Erik Versluijs

• Wikenros, Camilla; Nordli, Kristoffer; Amato, Giulia; Persson, Jens; Ausilio, Giorgia & Versluijs, Erik [Show all 9 contributors for this article] (2024). Carnivore guild utilization of hunter-provided food sources in boreal forest. Wildlife Biology. ISSN 0909-6396. doi: 10.1002/wlb3.01249.
• Neby, Magne; Andreassen, Harry Peter; Milleret, Cyril Pierre; Pedersen, Simen; Peris Tamayo, Ana-Maria & Sanchez, David Carricondo [Show all 8 contributors for this article] (2023). Small rodent monitoring at Birkebeiner Road, Norway. Biodiversity Data Journal. ISSN 1314-2836. 11. doi: 10.3897/BDJ.11.E105914. Full text in Research Archive Show summary

  Northern small mammal populations are renowned for their multi-annual population cycles. Population cycles are multi-faceted and have extensive impacts on the rest of the ecosystem. In 2011, we started a student-based research activity to monitor the variation of small rodent density along an elevation gradient following the Birkebeiner Road, in southeast Norway. Fieldwork was conducted by staff and students at the University campus Evenstad, Inland Norway University of Applied Sciences, which has a long history of researching cyclic population dynamics. The faculty has a strong focus on engaging students in all parts of the research activities, including data collection. Small rodents were monitored using a set of snap trap stations. Trapped animals were measured (e.g. body mass, body length, sex) and dissected to assess their reproductive status. We also characterised the vegetation at trapping sites.

• Versluijs, Erik; Niccolai, Laura Jeanne; Spedener, Mélanie; Zimmermann, Barbara; Hessle, Anna & Tofastrud, Morten [Show all 8 contributors for this article] (2023). Classification of behaviors of free-ranging cattle using accelerometry signatures collected by virtual fence collars. Frontiers in Animal Science. 4, p. 1–13. doi: 10.3389/fanim.2023.1083272. Full text in Research Archive Show summary

  Precision farming technology, including GPS collars with biologging, has revolutionized remote livestock monitoring in extensive grazing systems. High resolution accelerometry can be used to infer the behavior of an animal. Previous behavioral classification studies using accelerometer data have focused on a few key behaviors and were mostly conducted in controlled situations. Here, we conducted behavioral observations of 38 beef cows (Hereford, Limousine, Charolais, Simmental/NRF/Hereford mix) free-ranging in rugged, forested areas, and fitted with a commercially available virtual fence collar (Nofence) containing a 10Hz tri-axial accelerometer. We used random forest models to calibrate data from the accelerometers on both commonly documented (e.g., feeding, resting, walking) and rarer (e.g., scratching, head butting, self-grooming) behaviors. Our goal was to assess pre-processing decisions including different running mean intervals (smoothing window of 1, 5, or 20 seconds), collar orientation and feature selection (orientation-dependent versus orientation-independent features). We identified the 10 most common behaviors exhibited by the cows. Models based only on orientation-independent features did not perform better than models based on orientation-dependent features, despite variation in how collars were attached (direction and tightness). Using a 20 seconds running mean and orientation-dependent features resulted in the highest model performance (model accuracy: 0.998, precision: 0.991, and recall: 0.989). We also used this model to add 11 rarer behaviors (each< 0.1% of the data; e.g. head butting, throwing head, self-grooming). These rarer behaviors were predicted with less accuracy because they were not observed at all for some individuals, but overall model performance remained high (accuracy, precision, recall >98%). Our study suggests that the accelerometers in the Nofence collars are suitable to identify the most common behaviors of free-ranging cattle. The results of this study could be used in future research for understanding cattle habitat selection in rugged forest ranges, herd dynamics, or responses to stressors such as carnivores, as well as to improve cattle management and welfare.

• Eriksen, Ane; Versluijs, Erik; Fuchs, Boris; Zimmermann, Barbara; Wabakken, Petter & Ordiz, Andres [Show all 15 contributors for this article] (2022). A Standardized Method for Experimental Human Approach Trials on Wild Wolves. Frontiers in Ecology and Evolution. ISSN 2296-701X. 10. doi: 10.3389/fevo.2022.793307. Full text in Research Archive Show summary

  As wolves recolonize areas of Europe ranging from moderate to high anthropogenic impact, fear of wolves is a recurring source of conflict. Shared tools for evaluating wolf responses to humans, and comparing such responses across their range, can be valuable. Experiments in which humans approach wild wolves can increase our understanding of how wolves respond to humans, facilitating human-wolf coexistence. We have developed the first standardized protocol for evaluating wolf responses to approaching humans using high-resolution GPS data, and tested it on wild wolves. We present a field protocol for experimentally approaching GPS-collared wolves, a descriptive comparison of two statistical methods for detecting a measurable flight response, a tutorial for identifying wolf flight initiation and resettling positions, and an evaluation of the method when reducing GPS positioning frequency. The field protocol, a data collection form, and the tutorial with R code for extracting flight parameters are provided. This protocol will facilitate studies of wolf responses to approaching humans, applicable at a local, national, and international level. Data compiled in a standardized way from multiple study areas can be used to quantify the variation in wolf responses to humans within and between populations, and in relation to predictors such as social status, landscape factors, or human population density, and to establish a baseline distribution of wolf response patterns given a number of known predictors. The variation in wolf responses can be used to assess the degree to which results can be generalized to areas where GPS studies are not feasible, e.g., for predicting the range of likely wolf behaviors, assessing the likelihood of wolf-human encounters, and complementing existing tools for evaluating reports of bold wolves. Showing how wolves respond to human encounters should help demystify the behavior of wild wolves toward humans in their shared habitat.

