Response of littoral macroinvertebrate communities on rocks and sediments to lake residential development

2008 ◽  
Vol 65 (6) ◽  
pp. 1206-1216 ◽  
Author(s):  
Simon De Sousa ◽  
Bernadette Pinel-Alloul ◽  
Antonia Cattaneo
Keyword(s):  
Particle Deposition ◽  
Size Structure ◽  
Open Water ◽  
Residential Development ◽  
Taxonomic Composition ◽  
Total Biomass ◽  
Macroinvertebrate Communities ◽  
Littoral Invertebrates ◽  
Woody Litter ◽  
The Impact

Previously pristine lakes of the Laurentian region of Quebec, Canada, have faced increasing residential development of their watershed since the 1970s. We tested whether littoral invertebrates respond to this perturbation, even though open-water nutrients and chlorophyll are not yet altered. We examined changes in biomass, size structure, and taxonomic composition of macroinvertebrates living on rocks and sediments in 13 lakes representing a gradient of lakeshore residential development and watershed clearing. Littoral invertebrates provided early indication of lake perturbation, but their response varied according to the substratum. On rocks, total invertebrate biomass increased along the perturbation gradient and size structure shifted towards large organisms. These changes were likely mediated by a concomitant increase in epilithon biomass, suggesting a bottom-up control. No significant change in total biomass and size structure was observed for invertebrates in sediments. In contrast, taxonomic composition changed with lake development in sediments, but not on rocks. Taxonomic shifts were likely related to changes in sediment heterogeneity due to a decline of woody litter and increased fine particle deposition. Oligochaetes were positively associated to perturbation, whereas mayflies were negatively associated; these taxa could be used as indicators. Sediments were a better sentinel substratum than rocks for biomonitoring the impact of lake residential development.

Limited effects of stocked trout on littoral invertebrates in boreal foothills lakes

2012 ◽  
Vol 69 (1) ◽  
pp. 178-190 ◽  
Author(s):  
Leslie E. Nasmith ◽  
William M. Tonn ◽  
Cynthia A. Paszkowski ◽  
Garry J. Scrimgeour
Keyword(s):  
Community Composition ◽  
Size Structure ◽  
Invertebrate Community ◽  
Negative Effects ◽  
High Productivity ◽  
Recreational Angling ◽  
Key Characteristics ◽  
Littoral Zones ◽  
Littoral Invertebrates ◽  
The Impact

Stocking lakes with trout for the purposes of recreational angling is a management strategy that introduces a new predator into these systems and thus deserves careful scrutiny. To assess the impact of non-native trout on littoral invertebrates in naturally fish-bearing lakes in the boreal foothills of Alberta, Canada, we compared their community composition, abundance, and size structure in stocked (n = 5) and unstocked (n = 6) lakes over a 2-year period. We detected no clear negative effects of introduced trout on invertebrate community composition and only few taxa-specific examples of decreased or increased invertebrate abundance. Furthermore, predation by trout had inconsistent direct effects on the size structure of invertebrate populations. Indirect effects were suggested by increased abundances and sizes of some invertebrate taxa in stocked lakes and might also contribute to the limited overall differences that we observed. We propose that net effects of stocked trout on littoral invertebrates are influenced by key characteristics of receiving ecosystems. In our boreal foothills lakes, dense macrophyte cover in warm littoral zones, high productivity, abundant forage fish, and limited densities of trout all likely combine to allow littoral invertebrate communities to withstand the impact of introduced trout with minimal effects.

Macrozoobenthos response to environmental degradation in a heavily modified stream: Case study the Upper Elbe River, Czech Republic

Biologia ◽  
2010 ◽  
Vol 65 (3) ◽  
Author(s):  
Zdeněk Adámek ◽  
Claus Orendt ◽  
Georg Wolfram ◽  
Jan Sychra
Keyword(s):  
Water Quality ◽  
Size Structure ◽  
Habitat Characteristics ◽  
Macroinvertebrate Communities ◽  
Elbe River ◽  
Important Indicator ◽  
Natural Stream ◽  
River Bed ◽  
Macrophyte Community ◽  
The Impact

