Trace element pollution can adversely affect the brains of individuals and thus impact the entire population of apex predators, such as large European carnivores. We assessed exposure to prominent ...neurotoxicants As, Cd, Hg and Pb by measuring their brain stem levels in brown bears (
= 114), grey wolves (
= 8), Eurasian lynx (
= 3), and golden jackals (
= 2) sampled in 2015-2022 in Croatia. The highest of the non-essential elements was the Pb level in the bears' brains (median, Q1-Q3; 11.1, 7.13-24.1 μg/kg wet mass), with 4% of animals, all subadults, exceeding the established normal bovine levels (100 μg/kg wet mass). Species-specific differences were noted for Ca, Cd, Cu, Fe, Pb and Se brain levels. Female brown bears had higher As brain levels than males. Cubs and yearlings had lower brain Cd, but higher Zn, while subadults had higher Cu than adult bears. Hepatic As, Cd, Cu and Hg levels were shown to be a moderate proxy for estimating brain levels in bears (r
= 0.30-0.69). Multiple associations of As, Cd, Hg and Pb with essential elements pointed to a possible interaction and disturbance of brain Ca, Cu, Fe, Se and Zn homeostasis. Non-essential element levels in the brains of four studied species were lower than reported earlier for terrestrial meso-carnivores and humans. The age and sex of animals were highlighted as essential factors in interpreting brain element levels in ecotoxicological studies of large carnivores.
We investigated the level of five non-essential metal(loid)s (As, Cd, Hg, Tl, Pb) and nine essential metals (Mg, Ca, Mn, Fe, Co, Cu, Zn, Se, Mo) in hair and blood components of captive and ...free-ranging European brown bear populations in Croatia and Poland. Metal(loid) associations with biomarkers of oxidative stress (superoxide dismutase, SOD; glutathione-peroxidase, GSH-Px; malondialdehyde, MDA) and metal exposure (metallothionein, MT) were estimated in this top predatory mammal. Lead was the most abundant non-essential metal(loid) in both blood and hair, with 4 of 35 individuals having blood levels over 100 μg/L. A positive association was found between Pb level and SOD activity in blood. Free-ranging bears had higher blood SOD activity, Mn, Zn and Cd levels, hair Co, Cd, Tl and Pb compared to captive individuals, while the opposite was true for Mg and hair Ca thereby reflecting habitat and diet differences. With increasing age, animals showed lower levels of SOD activity and certain essential metals. Females had higher SOD activity and blood levels of some essential metals than males. Hair showed a higher Fe and Co level when sampled during the growth phase and was not predictive of non-essential metal(loid) blood levels. The established metal(loid) baseline values will enable future risk assessment in both captive and wild European brown bear populations.
•Free-ranging bears had higher essential and non-essential metals than captive ones.•Eleven percent of bears had Pb blood levels above 100 μg/L.•Blood Pb was associated with activity of superoxide-dismutase and essential metals.•All individual and ecological factors partly influenced metal(loid)s in hair and blood.•Hair collected throughout the year did not reflect non-essential metal(loid) levels in blood.
We provide the first known documentation of a fatal brown bear (Ursus arctos) poisoning with carbofuran (an acetylcholinesterase inhibitor) in Croatia. Diagnosis using liquid chromatography–mass ...spectrometry confirmed the presence of high concentrations of carbofuran in liver and kidney tissue (12.650 and 2.695 ppm, respectively). These measurements, combined with the very small distance between poisonous baits and the brown bear carcass, provided the basis on which we concluded that the animal consumed a lethal dose of carbofuran and succumbed to acute poisoning soon thereafter. We believe this mortality was caused by the illegal placement of this poison probably to eliminate perceived pests, such as jackals (Canis aureus) or foxes (Vulpes vulpes). Our documentation may help identify similar cases and raise awareness of the risks posed by illegal poisons for non-target species, particularly scavengers such as bears.
Wolf-dog hybridization in Croatia Kusak, Josip; Fabbri, Elena; Galov, Ana ...
Veterinarski arhiv,
01/2018, Letnik:
88, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Wolf-dog hybridization is considered as one of the main threats for wolf conservation since the admixture and introgression of domestic genes may disrupt local adaptations and threaten the long term ...survival of wild wolf populations. We investigated the occurrence of wolf-dog hybridization in Croatia by analyzing a panel of 12 autosomal microsatellite markers using Bayesian admixture tests, and assessed its directionality by the use of maternally and paternally inherited markers in combination with morphometric data and morphological features. A systematic analysis of morphologic features and morphometric data was used to rank the studied individuals into either phenotypic wild-type wolves or suspected hybrids. By combining Bayesian assignment results with phenotypic features, we set three thresholds which differentiated wolves from hybrids with maximized hybrid detection and a minimized chance for false positive hybrid identification. On the basis of phenotype, out of 176 wild canids, 157 (89.2%) were categorized as wolves and 19 (10.8%) as suspected hybrids. On the basis of the Bayesian admixture tests and phenotype together, five (2.8 percent) animals were classified as wolf-dog hybrids, four of them as backcrosses with wolves, and one as a backcross with a dog. Mitochondrial DNA suggested that all hybrids originated from the mating of female wolves and male dogs. Two male hybrids had Y chromosome haplotypes common to both wolves and dogs, while the other two had wolf private Y chromosome haplotypes. One wolf had a dog Y-haplotype, indicating a past introgression of dog genes. All hybrids were found in Dalmatia, where wolves settled recently, and where they live close to humans, with a high rate of human-caused mortality. These conditions are considered as favorable for wolf-dog hybridization. However, we found a low hybridization prevalence in Croatia, which is nonetheless expected to persist as long as the conditions favoring its occurrence are met. The ecological, sociological, conservation and management implications of hybrid occurrence are yet to be determined. Key words: wolf; dog; Canis lupus; hybridization; Croatia; Bayesian admixture analysis; microsatellites; parental markers
Monitoring arterial blood pressure (BP), represents a more accurate evaluation of hemodynamics than heart rate alone and is essential for preventing and treating intra- and post-operative ...complications in wildlife chemical immobilization.
