A field study of homing and orientation to the home site in Ulvaria subbifurcata (Pisces: Stichaeidae)

1977 ◽  
Vol 55 (9) ◽  
pp. 1551-1556 ◽  
Author(s):  
John M. Green ◽  
Robert Fisher
Keyword(s):  
Home Range ◽  
Field Study ◽  
Visual Cues ◽  
Field Experiments ◽  
Benthic Species ◽  
Homing Behavior ◽  
Orientational Response ◽  
Home Site ◽  
Home Area ◽  
Small Home Range

The movements, homing behavior, and initial orientation to the capture site were investigated in Ulvaria subbifurcata using an underwater habitat and scuba. Field experiments showed that this benthic species restricts its activity to a small home range, less than 3 m2, is capable of returning to that home area after being displaced at least 270 m, and can orient in the direction of the home site after displacements of at least 30 m. The conditions under which the orientation experiments were conducted indicate that visual cues are not necessary for the orientational response.

scholarly journals Testing the Effect of Hedge Height on Perceived Safety—A Landscape Design Intervention

2021 ◽  
Vol 13 (9) ◽  
pp. 5063
Author(s):  
Katinka H. Evensen ◽  
Helena Nordh ◽  
Ramzi Hassan ◽  
Aslak Fyhri
Keyword(s):  
Field Study ◽  
Field Experiments ◽  
Landscape Design ◽  
Urban Environments ◽  
Space Management ◽  
Perceived Safety ◽  
Urban Green Spaces ◽  
Outdoor Spaces ◽  
Surrounding Areas ◽  
The Impact

Access to safe, green urban environments is important for quality of life in cities. The objective of this study is to explore the impact of a safety-enhancing landscape design measure on visitors’ experiences in an urban park. Additionally, this paper combines the use of field and virtual reality (VR) experiments, contributing methodological insights into how to evaluate safety measures in green space management and research on perceived safety. In a field experiment (n = 266), we explored whether the height of a hedge along a pathway influenced perceived safety among users. The field study showed that cutting down the hedge improved the perceived prospect of the immediate surrounding areas for female users, which again made them feel safer in the park. We developed a VR experiment for an evening scenario in the same environment (n = 19) to supplement the field study and test the effect of the intervention further. The VR experiment also found a gender effect on perceived safety, with females reporting lower perceived safety, but no effect was shown for the height of the hedge. The results in this study show that environmental attributes such as perceived prospect and concealment should be considered in the design and management of urban green spaces. Additionally, this research demonstrates an approach to conducting field experiments to test the effects of actual design interventions and then further developing these experiments using VR technology. Further research on perceived safety in outdoor spaces is needed to make use of this combined method’s potential.

A field study of competition and interaction between Lemna minor and Lemna trisulca

1989 ◽  
Vol 67 (10) ◽  
pp. 2904-2911 ◽  
Author(s):  
Alexander L. McIlraith ◽  
Gordon G. C. Robinson ◽  
Jennifer M. Shay
Keyword(s):  
Life History ◽  
Field Study ◽  
Key Words ◽  
Field Experiments ◽  
Lemna Minor ◽  
Survey Methods ◽  
The Other ◽  
Transplant Experiment ◽  
Replacement Series ◽  
Vegetative Biomass

Field experiments and survey methods were used to assess competition and interaction between Lemna minor L. and Lemna trisulca L. at Delta Marsh, Manitoba. Sites were dominated by one or the other species or codominated by both. Replacement series experiments predicted codominance of L. minor and L. trisulca in an unshaded eutrophic site but predicted L. minor dominance when run for a longer time. Similar experiments conducted in a shaded eutrophic site predicted L. minor dominance. Addition series experiments showed that intraspecific and interspecific competition occurred in the unshaded site. In a eutrophic unshaded ditch, high densities of L. minor suppressed L. trisulca. In a eutrophic shaded site, high densities of L. minor and green algae inhibited L. trisulca, and in a sunny, less eutrophic site high density of each species inhibited the other. In a transplant experiment, L. minor biomass in shaded enclosures approached that found naturally in two shaded sites. Lemna trisulca persisted when shaded. Vegetative biomass trends in an unshaded eutrophic marsh ditch indicated spring and fall L. trisulca dominance and summer L. minor dominance. Shaded eutrophic sites were dominated by L. minor, whereas a less eutrophic site was dominated by L. trisulca. A model is developed to explain dominance patterns, and seasonal life-history responses are considered. Key words: Lemna, duckweed, competition, interaction, resources, light, nutrients.