AbstractBenthic macroinvertebrates are an important indicator of river health. However, their response upon water quality development downstream the pollution outlets considerably depends on the environmental habitat characteristics. Three successive stretches, each of them providing three different mesohabitats in stillwater (S), torrential (T) and riparian (R) zones were selected for evaluation of the impact of altered metapotamal river bed morphology (channelization) and chemical determinants of water quality on the Upper Elbe River. In downstream direction, the stretches are separated by weirs and characterized as a low polluted low modified natural stream (N), a low polluted channelized stream (C) and a channelized polluted stream (CP). Altogether, 111 benthic macroinvertebrate taxa were recorded in the Pardubice hotspot between Němčice and Přelouč. Despite different levels of stream bed and water quality degradation, micro- and mesohabitat characteristics appeared to be the most important factors determining the diversity of macrozoobenthos in riffle (substrate size structure) and in shoreline (macrophyte community composition and structure) mesohabitats. The diversity of macroinvertebrate communities was highest in riparian mesohabitats compared to stillwater and torrential ones. Saprobic indices increased in downstream direction, thus indicating the decline of water quality.

scholarly journals Intercomparison of five nets used for mesozooplankton sampling

2015 ◽  
Vol 16 (3) ◽  
pp. 550 ◽  
Author(s):  
D. ALTUKHOV ◽  
I. SIOKOU ◽  
M. PANTAZI ◽  
K. STEFANOVA ◽  
F. TIMOFTE ◽  
...  
Keyword(s):  
Black Sea ◽  
Size Structure ◽  
Mesh Size ◽  
Taxonomic Composition ◽  
The Black Sea ◽  
Total Biomass ◽  
Correction Factors ◽  
Fine Mesh ◽  
Large Animals ◽  
Ecosystem Changes

Intercomparison of nets commonly used for mesozooplankton sampling in the Black and Mediterranean seas was attempted within SESAME (Southern European Seas: Assessing and Modelling Ecosystem Changes) project. Five nets were compared: three Juday nets equipped with 150 μm, 180 μm and 200 μm mesh size, Nansen net (100 μm mesh size) and WP2 (200 μm mesh size). Replicated samples were collected at one station in the western Black Sea offshore waters in April 2009. Collected samples were analyzed at species level (except for meroplankton), stages (for copepods) and size length. A decrease of total abundance values was observed with increasing mesh size, due to the significantly higher numbers of animals smaller than 1 mm in the samples obtained by fine mesh size than with coarser nets. Few comparisons were revealed significant for the abundance of animals with 1-2 mm length, while no significance was detected for specimens larger than 2 mm. The above differences resulted in discripancies between nets regarding species and stages composition. Biomass values did not differ significantly between nets, due to the strong contribution to total biomass of the large animals fraction (Calanus euxinus). The smallest and the largest animals revealed high variability between replicates collected by Nansen, Juday- 200 μm and WP2 nets. Correction factors were calculated for the conversion of abundance values between each couple of nets. The detected differences between nets regarding the abundance and biomass, the community taxonomic composition and size structure, as well as the estimated correction factors, provide useful information for the harmonization of data obtained by the above nets in the Black Sea.

Patterns of Invertebrate Size and Abundance in Aquatic Habitats

1981 ◽  
Vol 38 (8) ◽  
pp. 896-904 ◽  
Author(s):  
Gary G. Mittelbach
Keyword(s):  
Body Size ◽  
Lognormal Distribution ◽  
Prey Size ◽  
Lepomis Macrochirus ◽  
Stomach Contents ◽  
Open Water ◽  
Total Biomass ◽  
Bare Sediment ◽  
Littoral Invertebrates