• Versluijs, Erik; Eriksen, Ane; Fuchs, Boris; Wikenros, Camilla; Sand, Håkan & Wabakken, Petter [Show all 7 contributors for this article] (2022). Wolf Responses to Experimental Human Approaches Using High-Resolution Positioning Data. Frontiers in Ecology and Evolution. ISSN 2296-701X. 10. doi: 10.3389/fevo.2022.792916. Full text in Research Archive Show summary

  Humans pose a major mortality risk to wolves. Hence, similar to how prey respond to predators, wolves can be expected to show anti-predator responses to humans. When exposed to a threat, animals may show a fight, flight, freeze or hide response. The type of response and the circumstances (e.g., distance and speed) at which the animal flees are useful parameters to describe the responses of wild animals to approaching humans. Increasing knowledge about behavioral responses of wolves toward humans might improve appropriate management and decrease conflicts related to fear of wolves. We did a pilot study by conducting 21 approach trials on seven GPS-collared wolves in four territories to investigate their responses to experimental human approaches. We found that wolves predominantly showed a flight response (N = 18), in a few cases the wolf did not flee (N = 3), but no wolves were seen or heard during trials. When wolves were downwind of the observer the flight initiation distance was significantly larger than when upwind, consistent with the hypothesis that conditions facilitating early detection would result in an earlier flight. Our hypothesis that early detection would result in less intense flights was not supported, as we found no correlation between flight initiation distances and speed, distance or straightness of the flight. Wolves in more concealed habitat had a shorter flight initiation distance or did not flee at all, suggesting that perceived risk might have been affected by horizontal visibility. Contrary to our expectation, resettling positions were less concealed (larger horizontal visibility) than the wolves’ initial site. Although our small number of study animals and trials does not allow for generalizations, this pilot study illustrates how standardized human approach trials with high-resolution GPS-data can be used to describe wolf responses at a local scale. In continuation, this method can be applied at larger spatial scales to compare wolf flight responses within and between populations and across anthropogenic gradients, thus increasing the knowledge of wolf behavior toward humans, and potentially improving coexistence with wolves across their range.

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• Eriksen, Ane; Lorand, Charlotte Muguette Renée; Versluijs, Erik; Chimienti, Marianna; Devineau, Olivier & Bouet, Lea [Show all 10 contributors for this article] (2024). Eksperimentelle nærmøter med ulv – oppdatering og framtidige planer.
• Eriksen, Ane; Lorand, Charlotte Muguette Renée; Versluijs, Erik; Chimienti, Marianna; Devineau, Olivier & Bouet, Lea [Show all 10 contributors for this article] (2024). Studying wolf flight responses during experimental approaches using fine-scale GPS and accelerometer data.
• Adamski, Genevieve; Versluijs, Erik; Zimmermann, Barbara & Tofastrud, Morten (2023). Outstanding in their field: factors influencing cattle habitat selection in Norwegian summer ranging areas.
• Versluijs, Erik (2023). Change point analysis and animation of movement data in R.
• Versluijs, Erik; Zimmermann, Barbara; Tofastrud, Morten; Hessle, Anna; Evans, Alina & Adamski, Genevieve [Show all 9 contributors for this article] (2023). Towards a shared forest: Studying the compatibility of free-ranging cattle and carnivores in boreal forests.
• Zimmermann, Barbara; Wikenros, Camilla; Mathisen, Karen Marie; Ausilio, Giorgia; Sand, Håkan & Hellbaum, Paige [Show all 12 contributors for this article] (2023). Elgforvaltning i grenseland.
• Zimmermann, Barbara; Mathisen, Karen Marie; Ausilio, Giorgia; Sand, Håkan; Wikenros, Camilla & Eriksen, Ane [Show all 13 contributors for this article] (2022). Motsatte norske og svenske mål for felles elgbestand. Hjorteviltet. ISSN 1502-3729.
• Wikenros, Camilla; Aronsson, Malin; Nordli, Kristoffer; Amato, Giulia; Ausilio, Giorgia & Versluijs, Erik [Show all 7 contributors for this article] (2022). Interaktioner mellan järv, varg och människa – nyttjande av vargdödade klövdjur och slaktrester från älgjakten. Sveriges Lantbruksuniversitet. ISSN 978-91-576-9946-6.
• Zimmermann, Barbara; Mathisen, Karen Marie; Ausilio, Giorgia; Sand, Håkan; Wikenros, Camilla & Eriksen, Ane [Show all 20 contributors for this article] (2022). Elgvandringer i grenseland med følger for skogbruk, jakt og rovdyr. Sveriges Lantbruksuniversitet. ISSN 978-91-576-9941-1.

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