Endless skies and open seas – how birds and fish navigate

Neuroforum ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Lisa Spiecker ◽  
Bo Leberecht ◽  
Corinna Langebrake ◽  
Malien Laurien ◽  
Shambhavi Rajendra Apte ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnetic Fields ◽  
Home Range ◽  
Environmental Conditions ◽  
Geomagnetic Field ◽  
Visual Cues ◽  
Quantum Mechanical ◽  
The Sun ◽  
Seasonal Migrations ◽  
Research Questions

Abstract Every year, billions of animals leave their home range and start seasonal migrations in order to find more favorable resources and to escape harsh environmental conditions. These round trips often span thousands of kilometers. To successfully navigate along their route, animals rely on various external references. While landmarks and celestial cues like stars or the sun are easy to imagine as guidance on these journeys, using the geomagnetic field for orientation is more elusive. The geomagnetic field is an omnipresent cue, which can be sensed and relied upon by many animals, even when visual cues are sparse. How magnetic fields can be perceived seems to vary between birds and fish. While birds seem to use a mechanism based on the quantum mechanical properties of electron spins, fish may have evolved a compass similar in its function to the technical devises developed by humans. How these mechanisms work precisely and how they are integrated are research questions addressed in SFB 1372.

scholarly journals Can't tell the caterpillars from the trees: countershading enhances survival in a woodland

2008 ◽  
Vol 275 (1651) ◽  
pp. 2539-2545 ◽  
Author(s):  
Hannah M Rowland ◽  
Innes C Cuthill ◽  
Ian F Harvey ◽  
Michael P Speed ◽  
Graeme D Ruxton
Keyword(s):  
Visual Cues ◽  
Field Experiments ◽  
Three Dimensional ◽  
Shape From Shading ◽  
The Body ◽  
Colour Pattern ◽  
Free Living ◽  
Background Matching ◽  
Lepidopteran Larvae ◽  
Beech Tree

Perception of the body's outline and three-dimensional shape arises from visual cues such as shading, contour, perspective and texture. When a uniformly coloured prey animal is illuminated from above by sunlight, a shadow may be cast on the body, generating a brightness contrast between the dorsal and ventral surfaces. For animals such as caterpillars, which live among flat leaves, a difference in reflectance over the body surface may degrade the degree of background matching and provide cues to shape from shading. This may make otherwise cryptic prey more conspicuous to visually hunting predators. Cryptically coloured prey are expected to match their substrate in colour, pattern and texture (though disruptive patterning is an exception), but they may also abolish self-shadowing and therefore either reduce shape cues or maintain their degree of background matching through countershading: a gradation of pigment on the body of an animal so that the surface closest to illumination is darker. In this study, we report the results from a series of field experiments where artificial prey resembling lepidopteran larvae were presented on the upper surfaces of beech tree branches so that they could be viewed by free-living birds. We demonstrate that countershading is superior to uniform coloration in terms of reducing attack by free-living predators. This result persisted even when we fixed prey to the underside of branches, simulating the resting position of many tree-living caterpillars. Our experiments provide the first demonstration, in an ecologically valid visual context, that shadowing on bodies (such as lepidopteran larvae) provides cues that visually hunting predators use to detect potential prey species, and that countershading counterbalances shadowing to enhance cryptic protection.

scholarly journals The watching eyes effect on charitable donation is boosted by fewer people in the vicinity

