Knowledge of genetic diversity and population structure is critical for conservation and management planning at the population level within a species' range. Many brown bear populations in Central ...Asia are small and geographically isolated, yet their phylogeographic relationships, genetic diversity, and contemporary connectivity are poorly understood. To address this knowledge gap, we collected brown bear samples from the Gobi Desert (n = 2360), Altai, Sayan, Khentii, and Ikh Khyangan mountains of Mongolia (n = 79), and Deosai National Park in the Himalayan Mountain Range of Pakistan (n = 5) and generated 927 base pairs of mitochondrial DNA (mtDNA) sequence data and genotypes at 13 nuclear DNA microsatellite loci. We documented high levels of mtDNA and nDNA diversity in the brown bear populations of northern Mongolia (Altai, Sayan, Buteeliin nuruu and Khentii), but substantially lower diversity in brown bear populations in the Gobi Desert and Himalayas of Pakistan. We detected 3 brown bear mtDNA phylogeographic groups among bears of the region, with clade 3a1 in Sayan, Khentii, and Buteeliin nuruu mountains, clade 3b in Altai, Sayan, Buteeliin nuruu, Khentii, and Ikh Khyangan, and clade 6 in Gobi and Pakistan. Our results also clarified the phylogenetic relationships and divergence times with other brown bear mtDNA clades around the world. The nDNA genetic structure analyses revealed distinctiveness of Gobi bears and different population subdivisions compared to mtDNA results. For example, genetic distance for nDNA microsatellite loci between the bears in Gobi and Altai (FST = 0.147) was less than that of the Gobi and Pakistan (FST = 0.308) suggesting more recent male-mediated nuclear gene flow between Gobi and Altai than between Gobi and the Pakistan bears. Our results provide valuable information for conservation and management of bears in this understudied region of Central Asia and highlight the need for special protection and additional research on Gobi brown bears.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We report the first survey of ecto- and endoparasites of brown bears (Ursus arctos gobiensis) in the Gobi Desert, Mongolia. We collected 40 ticks from 1 female (21 yr old, 48 kg) and 2 males (10 yr, ...155 kg; 5 yr, 108 kg) captured for research purposes in May 2018. We found Dermacentor nutalli (n = 35 ticks, 87.5%) on both male bears and Hyalomma asiaticum (n = 5 ticks, 12.5%) on one male. The female had no ticks. We also collected a fecal sample from each captured bear, and an additional 15 fecal samples in the field. Two (11%) of the 18 fecal samples collected contained eggs of Strongyloides spp.; 1 fecal (10-yr-old male) sample had 2 eggs, and 1 fecal sample collected in the field contained 1 egg. This is the first documentation of parasites of wild bears in Mongolia.
Information about population demography is crucial for developing and implementing conservation measures. The brown bear in the Gobi desert of southwestern Mongolia (referred to as the Gobi bear) is ...one of the smallest and most isolated brown bear populations in the world. We conducted genetic sampling (n = 2660 samples collected) using hair corrals around feeding sites at 13 water sources during 2009, 2013, and 2017 to evaluate population size, survival, and population trend. Bears were identified using 13 microsatellite loci and one sex marker. We detected 51 unique individuals (15F and 36M) from our targeted surveys in 2009, 2013, and 2017. Based on capture–mark–recapture robust design, population estimates were 23 (95% CI: 21–32) in 2009, 28 (95% CI: 25–35) in 2013, and 31 (95% CI: 29‐38) individuals in 2017. Spatial capture–recapture analysis suggested abundance was very low (N^ = 27; 95% CI: 22–35), and there was no significant change from 2009 to 2017. The population density was 0.93 bears/1000 km2 (95% CI: 0.74–1.17). Our population estimates suggested a stable population trend. However, the population is still very small, and the sex ratio is skewed toward males, raising concerns for future persistence. Annual survival based on Robust design CMR was 0.85. Low abundance and apparent survival for both sexes in this unhunted population coupled with a skewed sex ratio highlight the need for on‐the‐ground conservation action to conserve this isolated population of bears.
