scholarly journals Movement patterns of the grey field slug (Deroceras reticulatum) in an arable field

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
John Ellis ◽  
Natalia Petrovskaya ◽  
Emily Forbes ◽  
Keith F. A. Walters ◽  
Sergei Petrovskii
Keyword(s):  
Population Density ◽  
Recovery Period ◽  
Radio Tracking ◽  
Data Modelling ◽  
Correlated Random Walk ◽  
Turning Angle ◽  
Wheat Field ◽  
Arable Field ◽  
Slug Movement ◽  
Trapping Grid

Abstract We report the results of an experiment on radio-tracking of individual grey field slugs in an arable field and associated data modelling designed to investigate the effect of slug population density in their movement. Slugs were collected in a commercial winter wheat field in which a 5x6 trapping grid had been established with 2m distance between traps. The slugs were taken to the laboratory, radio-tagged using a recently developed procedure, and following a recovery period released into the same field. Seventeen tagged slugs were released singly (sparse release) on the same grid node on which they had been caught. Eleven tagged slugs were released as a group (dense release). Each of the slugs was radio-tracked for approximately 10 h during which their position was recorded ten times. The tracking data were analysed using the Correlated Random Walk framework. The analysis revealed that all components of slug movement (mean speed, turning angles and movement/resting times) were significantly different between the two treatments. On average, the slugs released as a group disperse more slowly than slugs released individually and their turning angle has a clear anticlockwise bias. The results clearly suggest that population density is a factor regulating slug movement.

Hoverfly (Diptera: Syrphidae) community of a cultivated arable field and the adjacent hedgerow near Debrecen, Hungary

Biologia ◽  
2014 ◽  
Vol 69 (3) ◽  
Author(s):  
Rita Földesi ◽  
Anikó Kovács-Hostyánszki
Keyword(s):  
Species Richness ◽  
Sampling Methods ◽  
Sampling Period ◽  
Total Abundance ◽  
Wheat Field ◽  
Arable Field ◽  
Group Feeding ◽  
Species Richness And Abundance ◽  
Total Species ◽  
Pan Traps

AbstractA hoverfly (Syrphidae) community was investigated in a cultivated wheat field and the adjacent hedgerow near Debrecen (Hungary). We monitored the change of species richness and abundance of hoverflies along three transects in the hedgerow and in the wheat field in different distances (10 m, 20 m) from the hedgerow. The effect of sampling methods on the number of hoverfly species and individuals was analyzed. Two sampling methods were used to catch hoverflies: netting and pan traps. The whole sampling period was divided into three subperiods, which are early (22nd April–2nd June), middle (11th June–1st August) and late (6th August–11th September). Altogether 1,214 individuals of 22 species were sampled. Fourteen species with 78% of individuals belonged to the aphidophagous group, feeding on aphids as larvae. Altogether 861 individuals of 22 hoverfly species were sampled by netting and 353 individuals of 10 species by pan traps. The total number of hoverfly species was significant lower in the late period than in the early. The total abundance was higher in the middle period compared to the early. The species richness and abundance of aphidophagous species followed a similar pattern as the total species values. The species richness and abundance of hoverflies were significant higher in 10 m and 20 m distance in the wheat field than along the hedgerow. The results suggest that the pan traps were less efficient in the hedgerow than the netting, but in the wheat field they sampled more hoverflies because of visually alluring effect on hoverflies in the absence of flowers.

A study of the home ranges, movements and behaviour of the feral cat population at Avonmouth Docks

1992 ◽  
Vol 19 (3) ◽  
pp. 263 ◽  
Author(s):  
RJC Page ◽  
J Ross ◽  
DH Bennet
Keyword(s):  
Social Interaction ◽  
Population Density ◽  
Group Living ◽  
Home Ranges ◽  
Low Density ◽  
Radio Tracking ◽  
Entire Study ◽  
Feral Cat ◽  
Males And Females ◽  
Emergency Measures

The feral cat population at a 178-ha dockland site was studied for 18 months by direct observation assisted by radio-tracking. Although food appeared to be abundant and widely distributed, the population density was low (10-15 adults km-2). There were few females in the population (7 of 22 cats of known sex) and little breeding success: only one weaned litter was seen during the entire study. Home range sizes were similar for males and females, and were much smaller (15 +/- 17 ha and 10+/-7 ha, respectively) than would be expected from the low density. The cats were mostly solitary rather than group-living, with little contact or social interaction. The implications of the findings for feral cat control are discussed, with particular emphasis on emergency measures for rabies outbreaks.

Population density, survival, and rabies in raccoons in an urban national park

1998 ◽  
Vol 76 (6) ◽  
pp. 1153-1164 ◽  
Author(s):  
Seth PD Riley ◽  
John Hadidian ◽  
David A Manski
Keyword(s):  
Population Density ◽  
National Park ◽  
Procyon Lotor ◽  
Survival Rates ◽  
Mortality Factor ◽  
Initial Contact ◽  
Radio Tracking ◽  
Canine Distemper ◽  
Mark Recapture ◽  
Urban Edge

Density and survival of a raccoon (Procyon lotor) population in Rock Creek Park, an urban national park inWashington, D.C., were estimated using mark–recapture and radio-tracking over an 8-year period following the appearance ofthe mid-Atlantic States (Mid-Atlantic) rabies epizootic. Raccoon density ranged from 333.3 to 66.7/km2 , with an overall parkestimate of 125/km2 . This density places the Rock Creek population within the range of other urban and suburban populationsand is many times greater than raccoon densities reported from other habitats. Density was particularly high in one thin spur ofparkland with the smallest ratio of area to urban edge. Raccoon survival rates were high except among juveniles during therabies epizootic. Data on rabies prevalence from Washington, D.C., indicate a cycle with peaks in 1983 during the initialepizootic and again in 1987 and 1991, a pattern similar to that seen in other carnivores and in rabies models. We found evidenceof decreased raccoon density during and after the 1987 rabies resurgence relative to the years following the original epizootic,when rabies prevalence was low. While hunting and trapping represent a major mortality factor for many rural raccoonpopulations, urban and suburban populations and protected populations may frequently be subject to epizootics of diseasessuch as canine distemper and rabies, even years after initial contact with a disease.

