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UNIVERSITÀ DEGLI STUDI DI PISA
Dipartimento di Scienze Veterinarie
Corso di laurea magistrale in Medicina Veterinaria
TESI DI LAUREA
Comparison of two non-invasive blood pressure monitoring
techniques in anaesthetized free-ranging brown bears (Ursus
arctos)
Relatore
Prof. Angela BRIGANTI
Correlatore
Prof. Ðuro HUBER
Candidato
Jacopo MORELLI
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A chi motiva con fervore ogni mio passo: la mia famiglia, Ilaria, la Natura.
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ABSTRACT
Introduction: monitoring arterial blood pressure (BP), representing a more accurate evaluation of hemodynamics than heart rate alone, is essential for preventing and treating intra- and post-operative complications in wildlife chemical immobilization.
Objective: to test correlation between standard oscillometry and Korotkoff’s technique in anaesthetized free-ranging brown bears in Croatia and Scandinavia, and to assess the seriousness of hypertension in both contexts.
Materials and Methods: 5 bears were snared and darted with xylazine and ketamine in Croatia, while 20 bears were darted with medetomidine and tiletamine-zolazepam from the helicopter in Scandinavia, within national and international projects. BP was simultaneously measured with both non-invasive techniques every 5 minutes, as well as other physiological parameters. Correlation between techniques, trends of BP variation, and the factors of the capture which most likely induced hypertension were assessed. Results: Oscillometry succeeded in measuring BP in 29.3% of total attempts vs 93.3% when performing Korotkoff’s technique. The former method provided lower values than the latter in yearlings, with the opposite effect in adults. Although all bears presented the common finding of a generally decreasing trend of SAP and MAP over time, consistent between the two techniques, in 11 of 20 bears several increments occurred mostly during the abdominal surgery (n = 8) in Scandinavia. All bears were hypertensive: the auscultatory technique detected moderate to severe systolic hypertension in 84.2% of bears in Scandinavia whereas 3 of 4 bears achieved at most a mild systolic hypertension in Croatia.
Discussion and conclusion: several inconsistent values occurred with the oscillometric method, showing lack of precision and low correlation with the auscultatory technique, which, contrarily, provided more reliable trends of variations in all bears. Korotkoff’s method resulted in a reliable and effective tool for BP assessment in brown bears, though further comparative studies with invasive BP are needed to test the accuracy of the method and to assess the incidence of target-organ damage in anaesthetized free-ranging brown bears. The anaesthetic protocol used in the present study in association with the capture methods produced hypertension in all the animals.
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INDEX:
Introduction: ... 6
1. The brown bear (Ursus arctos) ... 8
1.1. Between history and myth ... 8
1.2. Biology, anatomy and physiology: ... 9
Anatomy: ... 9
Physiology: ... 11
Reproduction: ... 15
Social system and diet: ... 16
1.3. Population, threats and management ... 16
Distribution and populations: ... 16
Major threats: ... 17
Conservation actions: ... 18
2. Background ... 20
2.2. Sweden ... 29
3. Chemical Immobilization of brown bears ... 37
3.1. General ... 37
3.2. Methods: trapping, chasing and stress ... 38
3.3 Remote drug delivery ... 41
3.4 Drugs ... 46
4. Arterial blood pressure of the immobilized brown bear ... 67
4.1. General ... 67
4.2. Hemodynamics monitoring: pros, cons and differences between NIBP and IBP in the field ... 75
4.3. Acute hypertension: risks and treatment ... 83
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5.1. Introduction ... 89
5.2. Objectives ... 90
5.3. Materials and Methods ... 91
Study area and animals ... 91
Capture methods, drugs and darting materials ... 92
Procedures... 95
Monitoring ... 97
Statistical analysis ... 103
5.4. Results ... 105
General ... 105
Blood pressure results ... 112
5.5. Discussion ... 125
Exertion, quality of the immobilization,HR, RR, SpO2 and Tr ... 125
Arterial blood pressure ... 129
5.6. Limits of the research ... 134
6. Conclusions ... 136
7. Appendix ... 137
8. Special thanks ... 140
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Introduction:
Why wildlife anaesthesia as a master thesis topic area and why brown bears?
Physical restraints of wildlife have been carried out from several centuries (such as the captures of both feral carnivores and herbivores for the venaciones, from latin venacio, hunt in english, in Ancient Roman Empire’s Games or in order to give these animals as a peace offering to kings or marajas , just to mention a few), but the very first episode of wildlife chemical restraint was carried out in 1820 and it was actually on a captive brown bear, by feeding it with a mixture of alcoholic drink and honey, after fasting, in order to drive the bear “drunk” and manipulate it easier. Both immobilization techniques, human safety and animal welfare improved with time, along with the development of veterinary scientific knowledge and growing public sensitivity.
The aims of these immobilizations were and are still vary, from entertainment to trade, from translocation to research purposes and in about one and half century techniques, chemical protocols, monitoring devices and procedures have changed heavily. Anesthetic protocols that allow quick induction, short processing time, wide therapeutic index range, safety for the team and rapid reversal are necessary for researchers performing minimally invasive procedures (e.g., morphometric measurements or attachment of telemetric devices). Further, thanks to previous studies and researches about post-anaesthesia effects on several wildlife species (from health to behavioural consequences), modern technologies and almost global increasing sensibility about animal welfare, today is no more ethically and professionally allowed to perform immobilizations on wildlife with less concern than we have with pets, livestock or zoo animals.
I started to be interested in wildlife as far as I can remember, but I got particularly into the bear topic especially after one accident of mortality of a wild “confident” brown bear in northern Italy due to the anaesthesia which was carried out to translocate her to another location. Accidents may happen anytime obviously, therefore wildlife veterinarians must know exactly what species they are working on, from its ecology to its physiology, they must evaluate the risk either the need of the immobilization and they must be trained for that specific activity such as anaesthesia, a procedure that only qualified veterinarians should perform. We have this paramount responsibility because wildlife mustn’t have less rights than domestic species.
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This study has the aim to assess how different drug protocols, capturing techniques, external features (such as ambient temperature, diet, latitude), internal features (e.g. different bear populations, age, size, gender) affects the physiology of wild brown bears (Ursus arctos), with a special concern in arterial blood pressure, measured by two different non-invasive techniques (Korotkoff’s method and standard oscillometry), both in Croatia and Scandinavia. Since each background has several variables we will assess the impact on the blood pressure made by the totality of the variables included in each context as a whole thing, stressing the resulting differences, their probable causes, the advantages and the disadvantages of both procedures and eventual further methods useful to reduce the risk of systemic and organ damage related to capture-induced alteration in blood pressure. There are no such studies published as far as we know, therefore we believe that these results will improve both the scientific knowledge and the safety of the wild either captive anaesthetized bears, then, as a final result, brown bear conservation.
