Peter Segerström

Risk of capture-related mortality in large free-ranging mammals: experiences from Scandinavia

Abstract Chemical capture and anaesthesia of free-ranging mammals will always involve some risk of mortality even in healthy animals. Deaths may be directly or indirectly attributable to the anaesthetic event itself (e.g. drug overdose, drowning during induction and dart trauma) or may be caused by secondary effects from the capture (e.g. stress, myopathy, trauma or instrumentation with radio-transmitters). In long-term research projects on five major wildlife species in Scandinavia, the capture-related mortality rates (number of captures) were: moose Alces alces 0.7% (N = 2,816), brown bears Ursus arctos 0.9% (N = 1,079), wolverines Gulo gulo 2.8% (N = 461), Eurasian lynx Lynx lynx 3.9% (N = 380), and gray wolves Canis lupus 3.4% (N = 89). We suggest that wildlife professionals should strive for a zero mortality rate but adopt the standard that a mortality rate of > 2% probably should not be accepted in any large mammalian species. This can be achieved by: 1) using an experienced professional capture team, 2) developing and following a capture protocol specific to each species, and 3) requiring that a mortality assessment be undertaken after any capture-related death. This assessment should re-evaluate the capture protocol, including how changes in anaesthetics and methodological approaches could have prevented the mortality.

Biomedical Protocols for Free-ranging Brown Bears, Gray Wolves, Wolverines and Lynx Editors

PREFACE Compilation of this document was initiated by the Norwegian Directorate for Nature Management in order to establish recommended protocols for capture, chemical immobilization, anesthesia and radiotagging of free-ranging brown bears (Ursus arctos), gray wolves (Canis lupus), wolverines (Gulo gulo) and Eurasian lynx (Lynx lynx). In addition, procedures to ensure proper sampling of biological materials for management, research and banking purposes have been included. The current protocols are based on nearly 3,000 captures of free-ranging brown bears, wolves, wolverines and lynx carried out from 1984 through 2012 in Scandinavia. Some of the results have been published as peer reviewed papers, conference presentations, theses, and reports. However, a large amount of data are still on file and will be published in the future. In addition, comprehensive reviews of the global literature on brown bears, wolves, wolverines and lynx have been carried out in order to include pertinent information from other sources. These protocols have been approved by all ongoing research projects on brown bears, wolves, wolverines and lynx in Scandinavia. We thank the contributors for their cooperative efforts. We also thank the Norwegian Directorate for Nature Management for their support.

Winter Lynx Lynx lynx Predation on semi-domestic Reindeer Rangifer tarandus in Northern Sweden

The predation behaviour of six lynx Lynx lynx family groups, i.e. adult females with dependent kittens, was studied using radio-tracking and snow-tracking in the Sarek area of northern Sweden during winter 1995/96 and 1996/97. One hundred and six daily radio-locations were obtained, and 340 km of intervening tracks were followed in the snow. Forty-one scats were collected, and 57 hunting attempts, 37 of which were successful, were recorded. Semi-domestic reindeer Rangifer tarandus contributed over 90% to lynx ingested meat calculated from both scats and kills. Eighty-three percent of hunting attempts on reindeer, and 53% of attempts on small prey species, mainly Lagopus sp. and mountain hares Lepus timidus, were successful. Four incidents of multiple-killing of reindeer were documented. Reindeer were generally in poor body condition, with an average femur marrow fat content of 27%. Lynx spent an average of three nights at each reindeer kill-site. Reindeer were less completely consumed than small prey (61% vs 99%). The amount of meat eaten from a reindeer was proportional to the number of lynx-nights on the kill. An overall kill rate of one reindeer per five days was calculated. We concluded that reindeer are a very important food source for lynx in winter, which potentially could lead to problems in resolving the camivore-livestock conflicts in the region.

