Life history and production of Hyalella azteca (Crustacea: Amphipoda) in a hypereutrophic prairie pond in southern Alberta

1992 ◽  
Vol 70 (7) ◽  
pp. 1417-1424 ◽  
Author(s):  
Yuan Hua Wenz
Keyword(s):  
Life History ◽  
Population Density ◽  
Adult Population ◽  
Hyalella Azteca ◽  
Annual Production ◽  
Adult Size ◽  
Frequency Method ◽  
Turnover Ratio ◽  
Peak Biomass ◽  
Southern Alberta

The life history and production of the amphipod Hyalella azteca were studied over an 18-month period in a hypereutrophic prairie pond in southern Alberta, Canada. The population reproduced once a year, with breeding commencing in June and continuing until August. Population density was highest in June. The mortality rate of the adult population increased with the onset of reproduction, and remained high until the end of winter. The population density was lowest during winter and early spring (January to May). Biomass (B) fluctuated in a similar manner to population density, but the peak biomass occurred in August and September. Annual production (P) was 23.12 g∙m−2 (dry weight), estimated by the size-frequency method. The corresponding annual turnover ratio (P/B) was 5.68. The unusually high annual production and turnover ratio are attributed to the high density and large adult size of this population.

Production of the amphipod Hyalella azteca (Saussure) in a northern Ontario lake

1983 ◽  
Vol 61 (9) ◽  
pp. 2051-2059 ◽  
Author(s):  
Dorothy H. Lindeman ◽  
Walter T. Momot
Keyword(s):  
Littoral Zone ◽  
Lake Ontario ◽  
Hyalella Azteca ◽  
Dry Weight ◽  
Annual Production ◽  
Frequency Method ◽  
Northern Ontario ◽  
Habitat Temperature ◽  
Size Frequency ◽  
Annual Biomass

Annual production of the amphipod, Hyalella azteca, was estimated in three habitats of the upper littoral zone of Dock Lake, Ontario, over a 2-year period (1980–1981). Cohort production (P) by the size frequency method was 1.39 g/m2 (dry weight), mean annual biomass (B) was 0.36 g/m2, and the P/B ratio was 3.9 for the 1980 year class. Five other methods for estimating production were applied to this cohort, providing comparable estimates ranging from 1.21 (instantaneous growth) to 1.65 (cohort G) g/m2. Size frequency estimates of annual production for 1980 and 1981 were 1.24 and 1.40 g/m2, respectively. The annual P/[Formula: see text] ratios of 3.9 and 4.0 for these 2 years agree with the cohort value. A comparison of production estimates for Hyalella azteca in the literature shows a gradient of production which correlates with the habitat temperature regime.

scholarly journals Neighbourhood characteristics as a predictor of adherence to dietary recommendations: A population-based cohort study of Finnish adults

2020 ◽  
pp. 140349482097149
Author(s):  
Hanna Lagström ◽  
Jaana I. Halonen ◽  
Sakari Suominen ◽  
Jaana Pentti ◽  
Sari Stenholm ◽  
...  
Keyword(s):  
Population Density ◽  
Dietary Habits ◽  
Metabolic Diseases ◽  
Adult Population ◽  
Age Groups ◽  
Population Based ◽  
Dietary Recommendations ◽  
Neighbourhood Characteristics ◽  
Severe Life Events ◽  
Dietary Score

Aims: To investigate the association of six-year cumulative level of socioeconomic neighbourhood disadvantage and population density with subsequent adherence to dietary recommendations, controlling for preceding dietary adherence, in adults in Finland. Methods: Population-based Health and Social Support (HeSSup) study participants from four age groups (20–24, 30–34, 40–44 and 50–54 years at baseline in 1998). Data on diet and alcohol consumption were obtained from the 2003 and 2012 surveys and information on neighbourhoods from Statistics Finland Grid database ( n = 10,414 men and women). Participants diet was measured as adherence to Nordic Nutrition recommendation (score range 0–100). Neighbourhood disadvantage was measured by median household income, proportion of those with primary education only and unemployment rate, and population density by the number of adult population between years 2007 and 2012. Linear models were used to assess the associations of neighbourhood characteristics with the score for adherence to dietary recommendations in 2012. Results: Cumulative neighbourhood socioeconomic disadvantage was associated with slightly weaker (1.49 (95% confidence interval (CI) −1.89 to −1.09) point decrease in dietary score) adherence while higher population density was associated with better (0.70 (95% CI 0.38−1.01) point increase in dietary score) adherence to dietary recommendations. These associations remained after controlling for prior dietary habits, sociodemographic, chronic cardio-metabolic diseases, and severe life events. Conclusions: These longitudinal findings support the hypothesis that neighbourhood characteristics affect dietary habits.