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1. The brown bear (Ursus arctos)
1.1. Between history and myth
Bears always played a dominant role in both Eurasian and North American primitive cultures and his relationship with the man was special. Wherever bears and men used to share the same area, the latter showed the same ambivalent attitude: although bears were chased, hunted, killed, their human-like appearance and their impressive strength instilled respect. This paradox is the cornerstone of the Bear Ceremonialism in the Northern
Hemisphere1. Even if the ceremonies in Eurasian communities and native American tribes were different from region to region, all were associated with the same impulse: the bear was honoured as the lord of the forest or as the supreme governor’s son, with the duty of protector of the justice. Several legends and stories recognised a strict link between bear and man, as they were part of the same kin, probably even because the bear was the aesthetically closer animal to people as far as they could know. One example is the ancient greek myth of Callisto, the beautiful nymph who broke the chastity vow to become one of the Zeus’s lovers, then became pregnant and the goddess Artemis punished her by changing her into a bear. Her human-like son Arcade, by the way, was born and grew up far from her until the moment when he hunted the bear who actually was his mother, but then Zeus decided to save Callisto by nestling her in the sky, so she became the Ursa Maior constellation and Arcade became Arcturus (from arktos=bear and ourà=tail), the brightest star in the northern celestial hemisphere.
Other communities, as Cherokee2, considered bears like relatives, but it didn’t prevent them to hunt this species wearing wooden masks and bear fur, as well as with Kiowa tribes. To Ojibway people, on the other hand, they were sacred and not hunted, like with Yavapi tribes, who thought that men differed from bears solely because of the ability to light the fire, or with Pueblos tribes, who didn’t eat bear meat because of assumed kinship, or finally with Yuchi tribes who used to pray and dance honouring bears during ceremonies3. Likewise, also in Europe and Asia many tales and traditions were influenced by bears, like in either Ket or Mansi people and even in Scandinavia: the famous
berserkers, in Norse mythology, were formidable warriors who devoted their life to the
god Wotan (Odin) and their name probably comes from beri, norse word for “bear”, and
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influenced cultures and they always gained a symbolic and aesthetic value in the past, but we must keep in mind that they are not interested in people and they are neither soft stuffed toys to pet nor killer demons to exterminate, but strong and intelligent animals worthy of everyone’s respect, no more and no less than others.
1.2. Biology, anatomy and physiology:
Kingdom Phylum Class Order Family Subfamily Gender Species Animalia Chordata Mammalia Carnivora Ursidae Ursinae Ursus arctos
The brown bear (sometimes called “grizzly” in North America) is one of the eight species of bears in the world and one of the largest terrestrial carnivores (the biggest one is the polar bear, Ursus maritimus), it has 74 chromosomes (2n) and it’s usually dark brown in colour, though it can vary from a light creamy shade through to black. The long guard hairs over the shoulders and back are often light coloured at the tips which, from a distance, give a grizzled appearance4.
There is considerable variability in the size of brown bears from different populations, depending on the food available. Determining representative weights of specific populations is also difficult as there are seasonal considerations to take into account-for instance, some bears can weigh almost twice as much in the fall as they might weigh in spring. Adult males may weigh 135 to 390 kg compared with 95 to 205 kg for females. At birth, cubs weigh 340 to 680 g. The largest bears are found on the west coast of British Columbia and Alaska, and on offshore islands along coastal Alaska, such as Kodiak and Admiralty. There, males average over 300 kg and females over 200 kg. Brown bears from the interior ranges of North America, Europe, and the sub-Arctic are roughly two-thirds the size of their Alaskan and Kamchatkan cousins5.
Anatomy:
Brown bears have many anatomical features similar to canids, even if with some exceptions.
The skeleton is large and robust, front and hind limbs are nearly equal in length, the radius and ulna bones are separate, allowing powerful twisting movements of the limbs and the fibula bone is also present. Large scapula bone with a pronounced spine is consistent with the skill of digging for food and to make dens. The feet are large (ursids are plantigrades)
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with five digits on each foot. The claws, which are non-retractile, are often longer than 8 cm. Heavy pads of fibrous connective tissue provide a cushioning effect. Brown bears mainly walk but also gallop and leap, they can even swim well. They climb, although adults climb trees less well than do American black bear (Ursus americanus). The front claws are mainly used for digging. These bears are very strong and can drag carcasses weighing more than the bear's own body weight. They can stand on their hind legs to see better and to reach food. The cranium reflects the omnivorous diet, is proportionally larger than in canids, though the dental formula is 3I 1C 4P 2M / 3J 1C 4P 3M = 42, so like wolves and dolichocephalic dogs. Interestingly, bears also have one to four epipharingeal pouches6 (brown bears have two) located dorsally to the esophagus, they are constant and unique morphological features of the family Ursidae suggesting involvement in the respiratory system most probably in important aspects of ursid phonation.
The gastrointestinal apparatus is similar to that in other bears and in canids: they are monogastric, the intestines are relatively short (total length of intestines 7-10 m) and undifferentiated, with a small or absent caecum and the general histological structure is similar to that of dogs, cats and other carnivores. Stomach capacity is almost half of total gastrointestinal volume, then bears have a much more heavily muscled pylorus than other mammals. Regarding the urinary apparatus, kidneys of bears are lobulated.
Males have an os penis up to 216 mm long in old males and some females have an os
clitorisI. Bears have small glandular ampullae at the distal ends of the vasa deferentia and, compared to canids, they have a small prostate gland. For mature bears, the testes show an annual cycle in weights, but with considerable variation between individual bears. Females have two pairs of teats in the pectoral region (most used), one pair in the abdominal region and one pair in the inguinal region. The body of the uterus is about 50 mm long, it splits into two uterine cornu, each about 150 mm long in the adult. The folds of the vulva increase in size during the breeding season and returns to the non-breeding size afterwards. The ovaries increase in size as the bear reaches sexual maturity and vary in size associated with the reproductive cycle. During late August to late October, for bears which have bred that year, there are corpora lutea on the ovaries and the uterus contains unimplanted blastocysts.
11 Physiology:
In general, active bears exhibit the basic systemic physiology common to other carnivorous mammals. The digestive system of the brown bear, for instance, is apparently similar in form and function to that of canids. Because bears are noncecal monogastrics, they cannot digest fibres efficiently7, so they cannot significantly increase fat reserves on foliage alone and highly digestible, high caloric foods are essential to their diet. Studies showed that although brown bears have evolved omnivorous food habits and morphological adaptations for herbivory, it digests cellulose poorly but has apparently conserved the ability to digest meat efficiently, almost as well as strictly carnivorous mammals. Moreover, the ability to digest high quality forage rapidly is presumably a necessary concomitant of denning.
We know very little about the sensory system of the brown bear. The most acute sense is smell10 but hearing and eyesight facilitate foraging and predatory behaviours. The popular myth that bears do not see well is contradicted by personal observations of brown bears observing other bears or humans from distances of 1-2 km.
Body temperature in the brown bear has a mean value of 37.2 ± 1.6 °C during the activity period, declining by 4-5 ºC during hibernation8.
