Community structure and dynamics of deep-water decapod assemblages from Le Danois Bank (Cantabrian Sea, NE Atlantic): Influence of environmental variables and food availability

2007 ◽  
Vol 75 (4) ◽  
pp. 797-816 ◽  
Author(s):  
Joan E. Cartes ◽  
Alberto Serrano ◽  
Francisco Velasco ◽  
Santiago Parra ◽  
Francisco Sánchez
Keyword(s):  
Community Structure ◽  
Food Availability ◽  
Deep Water ◽  
Environmental Variables ◽  
Ne Atlantic ◽  
Structure And Dynamics

Levels of Spatial Variability: The “Community” Problem

1990 ◽  
Vol 5 ◽  
pp. 13-30 ◽  
Author(s):  
D. A. Springer ◽  
A. I. Miller
Keyword(s):  
Community Structure ◽  
Spatial Variability ◽  
Species Distribution ◽  
Distribution Patterns ◽  
The Past ◽  
Structure And Dynamics ◽  
Evolutionary Units ◽  
The Way

The way we view species distribution patterns, particularly at the level commonly referred to as the “community”, has changed over the past 70 years in biology and, subsequently, in paleontology. Because the degree to which species associations can be interpreted as ecological and evolutionary units depends ultimately on recognition and interpretation of faunal spatial variability, we need to understand the nature of this variability at all levels of resolution before we can adequately address questions of “community” structure and dynamics. While it is possible to recognize spatial variability at several levels, from the distributions of individuals within a species to the overall pattern created by the global biota, we must ask whether these patterns really comprise a hierarchy with natural discontinuities (Fig. 1), or whether it is more realistic to view them as a continuous variability spectrum.

scholarly journals Impact of fish cage-culture on the community structure of zooplankton in a tropical reservoir

2011 ◽  
Vol 101 (1-2) ◽  
pp. 75-84 ◽  
Author(s):  
Juliana D Dias ◽  
Érica M Takahashi ◽  
Natália F Santana ◽  
Cláudia C Bonecker
Keyword(s):  
Community Structure ◽  
Food Availability ◽  
Community Dynamics ◽  
Zooplankton Community ◽  
Fish Farming ◽  
Spatial And Temporal Variation ◽  
Cage Culture ◽  
Tropical Reservoir ◽  
Zooplankton Community Structure ◽  
The Impact

We investigated the impact of fish cage culture on the zooplankton community structure in a tropical reservoir. We hypothesized that community abundance is greater near cages and increases over time due to the increase in food availability. Samplings were performed near, upstream and downstream from net cages, and before and after net cage installation. The abundance of zooplankton increased 15 days after the experiment was set up, followed by a reduction and finally increased. Rotifer abundance showed significant differences among sites (p<0.05) and sampling periods (p<0.001). Significant differences were also observed in total zooplankton and cladoceran abundance (p<0.001). The spatial and temporal variation of the physical and chemical variables were indirectly correlated with the structure and dynamic of the zooplankton community, as they indicated the primary production in the environment. Our hypothesis was rejected, since the zooplankton was abundant at the reference site. Only rotifers showed higher abundance near cages, due to the influence of food availability. Community dynamics during the experiment was also correlated to food availability. Our results suggest an impact of fish farming on the zooplankton community.

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 Assessment of Effect of Hydropower Plant Projects on Socio-Environmental Sustenance and Development in Rwanda: A Review Done At Rubagabaga Hydropower Ltd.

2022 ◽  
Vol 10 (01) ◽  
pp. 2888-2904
Author(s):  
Dr. MUTESI Jean Claude
Keyword(s):  
Community Structure ◽  
Null Hypothesis ◽  
Quantitative Research ◽  
Target Population ◽  
Positive Influence ◽  
Hydropower Plant ◽  
P Value ◽  
Structure And Dynamics ◽  
Hydropower Plants ◽  
The Impact

The study investigated the socio-economic and environmental impact of hydropower projects in Rwanda with a case study of Rubagabaga hydropower Ltd operating from Nyabihu District. It examines the impact of a socio-economic and environmental hydropower plant in Rwanda, identifies the challenge hydropower plants face in Rwanda, and finally investigates the relationship between hydro powers and their socio-economic impact in Rwanda? In this research, the quantitative research design is based on statistical data of the research that was used with quantitative and qualitative methods. Questionnaires were used to collect data. The target population of this study was made up of 252 participants including 154 respondents all from ten different villages surrounding the Rubagabaga plant in Nyabihu District. Data were analyzed using descriptive and correlation analysis and tables that were interpreted to confirm or deny the relevance of the main and specific objectives. Based on results from table no.16 demonstrates that the beta= 0.397 with the t value of 2.333 and the p-value of 0. 021. Since the p-value is less than 0.05, the researcher rejected the null hypothesis and considered it an alternate. There is a strong positive relationship between environmental assessment of hydropower plant projects and socio-environmental sustenance and development. In a nutshell, the researcher has rejected the null hypothesis and considered its alternate. Community structure and dynamics have a positive influence on socio-environmental sustenance and development. Table no.16 shows that beta= 0.341 with the t value of 2.668 as the p-value was 0.009. Since the p-value is less than 0.05. Therefore, the researcher rejected the null hypothesis and considered it an alternate. According to table no.21, the changes in community structure and dynamics of the hydropower plant project cause the increase of 0.341 (34.1%) of the socio-environment sustenance and development. The ratio of beta modal results for the t value expressed t=2.66 hence the probability value is significant on socio-environment sustenance and development noting that sig. =0.009. Carefully, the researcher has rejected the null hypothesis and considered its alternate. With this in mind, community structure and dynamics has a positive influence on socio-environmental sustenance and development. Table no.16 has shown beta= 0.478 with the t value of 4.543 as the p-value was 0.000 which is less than 0.05. According to the findings, the changes in government policies, stability, and support of hydropower plant project causes the increase of 0.478 (47.80%) of the socio-environment sustenance and development. The ratio of beta modal results for the t value expressed t= 4.54 hence the probability value is significant on socio-environment sustenance and development noting that sig. =0.000.

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.

scholarly journals Habitat Heterogeneity Determines Climate Impact on Zooplankton Community Structure and Dynamics

PLoS ONE ◽  
2014 ◽  
Vol 9 (3) ◽  
pp. e90875 ◽  
Author(s):  
Saskia A. Otto ◽  
Rabea Diekmann ◽  
Juha Flinkman ◽  
Georgs Kornilovs ◽  
Christian Möllmann
Keyword(s):  
Community Structure ◽  
Habitat Heterogeneity ◽  
Zooplankton Community ◽  
Climate Impact ◽  
Zooplankton Community Structure ◽  
Structure And Dynamics
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