scholarly journals Associations of eating and drinking habits with cardiovascular disease and diabetes in the adult population: data from the ESSE-RF epidemiological study

2021 ◽  
Vol 20 (5) ◽  
pp. 2982
Author(s):  
N. S. Karamnova ◽  
A. I. Rytova ◽  
O. B. Shvabskaya ◽  
Yu. K. Makarova ◽  
S. A. Maksimov ◽  
...  
Keyword(s):  
Salt Intake ◽  
Eating Habits ◽  
Adult Population ◽  
Daily Intake ◽  
Population Data ◽  
Processed Meat ◽  
Daily Consumption ◽  
Frequency Method ◽  
Animal Fats ◽  
Drinking Habits

The presence of a disease, the prognosis of which can be improved by dietary modification, motivates a patient to change their eating habits.Aim. To study the associations of dietary patterns and alcohol consumption with cardiovascular diseases (CVDs), diabetes, myocardial infarction (MI), and stroke in the adult population.Material and methods. The analysis was carried out using data from representative samples of population from 13 Russian regions aged 2564 years (n=19520; men, 7329; women, 12191). The response rate was ~80%. Dietary characteristics were assessed by frequency method.Results. In the diet of people with CVDs, the daily intake of vegetables/ fruits increases by 84% in men and by 19% in women, while the use of animal fats in cooking decreases by 28% and 20%m respectively (p<0,0001). Women with CVDs reduce the consumption of processed meat and sweets by 16 and 19%, respectively (p<0,005). Persons with prior MI reduce the consumption of sweets in the diet: men by 38% and women by 30%. Men with prior MI have higher daily consumption of cereals by 31%, vegetables and fruits by 46%, low-fat dairy products — 2,4 times. In addition, they are more adherent to a healthy and cardioprotective diet by 3,65 and 1,75 times, respectively. Dietary changes in those with prior stroke were noted only in women in the form of a 29% decrease in excess salt intake (p=0,0075). In the diet of people with diabetes, there is decreased consumption of sweets and an increased intake of vegetables/fruits: by 77 and 69% in men and by 79 and 69% in women, respectively (p<0,0001). Men with diabetes are 3 times more likely to adhere to a healthy diet, and women — 2,3 times (p=0,0039 and p<0,0001, respectively).Conclusion. Patients with CVDs, MI, and diabetes have a healthier diet than healthy persons.

scholarly journals Gambling and problem gambling in a sample of university students

2006 ◽  
Author(s):  
Robert J. Williams ◽  
Dennis Connolly ◽  
Robert T. Wood ◽  
Nadine Nowatzki
Keyword(s):  
University Students ◽  
Adult Population ◽  
Gambling Behaviour ◽  
Pathological Gamblers ◽  
Education Management ◽  
Problem Gamblers ◽  
The Past ◽  
Positive Attitudes ◽  
Southern Alberta ◽  
Median Amount

University students from southern Alberta (n = 585) were administered a questionnaire to assess their gambling behaviour. Seventy-two percent reported gambling in the past 6 months, with the most common types being lotteries and instant win tickets (44%) and games of skill against other people (34%). Most students who gambled spent very little time and money doing so (median time spent = 1.5 hrs; median amount of money spent = $0). While gambling is an innocuous activity for most, a significant minority of students are heavy gamblers who experience adverse consequences from it. Seven and one-half percent of students were classified as problem or pathological gamblers, a rate significantly higher than in the general Alberta adult population. The characteristics that best differentiated problem gamblers from non-problem gamblers were more positive attitudes toward gambling, ethnicity (41% of Asian gamblers were problem gamblers), university major (kinesiology, education, management), superior ability to calculate gambling odds, and older age.