Resting heart rate (HR) has been recorded among a range of 55-95 beats/min in summer (July, according to the most recent studies in Scandinavia using data from active animals with implanted bio-loggers8) and declines to 8-12 beats/min during hibernation, along with a dramatic drop of heart rate variability (HRV) as a proxy of sympathetic nervous system activity.
Determining normal values of either systolic, diastolic or mean arterial blood pressure (SAP, DAP and MAP, respectively) is slightly harder than other parameters, since no scientific studies reported such measurements in resting unanaesthetized brown bears as far as we know, though some unpublished reference reported in one study9 show higher values of baseline blood pressure (measured through non-invasive techniques) in captive unanaesthetized brown bears: mean SAP obtained from active, captive brown bears generally ranges between 208-225 mmHg in the active period and 175-185 mmHg during hibernation in January (Nelson pers. comm., unpubl. data). We have no clue, though, how the restraint and the blood pressure monitoring affected these bears in terms of stress and hemodynamic variations. Further, several blood pressure values have been obtained in
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healthy, active unanaesthetized adult panda (Ailuropoda melanoleuca) and sloth (Melursus
ursinus) bears, trained for this monitoring purpose at the Smithsonian’s National Zoo
(unpubl. data). These values suggest similar baseline reference values between the two species, and much more similar to canids compared to previous findings in awake captive grizzly bears. The measurements were carried out throughout a few-years-long follow up in the active period, from April till August, by using standard automated oscillometer devices (cuff width/arm circumference ratio of about 0.40) and the overall results are (mean ± SD) 141 ± 29 mmHg for SAP, 109 ± 23 mmHg for MAP and 91 ± 24 mmHg for DAP. Still, we don’t know exactly the concurrent biases nor if this difference is actually due to the different species.
Hence, since physiological baseline range values are still discussed, in all previous studies on blood pressure in bears the physiologic ranges have been extrapolated from those concerning dogs and men, as well as with mammals with similar vertical distance between heart and brain10 (e.g. in the giraffe, Giraffa camelopardalis, which has a 3 m vertical
heart-brain distance, the MAP is about 300 mmHg, much higher than shorter mammals in order to allow an appropriate perfusion to the upper parts of the body), since there is no clear proportional correlation between size of the body and blood pressure.
Therefore, can be assumed a probable baseline range of 110-170 mmHg SAP, 100-130 mmHg MAP and 70-110 mmHg DAP in resting brown bears, considering all what mentioned above. Still unclear is whether the blood pressure rises well above these ranges during an exertion (such as a run or a fight) and yet remains within a physiological range and so it is still well tolerated by the animal (e.g. in one past study on horses invasive blood pressure values, measured from the carotid arteries, increased consistently with the galloping speed increase and MAP rose from 97 ± 12 mmHg to 160 ± 20 mmHg11), or not. In vary studies has been shown that MAP variations, measured directly from the femoral artery, in bears is affected most likely by the same drug mechanisms as in canids (e.g. hypertension, bradycardia and hypoxemia when using α2-agonists such as xylazine or
medetomidine combined with ketamine or with tiletamine-zolazepam in either polar bears12,13 or black bears14, with MAP values rising above 200 mmHg and thus considering
them as hypertensive). Further, other studies showed that isoflurane dose-dependently increased HR and decreases MAP, perhaps by causing vasodilation, which would reduce systemic vascular resistance and the reflex stimulus of baroreceptors, either in Asiatic black bears15 or brown bears16, as observed in other species.
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Previous studies on, either captive or wild, anaesthetized brown bears assessed the cardiac function, by performing electrocardiography (ECG) and echocardiography, also on hibernating individuals16. Therefore, the authors could conclude that the ECGs from brown bears are similar to those of other caniform (suborder Caniformia) species. Moreover, there was no ST segment, since ventricular repolarization began immediately after the end of QRS, so the ventricular repolarization complex has been named ST-T and its vector orientation in the frontal plane is concordant with the QRS vector. The ECG is further characterized by peaked T waves (even without electrolytic alterations and with different amplitude between adults and subadults), notched QRS complexes, size-related association between P-Q segments and sinus arrhythmia is often observed both during hibernation and when using xylazine-ketamine or medetomidine-tiletamine-zolazepam for the anaesthesia17,18. Other specific echocardiographic and electrocardiographic findings are well described in the references.
Lower haemoglobin, haematocrit and MCV in yearlings compared to subadult and adult animals are well described phenomena in brown bears. Hypochromic microcytic anaemia in young19,20, growing bears has been a suggested cause, attributable to iron deficiency caused by growth demands. Also, captive bears may have higher values because of stereotypical licking iron bars of the enclosures. Between males and females there are significant differences for erythrocytes, sedimentation after 30 min, leukocytes and segmented neutrophils (all higher in males). Lower erythrocyte numbers in females is most likely physiologic as described in females of other species, such as rabbits and pigs. Lower monocyte counts in females have also been noted in humans where it is considered physiologic. Comparing captive and free-living bears, blood parameters with significant differences were leukocytes, segmented neutrophils and eosinophils (higher in captive bears), because of both the redistribution of the marginal neutrophil pool and the corticosteroid release due to the stress of the capture with foot snares20. Alkaline phosphatase (AP) and inorganic phosphorous are highest in yearlings and lowest in adults. Only juvenile mammals are able to mobilise magnesium from the skeleton in the face of inadequate dietary intake, which could explain why younger bears have significantly higher serum magnesium concentrations than subadults and adults. The higher values of lipase in females compared to males is in agreement with findings in polar bears21.
Increased serum values of lactate dehydrogenase (LDH), aspartate amino dehydrogenase (AST) and especially creatinine kinase (CK) could be a result of muscle damage after an
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intensive chase before immobilization, bear effort to escape from the foot-snare trap (significantly higher values compared to captive bears22) or dart trauma. The higher albumin/globulin ratio in subadult and adult bears compared to yearlings is likely due to the higher level of albumin and total protein in the older bears. The increase of gamma globulins with increasing age may indicate a still developing antibody producing mechanism in younger individuals. The higher values of cholesterol and triglycerides in yearlings compared to subadult and adult brown bears stand in contrast to a study of sloth bears.
Further detailed findings in haematology, biochemistry, blood gas analysis and acid-base status23 are exhibited in the reference studies, according to each immobilization procedure which was performed in the specific case.
Hibernation:
Torpor is a hypometabolic state of fasting and inactivity, a strategy applied at all latitudes from arctic to tropical regions and was described in members of at least seven mammalian orders. Hibernation is a specific kind of seasonal (winter) torpor defined as torpor bouts lasting consecutive days to several weeks during which drastic changes occur in the animal’s physiology.
