scholarly journals Community Trait Responses of Three Dominant Macrophytes to Variations in Flooding During 2011–2019 in a Yangtze River-Connected Floodplain Wetland (Dongting Lake, China)

2021 ◽  
Vol 12 ◽  
Author(s):  
Ying Huang ◽  
Xin-Sheng Chen ◽  
Feng Li ◽  
Zhi-Yong Hou ◽  
Xu Li ◽  
...  
Keyword(s):  
Species Richness ◽  
Plant Community ◽  
Shannon Index ◽  
Dongting Lake ◽  
Polygonum Hydropiper ◽  
Affected Plant ◽  
Miscanthus Sacchariflorus ◽  
Density And Biomass ◽  
And Function ◽  
Index Of Diversity

In lacustrine wetlands connected to rivers, the changes in flood regimes caused by hydrological projects lead to changes in the community traits of dominant macrophytes and, consequently, influence the structure and function of wetland vegetation. However, community trait responses of macrophytes to the timing and duration of flood disturbance have been rarely quantified. In 2011–2019, we investigated plant species diversity, density, and biomass in three dominant macrophyte communities (Carex brevicuspis C.B. Clarke, Miscanthus sacchariflorus (Maxim.) Hackel, and Polygonum hydropiper L.) through monthly field surveys in Dongting Lake wetlands. Partial least squares regressions were used to analyze how the variations in hydrological regimes affected plant community traits. Apparent inter-annual fluctuations in plant community traits were detected during 2011–2019. The species richness and Shannon index of diversity of Miscanthus and Polygonum communities increased, whereas the Shannon index of diversity of Carex community decreased. Variation in flooding had a greater effect on Polygonum and Carex community traits than on Miscanthus community traits. Flooding disturbed all plant communities, especially when the duration and timing varied. Shorter inundation periods caused the biomass of Miscanthus community to decline, and that of Carex and Polygonum communities to increase. Earlier flood recession caused the species richness and Shannon index of diversity of Polygonum and Miscanthus community to increase, and those of Carex community to decrease. These findings imply that shorter inundation durations and earlier flood recession generated by the operation of the Three Gorges Dam have changed the macrophyte growth pattern.

scholarly journals ASSESSMENT OF PLANT DIVERSITY INDICES OF GOMATI RIPARIAN CORRIDORS IN DISTRICT JAUNPUR, INDIA

2014 ◽  
Vol 20 ◽  
pp. 71-76
Author(s):  
Mayank Singh ◽  
M. P. Singh
Keyword(s):  
Species Richness ◽  
Plant Community ◽  
Diversity Indices ◽  
Riparian Ecosystems ◽  
Ecological Studies ◽  
Riparian Corridors ◽  
Central Elements ◽  
Different Seasons ◽  
Density Values ◽  
And Function

Riparian ecosystems, the central elements in many landscapes, are described as an ecotone stretchedout across the landscape because of their shape diversity and function as filters and corridors still theyare most disturbed and threatened by humans. The present work deals with seasonal dynamics inplant diversity indices at two distinct sites (I and II) at ecotonal belts of River Gomati, Jaunpur (U.P.).The diversity indices of plant community have been computed on the basis of density values recordedfrom April, 2012 to March, 2013. Site I showed more species richness and evenness as compared tosite II. Shannon and Weaver, Evenness, Marglef’s, McIntosh and Menhinic diversity indices valueswere higher at site I compared to site II. In contrast, the concentration dominance showed highervalue at site II, whereas Simpson values of diversity have fluctuated in different seasons at both thesites (I and II). It finally deals to formulate strategies and methods for the management of plantdiversity and other natural resources based on various ecological studies, and logical grounds.DOI: http://dx.doi.org/10.3126/eco.v20i0.11444ECOPRINTAn International Journal of EcologyVol. 20, 2013Page: 71-76

scholarly journals Plant community composition and species richness in the High Arctic tundra: From the present to the future

2017 ◽  
Vol 7 (23) ◽  
pp. 10233-10242 ◽  
Author(s):  
Jacob Nabe-Nielsen ◽  
Signe Normand ◽  
Francis K. C. Hui ◽  
Laerke Stewart ◽  
Christian Bay ◽  
...  
Keyword(s):  
Species Richness ◽  
Community Composition ◽  
Plant Community ◽  
Arctic Tundra ◽  
High Arctic ◽  
Plant Community Composition ◽  
The Future

scholarly journals Habitat, food, and small mammal community structure in Namaqualand

