| 1. |
- Hansson, L-A, et al.
(författare)
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A synthesis of animal movement across scales
- 2014
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Ingår i: Animal Movement Across Scales. - : Oxford University Press. - 9780199677184 ; , s. 259-267
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Bokkapitel (refereegranskat)abstract
- This chapter aims at synthesizing the knowledge presented in the chapters of the book’s three sections by addressing evolutionary compromises, dispersal, gene flow, and assisted movements. How climate change and other environmental changes at different scales may affect animal movement, migration, and dispersal in the future are also summarized here. Moreover, how the different senses are utilized for navigation and orientation and how these may lead to different movement and migration patterns are also discussed. Finally, how the recent technical revolution has affected animal movement research is addressed and the view on future perspectives of animal movement research is also provided.
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| 2. |
- Hansson, L-A, et al.
(författare)
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An introduction to animal movement
- 2014
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Ingår i: Animal movement across scales. - : Oxford University Press. - 9780199677191
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Bokkapitel (refereegranskat)
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| 3. |
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| 4. |
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| 5. |
- Barup, Kerstin, et al.
(författare)
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Multi-disciplinary lidar applications
- 2010
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Ingår i: Laser Applications to Chemical, Security and Environmental Analysis, LACSEA 2010. - 2162-2701. - 9781557528803
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Konferensbidrag (refereegranskat)abstract
- Lidar is a powerful technique normally associated with atmospheric monitoring. However, lidar techniques, also of the laser-induced fluorescence and laser-induced breakdown spectroscopy varieties, provide many new possibilities in unconventional fields including cultural heritage and ecological applications.
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| 6. |
- Bernath, Balazs, et al.
(författare)
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How could the Viking Sun compass be used with sunstones before and after sunset? Twilight board as a new interpretation of the Uunartoq artefact fragment
- 2014
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Ingår i: Royal Society of London. Proceedings A. Mathematical, Physical and Engineering Sciences. - : The Royal Society. - 1364-5021. ; 470:2166
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Tidskriftsartikel (refereegranskat)abstract
- Vikings routinely crossed the North Atlantic without amagnetic compass and left their mark on lands as far away as Greenland, Newfoundland and Baffin Island. Based on an eleventh-century dial fragment artefact, found at Uunartoq in Greenland, it is widely accepted that they sailed along chosen latitudes using primitive Sun compasses. Such instruments were tested on sea and proved to be efficient hand-held navigation tools, but the dimensions and incisions of the Uunartoq find are far from optimal in this role. On the basis of the sagasmentioning sunstones, incompatible hypotheses were formed for Viking solar navigation procedures and primitive skylight polarimetry with dichroic or birefringent crystals. We describe here a previously unconceived method of navigation based on the Uunartoq artefact functioning as a 'twilight board', which is a combination of a horizon board and a Sun compass optimized for use when the Sun is close to the horizon. We deduced an appropriate solar navigation procedure using a twilight board, a shadow-stick and birefringent crystals, which bring together earlier suggested methods in harmony and provide a true skylight compass function. This could have allowed Vikings to navigate around the clock, to use the artefact dial as a Sun compass during long parts of the day and to use skylight polarization patterns in the twilight period. In field tests, we found that true north could be appointed with such a medieval skylight compass with an error of about +/- 4 degrees when the artificially occluded Sun had elevation angles between +10 degrees and -8 degrees relative to the horizon. Our interpretation allows us to assign exact dates to the gnomonic lines on the artefact and outlines the schedule of the merchant ships that sustained the Viking colony in Greenland a millennium ago.
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| 7. |
- Blaho, Miklos, et al.
