomposition of plant litter in wetland ecosystems. However, there are few studies into microbial community succession in phyllosphere microbial communities in wetlands, and their functional attributes across a full period of wetland plant litter decomposition remain unclear. Here, we collected leaf samples of Typha latifolia var. orientalis (C. Presl.) Rohrb., an emergent wetland plant, during various stages of decomposition (growing, standing, lodging, and submerging stages) to investigate fungal and bacterial assemblage succession in the phyllosphere. We then parsed these assemblages into specific fungal trophic modes and bacterial phenotypes. Over the litter decomposition period, both fungal and bacterial assemblages underwent distinct succession, with generally increasing alpha diversity, and the proportion of litter microbes originating from sediments increased with decomposition. Saprotrophic and pathotrophic fungi dominated the fungal assemblage in the early stages of decomposition, but their dominance was replaced by undefined fungi as decomposition progressed. Relative abundances of both pathotrophic fungi and potentially pathogenic bacteria increased from the growing to the standing stage, implying that there was a turning point in assemblage composition shortly after plant leaf death. Gram-positive and gram-negative bacteria had opposite trends in their relative abundances over successive decomposition stages. When plant litter entered the water, bacteria tolerant of oxidative stress gradually decreased in abundance, but anaerobic bacteria abundance increased. We also aimed to determine the relationships between predicted microbial functional traits and leaf litter physicochemical attributes. Lignin and N content were the predominant predictors of decomposer fungal trophic modes and bacterial phenotypes. These findings provide evidence that the complex litter decomposition seen in wetlands is accompanied by a dynamic cross-kingdom succession of phyllospheric microbial communities, coupled with distinct changes in the phenotypes of the microbes present. Insights into phyllospheric microbial functional traits have implications for better elucidating the plant litter cycle for wetland plants.

Differences of Moss Mites Communities at Different Vegetation Succession Stages in Subalpine Wetland (Jiulongchi, Fanjing Mountain), Southwest China

Fanjing Mountain, China, is a World Man and Biosphere Reserve, a World Natural Heritage Property, and a Nature Reserve in China. Mites communities have been reported from the Fanjing Mountain. Wetland moss microhabitats provide a unique habitat for mites, and our objective is to document moss mites communities in the subalpine wetlands of Fanjing Mountain (Jiulongchi), with a particular focus on trends in moss mites at different stages of vegetation succession in the wetlands, which have rarely been described, and the research will provide fundamental data for biodiversity conservation in the face of global climate change. The succession sequence from bryophyte (hygrophyte) to shrub (mesophyte or xerophyte) in the open area of Jiulongchi wetland successively includes Polytrichum commune Hedw. (PC), Eleocharis yokoscensis (Franch. et Sav.) Tang et-Cypers sp. (EY-C), Senecio faberii Hemsl (SF), and Indocalamus longiauritus Hand.-Mazz. (IL) four typical communities. In April 2016, we collected moss samples under the four typical communities mentioned above, and analyzed the difference of moss mite communities using PCA, Kruskal–Wallis nonparametric test, and ANOVA. The results showed the following: (1) A total of 9058 moss mites belonging to 49 genera in 3 orders and 69 families were captured in the four plant communities, with the moss mites Parachipteria, Fuscozetes, and Tectocepheus being the dominant taxa of moss mites in Jiulongchi wetland. The core taxa of moss mites at different successional stages were 12 genera, with IL having the largest number of exclusive taxa (20 genera). (2) The abundance of moss mites showed an overall increasing trend from PC to IL habitats, with the number of families and genera showing a pattern of IL &gt; EY-C &gt; SF &gt; PC. The diversity index SF habitat possessed the maximum value, followed by IL, both of which were significantly different from PC. (3) The results of PCA analysis of moss mites showed that the mite community composition of PC habitats differed more from SF and IL, respectively, and less from EY-C. (4) There existed differences in the ecological taxa of predatory moss mites at different successional stages, with the Poronota group dominating the ecological taxa of oribatida. The research indicated that moss mites communities in subalpine wetlands were rich in species composition, and with the succession of vegetation from hygrophyte to mesophyte or xerophyte, the moss mites group as a whole develops in a direction favorable to its diversity, and the differences in moss mites ecological taxa also demonstrated the variability and complexity of the Jiulongchi wetland environment. This research presents the distribution pattern of moss mites in different vegetation succession stages in subtropical subalpine herbaceous wetlands. The moss mites evolution trend in response to climate-change-induced plant community succession needs further investigation.

