Extreme droughts in oligotrophic mountain grasslands cause substantial species abundance changes and amplify community filtering

Diversity and composition of benthic diatom algae and ciliates were studied at several beaches along the White and Barents seas: from highly exposed, reflective beaches with coarse-grained sands to sheltered, dissipative silty-sandy flats. For diatoms, the epipelic to epipsammic species abundance ratio was significantly correlated with the beach index and mean particle size, while neither α-diversity measures nor mean cell length were related to beach properties. In contrast, most of the characteristics of ciliate assemblages (diversity, total abundance and biomass, mean individual weight and percentage of karyorelictids) demonstrated a strong correlation to beach properties, remaining low at exposed beaches but increasing sharply in more sheltered conditions. β-diversity did not correlate with beach properties for either diatoms or ciliates. We suggest that wave action and sediment properties are the main drivers controlling the diversity and composition of the intertidal microbenthos. Diatoms and ciliates, however, demonstrated divergent response to these factors. Epipelic and epipsammic diatoms exhibited 2 different strategies to adapt to their environments and therefore were complementarily distributed along the environmental gradient and compensated for each other in diversity. Most ciliates demonstrated a similar mode of habitat selection but differed in their degree of tolerance. Euryporal (including mesoporal) species were relatively tolerant to wave action and therefore occurred under a wide range of beach conditions, though their abundance and diversity were highest in fine, relatively stable sediments on sheltered beaches, whereas the specific interstitial (i.e. genuine microporal) species were mostly restricted to only these habitats.

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Increased Moraxella and Streptococcus Species Abundance After Severe Bronchiolitis Is Associated With Recurrent Wheezing

PEDIATRICS ◽

10.1542/peds.2020-023861h ◽

2020 ◽

Vol 146 (Supplement 4) ◽

pp. S325.1-S325

Author(s):

Alexandra Navard-Keck ◽

Pooja Varshney

Keyword(s):

Species Abundance ◽

Recurrent Wheezing ◽

Streptococcus Species

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San Antonio Bay benthos species abundance before and after Hurricane Harvey, Feb. 2017 - July 2019

Biological and Chemical Oceanography Data Management Office ◽

10.1575/1912/bco-dmo.784677.1 ◽

2019 ◽

Author(s):

Paul Montagna

Keyword(s):

San Antonio ◽

Species Abundance ◽

Before And After

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STUDYING OF TERSKO-SULAKSKAYA LOWLAND VEGETATION UNDER THE RESULTS OF GROUND-BASED RESEARCH AND AUTOMATED INTERPRETATION

Vestnik of the Russian agricultural science ◽

10.30850/vrsn/2020/2/29-32 ◽

1970 ◽

pp. 29-32

Author(s):

M. I. Dzhalalova ◽

A. B. Biarslanov ◽

D. B. Asgerova

Keyword(s):

Plant Communities ◽

Satellite Imagery ◽

Vegetation Cover ◽

Anthropogenic Impacts ◽

Species Abundance ◽

Remote Sensing Data ◽

Indigenous Communities ◽

The State ◽

Anthropogenic Factors ◽

Internet Resource

The state of plant communities in areas located in the Tersko-Sulak lowland was studied by assessing phytocenotic indicators: the structure of vegetation cover, projective cover, species diversity, species abundance and elevated production, as well as automated decoding methods. There are almost no virgin soils and natural phytocenoses here; all of them have been transformed into agrocenoses (irrigated arable lands and hayfields, rice-trees and pastures). The long-term impact on pasture ecosystems of natural and anthropogenic factors leads to significant changes in the indigenous communities of this region. Phytocenoses are formed mainly by dry-steppe types of cereals with the participation of feather grass, forbs and ephemera, a semi-desert haloxerophytic shrub - Taurida wormwood. At the base of the grass stand is common coastal wormwood and Taurida wormwood - species resistant to anthropogenic influences. Anthropogenic impacts have led to a decrease in the number of species of feed-rich grain crops and a decrease in the overall productivity of pastures. Plant communities in all areas are littered with ruderal species. The seasonal dynamics of the land cover of the sites was estimated by the methods of automatic decoding of satellite images of the Landsat8 OLI series satellite for 2015, dated by the periods: spring - May 20, summer - July 23, autumn - October 20. Satellite imagery data obtained by Landsat satellite with a resolution in the multispectral image of 30 m per pixel, and in the panchromatic image - 10 m per pixel, which correspond to the requirements for satellite imagery to assess the dynamics of soil and vegetation cover. Lower resolution data, for example, NDVI MODIS, does not provide a reliable reflection of the state of soil and vegetation cover under arid conditions. In this regard, remote sensing data obtained from the Internet resource https://earthexplorer.usgs.gov/ was used.

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To the flora of сonjugates (Streptophyta, Conjugatophyceae) of the Valdai District area of the National Park «Valdaiskiy» (Novgorod Region, Russia)

Novosti sistematiki nizshikh rastenii ◽

10.31111/nsnr/2014.48.81 ◽

2014 ◽

Vol 48 ◽

pp. 81-88

Author(s):

A. F. Luknitskaya

Keyword(s):

Species Distribution ◽

National Park ◽

Species Abundance ◽

Water Bodies ◽

Number Of Species ◽

First Time

76 species, 3 varieties and 1 form from 21 genera of Streptophyta, Conjugatophyceae (Actinotaenium, Bambusina, Closterium, Cosmarium, Cylindrocystis, Euastrum, Gonatozygon, Haplotaenium, Micrasterias, Mougeotia, Netrium, Penium, Planotaenium, Pleurotaenium, Raphidiastrum, Spirogyra, Spirotaenia, Staurastrum, Staurodesmus, Tetmemorus, Xanthidium) were found in the basins of the Valdai District area of the National Park «Valdaiskiy» (Novgorod Region, Russia). The list of species is annotated with data on the species distribution in 55 collecting sites of 29 water bodies of the national park, and species abundance in collected samples according to Luknitskaya (2009). Among above mentioned genera, the genus Cosmarium is represented by the greatest number of species (20). Staurastrum chaetoceros has been found for the first time for the Novgorod Region.

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