Hibernation in bears is peculiar and different from the one in small mammals: body temperature is reduced only by about 4-5 °C (30-34 °C vs -2.9 °C in artic ground squirrels,
Urocitellus parryii) because of the large body size, the respiratory rate decreases to about
one breath a minute and the heart rate to 8-10 bpm. Nevertheless, bears exhibit an aerobic metabolism because the Hb-O2 affinity increases (left shift in the [O2]/PO2 curve)24. Blood
is redistributed, going mainly to the heart, lungs and brain. During hibernation the bears do not walk, eat, drink, defecate or urinate, water needs are satisfied by metabolic water from fat, only to awaken with low blood urea nitrogen levels, healthy lean body mass, strong bones and without evidence of thrombotic complications. Therefore, bear hibernation has been studied especially by human nephrologists because the identification of the mechanisms by which bears prevent the development of azotemia, sarcopenia, osteoporosis and atherosclerosis despite being inactive and anuric could lead to novel interventions for both prevention and treatment of patients with chronic kidney disease25. Has been
postulated the passage of the urea into the intestine, where it is hydrolysed by urease-expressing gut bacteria to release ammonia which is mostly recycled and resynthesized into amino acids, thus preserving skeletal muscle mass, too. Moreover α2-macroglobulin is
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increased during hibernation and it’s a protease inhibitor involved in the regulation of coagulation that increases clotting time. About preventing cortical and trabecular bone loss, several studies on black bears (U. americanus) showed that their parathyroid hormone (bPTH) positively correlates to bone formation markers during hibernation.
The shift from carbohydrate and protein metabolism to fat metabolism results in decreased urea production and reduced demand for the enzymes important for protein breakdown (alanine transaminase, aspartate transaminase, lactate dehydrogenase, γ-glutamyl transpeptidase, glutamate dehydrogenase, and amylase). Fat catabolism also results in increased blood lipids, triglycerides, cholesterol, and free fatty acids and fasting resulted in increased β-HBA, lower bile acids and urea levels. The general depression of metabolic rate is also represented by the decreased organ function, including decreased kidney (increased creatinine to about twice normal and magnesium), liver (increased ALP), and pancreas (decreased amylase) function and suppression of the innate immune system in winter26. Peripheral total blood leukocyte counts, neutrophils, and monocytes are
significantly lower during hibernation than during the active period whereas there is no change in total lymphocyte counts between the hibernation and active periods27. These latter findings are consistent with hibernation in small mammals, in fact is hypothesized that one reason they have periodic arousals is to reactivate the immune system to fight any pathogens entering in this state of low immune function (as seen in fungal infections in hibernating bats, Cyran et al. 2010).
Brown bears hibernate during the winter period when food is unavailable or of greatly reduced availability, entering their dens in September to December and emerging in March to May, so hibernation may last 3-7 months depending on the latitude, ambient temperature and whether there is an ongoing gestation or not (pregnant females enter their dens first and leave their dens latest6). Individuals which have fed sufficiently, laying down enough fat, den earlier than those which do not have sufficient fat reserves; these stay active and feeding until forced to den by low temperatures and snowstorms. Males lose about 22% of their autumn mass over the winter hibernation, females about 40%, due to the demands of reproductionI.
Reproduction:
Female brown bears reach sexual maturity at 3.5-7 years of age. Males become sexually mature at a similar age but could probably not be large enough to be able to enter the breeding population in the wild until they are 8-10 years old. Mating takes place from early
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May to the middle of July but implantation does not occur until about October or November (embryonic diapause), so the young are born from about January to March since gestation lasts approximately 2 months (54-59 days28). The pregnant female bear presents a constant average body temperature higher than preimplantation and lactation period and anyway higher compared to non-pregnant bears (>35.9 °C vs ~33.2 °C). Brown bears are the only mammals with delayed implantation, gestation, parturition and lactation during hibernation, when they do not eat, drink, urinate or defecate for several months, surviving solely on stored energy resources. The litter size ranges from one to four, but two is most common. Cubs remain with their mothers usually for at least 2.5 years, so the most frequently a female can breed is every 3 years. In some areas, such as the subarctic regions, the breeding interval is considerably longer because of shorter activity periods. Since the loss of the cubs during the mating season will induce a new oestrus cycle in the female, sexually selected infanticide, led by adult males, is very common in this species. Longevity in the wild is 20 to 25 years although rarely animals in excess of 35 years of age have been reportedI.
Social system and diet:
Under most circumstances, brown bears live as lone individuals, except for females accompanied by their cubs. During the breeding season, a male may attend a female for up to two weeks for mating. Brown bears are distributed in overlapping home ranges and male home ranges are larger than those occupied by females. Despite their propensity for a solitary existence, brown bears congregate at high densities where food is abundant, such as at salmon streams or garbage dumps. In such circumstances, adult males are the most dominant individuals. Brown bears mainly eat vegetation such as grasses, sedges, bulbs, and roots. They also eat fish, small mammals and insects such as ants. In some areas they have become significant predators of large hoofed mammals such as moose calves, roe deer, caribou, deer calves and occasionally livestock.
1.3. Population, threats and management
Distribution and populations:
The range of the brown bear is the widest of any species of bear in the world, living in habitats including dense coastal forests, boreal forests, sub alpine mountain areas, tundra, deciduous forests, desert and semi-desert areas.
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The brown bear species has been assessed as Least Concern (LC) by the IUCN Red List of Endangered Species survey, 2016. In total, 44 subpopulations have been identified globally, but because many of them are small, isolated, and in need of conservation attention, they have been assessed individually using the IUCN Red List criteria for isolated populations following the guidance of Gärdenfors et al. (2001) and IUCN (2016)29,30.
The total number of brown bears on earth is estimated to exceed 200,000. Russia has the largest number of brown bears, believed to exceed 100,000, while estimates in the U.S. (mainly in Alaska) are around 33,000, Canada 25,000, and Europe (excluding Russia) 15,400. In contrast with the relatively dense distribution of the individuals in the northern parts of the habitat, the southern portions of the range are highly fragmented, with many small populations.
In Europe, brown bears occur in 22 countries. Based on the existing data on distribution, as well as a range of geographical, ecological, social and political factors these can be clustered into 10 populations31: Scandinavian, Karelian, Baltic, Carpathian, Dinaric-Pindos, Eastern Balkan, Alpine, Abruzzo, Cantabrian, and Pyrenean. According to reported and updated census data, the largest population is the Carpathian population (> 8,000 bears), followed by the Scandinavian and Dinaric-Pindos populations (> 3,400 and 3,040 bears, respectively). The other populations are much smaller ranging from several hundred (e.g., Baltic ~700, Cantabrian ~200) to less than one hundred (e.g. Alps ~37 bears; Abruzzo ~50 bears, with the sub-species U. arctos marsicanus).