The objectives of the study were to test the correlation between standard oscillometry and Korotkoff's technique in anesthetized free-ranging brown bears in Croatia and Scandinavia and to assess the blood pressure in both locations.
Five bears were snared and darted with xylazine and ketamine in Croatia, and 20 bears were darted from a helicopter with medetomidine and tiletamine-zolazepam in Scandinavia. Blood pressure was simultaneously measured with both techniques every 5 minutes. Correlation between techniques, trends of BP variation, and the factors of the capture which likely influenced BP were assessed.
Successful measurements of BP were achieved in 93% of all attempts with the Korotkoff's technique but in only 29% of all attempts with oscillometry. The latter method mostly provided lower values of BP compared to Korotkoff's technique in yearlings. Most bears showed a decreasing trend in systolic and mean BP over time, consistent between the two techniques. All bears were hypertensive: the auscultatory technique detected moderate to severe systolic hypertension in 25% and 84% of bears in Croatia and in Scandinavia, respectively, with significantly higher BP in subadults and adults compared to yearlings. Only Korotkoff's method resulted in a reliable and effective tool for BP assessment in brown bears. The anesthetic protocols used in the present study in association with the capture methods produced hypertension in all animals.
In many contemporary societies, multiple functions are connected to hunting. Here, we use the concept of multifunctionality to investigate the role of hunting beyond its traditional function of ...supplying meat. Hunting may contribute, for example, to biodiversity conservation, recreation and the preservation of economies and cultures in rural areas. Our comparative analysis of hunting in eight study sites in Europe and Africa examines the tensions and trade-offs between these ecological, economic and social functions of hunting, and investigates the interplay between the institutions regulating these functions to better understand conflicts over hunting. Based on this analysis, we present institutional arrangements that have developed to address these challenges of multifunctionality, and explore the institutional change brought about by such arrangements. Finally, we discuss the implications of this study for policy and institutional design.
Free-ranging brown bears (Ursus arctos) were snared and subsequently darted with a combination of xylazine-ketamine in Croatia (n = 5) or darted from a helicopter with a combination of ...medetomidine-tiletamine-zolazepam in Scandinavia (n = 20). Three adults and one yearling (1 year old) bear were captured in Croatia, with one adult being captured twice. The Scandinavian bears were divided into Group A (yearlings, n = 7) and Group B (subadults, n = 2 and adults, n = 11). The exertion time (time from activation of the trap or from the start of the helicopter chase to recumbency) and the induction time (time from darting to recumbency) were recorded. The rectal temperature (Tr) was measured as soon as possible after induction and then monitored at frequent intervals (varied between individuals) in immobilized bears. Blood pressure (BP) was measured with a non-invasive method (Korotkoff's technique) every 5 minutes. The heart rate (HR), respiratory rate (RR), and arterial haemoglobin oxygen saturation (SpO2) were recorded every 5 minutes. Reliability of the BP monitoring technique, trends of variation of the physiological variables, and the factors related to the capture were assessed. Both exertion and induction times were longer in Croatian bears than in Scandinavian bears. In Croatian bears, the Tr was either constant or slightly decreasing, with hyperthermia recorded in two individuals (Tr > 39.0° C). In Scandinavian bears, 17 of 20 individuals developed an initial hyperthermia. Four of five bears in Croatia and 17 of 20 bears in Scandinavia showed a decreasing trend in systolic and mean BP over time. According to the Korotkoff method, all bears were hypertensive (mean BP > 130 mmHg) with varying severity, and the systolic pressure was significantly lower in yearlings when compared to subadults and adults. Yearlings had significantly (p < 0.05) higher HR than subadults and adults, however there was no significant differences in RR, SpO2, and Tr between the age groups. All Croatian bears and 13 of 20 Scandinavian bears were moderately to severely hypoxemic (SpO2 < 90%). Further studies with simultaneous invasive and non-invasive (Korotkoff) BP monitoring techniques are required to confirm the accuracy of methods used in this study. The data presented here provides evidence of the physiological impact of different capture methods and chemical immobilization of brown bears in Croatia and Scandinavia.
The composition of adipose tissue in brown bears (Ursus arctos) is highly variable and depends on an individual’s feeding habits. Fatty acid composition of subcutaneous adipose tissue (SAT) may ...provide insight into brown bear feeding habits, for which data are scarce. The aim of this study was to determine the lipid composition of SAT and variations in the composition of fatty substances with regard to gender and to assess SAT relative to season and body mass (BM) of brown bears in Croatia. Seventy-six tissue samples of brown bear SAT were analyzed in this study. We found that gender, season, and BM significantly affected the lipid composition of SAT. Both females and males had higher percentages of saturated fatty acids and monounsaturated fatty acids (MUFAs) in SAT in spring than in autumn, while the percentage of polyunsaturated fatty acids (PUFAs) was higher in autumn. The prevalence of MUFAs in SAT and the greater presence of PUFAs in autumn, together with the presence of odd-chain saturated fatty acids, indicate the importance of these fatty acids in brown bear physiology. We suggest that the lipid content of adipose tissue may provide valuable information on changes in brown bear condition in response to feeding habits and the effects of supplemental feeding.
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