Vegetation and climate change at the southern margin of the Neo-Tethys during the Cenomanian (Late Cretaceous): Evidence from Egypt.

Changes in terrestrial vegetation during the mid-Cretaceous and their link to climate and environmental change are poorly understood. In this study, we use plant macrofossils and analysis of fossil pollen and spores from the Western Desert, Egypt, to assess temporal changes in plant communities during the Cenomanian. The investigated strata have relatively diverse sporomorph assemblages, which reflect the nature of parent vegetation. Specifically, the palynofloras represent ferns, conifers, monosulcate pollen producers, Gnetales, and a diverse group of angiosperms. Comparisons of both, dispersed palynoflora and plant macrofossils reveal different characteristics of the palaeoflora owing to a plethora of taphonomical and ecological biases including the depositional environment, production levels, and discrepancies between different plant organs. A combination of detailed records of sporomorphs, leaves, and charcoal from the studied successions provide new understandings of the palaeoclimate and palaeogeography during the Cenomanian and Albian-Cenomanian transition in Egypt. The mixed composition of the palynofloral assemblages reflects the presence of different depositional situations with a weak marine influence, as evidenced by a minor dinoflagellate cysts component. The local vegetation comprised various categories including herbaceous groups including ferns and eudicots, fluvial, open environments, and xeric arboreal communities dominated by Cheirolepidiaceae and perhaps including drought- and/or salt-tolerating ferns (Anemiaceae) and other gymnosperms (Araucariaceae, Ginkgoales, Cycadales, and Gnetales) as well as angiosperms. The presence of riparian and freshwater wetland communities favouring aquatic and/or hygrophilous ferns (of Salviniaceae and Marsileaceae), is noted. The wide variation of depositional settings derived from the palynological data may be attributed to a prevalent occurrence of producers in local vegetation during the early Cenomanian of Egypt. For the purpose of this work on the studied Bahariya Formation and its equivalent rock units, where iconic dinosaurs and other fossil fauna roamed, we attempt to improve the understanding of Egypt's Cenomanian climate, which is reconstructed as generally warm and humid punctuated by phases of considerably drier conditions of varying duration.

The Influence of Konik Horses Grazing and Meteorological Conditions on Wetland Communities

Extensive management is one of the methods used in the conservation of fen meadows. The aim of the study was to characterize grassland communities grazed by Konik horses in the Biebrza National Park and to assess the influence of short-term grazing on the sward. During a 3-year period, phytosociological studies, measurements of the sward cover and height, as well as an assessment of the botanical composition of meadows were conducted in places grazed and excluded from grazing. The grasslands were mowed once a year at the turn of July and August, with the exception of mid-forest meadows. The area studied was dominated by communities of the Molinion alliance. Horses kept at a very low stocking rate reduced the height and cover of the sward. In the short-term, weather conditions, especially the duration of floods, had an even greater impact on the species composition of communities than grazing. Therefore, in order to protect the Molinia meadows, apart from extensive mowing, it is necessary to maintain appropriate habitat conditions, especially in terms of controlling the moisture, and conduct its regular monitoring.

The Role of Flavobacterium enshiense R6S-5-6 in the Wetland Ecosystem Revealed by Whole-Genome Analysis

The wetland is an important ecosystem for purifying pollutants and circulating nutrients. Numerous microorganisms contribute to maintaining this function. We obtained Flavobacterium enshiense R6S-5-6 which was isolated from Ungok (Ramsar) Wetland and conducted whole-genome sequencing to investigate what contribution R6S-5-6 could make to the wetland community. The complete genome sequence of R6S-5-6 has a size of 3,251,289 bp with 37.68% of GC content. Gene annotation revealed that R6S-5-6 has several pathways to break down pollutants, including denitrification, assimilatory sulfate reduction (ASR), and polyphosphate-accumulating process. Furthermore, R6S-5-6 has genes that can have a positive effect on plants living in wetlands, such as storing essential nutrients, promoting plant growth, and protecting plants against pathogens.