Major threats29:
In Europe, four of ten populations are Critically Endangered. Although the current public interest, financial investment and management actions, apparently protect most populations at least for their short to midterm survival, portions of populations in some countries are less secure due to lower local acceptance and consequently high human-caused mortality rates. The key threats for bears in Europe are identified as: habitat loss and fragmentation due to infrastructure development, disturbance, low acceptance because of competition with hunters for game species and because of damage to plantations, poultry and livestock, poor management structures, intrinsic factors, accidental mortality and persecution. There is a large amount of small, isolated populations of brown bears, and they are the most threatened due to their low numbers, high inbreeding risk and frequent contact with
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humans, such as the Marsican brown bear (U. a. marsicanus) in Italy, roaming just a couple of hours drive from Rome. In such small populations even few losses of individuals affect population growth32, on the other hand, preventing just a few deaths may avert a population decline33. Where brown bears form a large, contiguous population, they are sometimes hunted for sport or killed for control purposes, whereas in some other areas they are assessed as a strictly protected species. Unfortunately, most countries do not have the resources to implement adequate monitoring programs and sustainable management plans for the brown bear population. Furthermore, even with such plans in place, illegal or unreported kill may equal or exceed the legal and supposedly sustainable kill34, as it happens in the Asiatic Far East, where both brown bears and Asiatic black bear are poached for the commercial trade in gall bladders and paws. Additionally, in most countries the management goal is to reduce bear populations in order to improve the growth of game populations (moose, wild boar, deer, etc.) and so hunters’ benefits, too, even though the overall percentage of meat consumed by a bear is very low compared to the amount of grass, berries, and other vegetables included in their diet.
Conservation actions29:
There is a great variation of conservation actions for brown bears, among nations and regions within nations35,36. In Russia, Japan, Canada, Alaska, and parts of eastern and northern Europe, for instance, they are managed as a game animal, thus legally hunted for sport, fur or meat. In this case hunting regulations, usually designed to ensure a sustainable harvest of bears, vary among areas but often involve a lottery for a limited number of permits (a quota system) and restricted season length. On the other hand, most small populations are protected by national laws and international agreements. Brown bear as a species is listed under CITES Appendix II, while the populations in Bhutan, China, and Mongolia, and those classified as the subspecies U. a. isabellinus (northern India, Pakistan, Afghanistan, to Kazakhstan and Gobi Desert) are listed under Appendix I. Reintroductions, population augmentations, and connectivity management also have helped to restore numbers and geographic range in several locations in the U.S., southern Canada, and Western Europe.
In Europe most of the bear populations are protected by the Habitat Directive, which is mandatory for all EU countries, though Sweden, Finland, Romania, Estonia, Bulgaria, Slovenia, Slovakia, Bulgaria and Croatia currently use derogations under article 16 of the
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Habitat Directive to allow a limited kill of bears by hunters. Bosnia and Herzegovina and Norway manage bears as a game species with annual quotas as they are only limited by the Bern Convention. One fact about hunting male bears should be considered: sexually selected infanticide (SSI) is promoted by disruption of the male social organization when resident adult males die, thus allowing new males into an area or perhaps allowing other resident males to realign their home ranges. It has a solid and well-documented theoretical basis and should be expected in many species of large carnivores. In species exhibiting SSI, hunting adult males can promote it37-39 and this indirect effect of hunting should be considered when developing sustainable hunting quotas and management plans.
Trophy hunting of bears may enhance local acceptance of these animals by the public in some populations40, but nowadays, with increasing sensibility of people about animal
welfare in some countries, this has been likewise achieved by bear-watching tours and ecotourism, even with ten times higher income compared to trophy hunting. Thus, further studies and applications of different population management methods are required, such as immunocontraception by administration of heterologous zona pellucidae antigens, in addition to previous successful studies on many wildlife species such as American black bears (U. americanus)41.
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2. Background
As an Erasmus intern I was enrolled as an active participant of the university wildlife veterinary team both in Croatia and in Scandinavia.
In Croatia I worked as a member of the Large Carnivore Research team of the Faculty of Veterinary Medicine, University of Zagreb, in any ongoing fieldwork or lab activity (bear and lynx chemical immobilization, trap setting, bear radiotracking, bear necropsy, sample collection and database updating) during my stay. These activities were carried out within two different projects: the international EU LIFE DinAlp Bear Project and the project of Plitvice Lakes National Park (Istraživanje brojnosti, korištenja prostora i ponašanja medvjeda na
području NP Plitvička jezera, “Study of numbers, space use and behaviour of bears in the
area of Plitvice Lakes National Park”). In Scandinavia I worked along with the Veterinary Team of Evenstad Campus, Innland Norway University of Applied Sciences. Bear captures were mostly performed in Hälsingland-Dalarna county (Central Sweden) and only a few in Hedmark county (South-eastern Norway, just beyond the country border), within the Scandinavian Brown Bear Research Project (Skandinaviska Björnprojektet). Therefore, in this chapter I will mainly describe geography and climate of Sweden, since the few bears captured just beyond the Norwegian border belong to the same bear population and habitat, but I will briefly deal with both Norwegian and Swedish wildlife management. At that time, I had the privilege to join other ongoing activities connected with wildlife (e.g. European bison translocation for reintroduction purposes, led by Rewilding Europe association and WWF Romania, capturing and anaesthesia of red deer, wolverines and beavers, moose
tracking and many more). My main duty was the monitoring of physiological
Figure 2.1: EU LIFE DinAlp Bear
Project’s logo.
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parameters and the depth of the anaesthesia (as well as the administration of supplemental drugs when necessary) and sample collection.
2.1. Croatia
Figure 2.3: Physical map of Croatia.
Official name Republic of Croatia
Capital city Zagreb
Surface area land 56,594 km², coastal waters (inland and territorial waters)
31,067 km²
Bear distribution area 11,824 km2
Highest peak Dinara 1,831 m
Language Croatian
Human population 4,284,889
Bear estimated population 1,000
Political system unitary democratic parliamentary republic
Head of state President of the Republic
Membership of international organisations United Nations from 1992
NATO from 2009
European Union
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Physical patterns:
Although the land area of Croatia is not large (56,594 km², 19th in size among the countries of the European Union), it has an extremely varied relief, as it adjoins several large European relief forms. There are three main types of relief in Croatia: lowland Pannonian, mountainous Dinaric and coastal AdriaticII.
The lowlands occupy the largest area and the lowest areas are in the northeast region, which forms part of the Pannonian Plain, where the alluvial plains of the Sava, Drava and Danube alternate with the cinder plains of Baranja and Srijem.
Further west, isolated, wooded peaks rise up from the plains to a maximum of 1,000 m (Psunj, Papuk and Krndija). Along the edge of the Pannonian Plain is the hilly peri-Pannonian area with a large proportion of highland, sometimes exceeding 1,000 m absolute height (Medvednica, Ivančica, Žumberačka Gora). The transition to the mountainous region is formed by the hills and limestone plateaus of Pokuplje and Kordun. The real mountain region includes Gorski Kotar and Lika, with part of the Dinaric highland, basically lying NW-SE, with the highest mountains along the edges (Risnjak, Mala and Velika Kapela, Plješivica, Velebit and Dinara). In Gorski Kotar there is a sharp contrast between the highland area and the deeply hewn river valleys of the Čabranka,
Kupa and Dobra. In inland Lika there are extensive karst fields (Plaščansko, Gacko, Ličko and Krbavsko).