Reproductive biology of the parsley frog, Pelodytes punctatus, at the northernmost part of its range

1993 ◽  
Vol 14 (2) ◽  
pp. 131-147 ◽  
Author(s):  
M. Ohm ◽  
A.G. Toxopeus ◽  
J.W. Arntzen
Keyword(s):  
Reproductive Biology ◽  
Breeding Season ◽  
Adult Population ◽  
First Year ◽  
Adult Size ◽  
Dune System ◽  
Population Size Estimates ◽  
Coastal Dune System ◽  
Source Sink ◽  
Second Period

AbstractThe reproductive biology and population dynamics of Pelodytes punctatus were studied at the breeding season over a three year period in a coastal dune system located at the extreme northwestern border of the species' range. Adult population size estimates ranged from about 100 in the first year to 60 in the third year. Males were remarkably sedentary near the pond under artificially provided shelters. Many were observed during the most of the breeding season which lasted from mid-March or the end of March to the end of April or mid-May. Most spawning took place in the second half of March or early April. In two years out of three a second period of spawning involving fewer animals was observed in the first half of May. Both periods of spawning coincided with, or shortly followed, periods of rising median air temperature. Egg-clutches were deposited in the deepest parts of pond, mainly on submerged vegetation not reaching the surface. An average sized clutch contained approximately 360 eggs. Development of the embryos until hatching took from 4 to 14 days, depending on the ambient temperature. Larval development and growth were fast. Recently metamorphosed froglets at a size of around 18 mm were found from the end of May onwards. Juveniles may reach adult size in the autumn of the year that they were born. Adult frogs did not show a strong fidelity to the breeding pond between years. In the study area the population structure of Pelodytes punctatus seems to be best described by a source - sink model in which flourishing populations in the dunes give rise to short lived satellite populations outside the dunes.

Multiple warren use by subadult wild rabbits, Oryctolagus cuniculus, and its implications for disease transmission

2017 ◽  
Vol 44 (7) ◽  
pp. 582 ◽  
Author(s):  
Scott Jennings ◽  
Gregory Mutze
Keyword(s):  
Population Density ◽  
Breeding Season ◽  
Disease Transmission ◽  
Critical Role ◽  
Late Summer ◽  
Adult Size ◽  
Contact Rates ◽  
Rabbit Haemorrhagic Disease ◽  
European Rabbits ◽  
Haemorrhagic Disease

Context Contact rates are a key determinant of disease transmission. Territorial behaviour has generally been considered to limit contact between European rabbits occupying different warrens, particularly during the breeding season. Aims We investigated warren use by subadult rabbits during a period of low population density to determine their potential role in transmission of rabbit haemorrhagic disease and myxomatosis. Methods Subadult rabbits were radio-collared in late summer and relocated twice-weekly for 25 weeks, during which time they grew to adult size and breeding commenced. Key results Rabbits of both sexes used an average of four warrens each on a regular basis, even after older rabbits had commenced breeding. Warrens used by individual rabbits formed a continuously overlapping, irregular array. Subadult rabbits did not belong to separate social groups that utilised separate groups of warrens. Conclusions Subadult or young adult rabbits did not display the same territorial warren fidelity that had been previously described for rabbits. They have potential to carry pathogens between warrens at a landscape scale. Implications Movement of subadult rabbits between warrens is therefore likely to play a critical role in disease transmission, particularly when population density is low. This may help to explain the prevalent seasonality of RHD epizootics in spring when first-born litters of each breeding season typically reach that size.

Effects of wave exposure on the proportion of gametophytes and tetrasporophytes of Mazzaella oregona (Rhodophyta: Gigartinales) from Pacific Canada

2003 ◽  
Vol 83 (4) ◽  
pp. 701-704 ◽  
Author(s):  
Benita Mudge ◽  
Ricardo Scrosati
Keyword(s):  
Population Structure ◽  
Life History ◽  
Population Density ◽  
Relative Abundance ◽  
Inverse Relationship ◽  
Sympatric Species ◽  
Wave Exposure ◽  
High Wave ◽  
Red Seaweeds ◽  
Barkley Sound

The proportion of life history phases in red seaweeds is an important descriptor of population structure. This paper describes the relative abundance of gametophytes and tetrasporophytes of Mazzaella oregona (Rhodophyta: Gigartinales; formerly M. heterocarpa), focusing particularly on the effects of wave exposure on the proportion of both life history phases. In two different rocky points in Barkley Sound (Pacific Canada), gametophytes were, in proportion to tetrasporophytes, relatively more abundant under low wave exposure than under high wave exposure in July 2002, during the period of highest abundance for this species. The inverse relationship between the G:T ratio and the degree of wave exposure also occurs for local M. splendens, but not for local M. parksii. Differences in frond size and population density between these three sympatric species are related to the effects of wave exposure on their G:T ratio.

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