Correction to: Long-term egret (Egretta garzetta) habitation alters topsoil and subsoil phosphorus fractions and bacterial communities in coastal wetlands

Correction to: Long-term egret (Egretta garzetta) habitation alters topsoil and subsoil phosphorus fractions and bacterial communities in coastal wetlands

Plant Diversity and Quantitative Characteristics Of Wetland Community on the North Bank of Hanjiang River in Cheng GU, Shaanxi Province, China

Four water ecological surveys were carried out on the north bank of Hanjiang river in two seasons from 2020 to 2021. Based on the field wetland quadrat survey and literature data, the species diversity index was determined. The research showed that there are 360 species of wetland plants belonging to 108 families and 264 genera on the north bank of Hanjiang river, and the geographical composition of seed plants is at the genus level, mainly temperate distribution types, with 160 species. In the community species diversity index, the mean value of Patrick index was 18.80 ± 5.19. The mean Shannon Wiener diversity index was 2.15 ± 0.39. The mean value of Simpson dominance index was 0.81 ± 0.10. The average Pielou evenness index was 0.75 ± 0.10. The mean value of Margalef index was 3.44 ± 0.87. The Patrick index and Margalef index of the Bidens pilosa form were the lowest. The Shannon-Wiener diversity index，the Simpson index，and the Pielou index of the Potamogeton malaianus form were the lowest. The Patrick index of the Colocasia esculenta form was the highest,and the Pielou of the Sapium sebiferum form was the highest. The Shannon- Wiener diversity index and Simpson index of the Populus canadensis form group were the highest, and the Margalef index of the Flueggea virosa form was the highest. The research results provide basic data and scientific basis for the protection and restoration of wetland ecosystems and management of wetland resources in Yuan'an and similar areas. Bangladesh J. Bot. 51(4): 839-848, 2022 (December) Special

Short and dynamic: succession of invertebrate communities over a hydroperiod in ephemeral wetlands on arable land

ABSTRACT The temporal dynamics of aquatic invertebrate communities are known to be influenced by the length of hydroperiods, but only temporary wetlands with relatively long hydroperiods have been well studied. By contrast, few studies have focused on ephemeral wetlands, primarily represented by extremely ephemeral rock pools. In Central Europe, many ephemeral wetlands develop spontaneously directly on arable land, often on the sites of former natural wetlands that have been drained and converted to agricultural land. Here, we focused on aquatic invertebrates in 10 ephemeral pools over periods of inundation to desiccation on arable land in southern Moravia. Despite relatively short hydroperiods of 5–11 weeks, we observed significant changes in community composition, including species replacement. Dynamics differed between macroinvertebrates and microcrustaceans and between different macroinvertebrate feeding and dispersal groups. Predation pressure increased over time and was highest during drying. Passive dispersers were most abundant during the middle phase, whereas the abundance of active dispersers increased throughout the hydroperiod. Because no significant effect of any environmental factor was detected on community change, we hypothesized that community dynamics were driven by differences in species traits and biotic interactions rather than by the changing environment. This study fills a knowledge gap on the temporal dynamics of aquatic invertebrate communities in temporary wetlands by investigating wetlands with short, but not extremely ephemeral, hydroperiods.

