Aggregation in Littoral Amphipod Populations: Transformation Controversies Revisited

1987 ◽  
Vol 44 (8) ◽  
pp. 1510-1515 ◽  
Author(s):  
R. L. France
Keyword(s):  
Literature Review ◽  
Power Law ◽  
Habitat Type ◽  
Canadian Shield ◽  
Power Relationship ◽  
Square Root ◽  
South Central ◽  
Root Transformation ◽  
Fourth Root ◽  
Shield Lakes

Spatial variability in amphipod (Hyalella azteca) density was examined in 17 Canadian Shield Lakes in south-central Ontario. Aggregation was measured by the exponent of the power relationship between density and variance. The average b index was 1.45, although this value varied depending on lake and habitat type. Whereas this should indicate the use of a fourth-root transformation, neither this nor the logarithmic transformation was as effective as the square-root in stabilizing variance. A literature review suggests that if a universal transformation is sought for benthos data, it should not be the commonly used log transformation. The observation that the square-root transformation seemed to work better on average than the fourth-root transformation, even in the region suggested by theory for the latter, suggests that complications may arise in the uncritical use of Taylor's Power Law.

Empirical Prediction of Crustacean Zooplankton Biomass in Nutrient-Poor Canadian Shield Lakes

1986 ◽  
Vol 43 (4) ◽  
pp. 788-796 ◽  
Author(s):  
N. D. Yan
Keyword(s):  
Total Phosphorus ◽  
Trophic State ◽  
Zooplankton Biomass ◽  
Canadian Shield ◽  
Phosphorus Concentration ◽  
Trophic State Index ◽  
Entire Study ◽  
South Central ◽  
Wide Range ◽  
Shield Lakes

A comparison of the predictive power of nine existing empirical zooplankton biomass models indicated that lake water phosphorus concentration may be a better predictor of zooplankton biomass in Canadian Shield lakes than phytoplankton biomass, chlorophyll a, midsummer epilimnetic temperature, mean surface water temperature, mean depth, and Carlson's trophic state index. To develop models specifically applicable to nutrient-poor Canadian Shield lakes, a variety of morphometric, chemical, and planktonic parameters were assessed for three consecutive years from 16 Canadian Shield lakes in south-central Ontario. Total nitrogen was the best univariate predictor of zooplankton biomass for data averaged over single ice-free seasons, but total phosphorus was the best predictor when data were averaged over the entire study period. Consideration of pH and maximum depth improved certain models. Total phosphorus is clearly a good predictor of (long-term) average zooplankton biomass in nutrient-poor lakes as it is in lakes exhibiting a wide range in trophic state.

Aggregation, Transformation, and the Design of Benthos Sampling Programs

1979 ◽  
Vol 36 (12) ◽  
pp. 1454-1463 ◽  
Author(s):  
John A. Downing
Keyword(s):  
Small Diameter ◽  
Population Data ◽  
Power Relationship ◽  
Precision Data ◽  
Root Transformation ◽  
Fourth Root ◽  
Sampling Transformation ◽  
Relationship Of ◽  
The Relationship ◽  
Benthic Animals

Solutions are offered to the problems of data transformation and the design of efficient programs for sampling the benthos of lakes and large rivers. All types of benthic animals from many types of substrate, sampled with diverse sampling gear, are aggregated in a similar fashion. Aggregation can be indexed by the unbiased exponent of the power relationship between density and variance. A single variance stabilizing transformation can be used for all macrobenthos population data since the relationship of sample variance to mean density is similar in all taxa of benthic animals. Stabilized variance in population data satisfies one of the main assumptions of the analysis of variance and allows use of normal statistics provided that the other assumptions are met. The fourth-root transformation stabilized the variance in all macrobenthos samples while either the commonly used square root or logarithmic transformations did not. Sampling programs can be optimized empirically. Standard deviation (s) is predictable from mean density (M; m−2) and sampler size (A; cm2) from the equation: log10s = 0.581 + 0.696 log10M − 2.82 × 10−4 A. The data show that it is easier to obtain a precise estimate of macrobenthos density at high densities. Small diameter samplers are most efficient in obtaining high levels of precision. Data were taken from the literature. Key words: aggregation, benthos, freshwater, regression, sampling, transformation

Cadmium concentrations of crustacean zooplankton of acidified and nonacidified Canadian Shield lakes