DNA-Based Individual and Sex Identification from Wolverine (Gulo Gulo) Faeces and Urine

Non-invasive genetic analyses are important for studies of species that are rare, sensitive or at risk of extinction. This study investigates the possibility of using faeces and urine to obtain microsatellite genotypes for individual identification of wolverines (Gulo gulo). The reliability of the employed method was assessed by analysing independent amplifications of non-invasive samples (a multiple-tube approach) and by comparing genotypes obtained from faeces to genotypes obtained from blood or tissue of the same individual. Ten microsatellite markers were successfully amplified in 65% of the faecal samples (n = 32) and 40% of the urine samples (n = 22). Allelic dropout was found in 12 and 14% of the amplifications from extracts of faeces and urine, respectively. Nevertheless, all multi-locus genotypes were correct, as judged from comparison to data from tissue or blood samples, after three replicates. These results suggest that a non-invasive approach based on DNA-analysis of faeces can be a powerful tool in population monitoring of wolverines, potentially providing reliable estimates of population size and immigration rate. A second objective of the study was to develop markers for DNA-based sex identification in wolverines using non-invasive samples. We developed two Y-linked markers, one that was specific to wolverine and one that also successfully identified sex in another mustelid. Importantly, none of the markers amplified potential prey species such as reindeer or rodents.

Estimating total lynx Lynx lynx population size from censuses of family groups

Counts of reproductive units, i.e. family groups, constitute the main monitoring index for lynx Lynx lynx populations in Scandinavia. However, for some purposes it is necessary to extrapolate from the number of family groups to obtain an estimate of total population size. Using data on survival and reproduction from radio-marked lynx from three Scandinavian study areas, we simulated the lynx population structure in February. The average proportions of family groups out of all independent individuals, i.e. adults and yearlings, in these simulations were 21% ± 2.1 (SD), 22% ± 3.6 and 27% ±3.1 for the data sets from northern Sweden (Sarek), southeastern Norway (Hedmark) and south-central Sweden (Bergslagen), respectively, and the overall mean for all three study areas was 23% ± 3.8. This translated into extrapolation factors of 6.14 ± 0.44,6.24 ± 0.73 and 5.48 ± 0.40 for the three study areas, respectively, leading to an overall mean for all three study areas of 5.95 ± 0.64. We conclude, that it is possible to extrapolate from the number of family groups to obtain an estimate of total lynx population size with a statistical measure of uncertainty.

Effects of Species Behavior on Global Positioning System Collar Fix Rates

Abstract Use of Global Positioning System (GPS) telemetry is increasing in wildlife studies and has provided researchers and managers with new insight into animal behavior. However, performance of GPS collars varies and a major concern is the cause of unsuccessful fixes. We examined possible factors causing missed fixes in GPS collars on sympatric free-ranging Eurasian lynx (Lynx lynx) and wolverines (Gulo gulo) in northern Sweden. We tested for effects of species, activity, habitat, individual, and collar on fix rate. Species was the most important factor affecting fix rate. Fix rate of GPS collars on lynx (80%) was almost twice as high as on wolverines (46%). Fix rate decreased during periods of low activity (day beds) for both species. Fix rate also decreased for females (both lynx and wolverine) for a period after they gave birth. We found no effect of proportion of forest within individual home range on fix rate. We conclude that species behavior, characteristics, and activity pattern are important factors affecting fix rate that we recommend be taken into consideration prior to analyzing GPS location data.

Reproductive Characteristics of Female Wolverines (Gulo gulo) in Scandinavia

Abstract We studied reproduction of 56 female wolverines (Gulo gulo) in 2 areas of northern Scandinavia. Minimum average age at 1st reproduction was 3.4 years. Mean proportion of females (≥3 years old) reproducing was 0.53 (95% confidence interval [CI] = 0.43–0.63, n = 94), and the annual mean was 0.58 (95% CI = 0.35–0.80, n = 83). Mean annual birth rate was 0.74 (95% CI = 0.33–1.14, n = 83) young per female (≥ 3 years old). Mean size of 74 litters was 1.88 (95% CI = 1.68–2.07, range = 1–4). Examination of our data suggests that female wolverines have low productivity and low capacity to compensate for increased mortality. Therefore, wildlife managers should consider wolverine demographics, especially mortality of adult female wolverines, when developing and implementing conservation policies and harvest regulations.