Co-occurrence of Tetracycline Antibiotic Resistance Genes and Microbial Communities in Plateau Wetlands Under the Influence of Human Activities

The widespread use of antibiotics has led to a large number of antibiotics entering the environment, to which microorganisms have become resistant. In recent years, with the intensification of human activities in the plateau region, the occurrence and migration of antibiotic resistance genes (ARGs) in plateau wetlands have attracted considerable attention. Here, we selected the Caohai National Wetland Park, located in the Yunnan-Guizhou Plateau, as our study area. The contents of tetracyclines, sulfonamides, quinolones, and macrolides in sediments from the upstream (the pristine habitat near the spring eye) and downstream (the sewage discharge outlet of residents) areas of the river in the park were analyzed. Among them, the detection content of tetracycline antibiotics was 103.65-2185 μg·kg-1, which was the highest antibiotic detection content. To further investigate the occurrence characteristics and influencing factors of tetracycline resistance genes, the influence of environmental factors, bacterial community structure, and pathogenic bacteria on tetracycline ARGs under the influence of human activities were revealed via correlation analysis and network analysis. The results showed that a total of 15 tetracycline resistance genes were detected in the upstream and downstream sediments. Among them, seven resistance genes including tetPA, tetD, and tetPB were detected in the upstream, and 13 resistance genes such as tetPA, tetE, tetM, and tetX were detected in the downstream. The abundance of eight new resistance genes in the downstream accounted for 43.44% of the downstream genes. The tetracycline-like antibiotics and soil physicochemical indicators (i.e., available phosphorus, total organic carbon, nitrate nitrogen, and total phosphorus) were the main environmental factors affecting the distribution of tetracycline ARGs. Additionally, the bacteria detected in the upstream and downstream sediments belonged to 64 bacterial phyla, among which Proteobacteria, Firmicutes, and Bacteroidota were the main phyla affecting the abundance of tetracycline ARGs; meanwhile, 27 pathogenic bacteria were detected in the upstream and downstream sediments. Network analysis showed that the correlation between the eight new resistance genes and pathogens in the downstream area accounted for 70% of the network connectivity, and Listeria monocytogenes, Enterococcus faecalis, and Bacteroides vulgatus were identified as potential hosts for the transmission of tetracycline ARGs. Compared to the pristine habitat, the discharge of domestic sewage introduced large amounts of antibiotics and also changed the microenvironment and microbial community structure of the river wetland. Additionally, it increased the species of ARGs in sediments, which promoted the spread and transmission of ARGs among microorganisms and even pathogens.

Fungi and cercozoa regulate methane-associated prokaryotes in wetland methane emissions.

Wetlands are natural sources of methane (CH4) emissions, providing the largest contribution to the atmospheric CH4 pool. Changes in the ecohydrological environment of coastal salt marshes, especially the surface inundation level, cause instability in the CH4 emission levels of coastal ecosystems. Although soil methane-associated microorganisms play key roles in both CH4 generation and metabolism, how other microorganisms regulate methane emission and their responses to inundation has not been investigated. Here, we studied the responses of prokaryotic, fungal and cercozoan communities following 5 years of inundation treatments in a wetland experimental site, and molecular ecological networks analysis (MENs) was constructed to characterize the interdomain relationship. The result showed that the degree of inundation significantly altered the CH4 emissions, and the abundance of the pmoA gene for methanotrophs shifted more significantly than the mcrA gene for methanogens, and they both showed significant positive correlations to methane flux. Additionally, we found inundation significantly altered the diversity of the prokaryotic and fungal communities, as well as the composition of key species in interactions within prokaryotic, fungal, and cercozoan communities. Mantel tests indicated that the structure of the three communities showed significant correlations to methane emissions (p < 0.05), suggesting that all three microbial communities directly or indirectly contributed to the methane emissions of this ecosystem. Correspondingly, the interdomain networks among microbial communities revealed that methane-associated prokaryotic and cercozoan OTUs were all keystone taxa. Methane-associated OTUs were more likely to interact in pairs and correlated negatively with the fungal and cercozoan communities. In addition, the modules significantly positively correlated with methane flux were affected by environmental stress (i.e., pH) and soil nutrients (i.e., total nitrogen, total phosphorus and organic matter), suggesting that these factors tend to positively regulate methane flux by regulating microbial relationships under inundation. Our findings demonstrated that the inundation altered microbial communities in coastal wetlands, and the fungal and cercozoan communities played vital roles in regulating methane emission through microbial interactions with the methane-associated community.

