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

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.

Limnologica ◽  
2015 ◽  
Vol 55 ◽  
pp. 13-20 ◽  
Author(s):  
Francis S. Magbanua ◽  
Nikki Yvette B. Mendoza ◽  
Christine Jewel C. Uy ◽  
Christoph D. Matthaei ◽  
Perry S. Ong

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Tatenda Dalu ◽  
Rivoningo Chauke

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.


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