Publications by authors named "Roy Andersen"

2 Publications

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Physiologic evaluation of medetomidine-ketamine anesthesia in free-ranging Svalbard (Rangifer tarandus platyrhynchus) and wild Norwegian reindeer (Rangifer tarandus tarandus).

J Wildl Dis 2013 Oct;49(4):1037-41

1  Section of Arctic Veterinary Medicine, Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, NO-9292 Tromsø, Norway.

Previously published studies indicated that combinations of medetomidine and ketamine were effective for both Svalbard (Rangifer tarandus platyrhynchus) and wild Norwegian reindeer (Rangifer tarandus tarandus). Both previous studies indicated that reindeer were hypoxemic on the basis of pulse oximetry. We conducted a physiologic evaluation of these two protocols using arterial blood gases. Medetomidine (10 mg) and ketamine (200 mg) were administered by dart from the ground in Svalbard reindeer (October 2010) and from a helicopter for wild reindeer (March 2012). Of tested animals, all seven wild reindeer and five of seven Svalbard reindeer were hypoxemic before oxygen administration. Nasal oxygen insufflation (1 L/min for five Svalbard reindeer and one wild reindeer and 2 L/min for four wild reindeer) corrected hypoxemia in all cases evaluated. For reversal, all animals received 5 mg atipamezole per mg medetomidine intramuscularly.
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http://dx.doi.org/10.7589/2013-03-049DOI Listing
October 2013

Diet shift of a facultative scavenger, the wolverine, following recolonization of wolves.

J Anim Ecol 2008 Nov 23;77(6):1183-90. Epub 2008 Jul 23.

Norwegian Institute for Nature Research, Trondheim, Norway.

1. Wolves Canis lupus L. recolonized the boreal forests in the southern part of the Scandinavian peninsula during the late 1990s, but so far there has been little attention to its effect on ecosystem functioning. Wolf predation increases the availability of carcasses of large prey, especially moose Alces alces L., which may lead in turn to a diet switch in facultative scavengers such as the wolverine Gulo gulo L. 2. Using 459 wolverine scats collected during winter-spring 2001-04 for DNA identity and dietary contents, we compared diet inside and outside wolf territories while controlling for potential confounding factors, such as prey density. We tested the hypothesis that wolverine diet shifted towards moose in the presence of wolves, while taking into account possible sexual segregation between the sexes. Occurrence of reindeer, moose and small prey was modelled against explanatory covariates using logistic mixed-effects models. Furthermore, we compared diet composition and breadth among habitats and sexes. 3. Occurrence of reindeer, moose and small prey in the diet varied with prey availability and habitat. As expected, diet contained more moose and less reindeer and small prey in the presence of wolves. Their diet in tundra consisted of 40% reindeer Rangifer tarandus L., 39% moose and 9% rodents. In forest with wolf, their diet shifted to 76% moose, 18% reindeer and 5% rodents; compared to 42% moose, 32% reindeer and 15% rodents in forest without wolf. This diet switch could not be explained by higher moose density in wolf territories. Female diet consisted of more small prey than for males, but there was a tendency for females to use the highly available moose carrion opportunistically and to hunt less on small prey within wolf territories. 4. Our study highlights how wolves increase scavenging opportunities for wolverines, and how sexual differences in diet may also apply to large scavengers. Due to their more restricted home range, female wolverines are forced to rely more on hunting small prey. The relatively high occurrence of wolf kills, however, forms an important food source to wolverines in this area. The recolonization of wolves may therefore have contributed to the consequent recolonization of wolverines into the same area.
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http://dx.doi.org/10.1111/j.1365-2656.2008.01445.xDOI Listing
November 2008