BIODIVERSITY OF AQUATIC PLANTS AND MICROFLORA IN TAGWAI DAM, NIGERIA

Aquatic biodiversity of microflora and plants are the varieties of organisms and the ecosystems that make up the wetlands of the world and their interactions. Tagwai Dam is located in Chanchaga local government area of Niger State, Nigeria, located between longitude 60°39' to 60°44' East and latitude 34° to 90°37' North to South-west of Minna, Niger State, Nigeria. Transect sampling collection of aquatic flora and phytosociological method was adopted by using planktonic net, sterilized poly pots and plastic bottles from five sampling stations. Isolation and identification of microflora was conducted using serial dilution for bacterial species and biochemical tests for the identification. Agar pour plate method for the isolation and morphological characteristics for the identification of fungal species. The dominant families of aquatic plants included Araceae, Nymphaeaeceae, Alismataceae, Marsileaceae and Ceratophyllaceae. The identified bacterial species were Salmonella species, Proteus species, Psuedomonas species, Enterobacter species, while, the fungal species identified were Aspergillus species, Mucor pusillus, Penicillum notatum and Candida albicans were the most dominant microflora found from the sampling stations. The abundance and identification of these aquatic plants and microflora revealed there biodiversity and importance as they serve source of food and energy to the wetland. Aquatic plants and micro flora make up the ecosystem more reliable and comfortable for the aquatic animals and zooplanktons. They are the primary source of energy, the first organisms in food chain in a wetland community.

Finite Element-Based Simulation Analysis of Wetland Plant Mechanics

Despite tidal action, which is influenced by sea level rise, having a substantial impact on plant communities, salt marsh plant communities in coastal wetlands also act as a coastal zone barrier. Phragmites australis and Spartina alterniflora were selected for the experiment in the Yellow River Delta wetland. The mechanical characteristics of the plants in the Yellow River Delta were investigated by field sampling, and the mechanical experimental data were used to simulate plant stresses under natural conditions using the ANSYS model based on finite element theory. The results are as follows: Assuming that the 2 plants have the same stem diameter, the deformation of S. alterniflora is greater than that of P. australis under both static tension and pressure conditions, confirming the phenomenon that the P. australis material has stronger strength resistance properties. When this model was applied to the force analysis in the natural state, it was discovered that the material strength attribute of P. australis is higher than that of S. alterniflora . From the perspective of morphology and structure, the stout stem of S. alterniflora can greatly alleviate the stress of itself under external force and greatly reduce the invasion effect of external force because field conditions are limited and do not reflect immediate mechanical feedback. The model simulation provides a way to accurately and efficiently obtain the mechanical action of plant body when discussing the mechanical action similar to wave action on plant stem and to explain some ecological phenomena from the perspective of mechanics.