2016 ◽  
Vol 7 (2) ◽  
pp. 9-12
Author(s):  
Ryo Oda ◽  
Ryota Ichihashi
Keyword(s):  
Field Study ◽  
Charitable Giving ◽  
Field Experiments ◽  
Field Studies ◽  
Prosocial Behaviors ◽  
Charitable Donation ◽  
Charitable Donations ◽  
Large Groups

Previous field experiments have found that artificial surveillance cues facilitated prosocial behaviors such as charitable donations and littering. Several previous field studies found that the artificial surveillance cue effect was stronger when few individuals were in the vicinity; however, others reported that the effect was stronger in large groups of people. Here, we report the results of a field study examining the effect of an artificial surveillance cue (stylized eyes) on charitable giving. Three collection boxes were placed in different locations around an izakaya (a Japanese-style tavern) for 84 days. The amount donated was counted each experimental day, and the izakaya staff provided the number of patrons who visited each day. We found that the effect of the stylized eyes was more salient when fewer patrons were in the izakaya. Our findings suggest that the effect of the artificial surveillance cue is similar to that of “real” cues and that the effect on charitable giving may weaken when people habituate to being watched by “real” eyes. 

scholarly journals Right-to-Choose Auctions: A Field Study of Water Markets in the Limari Valley of Chile

2010 ◽  
Vol 39 (2) ◽  
pp. 213-226 ◽  
Author(s):  
Jonathan E. Alevy ◽  
Oscar Cristi ◽  
Oscar Melo
Keyword(s):  
Field Study ◽  
Research Team ◽  
Field Experiments ◽  
Time Preferences ◽  
Water Markets ◽  
Risk Attitudes ◽  
Sequential Auction ◽  
The Difference ◽  
Water Volumes ◽  
The Right

Field experiments were conducted with farmers in the Limari Valley of Chile to test extant theory on right-to-choose auctions. Water volumes that differed by reservoir source and time of availability were offered for sale by the research team. The auctions were supplemented by protocols to elicit risk and time preferences of bidders. We find that the right-to-choose auctions raise significantly more revenue than the benchmark sequential auction. Risk attitudes explain a substantial amount of the difference in bidding between auction institutions, consonant with received theory. The auction bidding revealed distinct preferences for water types, which has implications for market re-design.

scholarly journals Partial Migration, and Lek and Nesting Area Fidelity in Female Great Bustards

The Condor ◽  
2000 ◽  
Vol 102 (1) ◽  
pp. 127-136 ◽  
Author(s):  
Juan C. Alonso ◽  
Manuel B. Morales ◽  
Javier A. Alonso
Keyword(s):  
Home Range ◽  
Breeding Birds ◽  
First Year ◽  
Migration Patterns ◽  
Seasonal Movements ◽  
Northwestern Spain ◽  
Wintering Areas ◽  
Small Home Range ◽  
First Year Of Life ◽  
Population Numbers

AbstractWe examined the seasonal movements of wing-tagged and radio-marked adult female Great Bustards Otis tarda in a population in northwestern Spain. Four different movement patterns were found: females that migrated between breeding and wintering areas (20%), females that only left their year-round home range area to mate (32%), females that migrated from a wintering-mating area to a nesting-summering area (16%), and females that stayed all year round within a relatively small home range area (32%). All females displayed fidelity to their nesting and wintering areas, and most also showed fidelity to their leks. Migration patterns were not affected either in timing or distance by breeding success. The maximum distance between natal and dispersal locations during their first year of life was significantly higher in migratory females than in sedentary ones. These patterns explained the seasonal variations in population numbers observed in the study area. Surveys showed that the number of females increased from 600–700 breeding birds, with 1,000–1,100 birds present from October to March.

scholarly journals Female home range size is regulated by resource distribution and intraspecific competition: a long-term field study