Full text
Available for:
FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
We successfully immobilized 185 grizzly bears (Ursus arctos horribilis) with tiletamine hydrochloride (HCl) and zolazepam HCl during May-June 1986-87. One hundred eighty bears were captured in ...several areas in Alaska by darting from a helicopter; 5 were immobilized from traps or snares in Banff National Park in Alberta, Canada. Use of the recommended dose for immobilizing grizzly bears (7-9 mg/kg) resulted in a mean induction time of 4.1 ± 1.8 (SD) minutes and a safe handling period of 45-75 minutes. Tiletamine HCl/zolazepam HCl was an excellent drug for immobilizing grizzly bears because of rapid induction, timely and predictable recovery, wide safety margin, and few adverse side effects.
Full text
Available for:
BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Abstract
The Gobi Desert in Mongolia, home to the critically endangered Gobi bear (Ursus arctos isabellinus), has few water resources for the animals that inhabit this environment. The majority of ...these water resources are shallow, small bodies of water, from approximately 30 cm to 3 m in diameter. Due to the harsh nature of the Gobi Desert environment, such pools of water are crucial resources for wildlife inhabiting the area and little information is currently available on the presence of organisms, including cyanobacteria, and the toxins they produce within these waters. Drinking water sources and small pools within the Gobi Desert were sampled on two separate occasions in October 2008 and April-May 2009. Samples were assessed for the presence of cyanobacteria; subsamples were taken for the analysis of β-N-methylamino-L-alanine (BMAA) and 2,4-diaminobutyric acid (DAB). According to LC-MS/MS analyses, both of these neurotoxic amino acids were present in both years and BMAA was present when cyanobacteria were major components of the pools. The results indicate that assessment of cyanotoxins to organisms that live in desert environments is warranted.
Full text
Available for:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
A population of muskoxen (Ovibos moschatus), successfully restored to northeastern Alaska in the 1970's, has become a source of food for grizzly bears (Ursus arctos). We tested whether grizzly bear ...predation on this population of muskoxen increased over time and described multiple kills of muskoxen by grizzly bears. We identified bear-muskox events from data collected between April 1982 and June 2001 during bear and muskox surveys and radiorelocation flights and from field notes, mortality records of radiocollared muskoxen, and other observations made by biologists, pilots, and local residents. Ninety-two bear-muskox events observed in 1982-2001 included 46 known kills, 37 possible kills or scavenging events, and 9 chases. Ten of 61 radiocollared muskoxen that died between 1982 and 2001 were killed by bears and 14 others were possibly killed or scavenged. The number of known kills and possible kills or scavenging increased significantly over time. Multiple kills, where 2 or more muskoxen were killed from a group, contributed to the number of known kills. Twenty-eight of 46 muskoxen (61%) killed by bears died during multiple kills. Twenty-two of these deaths occurred in 1998-2001. Ten marked grizzly bears were implicated in single or multiple kills, suggesting that several bears in northeastern Alaska became proficient predators of muskoxen in spite of the group-defensive behavior and formidable horns of muskoxen. The low numbers of muskox calves observed in 2000 and 2001 (<5 calves/100 females >2 years of age) may be due in part to predation of neonatal calves by grizzly bears. The successful return of muskoxen to northeastern Alaska has created a predictable source of large mammal protein for some grizzly bears.
Changes in age-specific reproductive rates can have important implications for managing populations, but the number of female brown (grizzly) bears (Ursus arctos) observed in any one study is usually ...inadequate to quantify such patterns, especially for older females and in hunted areas. We examined patterns of reproductive maturation and senescence in female brown bears by combining data from 20 study areas from Sweden, Alaska, Canada, and the continental United States. We assessed reproductive performance based on 4,726 radiocollared years for free-ranging female brown bears (age ≥3); 482 of these were for bears ≥20 years of age. We modeled age-specific probability of litter production using extreme value distributions to describe probabilities for young- and old-age classes, and a power distribution function to describe probabilities for prime-aged animals. We then fit 4 models to pooled observations from our 20 study areas. We used Akaike's Information Criterion (AIC) to select the best model. Inflection points suggest that major shifts in litter production occur at 4-5 and 28-29 years of age. The estimated model asymptote (0.332, 95% CI = 0.319-0.344) was consistent with the expected reproductive cycle of a cub litter every 3 years (0.333). We discuss assumptions and biases in data collection relative to the shape of the model curve. Our results conform to senescence theory and suggest that female age structure in contemporary brown bear populations is considerably younger than would be expected in the absence of modern man. This implies that selective pressures today differ from those that influenced brown bear evolution.