Koedoe ◽  
2006 ◽  
Vol 49 (1) ◽  
Author(s):  
M. Van Deventer ◽  
J.A.J. Nel
Keyword(s):  
Species Richness ◽  
Food Availability ◽  
Small Mammal ◽  
Plant Cover ◽  
Plant Litter ◽  
Shrub Cover ◽  
Habitat Features ◽  
Habitat Differences ◽  
Elephant Shrew ◽  
Density And Biomass

The effect of habitat differences and food availability on small mammal (rodent and elephant shrew) species richness, diversity, density and biomass was investigated in Namaqualand, South Africa. Species richness in the three habitats sampled, namely Upland Succulent Karoo, Dry Riverine Shrub and North-western Mountain Renosterveld was low, with only 2–4 species per habitat. Rodents trapped were predominantly Gerbillurus paeba and Aethomys namaquensis, with fewer Mus minutoides and Petromyscus sp. The only non-rodent was the elephant shrew Elephantulus edwardii. Ten habitat features, the percentage of total plant cover, tree cover, shrub cover, grass cover, plant litter, total basal cover, sand, gravel or rock cover, and the dominant plant height were recorded at 30 randomly chosen points on five sampling grids in each habitat. Small mammal density and biomass was significantly correlated with food availability (green foliage cover, seeds, and relative density and biomass of insects). Species richness and diversity of small mammals were significantly correlated with shrub cover. Numbers and biomass of specific species correlated significantly with different habitat features in each case.

scholarly journals The Relationship between the Community Structure and Function of Bacterioplankton and the Environmental Response in Qingcaosha Reservoir

Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3155
Author(s):  
Shumin Liu ◽  
Fengbin Zhao ◽  
Xin Fang
Keyword(s):  
Water Quality ◽  
Community Structure ◽  
High Throughput Sequencing ◽  
Scientific Basis ◽  
Vital Role ◽  
Structure And Function ◽  
Environmental Response ◽  
Temporal And Spatial ◽  
Density And Biomass ◽  
And Function

Phytoplankton and bacterioplankton play a vital role in the structure and function of aquatic ecosystems, and their activity is closely linked to water eutrophication. However, few researchers have considered the temporal and spatial succession of phytoplankton and bacterioplankton, and their responses to environmental factors. The temporal and spatial succession of bacterioplankton and their ecological interaction with phytoplankton and water quality were analyzed using 16S rDNA high-throughput sequencing for their identification, and the functions of bacterioplankton were predicted. The results showed that the dominant classes of bacterioplankton in the Qingcaosha Reservoir were Gammaproteobacteria, Alphaproteobacteria, Actinomycetes, Acidimicrobiia, and Cyanobacteria. In addition, the Shannon diversity indexes were compared, and the results showed significant temporal differences based on monthly averaged value, although no significant spatial difference. The community structure was found to be mainly influenced by phytoplankton density and biomass, dissolved oxygen, and electrical conductivity. The presence of Pseudomonas and Legionella was positively correlated with that of Pseudanabaena sp., and Sphingomonas and Paragonimus with Melosira granulata. On the contrary, the presence of Planctomycetes was negatively correlated with Melosira granulata, as was Deinococcus-Thermus with Cyclotella sp. The relative abundance of denitrifying bacteria decreased from April to December, while the abundance of nitrogen-fixing bacteria increased. This study provides a scientific basis for understanding the ecological interactions between bacteria, algae, and water quality in reservoir ecosystems.

scholarly journals Year-to-year crop shifts promote weed diversity in tropical permanent rainfed cultivation

2020 ◽  
Author(s):  
Margot Neyret ◽  
Anneke de Rouw ◽  
Nathalie Colbach ◽  
Henri Robain ◽  
Bounsamay Soulileuth ◽  
...  
Keyword(s):  
Upland Rice ◽  
Centella Asiatica ◽  
Shannon Index ◽  
Species Number ◽  
List Type ◽  
Herbaceous Species ◽  
Frequent Change ◽  
Young Tree ◽  
Species Dominance ◽  
Density And Biomass