(författare)
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Spottier Targets Are Less Attractive to Tabanid Flies: On the Tabanid-Repellency of Spotty Fur Patterns
- 2012
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:8
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Tidskriftsartikel (refereegranskat)abstract
- During blood-sucking, female members of the family Tabanidae transmit pathogens of serious diseases and annoy their host animals so strongly that they cannot graze, thus the health of the hosts is drastically reduced. Consequently, a tabanid-resistant coat with appropriate brightness, colour and pattern is advantageous for the host. Spotty coats are widespread among mammals, especially in cattle (Bos primigenius). In field experiments we studied the influence of the size and number of spots on the attractiveness of test surfaces to tabanids that are attracted to linearly polarized light. We measured the reflection-polarization characteristics of living cattle, spotty cattle coats and the used test surfaces. We show here that the smaller and the more numerous the spots, the less attractive the target (host) is to tabanids. We demonstrate that the attractiveness of spotty patterns to tabanids is also reduced if the target exhibits spottiness only in the angle of polarization pattern, while being homogeneous grey with a constant high degree of polarization. Tabanid flies respond strongly to linearly polarized light, and we show that bright and dark parts of cattle coats reflect light with different degrees and angles of polarization that in combination with dark spots on a bright coat surface disrupt the attractiveness to tabanids. This could be one of the possible evolutionary benefits that explains why spotty coat patterns are so widespread in mammals, especially in ungulates, many species of which are tabanid hosts.
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| 8. |
- Blaho, Miklos, et al.
(författare)
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Stripes disrupt odour attractiveness to biting horseflies: Battle between ammonia, CO2, and colour pattern for dominance in the sensory systems of host-seeking tabanids
- 2013
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Ingår i: Physiology & Behavior. - : Elsevier BV. - 1873-507X .- 0031-9384. ; 119, s. 168-174
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Tidskriftsartikel (refereegranskat)abstract
- As with mosquitoes, female tabanid flies search for mammalian hosts by visual and olfactory cues, because they require a blood meal before being able to produce and lay eggs. Polarotactic tabanid flies find striped or spotted patterns with intensity and/or polarisation modulation visually less attractive than homogeneous white, brown or black targets. Thus, this reduced optical attractiveness to tabanids can be one of the functions of striped or spotty coat patterns in ungulates. Ungulates emit CO2 via their breath, while ammonia originates from their decaying urine. As host-seeking female tabanids are strongly attracted to CO2 and ammonia, the question arises whether the poor visual attractiveness of stripes and spots to tabanids is or is not overcome by olfactory attractiveness. To answer this question we performed two field experiments in which the attractiveness to tabanid flies of homogeneous white, black and black-and-white striped three-dimensional targets (spheres and cylinders) and horse models provided with CO2 and ammonia was studied. Since tabanids are positively polarotactic, i.e. attracted to strongly and linearly polarised light, we measured the reflection-polarisation patterns of the test surfaces and demonstrated that these patterns were practically the same as those of real horses and zebras. We show here that striped targets are significantly less attractive to host-seeking female tabanids than homogeneous white or black targets, even when they emit tabanid-luring CO2 and ammonia. Although CO2 and ammonia increased the number of attracted tabanids, these chemicals did not overcome the weak visual attractiveness of stripes to host-seeking female tabanids. This result demonstrates the visual protection of striped coat patterns against attacks from blood-sucking dipterans, such as horseflies, known to transmit lethal diseases to ungulates. (C) 2013 Elsevier Inc. All rights reserved.
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| 9. |
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| 10. |
- Boström, Jannika, et al.
(författare)
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Autumn migratory fuelling : a response to simulated magnetic displacement in juvenile wheatears, Oenathe oenathe
- 2010
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 64:11, s. 1725-1732
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Tidskriftsartikel (refereegranskat)abstract
- Recent experiments exposing migratory birds to altered magnetic fields simulating geographical displacements have shown that the geomagnetic field acts as an external cue affecting migratory fuelling behaviour. This is the first study investigating fuel deposition in relation to geomagnetic cues in long-distance migrants using the western passage of the Mediterranean region. Juvenile wheatears (Oenanthe oenanthe) were exposed to a magnetically simulated autumn migration from southern Sweden to West Africa. Birds displaced parallel to the west of their natural migration route, simulating an unnatural flight over the Atlantic Ocean, increased their fuel deposition compared to birds experiencing a simulated migration along the natural route. These birds, on the other hand, showed relatively low fuel loads in agreement with earlier data on wheatears trapped during stopover. The experimental displacement to the west, corresponding to novel sites in the Atlantic Ocean, led to a simulated longer distance to the wintering area, probably explaining the observed larger fuel loads. Our data verify previous results suggesting that migratory birds use geomagnetic cues for fuelling decisions and, for the first time, show that birds, on their first migration, can use geomagnetic cues to compensate for a displacement outside their normal migratory route, by adjusting fuel deposition.
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