环境筛选和扩散限制对长江流域湖北段湿地植物群落构建的共同影响

PDF HTML阅读 XML下载 导出引用 引用提醒 环境筛选和扩散限制对长江流域湖北段湿地植物群落构建的共同影响 DOI: 10.5846/stxb202201110110 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 湖北省教育厅项目（T201701）；湖北省科技厅项目（2020CFA005）；国家自然科学基金项目（31570366） Environmental filtering and dispersal limitation jointly affect wetland plant community assembly in Hubei section of the Yangtze River Basin Author: Affiliation: Fund Project: Project of Department of Education of Hubei Province(T201701); Project of Department of Science and Technology of Hubei Province(2020CFA005);Project of National Natural Science Foundation of China(31570366) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:湿地植物群落构建机制的研究可为湿地生态系统管理和受损湿地生态恢复与重建提供重要理论依据。地处长江流域的湖北省是我国湿地资源最为丰富的地区之一，通过野外调查研究了长江流域湖北段内不同类型湿地中的主要湿地植物群落类型，分析了研究区内湿地植物群落物种β多样性格局；利用相关性检验（Mantel test）方法和基于相似或相异度矩阵的多元回归模型（MRM）分析了环境差异和地理距离与湿地植物群落的物种相异性的相关性，及其对该区域湿地植物群落构建的相对贡献率。结果表明长江流域湖北段8个不同类型湿地内的湿地植物群落物种相异性指数差异显著，群落间物种相异性指数与地理距离和环境距离均呈显著正相关关系；MRM分析表明环境筛选和扩散限制共同解释了研究区内群落物种变异指数的54.72%；其中，环境距离独立解释率为22.03%，地理距离独立解释率为9.98%，二者联合解释率为22.71%。结果表明环境筛选和扩散限制共同影响了长江流域湖北段湿地植物群落构建过程，且环境筛选贡献更大。建议除了考虑空间尺度、环境因子、植被类型外，未来需进一步研究时间尺度及人类干扰等因子对该区域湿地植物群落构建的影响。 Abstract:Studies on the mechanism of wetland plant community assembly can provide an important theoretical basis for wetland ecosystem management and ecological restoration and reconstruction of the damaged wetlands. There are very abundant wetland resources in Hubei Province located in the Yangtze River Basin. In this study, we investigated main wetland plant communities by conducting the field survey and analyzed the β-diversity of wetland plant community in Hubei section of the Yangtze River Basin. The correlation between species dissimilarity of wetland plant communities and environmental distance and geographic distance, and relative contribution of environmental differences and geographic distance for accounting for community assembly were tested, using the Mantel test method and a multiple regression model based on similarity or dissimilarity matrices. The results showed that the species dissimilarity index of wetland plant communities in eight different types of wetlands in Hubei section of the Yangtze River Basin were significantly differed. The species dissimilarity indexes among wetland communities significantly were positively correlated with geographical distance and environmental differences. MRM analysis showed that environmental filtering and diffusion limitation together explained 54.72% of the community species variability index in the study area. The independent effects of the two tested hypotheses above mentioned were 22.03% and 9.98%, respectively. Our findings implied that the combined effects of environmental filtering and diffusion limitation decided wetland plant community assembly in Hubei section of the Yangtze River Basin, and in comparison to diffusion limitation, the environmental filtering had stronger effects. We argue that other factors, such as time scale and interference, should be considered in a study of wetland plant community assembly, beside spatial scale, environmental factors, and vegetation types. 参考文献 相似文献 引证文献

Long-term egret (Egretta garzetta) habitation alters topsoil and subsoil phosphorus fractions and bacterial communities in coastal wetlands

Long-term egret (Egretta garzetta) habitation alters topsoil and subsoil phosphorus fractions and bacterial communities in coastal wetlands

Disentangling direct and indirect effects of extreme events on coastal wetland communities.

One of the primary ways in which climate change will impact coastal freshwater wetlands is through changes in the frequency, intensity, timing and distribution of extreme weather events. Disentangling the direct and indirect mechanisms of population- and community-level responses to extreme events is vital to predicting how species composition of coastal wetlands will change under future conditions. We extended static structural equation modelling approaches to incorporate system dynamics in a multi-year multispecies occupancy model to quantify the effects of extreme weather events on a coastal freshwater wetland system. We used data from an 8-year study (2009-2016) on St. Marks National Wildlife Refuge in Florida, USA, to quantify species-specific and community-level changes in amphibian and fish occupancy associated with two flooding events in 2012 and 2013. We examine how physical changes to the landscape, including potential changes in salinity and increased wetland connectivity, may have contributed to or exacerbated the effects of these extreme weather events on the biota of isolated coastal wetlands. We provide evidence that the primary effects of flooding on the amphibian community were through indirect mechanisms via changes in the composition of the sympatric fish community that may have had lethal (i.e. through direct predation) or non-lethal (i.e. through direct or indirect competitive interactions) effects. In addition, we have shown that amphibian species differed in their sensitivity to direct flooding effects and indirect changes in the fish community and wetland-specific conductance, which led to variable responses across the community. These effects led to the overall decline in amphibian species richness from 2009 to 2016, suggesting that wetland-breeding amphibian communities on St. Marks National Wildlife Refuge may not be resilient to predicted changes in coastal disturbance regimes because of climate change. Understanding both direct and indirect effects, as well as species interactions, is important for predicting the effects of a changing climate on individual species, communities and ecosystems.