Home range and microhabitat use by the long-footed potoroo, Potorous longipes

1998 ◽  
Vol 25 (4) ◽  
pp. 357 ◽  
Author(s):  
K. Green ◽  
A. T. Mitchell ◽  
P. Tennant
Keyword(s):  
Home Range ◽  
Environmental Changes ◽  
Home Range Size ◽  
Microhabitat Use ◽  
Radio Tracking ◽  
Geographical Differences ◽  
Eucalypt Forest ◽  
Old Growth Forest ◽  
Minimum Numbers ◽  
Trapping Grid

Long-footed potoroos were studied at two widely-separated sites in Victoria, one in regenerating eucalypt forest in East Gippsland and the other in old-growth forest in Central Gippsland. Trap-revealed use of microhabitat at Bellbird (East Gippsland) showed a change from the 1980s to 1990s, with an increased amount of foraging in more open, drier areas. Over the same period, there was an increase in the size of home range of animals and a near-doubling of the minimum numbers of animals known to be alive on the trapping grid at Bellbird. These changes occurred over a period when few environmental changes occurred on the grid other than control of feral predators. Radio-tracking data from 12 animals at the two sites showed a similar trend in use of microhabitat by most animals, but there was individual variation. Differences between the sites were that home-range size was smaller at the Riley trapping grid (Central Gippsland), there was greater overlap in home range, and animals there foraged for significantly shorter bouts. This confirmed earlier speculation from reproductive and dietary studies that there is better quality habitat at Riley, but the sites were so dissimilar that differences in home range and foraging could not be ascribed to either the logging regime or to geographical differences between the sites.

The Effect of Exercise and Distraction on Blood Pressure Recovery Following an Anger-Provoking Stressor in Normotensive Young Adults

2015 ◽  
Vol 29 (2) ◽  
pp. 45-54 ◽  
Author(s):  
Faye S. Routledge ◽  
Judith A. McFetridge-Durdle ◽  
Marilyn Macdonald ◽  
Lynn Breau ◽  
Tavis Campbell
Keyword(s):  
Blood Pressure ◽  
Cardiovascular Health ◽  
Exercise Intervention ◽  
Recovery Period ◽  
Intervention Group ◽  
Exercise Group ◽  
State Anger ◽  
Increased Risk ◽  
Anger Reactivity ◽  
Quiet Sitting

Ruminating about a prior anger provoking event is found to elevate blood pressure (BP) and delay BP recovery. Delayed BP recovery may be associated with increased risk of hypertension. Interventions that improve BP recovery may be beneficial for cardiovascular health. The purposes of this study were to evaluate the influence of rumination and anger on BP reactivity and recovery, to compare the effect of an exercise intervention or distraction intervention on BP recovery and to explore if exercise improved BP recovery by distracting participants from stressor-related rumination and anger. Healthy, normotensive participants (n = 79, mean age 22.2 ± 4.0 years) underwent an anger-recall interview stressor task, 3 min of exercise (walking), distraction (reading) or no-intervention (quiet sitting) and a 15 min recovery period. State anger reactivity was associated with Δ diastolic (D) BP reactivity and approached significance with Δ systolic (S) BP reactivity. Trait rumination was associated with greater SBP during recovery. Δ SBP recovery did not differ between the exercise, distraction and no-intervention groups. Although there were no differences in Δ DBP recovery between the exercise and no-intervention groups, distraction improved Δ DBP recovery compared to the exercise intervention but not the no-intervention. The proportion of anger-related thoughts (state rumination) in the exercise group did not differ from the distraction or no-intervention groups. However, a smaller proportion of participants in the distraction intervention reported an anger-related thought during recovery compared to the no-intervention group with 76% of their thoughts relating to the provided distraction. Overall, post-stressor exercise was not found to improve BP recovery while reading was effective at distracting individuals from angry thoughts (state rumination) but had no effect on BP compared to no-intervention.

Convergence of regional population density in Russia over 120 years

2020 ◽  
pp. 133-158
Author(s):  
K. A. Kholodilin ◽  
Y. I. Yanzhimaeva
Keyword(s):  
Population Density ◽  
Spatial Dependence ◽  
Population Distribution ◽  
Regional Level ◽  
Capital City ◽  
County Level ◽  
Spatial Effects ◽  
Russian Regions ◽  
Regional Population ◽  
Regional Population Density

A relative uniformity of population distribution on the territory of the country is of importance from socio-economic and strategic perspectives. It is especially important in the case of Russia with its densely populated West and underpopulated East. This paper considers changes in population density in Russian regions, which occurred between 1897 and 2017. It explores whether there was convergence in population density and what factors influenced it. For this purpose, it uses the data both at county and regional levels, which are brought to common borders for comparability purposes. Further, the models of unconditional and conditional β-convergence are estimated, taking into account the spatial dependence. The paper concludes that the population density equalization took place in 1897-2017 at the county level and in 1926—1970 at the regional level. In addition, the population density increase is shown to be influenced not only by spatial effects, but also by political and geographical factors such as climate, number of GULAG camps, and the distance from the capital city.

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