The size distributions of invertebrate prey found in the vegetation, bare sediment, and open water habitats of a small, Michigan lake were quantified for the months of May through August, 1979. The distribution of prey body size in each habitat generally conformed to a lognormal distribution, allowing a simple characterization of prey size and abundance in each habitat. Seasonally, the abundance of large littoral invertebrates declined markedly, shifting the distribution of prey size in the vegetation and bare sediment habitats towards smaller prey. The total biomass of vegetation-dwelling prey (exclusive of gastropods) also declined dramatically from May to August. These seasonal changes in prey size and abundance were correlated with a reduction in foraging intake for the dominant fish species in the lake, the bluegill sunfish (Lepomis macrochirus). Bluegills whose diet was > 80% vegetation prey showed a > 3-fold decline in stomach contents (prey weight/fish weight) from May to Ausut, during which time prey biomass in the vegetation declined 2.5-fold.Key words: body size, lognormal distribution, benthos, foraging, Lepomis, Michigan

Impacts of altered benthic invertebrate communities on the feeding ecology of yellow perch (Perca flavescens) in metal-contaminated lakes

2005 ◽  
Vol 62 (1) ◽  
pp. 153-162 ◽  
Author(s):  
J Kövecses ◽  
G D Sherwood ◽  
J B Rasmussen
Keyword(s):  
Yellow Perch ◽  
Size Structure ◽  
Perca Flavescens ◽  
Stomach Contents ◽  
Benthic Invertebrate ◽  
Taxonomic Composition ◽  
Benthic Macroinvertebrate ◽  
Macroinvertebrate Communities ◽  
Trophic Links ◽  
Benthic Invertebrate Communities

Metal contamination can disrupt trophic links in food webs by altering the taxonomic composition and size structure of benthic macroinvertebrate communities. Benthic macroinvertebrates and yellow perch (Perca flavescens) were collected from six lakes along a gradient of cadmium (Cd) and copper (Cu) contamination in Quebec, Canada. The two most contaminated lakes had significantly lower densities of several benthic macroinvertebrate taxa and significantly lower Shannon's index than less contaminated lakes. The stomach contents of perch from the most contaminated lakes were less diverse, with a greater reliance on chironomids and (or) zooplankton than perch from other study lakes. The size of prey in perch from the most contaminated lakes did not increase with age and the mean prey size was smaller than in other, less contaminated lakes. Perch from lakes with medium to low levels of contamination weighed significantly more than perch from lakes with high levels of contamination. This reduction in growth is attributed to the increased costs of foraging on a simplified prey base in metal-contaminated systems.

scholarly journals Transitions in oral and gut microbiome of HPV+ oropharyngeal squamous cell carcinoma following definitive chemoradiotherapy (ROMA LA-OPSCC study)

2021 ◽  
Author(s):  
Marc Oliva ◽  
Pierre H. H. Schneeberger ◽  
Victor Rey ◽  
Matthew Cho ◽  
Rachel Taylor ◽  
...  
Keyword(s):  
Squamous Cell Carcinoma ◽  
Cell Carcinoma ◽  
Squamous Cell ◽  
Taxonomic Composition ◽  
Oropharyngeal Squamous Cell Carcinoma ◽  
Oral Microbiome ◽  
Metagenomic Sequencing ◽  
Α Diversity ◽  
16S Rna ◽  
The Impact

Abstract Background Oral and gut microbiomes have emerged as potential biomarkers in cancer. We characterised the oral and gut microbiomes in a prospective observational cohort of HPV+ oropharyngeal squamous cell carcinoma (OPSCC) patients and evaluated the impact of chemoradiotherapy (CRT). Methods Saliva, oropharyngeal swabs over the tumour site and stool were collected at baseline and post-CRT. 16S RNA and shotgun metagenomic sequencing were used to generate taxonomic profiles, including relative abundance (RA), bacterial density, α-diversity and β-diversity. Results A total of 132 samples from 22 patients were analysed. Baseline saliva and swabs had similar taxonomic composition (R2 = 0.006; p = 0.827). Oropharyngeal swabs and stool taxonomic composition varied significantly by stage, with increased oral RA of Fusobacterium nucleatum observed in stage III disease (p < 0.05). CRT significantly reduced the species richness and increased the RA of gut-associated taxa in oropharyngeal swabs (p < 0.05), while it had no effect in stool samples. These findings remained significant when adjusted by stage, smoking status and antibiotic use. Conclusions Baseline oral and gut microbiomes differ by stage in this HPV+ cohort. CRT caused a shift towards a gut-like microbiome composition in oropharyngeal swabs. Stage-specific features and the transitions in oral microbiome might have prognostic and therapeutic implications.