The coastal region extends from the mountains. In the north, it includes the Istrian peninsula, while south of Rijeka the coastal belt is narrow, bordered by high mountains (Velebit) on one side and islands on the other. The southern stretch of coastline
Figure 2.4: The dense mixed forest in the Croatian inland.
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corresponds to the historically established region of Dalmatia. The main feature of this area is the dominant karst relief. It is divided into islands, the coastal belt and the hilly area of Zagora in the hinterland. The coastal zone is proportionally narrow, bordered inland by steep mountain slopes. It is widest and lowest in the flysch zones of Ravni Kotari in the north, in the central Kaštel region, and in the River Neretva delta in the south. In the hinterland is Dalmatinska Zagora, a hilly region with several broad karst fields.
About half the territory of Croatia is karst land, while part of the wider region is composed of the same material, Dinaric karst, named after the Croatian mountain, and continues into Slovenia in the northwest and Bosnia and Herzegovina and Montenegro in the east and southeast. Karst land is characterised by the predominantly underground circulation of water through porous carbonate rock (limestone, dolomite). As the water dissolves calcium carbonate, it creates characteristic surface formations (sink-holes, clefts, valleys, fields) and underground formations (chasms, caves, grottos). About 50 caves deeper than 250 m have been discovered. Lukina Jama in the Hajdučki Kukovi region, in the Northern Velebit National Park, is among the 20 deepest caves in the world (explored to a depth of 1,421 m).
Climate and ambient temperature:
Thanks to its position in the moderate climate belt along the 45th parallel, Croatia enjoys a predominantly moderate climate, with four clearly marked seasons. Local climate differences are determined primarily by the diversity of the relief and proximity to the Adriatic Sea.
In the Pannonian area, the climate is predominantly warm and humid. Mean January temperatures are between 0 °C and -2 °C, while mean July temperatures are around 22 °CIII. Mean annual temperatures and temperature amplitudes rise from west to east. Snow stays on the ground for 25-40 days of the year.
The highlands also have a continental climate, but with a significantly modified relief: temperatures are lower (in winter from -2 °C to -4 °C and in summer under 20 °C). Precipitation levels are higher, while snow stays on the ground for 50-60 days of the year. The coastal area has a Mediterranean climate. The mean January temperature is 6 °C in the north and 8 °C in the south, while in the hinterland it is 4 °C. Summer temperatures are over 22 °C in all parts. Throughout the year, but particularly in winter, weather conditions on the coast are determined by winds, among which the best known are the jugo (south wind) and the bura (north wind).
24 Nature protection:
The first legal norms in Croatia by which natural goods were protected date back to the 13th century, when deforestation in the area of Trogir, Korčula and Dubrovnik was restricted. The movement to protect nature, founded by experts, began in the 19th century. The Nature Protection Act defines 9 categories of spatial protection, and the most valuable protected areas comprise two strict reserves, eight national parks and eleven nature parks.
National parks, such as Plitvice Lakes NP, cover extensive, unique areas with one or more preserved ecosystems. A nature park is a partially cultivated area with important ecological features, in which certain economic activities are permitted. National and nature parks cover a total surface area of 5,151 km², which is 9.1% of the country. Other protected nature categories are special reserves, regional parks, natural monuments, important landscapes, forest parks and monumental park architecture. All nature protection activities are managed by the State Agency for Nature Protection.
Plitvice Lakes National Park (Plitvička Jezera Nacionalni Park)
Plitvice Lakes National Park, the oldest national park, declared in 1949, and inscribed in the UNESCO World Natural Heritage List in 1979. It lies at the south end of the slopes of Mala Kapela chain at the height between 450 and 1,280 m and it is also where the five bears included in the study have been captured by the Large Carnivore Research team in 2016, in order to take blood and hair samples and to place GPS-VHF radio collars on the bears within the Plitvička Jezera NP Project.
The brown bear research project started there in 1981 when the first bears has been radio-collared.
This is an area of alpine topography that exerts a considerable impact on climatic phenomena and consequently, on the vegetation of the area. According to Koeppen's classification, the climate type prevailing here is CfbIV (moderately warm and humid, with hot summers). The average ambient temperatures42,V detected during the spring captures
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(all were carried out at night) in 2016 were from a minimum of 5°C in April up to a maximum of 16°C in late May.
Apart from being defined by latitude, height above sea level, ground inclination and sun exposure, the prevailing vegetation is also defined by geologic bedrocks, soil and the farming methods used. Limestone and dolomitic rocks of various ages (Triassic, Jurassic, Cretaceous) make up the geological bedrock. Considering the relief, climate and land farming in the recent past, vast forest surfaces in their various stages, from thicket to virgin forest (as in Čorkova uvala, Large Carnivore Research Team’s fieldwork station), have remained very well preserved. Forests cover approximately 75% of the Park and used to be managed in the past based on the so-called Rules of Forest Management (the first Rules for Ljeskovac Forest Management date back to 1883), until the present Nature Protection Act, according to which the forests are left to develop naturally.
The site contains 84 ha of virgin forest ofVI: beech (Fagus sylvatica), representing 72.8%
of all tree and it is normally found on 700-900 m above sea level, fir (Abies alba), comprising 22.1% of the forests and is found higher than 900 m above sea level, and juniper (Juniperus sp.) trees up to 700 years old in Čorkova uvala. This is one of the rare remnants of old growth forests of the Dinaric beech-fir (Omphalodo fagetum) forest located at 860-1,028 m above sea level. The site is faunistically rich and the species inhabiting the site, such as the brown bear, the wolf (Canis lupus), the lynx (Lynx lynx), the wild cat (Felis silvestris) and the European otter (Lutra lutra), complement well other World Heritage values.
Dinara-Pindos bear population and its management in Croatia
The current estimate of the number of bears of the Dinara-Pindos population in Croatia is at least 1,000 individuals43.
The total bear distribution area41 in Croatia extends over 11,824 km2. Permanent bear presence habitats (9,253 km2) are areas in which bears satisfy all their food, water, space, cover, breeding and denning needs and where they are present throughout all year. In those areas all prescribed protective measures are implemented in order to ensure the stability of the population and local inhabitants accept bears as a part of their natural environment. Sporadic bear presence habitats (2,570 km2) are areas where the number of bears does not
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These are habitats to which bears are returning and which are usually connected to permanent bear presence areas in Croatia, Slovenia, or Bosnia and Herzegovina.