Distance rules for minimum counts of Eurasian lynx Lynx lynx family groups under different ecological conditions

Abstract Monitoring of lynx Lynx lynx populations in Scandinavia is largely based around unreplicated minimum counts of family groups, i.e. adult females with dependent kittens. When observations cannot be separated from each other on the basis of back-tracking in the snow it is desirable to use a distance rule to separate observations of groups that are so far apart that they are unlikely to be derived from the same group. We have analysed radio-telemetry derived movement data from five study areas, corresponding to three ecologically different regions, in Scandinavia, and included data from Poland for comparison. We derive examples of two different distance rules; one is a static rule based on home-range size and length which is suitable for observations accumulated during a whole winter, and the other is a dynamic rule suitable for observations collected within 1-7 days of each other. Because of inter-study area variation in home-range size and movement there is a need to use different rules in different regions. Within Scandinavia, average maximum home-range lengths varied from 28 to 54 km, and average maximum daily distances travelled varied from eight to 16 km in the three regions. This implies that locally collected movement data are a prerequisite for application of this type of methodology.

CAPTURE AND MEDETOMIDINE-KETAMINE ANESTHESIA OF FREE- RANGING WOLVERINES (GULO GULO)

Capture and anesthesia with medetomidine-ketamine were evaluated in free-ranging wolverines (Gulo gulo) immobilized for marking with radiocollars or intraperitoneal radiotransmitters in Norrbotten, Sweden, during early June 2004 and 2005. Twelve juvenile wolverines were captured by hand and injected with 0.14±0.03 mg/kg (mean±SD) medetomidine and 7.5±2.0 mg/kg ketamine. Twelve adult wolverines were darted from a helicopter or the ground, or captured by hand. Adults received 0.37±0.06 mg/kg medetomidine and 9.4±1.4 mg/kg ketamine. Arterial blood samples were collected between 15 min and 30 min and between 45 min and 60 min after drug administration and immediately analyzed for selected hematologic and plasma variables. Hyperthermia was recorded initially in one juvenile wolverine and 11 adults. Rectal temperature, heart rate, and lactate decreased significantly during anesthesia, whereas hemoglobin oxygen saturation, pH, partial pressure of arterial carbon dioxide, and base excess increased. Adult wolverines darted from a helicopter had a significantly higher rectal temperature, higher glucose and hematocrit values, and a lower heart rate than juveniles captured by hand. Impaired arterial oxygenation was evident in all wolverines. This study provides baseline data on physiologic variables in adult and juvenile wolverines captured with different methods and anesthetized with medetomidine-ketamine.

Paternity and mating system in wolverines Gulo gulo

Abstract Knowledge of the wolverine Gulo gulo mating system is limited. In this study, we use 20 microsatellite loci for paternity testing in 145 wolverine offspring with known mothers. Samples were collected during > 10 years in two Scandinavian populations, mainly in connection with radio-telemetry studies and as part of long-term population monitoring. In total, 51% of the offspring were assigned a father. Our results demonstrate that the wolverine exhibits a polygamous mating system as some males were shown to produce offspring with more than one female in a single year. Females often reproduced with the same male in subsequent breeding years, but sometimes changed their partner, potentially as a consequence of a change in the territory-holding male in the area. In the majority of litters, siblings were unambiguously assigned the same father, indicating that multiple paternity is rare. Of 23 breeding pairs, for which telemetry data were available, 20 had overlapping home ranges, suggesting that pair formation generally is consistent with the territories held by wolverine males and females.