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.

Macroinvertebrate Communities and Environment in a Southern African Mountain Stream

1988 ◽  
Vol 45 (12) ◽  
pp. 2168-2181 ◽  
Author(s):  
J. M. King ◽  
J. A. Day ◽  
P. R. Hurly ◽  
M-P. Henshall-Howard ◽  
B. R. Davies
Keyword(s):  
Community Structure ◽  
Environmental Variables ◽  
Mediterranean Ecosystems ◽  
Mountain Stream ◽  
Functional Feeding Groups ◽  
Stepwise Discriminant Analysis ◽  
Macroinvertebrate Communities ◽  
Strong Correlations ◽  
Stream Community ◽  
Community Changes

In a study of a second-order southern African stream, complementary classification and multidimensional scaling (MDS) techniques revealed longitudinal changes in macroinvertebrate community structure, but no temporal changes. Stepwise discriminant analysis and multiple linear regression were used to identify environmental variables correlated with the community changes but produced conflicting results depending on the information used, possibly because of strong correlations between some of the variables. The MDS plot of biotic samples illustrated that potassium levels correlated most strongly with community distribution. Because of the large number of variables now shown worldwide to correlate with faunal distributions, we suggest ways to choose the variables to suit the kind of study to be undertaken. Attempts to assign the invertebrates to functional feeding groups (FFGs) were unsatisfactory as the relevant categories are poorly defined and often inadequate for classifying the fauna. We suggest that until these categories are more clearly defined, and more uniformly applied, concepts relating to FFGs cannot be tested satisfactorily. The stream community in Langrivier is more similar to communities found in two other mediterranean ecosystems than to those in other southern African rivers, probably because of the greater predictability of flow in the former.

Water level thresholds of benthic macroinvertebrate richness, structure, and function of boreal lake stony littoral habitats

2011 ◽  
Vol 68 (10) ◽  
pp. 1695-1704 ◽  
Author(s):  
Michael S. White ◽  
Marguerite A. Xenopoulos ◽  
Robert A. Metcalfe ◽  
Keith M. Somers
Keyword(s):  
Community Structure ◽  
Water Level ◽  
Macroinvertebrate Community ◽  
Functional Mobility ◽  
Water Level Fluctuations ◽  
Benthic Macroinvertebrate ◽  
Functional Composition ◽  
Macroinvertebrate Communities ◽  
Taxa Richness ◽  
Littoral Habitats

We investigated the role of water level fluctuation on benthic macroinvertebrate communities of stony littoral habitats located in the Boreal Shield Ecozone. Using the reference condition approach (RCA), regression analysis, nonmetric multidimensional scaling (NMDS), and analysis of variance (ANOVA), we analyzed the benthic macroinvertebrate community structure of 20 natural lakes and 28 hydroelectric reservoirs to determine if they are structured by change in water level (amplitude). Along a gradient of amplitude intensity, we found that taxa richness decreases with increasing amplitude (r2 = 0.47–0.60). Littoral benthic macroinvertebrate community structure is significantly different in reservoirs that experience amplitudes > 2.0 m. Out of 28 reservoirs, 13 fell outside the 95.5% confidence ellipse determined by 20 reference lakes. Functional mobility group and functional feeding group composition are also altered with increasing amplitude (nonparametric ANOVA, P < 0.05). Further, a change in benthic macroinvertebrate functional composition occurs after a change in taxa richness. Interestingly, reservoirs that experienced amplitudes < 2.0 m had benthic macroinvertebrate communities whose structural and functional composition is similar to lakes experiencing natural water level fluctuations.

scholarly journals A Model of the Effect of Environmental Variables on the Presence of Otters along the Coastline of the Isle of Skye

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
Paul Yoxon
Keyword(s):  
Intertidal Zone ◽  
Environmental Variables ◽  
Quantitative Method ◽  
Logistic Regression Model ◽  
High Water ◽  
Independent Variables ◽  
Dependent Variables ◽  
Negative Effect ◽  
Isle Of Skye ◽  
Positive Effect

A survey of Eurasian otters (Lutra lutra) along the Skye coastline revealed a variation in distribution on different coastal types. Factors like geology, width of the intertidal zone, intertidal makeup, slope of coastline, inland vegetation, and number of freshwater pools could influence otter distribution. A quantitative method based on a logistic regression model is applied to take into account three scalable and four categorical environmental variables which may or may not affect otter distribution. Otter presence or absence in 500 m coastal sections was compared with binary dependent variables and a set of independent variables on 622 coastal sites. Analysis shows that this method can be used to characterise combinations of factors to predict if otters are likely to occur on a particular coastline. Geology, height 25 m above High Water Mark (indicating slope of coastline), and number of freshwater pools all affect otter utilisation of the coastal zone. Coastlines with Torridonian and Mesozoic rocks and the Landslip area show a positive effect on otters, while all other coastlines have a negative effect. Although primarily of theoretical importance, the model could be used as a tool to locate coastlines elsewhere which are of potential conservation importance for otters.

Macroinvertebrate community structure in relation to environmental variables in a Swiss glacial stream

2001 ◽  
Vol 46 (12) ◽  
pp. 1641-1661 ◽  
Author(s):  
Brigitte Lods-Crozet ◽  
Emmanuel Castella ◽  
Diana Cambin ◽  
Christiane Ilg ◽  
Sandra Knispel ◽  
...  
Keyword(s):  
Community Structure ◽  
Environmental Variables ◽  
Macroinvertebrate Community ◽  
Glacial Stream

scholarly journals Influence of environmental variables on macroinvertebrate community structure in Lianhuan Lake

2021 ◽  
Author(s):  
Qianming Dou ◽  
Xue Du ◽  
Yanfeng Cong ◽  
Le Wang ◽  
Chen Zhao ◽  
...  
Keyword(s):  
Community Structure ◽  
Dissolved Oxygen ◽  
Chlorophyll A ◽  
Total Phosphorus ◽  
Environmental Variables ◽  
Pearson Correlation ◽  
Macroinvertebrate Community ◽  
Limiting Factors ◽  
Ecological Environment ◽  
Lake Ecosystem

The characteristics of macroinvertebrate community structure can effectively reflect the health status of lake ecosystem and the quality of the lake ecological environment. It is of great significance to identify the limiting factors of macroinvertebrate community structure for the maintenance of lake ecosystem health. In this study, the community composition of macroinvertebrate assemblages and their relationships with environmental variables in 13 small lakes within Linhuan Lake was investigated. Self-organizing map, K-means clustering analysis, principal component analysis, pearson correlation analysis, and redundancy analysis were used to analyze the correlation and variability between macroinvertebrates community index and environmental factors. The results showed that the environmental variables (pH, total phosphorus, nitrate, water temperature, dissolved oxygen, conductivity, chemical oxygen demand, and ammonium) had a significant effect on the classification of macroinvertebrate community. Molluscs were significantly negatively correlated with pH and chlorophyll a, while annelids and aquatic insects were significantly positively correlated with chlorophyll a and dissolved oxygen. Species richness and Shannon’s diversity of macroinvertebrates were significantly negatively correlated with total phosphorus while biomass of macroinvertebrates was significantly negatively correlated with pH. High alkalinity characteristics and eutrophication of the lake have a serious impact on the macroinvertebrate community. Human interference and unreasonable industrial and surface runoff from agricultural farms destroy the ecological environment and affect the community structure of macroinvertebrate. Thus, the improvement of the macroinvertebrate’s community structure should be carried out by improving the Lianhuan Lake watershed ecological environment and controlling watershed environmental pollution.

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