Relating Benthic Infaunal Community Structure to Environmental Variables in Estuaries Using Nonmetric Multidimensional Scaling and Similarity Analysis

1998 ◽  
pp. 233-246
Author(s):  
G. McRae ◽  
D. K. Camp ◽  
W. G. Lyons ◽  
T. L. Dix
Keyword(s):  
Community Structure ◽  
Multidimensional Scaling ◽  
Environmental Variables ◽  
Nonmetric Multidimensional Scaling ◽  
Similarity Analysis ◽  
Infaunal 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 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.

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

scholarly journals Assessing macroinvertebrate communities in relation to environmental variables: the case of Sambandou wetlands, Vhembe Biosphere Reserve

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Tatenda Dalu ◽  
Rivoningo Chauke
Keyword(s):  
Community Structure ◽  
Water Depth ◽  
Environmental Variables ◽  
Anthropogenic Activities ◽  
Biosphere Reserve ◽  
High Water ◽  
Macroinvertebrate Community ◽  
Macroinvertebrate Communities ◽  
Negative Effect ◽  
Macrophyte Cover

AbstractThe Vhembe Biosphere Reserve, South Africa, contains many wetlands that serve as wildlife habitats and provide vital ecosystem services. Some of the wetlands are continuously being degraded or destroyed by anthropogenic activities causing them to disappear at an alarming rate. Benthic macroinvertebrates are known as good water quality bioindicators and are used to assess aquatic ecosystem health. The current study investigated habitat quality using macroinvertebrate community structure and other biotic variables (i.e. phytoplankton, macrophytes) in relation to environmental variables in the Sambandou wetlands using canonical correspondence analysis (CCA). A total of fifteen macroinvertebrate families were identified over two seasons. The CCA highlighted seven variables, i.e. pH, phosphate concentration, temperature, ammonium, macrophyte cover, conductivity and water depth, which were significant in structuring macroinvertebrate community. Picophytoplankton and microphytoplankton concentrations decreased from winter to summer, whereas nanophytoplankton concentration increased from winter to summer. Thus, the dominance of small-sized phytoplankton indicated nutrient limitation and decreased productivity, whereas winter sites 2 and 3 were dominated by large-celled phytoplankton, highlighting increased productivity. Winter sites were mostly negatively associated with CCA axis 1 and were characterised by high temperature, phosphate and ammonium concentrations, macrophyte cover, pH and conductivity. Summer sites were positively associated with axis 1, being characterised by high water depth and pH levels. The results obtained highlighted that agricultural activities such as cattle grazing and crop farming and sand mining/poaching had a negative effect on macroinvertebrate community structure.

scholarly journals Zooplankton of a stressed area in the Damietta coast of the Mediterranean Sea

2017 ◽  
Vol 58 (2) ◽  
pp. 245-260 ◽  
Author(s):  
Wael S. Eltohamy ◽  
Ahmad Alzeny ◽  
Yasmine A. M. Azab
Keyword(s):  
Community Structure ◽  
Mediterranean Sea ◽  
Ballast Water ◽  
Environmental Variables ◽  
Species Invasions ◽  
The Mediterranean ◽  
June July ◽  
Zooplankton Communities ◽  
The Impact ◽  
Univariate Analyses

The spatial pattern of zooplankton communities at Damietta coast, southeastern Mediterranean was studied to assess the impact of human activities on the abundance and community structure. Twenty-five stations from five different stressed sites were sampled in June-July 2014. Thirty-four zooplankton taxa were recorded, in addition to the larvae of copepods and meroplankton. Copepoda was the most abundant group among which, Oithona nana, Euterpina acutifrons, and Parvocalanus cirrostratus were the most frequent. The calanoid copepod Pseudodiaptomus trihamatus is a new record for the Mediterranean Sea that may have been introduced via ballast water. Multivariate/Univariate analyses demonstrated that 1) the environmental variables and zooplankton communities represented significant differences among five sites; 2) the spatial variations of community structure were undoubtedly due to land-based effluents; and 3) among all environmental variables, salinity and phytoplankton biomass had the major determining effects on the spatial patterns of zooplankton categories. The results indicates that not only the discharged water makes the Damietta coast at risk, but also the ballast water is not less dangerous. Hence, we emphasize the need for activation of the ballast water management to reduce the risk of future species invasions.

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