Bears are distributed over the entire Gorski Kotar and Lika regions, the western and southern part of the Karlovac county, the Učka and Ćićarija mountains in Istria, the central and northern part of the island of Krk, the Žumberak mountains, the coastal part from Bakar to Maslenica and the area surrounded by the Kamešnica, Mosor and Biokovo massifs. The best habitats in Gorski Kotar, Velika Kapela, Mala Kapela and Velebit, have an average density of 10 or more bears per 100 km². High population density drives frequent migration of younger males to neighbouring peripheral areas of the bear range (Učka, Ćićarija, Pokuplje, Priobalje, etc.). 94.2% of the permanent bear presence areas are hunting units, and 5.8% are located in national parks, where they are permanently protected.
Brown bear in Croatia is a game species, but with accession to EU in 2013 it also became a “strictly protected” species and the main management agency for bears in Croatia is the Hunting unit within the Ministry of Agriculture. Since the bear became a protected species, the management is shared with the Directorate for Nature Protection within the Ministry for Protection of Environment and Nature. The operational management follows the Brown bear management plan for the Republic of Croatia. The Brown bear management committee prepares the yearly Action plan and supervises the implementation. The Bear Response Team helps with the actions in the field including the management of bears showing problem behaviour. In the last five years quota for bear hunting has been set to 100 to 120 bears plus up to 30 or 40 individuals expected to be lost due to other reasons including the intervention removal of problem ones. On multi-year average only 83% of hunting quota has been fulfilled and other losses were also lower than anticipated (77%).
Figure 2.7: Hunting grounds consist in shelters
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According to the management plan the total habitat capacity is around 1,100 bears and the social capacity (acceptance) may be around 900. Currently both have been reached and active management has to keep the population within the given limits. Continued tradition of living with bears makes coexistence easier as local inhabitants know how to minimize the livestock depredation and destruction of beehives. The damages that occur are compensated by hunting organizations that are in most cases comprised by local inhabitants as well. Hence the total amounts paid per year are very low, on average about 6,000 €, or only 6 €/bear/year. Comparably low bear damages can only be found in Sweden (3.6 €/bear/years), while on the other extreme is Norway where one single bear causes twice as much damage as 1,000 bears in Croatia (12,666 €/year/bear). Intensive activities are planned within LIFE DinAlp Bear Project to overcome these difficulties. The Brown Bear Management Committee and the Bear Emergency Team are the bodies that care for the implementation of the Brown
Bear Management plan and the implementation of the yearly Bear Action Plans. That work includes decisions on the size and distribution of hunting quotas and on emergency removals of problem bears after other measures have failed.
Monitoring the population:
In order to monitor the bears and thus see their use of area, documentation of their dispersal, in relation of human activities and infrastructures (e.g. green bridges, sub-way passages, doors and ramps built on the sides of the highways in order to let wildlife escape if they eventually get in) park rangers and researchers may dispose of several devices, such as camera-traps, both VHF (Very High Frequency) and GPS (Global Positioning System) transmitters on the collars (Vectronic Aerospace®,
Berlin D-12489, Germany) and receivers. Hence, it is possible to
Figure 2.9: B50 (Nikola), the first brown bear that was captured
and collared in the current study.
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manually localize (radio-track) bears which carries radio transmitters by using VHF receivers, estimating the position of the animal within a few hundred meters of accuracy by triangulating the directions of the signal from different locations. Radio-tracking from cars is tricky since, to receive the transmitter signal from ground, the operator must be within a few kilometres, or sometimes a few hundred meters, from the bear, depending on terrain (hilly and heterogeneous in most of the current study area). Otherwise it can be done from an airplane or a helicopter as well. Anyway, as bears move over extensive areas, it requires a high investment of time and fuel to manually radio-track them. The GPS receiver calculates its position in longitude, latitude and elevation by receiving signals from satellites and can take positions very accurately and frequently, without restrictions to specific periods. These collars also have a GSM-module and an activity sensor. All position and activity data are saved in the GPS, and the GSM module sends the latest positions as an SMS to a receiving station. The researchers can access all the data by linking to a database that is connected to the receiving station and the radio transmitter is only turned on when they need to track the bear manually. The activity sensor measures the bear’s movements in X and Y axis and can give a rough estimation of the bear’s level of activity. Radio-collars should be fitted according to the size, age and sex of the animal, and they should be tight enough to let easily insert two fingers between the collar and the neck by the operator. The weight of the radio-collar should not exceed 2% of the animal's body mass44, so when changing the collar, the neck should be examined for hair loss and possible skin irritation.
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2.2. Sweden
Figure 2.11: Map of Sweden.
Extended name Kingdom of Sweden
Capital city Stockholm
Surface area 449,964 km2 land, waters 39,960 km2
Bear distribution area 149,800 (permanent71) – 316,400 km2
Highest peak Kebnekaise, 2,111 m
Language Swedish
Human population 10,014,873
Bear estimated population 3,300
Political system Unitary parliamentary constitutional
monarchy
Head of state King
Membership of international organisations United Nations from 1946
Nordic Council from 1952
NATO from 1994
Euro-Atlantic Partnership Council
from 1997
30 Physical patterns:
Situated in Northern Europe, Sweden lies west of the Baltic Sea and Gulf of Bothnia, providing a long coastline, and forms the eastern part of the Scandinavian Peninsula. To the west is the Scandinavian mountain chain (Skanderna), a range that separates Sweden from Norway. Finland is located to its north-east. It has maritime borders with Denmark, Germany, Poland, Russia, Lithuania, Latvia and Estonia, and it is also linked to Denmark (south-west) by the Öresund Bridge. Its border with Norway (1,619 km long) is the longest uninterrupted border in Europe and it does not work as an unpassable barrier for large carnivores like bears and wolves, as they continuously migrate across the border in both directions.
The country is traditionally divided into three regions: to the north is Norrland, the vast mountain and forest region; in central Sweden is Svealand, an expanse of lowland in the east and highland in the west; and in the south is Götaland, which includes the Småland highlands and, at the southern extremity, the small but rich plains of Skåne. In the far north the region of Lappland overlaps Norrland and northern Finland45.
Norrland is the largest and most sparsely populated of the regions, covering 3/5 of the country. The region features an undulating surface of rounded hills and mountains, large lakes, and extensive river valleys. To the west lie the Kölen Mountains, through which runs the border demarcating Sweden and Norway. This range is characterized by numerous glaciers, the southernmost of which is on Helags Mountain (Helagsfjället), near the Norwegian border. At the region’s far northern edge, north of the Arctic Circle, are Sweden’s highest peaks: Mount Kebne (Kebnekaise) and Mount Sarek (Sarektjåkkå), both over 2.000 m high, in Sarek National Park.
The interior of southern Sweden, Småland, is a wooded upland with elevations of 300-400 m. A region of poor and stony soils, Småland has been cultivated through the ages with some difficulty, as evidenced by the enormous mounds of stone cleared from the land. More recently the area has been characterized by flourishing small factories.
