The zooplankton of the Forth, Scotland

1987 ◽  
Vol 93 (3-4) ◽  
pp. 377-388 ◽  
Author(s):  
C. J. L. Taylor
Keyword(s):  
Community Structure ◽  
Fresh Water ◽  
Environmental Variables ◽  
Species Complex ◽  
Species Abundance ◽  
Abundance And Distribution

SynopsisA description of the community structure of the Forth estuary's zooplankton was obtained by sampling monthly at nine stations ranging from fresh water to fully marine conditions for an eighteen-month period. The variation in species abundance and distribution is related to environmental variables. The apparent spatial and temporal successions of members of the Acartia species complex are described, as are the episodes of predation spreading from the firth and the domination of the upper estuary by Eurytemora. It is observed that the estuary of the Forth is rare among British estuaries in its ability to support a truly pelagic self-maintaining assemblage of species.

scholarly journals Diversity and Community Structure of Oribatid Mites (Acari, Oribatei) at Memorial Complexes of a Megapolis

2013 ◽  
Vol 47 (4) ◽  
pp. 291-297
Author(s):  
L. A. Kolodochka ◽  
O. S. Shevchenko
Keyword(s):  
Community Structure ◽  
Species Diversity ◽  
Species Complex ◽  
Common Species ◽  
Oribatid Mites ◽  
Direct Relation ◽  
City Center ◽  
Degree Of Dominance ◽  
Different Types ◽  
The City

Abstract In different types of substrate (soil, litter, lichens and mosses) collected at three memorial complexes (cemeteries) of Kyiv (Ukraine), 70 species from 57 genera, 34 families of oribatid mites were found. A few eurytopic species capable of tolerance to different types of pollution make up an essential part in each species complex. The species diversity and complexity of oribatid community structure at researched areas increased with distance from the city center. There was no direct relation between the degree of dominance of most common species and the cemetery’s relative remoteness from the center of the city.

scholarly journals Community Structure of Benthic Algae in a Lotic Ecosystem, Karbala Province-Iraq

2017 ◽  
Vol 14 (4) ◽  
pp. 692-706 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Community Structure ◽  
Chlorophyll A ◽  
Total Nitrogen ◽  
Environmental Variables ◽  
Nitrogen Limitation ◽  
Benthic Algae ◽  
Concrete Lining ◽  
Qualitative And Quantitative ◽  
Quantitative Studies ◽  
Lotic Ecosystem

This study focused on benthic algae (epipelic and attached algae on concrete lining stream) in Bani-Hassan stream in Holly Karbala, Iraq. The qualitative and quantitative studies of benthic algae were done by collecting 240 samples from five sites in the study area for the period from December 2012 to November 2013. Also, the environmental variables of the stream were examined in term of temporary and spatial. The results showed that the stream was alkaline, hard, oligohaline and a well aerated. The total nitrogen to the total phosphorus (TN: TP) ratio indicates nitrogen limitation. 129 species of benthic algae belonging to 57 genera were identified. Bacillariophyceae (diatoms) was the predominant taxon (95 species) followed by Chlorophyceae (16 species), Cyanophyceae (14 species), Euglenophyceae (3 species) and Pyrophyceae (one species). Some genera were found throughout the study period: Nitzschia, Navicula, Cymbella, Gomphonema, Surirella, Cocconeis, Aulacoseira, Oscillatoria, Lyngbya, Spirulina, and ? Scenedesmus. Site 3 recorded the highest total number of algae in spring 2013, and the lowest total number was at site 5 in Autumn 2013. The chlorophyll-a concentration did not match the total number of algae.

scholarly journals Rediscovery of the endemic gastropod Dianella schlickumi (Gastropoda, Hydrobiidae) and its discrimination from Dianella thiesseana: environmental correlates and implications for their conservation

2018 ◽  
Vol 27 ◽  
pp. 35-58
Author(s):  
Chrysoula Ntislidou ◽  
Canella Radea ◽  
Sinos Giokas ◽  
Martin T. Pusch ◽  
Maria Lazaridou ◽  
...  
Keyword(s):  
Community Structure ◽  
Environmental Variables ◽  
Redundancy Analysis ◽  
Habitat Degradation ◽  
Effective Management ◽  
Environmental Correlates ◽  
Narrow Endemic ◽  
Morphometric Analyses ◽  
Management Plans ◽  
Anatomical Characters

The aquatic snail genus Dianella (Gastropoda: Hydrobiidae) has only two representatives in Greece: Dianellaschlickumi Schütt, 1962 and Dianellathiesseana (Kobelt, 1878). D.schlickumi, a narrow endemic species to Lake Amvrakia (in Aitoloakarnania, western-central Greece), is considered as Critically Endangered (Possibly Extinct, sensu IUCN 2017). Our study confirmed its presence in Lake Amvrakia, where it had not been detected for more than 30 years. We document the unknown anatomical characters based on the D.schlickumi specimens. Moreover, the presence of D.thiesseana in the nearby lakes Trichonis and Lysimachia was also confirmed, while morphometric analyses enabled the discrimination between the two species. Redundancy Analysis revealed conductivity, dissolved oxygen and pH as the main environmental variables related to the above species’ distribution, shaping their community structure. Both Dianella species require urgent conservation measures to be enforced, due to their habitat degradation from human activities, which are limiting and fragmenting their range. For that purpose, effective management plans have to be elaborated and implemented at the mentioned lakes, focusing on the reduction of human pressures and on the improvement of their habitats.