1990 ◽  
Vol 24 (9) ◽  
pp. 1367-1372 ◽  
Author(s):  
Norman D. Yan ◽  
Gerald L. Mackie ◽  
Peter J. Dillon
Keyword(s):  
Canadian Shield ◽  
Crustacean Zooplankton ◽  
Shield Lakes

scholarly journals LitRev: A data driven method for quick literature review from PubMed

2021 ◽  
Author(s):  
Gourab Das
Keyword(s):  
Literature Review ◽  
Mutual Information ◽  
Power Law ◽  
Data Driven ◽  
Power Law Distribution ◽  
Information Score ◽  
Data Driven Approach

LitRev is a novel robust data driven approach, devel-oped for quick literature review on a particular topic of interest. This method identifies common biological phrases that follow a power law distribution and important phrases which have the normalized point wise mutual information score greater than zero.

Calibration of the zooplankton community size spectrum as an indicator of change in Canadian Shield lakes

2019 ◽  
Vol 76 (12) ◽  
pp. 2268-2287
Author(s):  
Lauren Emily Barth ◽  
Brian John Shuter ◽  
William Gary Sprules ◽  
Charles Kenneth Minns ◽  
James Anthony Rusak
Keyword(s):  
Zooplankton Community ◽  
Canadian Shield ◽  
Rate Of Change ◽  
Crustacean Zooplankton ◽  
Size Spectrum ◽  
Community Size ◽  
Mean Values ◽  
Sampling Protocols ◽  
Stable Characteristic ◽  
Shield Lakes

Developing the crustacean zooplankton community size spectrum into an indicator of change in lakes requires quantification of the natural variability in the size spectrum related to broad-scale seasonal, annual, and spatial factors. Characterizing seasonal patterns of variation in the size spectrum is necessary so that monitoring programs can be designed to minimize the masking effects that seasonal processes can have on detecting longer-term temporal change. We used a random effects model to measure monthly, annual, and interlake variability in the slope (i.e., relative abundance of small and large organisms) and centered height (i.e., total abundance) of the crustacean zooplankton normalized abundance size spectrum from 1981 to 2011 among eight Canadian Shield lakes. Consistent with theoretical predictions, the slope was a relatively stable characteristic of the zooplankton community compared with the height, which varied significantly among lakes. We identified a seasonal signal in height and slope and used a mixed effects model to characterize the linear rate of change from May to October; there was an overall decline in height and an overall increase in slope. Seasonal variance was greater than annual variance for both the height and the slope, suggesting that long-term monitoring of lakes and interlake comparisons using zooplankton size spectra should be based on temporally standardized sampling protocols that minimize the effects of seasonal processes. We recommend sampling the zooplankton community in midsummer because this results in size spectrum estimates close to seasonal mean values.

scholarly journals Control of Citrus Thrips on Lemons, 1996

1997 ◽  
Vol 22 (1) ◽  
pp. 64-65
Author(s):  
D. L. Kerns ◽  
T. Tellez
Keyword(s):  
Square Root ◽  
Air Blast ◽  
Root Transformation ◽  
Fruit Damage

Abstract Eight year old lemon trees in Yuma, AZ were treated with insecticides for control of citrus thrips. The treatments were arranged in a RCB design, consisting of four replicates. Each plot (30 by 90 ft) consisted of three trees 30 ft apart in a row. Applications were made using a backpack air-blast sprayer calibrated to deliver 100 gpa. Treatments were initiated approximately 14 days after petal fall and were applied on Apr 3, Apr 30 and May 15. Evaluations were made on 5 Apr, 9 Apr, 15 Apr, 23 Apr, 29 Apr, 2 May, 6 May, 13 May, 17 May, 20 May and 29 May. Percent infested fruit were estimated by sampling by sampling ten fruit per tree for the presence or absence of immature CT. Fruit damage was assessed on Aug 16 by rating the degree of rind scarring: 1 = no scarring, 2 = slight scarring around the calyx, 3 = significant scarring around the calyx, 4 = slight scarring on the side of the fruit and 5 = major scarring on the side of the fruit. Percentage fruit infested with immature CT were transformed using a square-root transformation for analysis, percentage values are presented in the tables. Differences among treatments were separated using ANOVA and an F protected LSD.

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