Except for a stretch of scenic “high coast,” the Bothnian coastal plain is low-lying and stretches from Norrland into Svealand. Most of the fairly level surface of eastern Svealand and northern Götaland was pressed below sea level by glaciers, leaving a landscape of fragmented bedrock, fertile clayey plains, numerous lakes, and sandy ridges. Today these are intermingled with mixed forests and farmland. Sweden’s landscape changes from the hills of Småland to the fertile plains of Skåne, which is physically and economically more
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similar to Denmark than to the rest of Sweden. This is Sweden’s oldest settled and most densely populated agricultural area.
Climate and ambient temperatures:
About 15% of the country lies within the Arctic Circle. From about late May until mid-July, sunlight lasts around the clock north of the Arctic Circle, but, even as far south as Stockholm, the nights during this period have only a few hours of semidarkness. In mid-December, on the other hand, Stockholm experiences only about 5.5 hours of daylight; in areas as far north as Lappland, there are nearly 20 hours of total darkness relieved by a mere 4 hours of twilight.
Considering its northerly geographic location Sweden enjoys a favourable climate. From the southwest, Atlantic low-pressure winds blow in air warmed by the North Atlantic Current and make the weather mild but changeable. Another type of influence comes from continental high pressures to the east. These create sunny weather, which is hot in summer and cold in winter. The interaction between the Atlantic and continental influences causes periodic shifts in climate.
The north-to-south extension of the country and the higher elevation of the northern part results in great regional differences in winter climate. The northern interior receives heavy snowfall for up to eight months of the year and has severe temperatures that drop as low as -30 to -40 °C. Sea ice covers the Gulf of Bothnia from November to May, whereas in Southern Sweden average January temperatures range between -5 and 0 °C and coastal waters seldom freeze.
Summer temperatures vary far less, although summer is much shorter in the north. In terms of average daily temperature, “spring” arrives in Skåne during February but not until late May in northernmost Norrland; then it may come virtually overnight. The mean July temperature in the northernmost point on the Gulf of Bothnia is 15 °C,
and 17 °C in the south. Figure 2.12: The sparse vegetation and the lack of undergrowth make visible large wild animals from e.g. a helicopter.
32 Nature protection:
Most of Sweden is dominated by forests of Norway spruce (Picea abies), Scots pine (Pinus
sylvestris), and birch (Betula spp.). Southern Sweden has more mixed forests, and in the far
south deciduous trees such as beech, oak (Quercus spp.), linden (Tilia spp.), ash (Fraxinus
spp.), elm (Ulmus spp.), and maple (Acer spp.) are common. The forests are rich in berries,
lingonberries and blueberries among them, and mushrooms.
In the high mountains coniferous trees give way to mountain birches, which extend up to the tree line at an elevation of 480-880 m. The treeless mountains with their heaths, marshes, and boulder fields have Alpine flora. Dwarf birch and willows (Salix spp.) are typical. Bears and lynx still inhabit the northern forests, while wolves are making a comeback, having become almost completely extinct in the 20th century. Throughout the country are large numbers of mammals such as moose (Alces alces), roe deer (Capreolus capreolus), foxes (Vulpes
vulpes), and hares (Lepus spp.). Hunting and fishing are closely regulated, and many
species of animals are fully protected. Large herds of domesticated reindeer owned by Sami (Lapps) graze the northern mountains and forests.
Sweden has been in the vanguard of countries seeking to preserve the natural environment. It was the first European country to establish a national park (Sarek National Park was established in 1909), thereby preserving part of Europe’s last wilderness. The first Nature Conservancy Act
was adopted in 1909, and in Figure 2.14: Spruce, pine, and birch trees dominate most of the forests in
Scandinavia.
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1969 a modern environmental protection act was passed. Since then tens of thousands of square miles have been set aside as national parks and nature reserves. Serious environmental problems persist nevertheless. About 1/5 of the lakes in Sweden have been damaged by acidification, and groundwater is threatened, too. Pollution in the Baltic Sea and the coastal waters of the Kattegat and Skagerrak also is considered severe.
The Scandinavian Brown Bear Research Project:
The Project started in 1984 and from 1987 it has been a Swedish-Norwegian collaboration. The project has two study areas: one is near Jokkmok in Northern Sweden and the second one is in Hälsingland-Dalarna in Central Sweden and Southeastern Hedmark in Norway.
The primary goals and ambitions of the Scandinavian Brown Bear Research Project (SBBRP) are:
• to document the basic ecology of the Scandinavian brown bear
• to provide the management authorities with data and our interpretations of the results to help them reach their goals regarding bear management
• to provide information about brown bears to the general public.
The primary method is to follow individual female bears and their female offspring from birth to death, thus creating genealogical trees, many of which now cover five generations. Since the project started the research has expanded and also new techniques has been introduced and improved, such as genetics and GPS telemetry, which have become the fundamentals of the project’s research activity.
In order to add bears to the study sample, they are identified from the helicopter, chemically immobilized by a team of professional experts (veterinarians, biologists, ecologists, field technicians) and radio-marked (with a VHF/GPS collar) either because they are cubs of a previously radio-marked female bears or because they are a partner of a previously radio-marked bear during the breeding season.
Along with VHF/GPS-collars the project is provided with another useful device to monitor the bears, usually known as “implant” (intraperitoneal Very High Frequency implants, either from Telonics®, Mesa AZ 85204-6699, USA or from Advanced Telemetry
Systems®, Isanti MN 55040-7123, USA) that is surgically implanted into the abdomen of
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order to replace a bigger collar since their neck circumference will grow up along with them. Also, adult radio-marked bears have it too, along with GPS-collars as a back-up to find them again, should their GPS-receiver fail. As the GPS-receivers continue to be improved, the project leaders hope that soon it will not be necessary to use an implant as a back-up, however they are anyway routinely removed after 3-5 years.
Adult radio-marked bears are captured when their transmitter or receiver needs to be replaced, whereas females with cubs of the year are not captured. Generally, GPS-collars are replaced every 1-3 years, depending on the number of locations sent. To ensure that the collar will eventually fall off the bear, in case of lost contact, the collar belts are fitted with a break-away zone, a strap of cotton fabric, that rots and weakens over time.
During the spring, all the members of a family (radio-marked female with yearlings) are routinely captured: the female yearlings are equipped with an implant, male yearlings are only ID marked with an eartag, ID tattoo, and microchip, so that they can be eventually identified later if they are shot during the bear hunt or in case of capture as adult bears.
Nowadays, SBBRP’s basic research is focused on understanding the followingVII:
• the social organization of female and male bears, including chemical communication • the mating system, including the role of MHC (major histocompatibility complex) in
mate choice and the role of sexually selected infanticide • life history strategies (growth and reproduction)
• population ecology, including the individuals’ contribution to population growth • genetics, including spatial genetic relationships and heritability of traits
• general physiology, including cooperation with researchers working on human physiology questions.
Scandinavian bear population and its management
The Swedish brown bears constitute the majority of the Scandinavian bear population and they are distributed throughout the northern 2/3 of Sweden, additionally divided in three,
Figure 2.15: A VHF intraperitoneal transmitter (implant) is