2010 ◽  
Vol 79 (1) ◽  
pp. 195-203 ◽  
Author(s):  
Carsten Schradin ◽  
Gabriela Schmohl ◽  
Heiko G. Rödel ◽  
Ivana Schoepf ◽  
Stella M. Treffler ◽  
...  
Keyword(s):  
Home Range ◽  
Field Study ◽  
Intraspecific Competition ◽  
Resource Distribution ◽  
Home Range Size ◽  
Range Size ◽  
Term Field

scholarly journals Assessment of size selectivity in hydraulic clam dredge fisheries

2017 ◽  
Vol 74 (3) ◽  
pp. 339-348 ◽  
Author(s):  
Antonello Sala ◽  
Jure Brčić ◽  
Bent Herrmann ◽  
Alessandro Lucchetti ◽  
Massimo Virgili
Keyword(s):  
Data Analysis ◽  
Field Study ◽  
Fishery Management ◽  
Selection Process ◽  
Hole Diameter ◽  
Knife Edge ◽  
Size Selectivity ◽  
Benthic Species ◽  
Size Selection ◽  
Modelling Approach

In hydraulic dredge clam fisheries, the onboard mechanical sorting can be considered as the main catch selection process. The catch is mechanically sorted by a sieve made up of a series of successive grids with holes of decreasing diameter. The effect of the grid hole diameter and sorting speed of the vibrating sieve of a hydraulic dredger was investigated in a field study to determine its clam selection properties and to formulate proposals aimed at improving fishery management. Data analysis demonstrates that it is technically impossible to achieve a knife-edge selection and that there is scope for improving the size selection process, for instance by increasing grid hole diameter, which, however, can be accompanied by a reduced catch of both undersized and commercial-sized individuals. An increase in the hole diameter to 21.71 mm, while ensuring less than 5% retention of undersized individuals, would entail a retention of 67% of the commercial sizes. The modelling approach applied can be extended to investigations of other dredge gear types and nonmobile benthic species.

Control of Yellow Nutsedge (Cyperus esculentus) and Smooth Pigweed (Amaranthus hybridus) in Summer Squash with Halosulfuron

2008 ◽  
Vol 22 (4) ◽  
pp. 660-665 ◽  
Author(s):  
Brian W. Trader ◽  
Henry P. Wilson ◽  
Thomas E. Hines
Keyword(s):  
Field Study ◽  
Field Experiments ◽  
Cyperus Esculentus ◽  
Weed Species ◽  
Amaranthus Hybridus ◽  
Yellow Nutsedge ◽  
Application Method ◽  
Summer Squash ◽  
Smooth Pigweed

Field experiments were conducted in 1999, 2000, and 2001 to investigate PRE and POST applications of halosulfuron-methyl in combination with clomazone plus ethalfluralin for control of sedge and smooth pigweed in summer squash. Halosulfuron was applied PRE or POST to summer squash at 9, 18, or 27 g ai/ha in combination with a PRE application of clomazone at 175 g ai/ha plus ethalfluralin at 630 g ai/ha. Smooth pigweed control by addition of halosulfuron at 18 and 27 g/ha in combination with clomazone plus ethalfluralin PRE was greater than 89% independent of application method. Yellow nutsedge control was greater than 83% with POST applications of halosulfuron at 18 and 27 g/ha in combination with clomazone plus ethalfluralin PRE. Yellow nutsedge control was greater than 60% from all POST halosulfuron applications at 9, 18, or 27 g/ha in the greenhouse. In a separate field study without ethalfluralin PRE, rice flatsedge control was more than 85% from halosulfuron applied POST at 18 and 27 g/ha. Yellow summer squash and zucchini squash were injured as much as 52 and 47%, respectively, from inclusion of halosulfuron PRE or POST at 27 g/ha in treatments. Summer squash yields were generally not affected by halosulfuron rate, and were comparable to or higher than summer squash treated by only the mixture of clomazone plus ethalfluralin. In these studies, summer squash were injured by halosulfuron applied at 9 to 27 g/ha PRE or POST, yet rapidly recovered, making this herbicide acceptable for use in combination with clomazone and ethalfluralin for controlling several common weed species.

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