Full text
Available for:
BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
A thermal desorption unit has been interfaced to an electrospray ionization-ion mobility-time-of-flight mass spectrometer. The interface was evaluated using a mixture of six model volatile organic ...compounds which showed detection limits of <1 ng sample loaded onto a thermal desorption tube packed with Tenax, equivalent to sampled concentrations of 4 μg L−1. Thermal desorption profiles were observed for all of the compounds, and ion mobility-mass spectrometry separations were used to resolve the probe compound responses from each other. The combination of temperature programmed thermal desorption and ion mobility improved the response of selected species against background ions. Analysis of breath samples resulted in the identification of breath metabolites, based on ion mobility and accurate mass measurement using siloxane peaks identified during the analysis as internal lockmasses.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
To investigate risk factors associated with Barrett's oesophagus and oesophageal adenocarcinoma.
This all-Ireland population-based case-control study recruited 224 Barrett's oesophagus patients, 227 ...oesophageal adenocarcinoma patients and 260 controls. All participants underwent a structured interview with information obtained about potential lifestyle and environmental risk factors.
Gastro-oesophageal reflux was associated with Barrett's OR 12.0 (95% CI 7.64-18.7) and oesophageal adenocarcinoma OR 3.48 (95% CI 2.25-5.41). Oesophageal adenocarcinoma patients were more likely than controls to be ex- or current smokers OR 1.72 (95% CI 1.06-2.81) and OR 4.84 (95% CI 2.72-8.61) respectively and to have a high body mass index OR 2.69 (95% CI 1.62-4.46). No significant associations were observed between these risk factors and Barrett's oesophagus. Fruit but not vegetables were negatively associated with oesophageal adenocarcinoma OR 0.50 (95% CI 0.30-0.86).
A high body mass index, a diet low in fruit and cigarette smoking may be involved in the progression from Barrett's oesophagus to oesophageal adenocarcinoma.
Accurate density and population estimates are needed to manage bear populations but are difficult to obtain. Most such estimates reported for bears are largely subjective and lack estimates of ...precision. Fifteen brown bear (Ursus arctos) and 3 black bear (U. americanus) density estimates were obtained in Alaska during 1985 through 1992 using 2-9 replicates of capture-mark-resight (CMR) techniques in 17 different areas. Our studies used radiotelemetry to document movements of marked animals into and from search areas. This procedure essentially eliminated the need to correct density estimates for edge or periphery effects caused by absence of geographic closure. To estimate population size, we used a maximum-likelihood estimator modified to accommodate temporary movements of marked animals into and from our search areas. Our approach permitted direct calculations of density from our population estimates. Our procedures provided density estimates that were repeatable, were comparable among areas, included estimates of precision, and were more objective than methods historically used to estimate bear abundance. Our density estimation procedures have widespread applicability for other wildlife studies using radiotelemetry. Our estimates were obtained within a wide spectrum of habitats and provided a range of Alaskan densities from 10.1 to 551 brown bears (all ages)/1,000 km2 and from 89 to 289 black bears (all ages)/1,000 km2 Our highest brown bear density is probably near the maximum for this species, but areas with lower densities (3.9/1,000 km2) have been reported in Alaska. Areas with black bear densities higher than in our study areas probably occur in Alaska. Brown bear densities were 6-80 times greater in coastal areas where abundant runs of multiple species of salmon (Oncorhynchus spp.) were available to bears than in interior areas. Our CMR technique provided useful data for bear population management and impact assessments and has potential for application to other species and areas.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
PDF