AbstractIn the past decades, the expansion and modernisation of agriculture in the mountainous areas of Southeast Asia has had severe impacts on biodiversity, as the once species-rich forests were turned into homogeneous fields receiving ample external inputs. A common feature of permanent cropping with annual crops is the frequent change of crop choice, depending on market opportunities or other motives. However, the precise effect of crop shifts on weeds in tropical areas is largely unknown. In this study, we investigated the short-term effect of crop sequences on the diversity of weed communities in smallholder fields in Northern Thailand. Crop choices were upland rice, maize, fallow and young tree plantations with or without intercrop. We counted the number of crop shifts and the number of crops involved during a 3-years period preceding weed sampling. We showed that the number of crop shifts did not affect weed density and biomass. However, herbaceous species number and diversity (measured as Shannon index) increased by 36% and 46% respectively, while herbaceous species dominance decreased by 38%, in fields with yearly crop shifts compared to fields with no shifts in the previous three years. The effect of a particular crop on diversity, or the effect of intercropping with young trees, was weaker. It was likely due to the more variable resources (especially light) in fields with two crop shifts, allowing species with different niches to co-exist. Crop type and frequent crop shifts did not affect shrub and tree species number, diversity or dominance. Some species were strongly associated with fields with no crop shift in the sequence (e.g. the tree Antidesma velutinosum) or to fields with two crop shifts in the sequence (e.g. the herb Centella asiatica, the C4 grass Digitaria radicosa). Overall, this study showed that in this agronomical system, maintaining yearly crop shifts does not significantly affect weed abundance, but supports in-field plant species diversity, which is likely to impact the services provisioned by tropical mountainous agro-ecosystemsHighlightsFrequent crop shifts in a crop sequence increased weed richness and diversity.Crop shifts had a stronger effect on weed richness and diversity than the current crop.The number of crop shifts did not affect weed biomass and density.Graphical abstract

scholarly journals Assessment of species diversity and distribution of woody species on selected plots in Olokemeji Forest Reserve, Ogun State, Nigeria

2021 ◽  
Vol 22 (3) ◽  
pp. 43-50
Author(s):  
D.M. Taiwo ◽  
S.I. Udoh ◽  
S.O. Olaoti-Laaro ◽  
O.R. Jeminiwa ◽  
M.S. Jeminiwa
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Woody Species ◽  
Tectona Grandis ◽  
Importance Value ◽  
Forest Reserve ◽  
Lowland Rain Forest ◽  
Ogun State ◽  
The Status ◽  
And Function

The Assessment of forest species composition and species diversity is essential in understanding the status of tree population and diversity for conservation purpose. Olokemeji forest reserve is situated in the lowland rain  forest of south-western Nigeria and it occupies a total land area of 58.88 km2 . Six study plots of 50m2 each were randomly selected and designated as Frequently Burnt Plot 1, Frequently Burnt Plot 2, Harvested Plot, Unharvested Unburnt Plot, Arable Plot 1 and Arable Plot 2 for the purpose of assessment of species diversity and distribution of woody species. Seven species of trees were identified belonging to five families. One hundred and eighty two stands were enumerated, with Unharvested Unburnt Plot having the highest number of trees at 50. The dominance index for the woody flora was 1 in Frequently Burnt Plot 1 and 2 as well as Arable Plot 1 and 2 except for the Harvested Plot that had the lowest (0.29) while the Unharvested Unburnt Plot had 0.75. Highest species richness was recorded at the Harvested Plot at 0.71. The species diversity in Harvested Plot was low (1.54), while it was extremely low in Unharvested Unburnt Plot (0.43). Evenness index was lowest in the Unharvested Unburnt Plot at 0.43. Tectona grandis had the highest relative importance value in the Frequently Burnt Plot 1. The low species richness and species diversity is a direct indication of anthropogenic interference in the study plots and the forest reserve; this requires urgent mitigation to prevent a total loss of its structure and function as expected of a forest reserve. Keywords: Species, Diversity, Evenness, Anthropogenic, Forest, Dynamics

scholarly journals Influence of chemosynthetic ecosystems on nematode community structure and biomass in the deep eastern Mediterranean Sea

2012 ◽  
Vol 9 (12) ◽  
pp. 18131-18173
Author(s):  
N. Lampadariou ◽  
V. Kalogeropoulou ◽  
K. Sevastou ◽  
K. Keklikoglou ◽  
J. Sarrazin
Keyword(s):  
Species Richness ◽  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Nematode Community ◽  
Cold Seep ◽  
Mud Volcanoes ◽  
Mussel Bed ◽  
Remotely Operated Vehicle ◽  
Eastern Mediterranean Sea ◽  
Density And Biomass