Landscape Influences on Stream Habitats and Biological Assemblages

2006 ◽  
Keyword(s):  
Land Cover ◽  
Ictalurus Punctatus ◽  
Environmental Variables ◽  
Agricultural Land ◽  
Fish Assemblages ◽  
Spatial Scales ◽  
Species Abundance ◽  
Ecological Condition ◽  
Basin Scale ◽  
Assemblage Metrics

<em>Abstract.</em>—We analyzed data from 38 sites on 31 large rivers in Wisconsin to characterize the influence of environmental variables at the basin, reach, and site scales on fish assemblages. Electrofishing and site habitat data were collected for a distance of 1.6 km per site. Environmental variables included conductivity, substrate, and fish cover at the site scale; distance to impoundments, dams, and length of riverine habitat at the reach scale; and land cover, climate, and geology at the basin scale. Of the 77 fish species found, 39 occurred in more than 10% of the sites and were retained for analyses of fish abundance and biomass. Redundancy analysis (RDA) was used to relate species abundance, biomass, and 16 assemblage metrics to environmental variables at the three spatial scales. The site and basin scales defined fishes along a gradient from high conductivity, fine substrate, and agricultural land cover to low conductivity, rocky substrate, and forested land cover. For abundance and biomass, the strongest assemblage pattern contrasted northern hog sucker <em>Hypentelium nigricans</em>, blackside darter <em>Percina maculata</em>, and logperch <em>P. caprodes </em>with common carp <em>Cyprinus carpio</em>, channel catfish <em>Ictalurus punctatus</em>, and sauger <em>Sander canadensis</em>. The <em>H. nigricans </em>group, along with high values of index of biotic integrity and some assemblage metrics (percent lithophilic spawners, percent round-bodied suckers), corresponded with the forested end of the ecological gradient, whereas the <em>C. carpio </em>group and percent anomalies corresponded with the agricultural end. Natural environmental conditions, including bedrock geology type, bedrock depth, surficial geology texture, basin area, and precipitation, also influenced the fish assemblage. Partial RDA procedures partitioned the explained variation among spatial scales and their interactions. We found that widespread land cover alterations at the basin scale were most strongly related to fish assemblages across our study area. Understanding the influence of environmental variables among multiple spatial scales on fish assemblages can improve our ability to assess the ecological condition of large river systems and subsequently target the appropriate scale for management or restoration efforts.

scholarly journals Effects of climate and spawning stock structure on the spatial distribution of Northeast Arctic cod larvae

2020 ◽  
Author(s):  
Clarissa Akemi Kajiya Endo ◽  
Frode B Vikebø ◽  
Natalia A Yaragina ◽  
Solfrid Sætre Hjøllo ◽  
Leif Christian Stige
Keyword(s):  
Spatial Distribution ◽  
Environmental Variables ◽  
Barents Sea ◽  
Condition Index ◽  
Ocean Current ◽  
Larval Abundance ◽  
Near Surface ◽  
Spawning Stock ◽  
Long Time ◽  
Abundance And Distribution

Abstract The spatial distribution of fish early life stages can impact recruitment at later stages and affect population size and resilience. Northeast Arctic (NEA) cod spawning occurs along the Norwegian coast. Eggs, larvae, and pelagic juveniles drift near-surface towards the Barents Sea nursery area. In this study, a 35-year long time series of NEA cod larvae data was analysed in combination with factors that potentially may affect the distribution of eggs and larvae. These factors included biological aspects of the spawning stock, and environmental variables, such as water temperature, wind, ocean current, and prey abundance. Our aim was to shed light on how these factors influence larval abundance and distribution and how larval abundance and distribution influenced recruitment at age 3. We found that biomass and mean weight of the spawners were positively associated with larval abundance and that a high liver condition index of the spawners was associated with a north-easterly distribution of the larvae. The environmental variables showed generally weak or no correlations with abundance or distribution of larvae. Lastly, we found significant association between larval abundance and year-class abundance at age 3, while the spatial distribution metrics of the larvae, i.e. distribution extent, mean longitude, and mean latitude, showed no significant association with future year-class abundance.

Influence of environmental variables on the distribution and community structure of mesozooplankton in the coastal waters of the eastern Arabian Sea

2020 ◽  
Vol 39 ◽  
pp. 101480
Author(s):  
P. Ezhilarasan ◽  
Vishnu Vardhan Kanuri ◽  
P. Sathish Kumar ◽  
M. Kumaraswami ◽  
G. Durga Rao ◽  
...  
Keyword(s):  
Community Structure ◽  
Coastal Waters ◽  
Environmental Variables ◽  
Arabian Sea ◽  
Eastern Arabian Sea
Sign in / Sign up

Export Citation Format

Share Document