Homeostatic Characteristics of Single Species Fish Stocks in Arctic Lakes

1983 ◽  
Vol 40 (7) ◽  
pp. 987-1024 ◽  
Author(s):  
Lionel Johnson
Keyword(s):  
Stock Returns ◽  
Dominant Species ◽  
Size Structure ◽  
Arctic Charr ◽  
Arctic Lakes ◽  
Large Individual ◽  
Total Biomass ◽  
Length Frequency ◽  
Initial State ◽  
Fish Stocks

The results of investigations on the fish stocks of seven Arctic lakes covering a period of 23 yr are described. These lakes have remained largely undisturbed since their formation in late glacial times; all but one are completely autonomous and of comparatively small size. Such lakes provide a unique opportunity for the development and testing of conceptual models. In all cases the only fish species present is Arctic charr, Salvelinus alpinus. Length frequency distributions derived from gillnet catch curves are shown to be, within reasonable limits, representative of the actual populations in the lake, and not artifacts of the sampling procedure. Length frequency curves show a unimodal or bimodal distribution and this structure, in the absence of perturbation, appears to remain constant indefinitely. Individuals are of great age but age-at-length is highly variable. Age and size structure are shown to be comparable with the age and size structure of the dominant tree species in a climax forest; it is concluded that forces of great generality fashion these configurations. It is hypothesized that all species tend to move towards a state of least energy dissipation; this can be most readily seen in the dominant species at the climax in an autonomous system. The dominant species is characterized by large individual size, a high degree of uniformity, high total biomass, great mean age, indeterminate age-at-death, and a low incidence of replacement stock. After severe perturbation it is shown that the charr stock returns to a state of least dissipation without oscillation. Absence of oscillation during the return to the initial state, combined with the long-term stability shown in control lakes, indicates the presence of an effective damping mechanism; this in turn indicates the existence of organization within the stock as a whole. Organization develops through an interactive mechanism described under the doctrine of homeokinesis, which is responsible for energy equipartitioning and the maintenance of uniformity. These concepts help to explain phenomena observed in more complex systems and help our understanding of ecosystem functioning.

Elements in the development of conservation plans for Atlantic salmon (Salmo salar)

1998 ◽  
Vol 55 (S1) ◽  
pp. 312-323 ◽  
Author(s):  
Julian J Dodson ◽  
R John Gibson ◽  
Richard A Cunjak ◽  
Kevin D Friedland ◽  
Carlos Garcia de Leaniz ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Size Structure ◽  
Public Awareness ◽  
Biological Information ◽  
Conservation Unit ◽  
Atlantic Salmon Salmo Salar ◽  
Conservation Plan ◽  
Conservation Plans ◽  
The Impact

This paper examines two areas to be considered in developing conservation plans for Atlantic salmon (Salmo salar): goal statements and the general framework for the implementation of a conservation plan. From a biological perspective, the appropriate conservation unit for Atlantic salmon is the Evolutionary Significant Unit (ESU). As conservation decisions will rarely be based solely on biological information, the Operational Conservation Unit (OCU) is defined as resulting from the interplay between biological requirements and socio-economic issues. A multi-scale habitat inventory of Atlantic salmon rivers to know what their status is relative to historical conditions is the first step in a functional conservation plan. The viability of salmon populations may be assessed according to 6 variables: abundance, resilience, age and size structure, sex ratio, spatial and geographical distribution. A genetically viable population possesses the species' evolutionary legacy and the genetic variation on which future evolutionary potential depends. Four factors important to monitoring changes in a population's genetic health are genetic diversity, effective population size, genetic bottlenecks and founder effects and gene flow. Implementation of a conservation plan must be proactive to maintain the quality of the OCUs. Commercial and recreational fisheries need to be limited and several case studies are reviewed. The importance of avoiding the introduction of exotics and minimizing the impact of sampling methodology, as well as the pitfalls of planting eggs, fry, or parr, are addressed. Finally, the importance of fostering public awareness of the value of conservation is essential to apply the political pressure necessary to preserve natural resources.

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