Abstract. Mud volcanoes are a special type of cold seeps where life is based on chemoautotrophic processes. They are considered as extreme environments and are characterised by unique megafaunal and macrofaunal communities. However, very few studies on mud volcanoes taking into account the smaller meiobenthic communities have been carried out. Two mud volcanoes were explored during the MEDECO cruise (2007) with the Remotely Operated Vehicle (ROV) Victor-6000; Amsterdam, located south of Turkey between 1700 and 2000 m depth (Anaximander mud field) and Napoli, south of Crete, located along the Mediterranean Ridge at about 2000 m depth (Olimpi mud field). The major aim of this study was to describe distributional patterns of meiofaunal communities and nematode assemblages from different seep microhabitats. Meiofaunal taxa and nematode assemblages at both mud volcanoes differed significantly from other Mediterranean sites in terms of standing stocks, dominance and species diversity. Density and biomass values were significantly higher at the seep sites, particularly at Amsterdam. Nematodes, the dominant meiofaunal taxon, displayed deeper penetration vertically into the sediment at the seep areas, indicating that biological rather than physicochemical factors are responsible for their vertical distribution. Patterns of nematode diversity varied, displaying both very high or very low species richness and dominance, depending on the habitat studied. The Lamellibrachia periphery and mussel bed of Napoli exhibited the highest species richness while the reduced sediments of Amsterdam yielded a species-poor nematode community, dominated by two successful species; one belonging to the genus Aponema and the other to the genus Sabatieria. Analysis of β-diversity showed that habitat heterogeneity of mud volcanoes contributed substantially to the total nematode species richness in the eastern Mediterranean Sea. These observations indicate a strong influence of mud volcanoes and cold-seep ecosystems on the meiofaunal communities and nematode assemblages.

scholarly journals Laboratory study on the effects of nutrient enrichment on a phytoplankton population in Sawa Lake, Iraq

2008 ◽  
Vol 5 (2) ◽  
pp. 230-236 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Population Dynamics ◽  
Lake Water ◽  
Nutrient Enrichment ◽  
Cell Number ◽  
Shannon Index ◽  
Nitrogen And Phosphorus ◽  
Phytoplankton Population ◽  
Phytoplankton Cell ◽  
Nitrogen Phosphorus ◽  
Index Of Diversity

Nutrient enrichment of Sawa lake water was made using different nitrogen and phosphorus concentrations during autumn and spring at three stations. Different concentrations of nitrogen, phosphorus and N: P ratios were used to test variations in phytoplankton population dynamics. Nitrogen at a concentration of 25 µmole.l-1 and N: P ratio of 10:1 gave highest phytoplankton cell number at all stations and seasons. A total of 64 algal taxa dominated by Bacillariophyceae followed by Cyanophyceae and Chlorophyceae were identified. The values of Shannon index of diversity were more than one in the studied stations.

scholarly journals Liver-specific knockdown of ANGPTL8 alters the structure of the gut microbiota in mice

2020 ◽  
Vol 70 (1) ◽  
Author(s):  
Yinlong Cheng ◽  
Yining Li ◽  
Yonghong Xiong ◽  
Yixin Zou ◽  
Siyu Chen ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Gut Microbiome ◽  
Shannon Index ◽  
Microbiota Composition ◽  
Functional Prediction ◽  
Adeno Associated Virus ◽  
Virus Serotype ◽  
Significant Difference ◽  
And Function ◽  
Gut Microbiota Composition

Abstract Purpose To investigate the effect of liver-specific knockdown of ANGPTL8 on the structure of the gut microbiota. Methods We constructed mice with liver-specific ANGPTL8 knockdown by using an adeno-associated virus serotype 8 (AAV8) system harbouring an ANGPTL8 shRNA. We analysed the structure and function of the gut microbiome through pyrosequencing and KEGG (Kyoto Encyclopedia of Genes and Genomes) functional prediction. Results Compared with controls, ANGPTL8 shRNA reduced the Simpson index and Shannon index (p < 0.01) of the gut microbiota in mice. At the phylum level, the sh-ANGPTL8 group showed a healthier gut microbiota composition than controls (Bacteroidetes: controls 67.52%, sh-ANGPTL8 80.75%; Firmicutes: controls 10.96%, sh-ANGPTL8 8.58%; Proteobacteria: controls 9.29%, sh-ANGPTL8 0.98%; F/B ratio: controls 0.16, sh-ANGPTL8 0.11). PCoA and UPGMA analysis revealed a significant difference in microbiota composition, while KEGG analysis revealed a significant difference in microbiota function between controls and the sh-ANGPTL8 group. Conclusion Our results revealed that inhibition of ANGPTL8 signalling altered the structure of the gut microbiome, which might further affect the metabolism of mice. We have thus identified ANGPTL8 as a novel hepatogenic hormone potentially involving the liver-gut axis and regulating the structure of the gut microbiota.

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