Infanticide in brown bear: a case-study in the Italian Alps – Genetic identification of perpetrator and implications in small populations

Sexually Selected Infanticide (SSI) is thought of as a male reproductive strategy in social mammalian species, because females who lose cubs may quickly re-enter oestrus. SSI has rarely been documented in non-social mammals and, in brown bears, SSI has been studied mainly in an eco-ethological perspective. The authors examined the first genetically documented infanticide case which occurred in May 2015 in brown bears in Italy (Trentino, Central-Eastern Alps). The infanticide killed two cubs and their mother. Hair samples were collected from the corpses as well as saliva, through swabs on mother’s wounds, with the aim of identifying the genotype of the perpetrator. The samples were genotyped by PCR amplification of 15 autosomal microsatellite loci, following the protocol routinely used for individual bear identifications within the Interregional Action Plan for Brown Bear Conservation in the Central-Eastern Alps (PACOBACE). Reliable genotypes were obtained from the mother, cubs and putative perpetrator. The genotypes were matched with those populating the PACOBACE database and genealogies were reconstructed. Both mother and perpetrator genotypes were already present in the database. Kinship analyses confirmed mother-cubs relationships and identified the father of the cubs. In this study, for the first time, the authors used the open-source LRmix STUDIO software, designed to analyse human forensic genetic profiles, to solve a case in wildlife. Through LRmix STUDIO, those alleles that do not belong to the victims were isolated and, finally, the perpetrator was identified. This study presents a method that allows, through the application of different models, the genetic identification of the conspecific perpetrator with the highest probability. The identification of the infanticidal male is relevant for the better management and conservation of wild populations with small effective population size (Ne) and low population growth rate, especially in the case of recently established populations in human-dominated landscapes. This procedure will have predictably wide applications, supplying important data in the monitoring of small and isolated populations.

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Vital rates of two small populations of brown bears in Canada and range-wide relationship between population size and trend

10.26686/wgtn.14607597.v1 ◽

2021 ◽

Author(s):

ML McLellan ◽

BN McLellan ◽

R Sollmann ◽

Heiko Wittmer

Keyword(s):

Population Change ◽

Brown Bear ◽

High Rate ◽

Population Increase ◽

First Year ◽

Small Populations ◽

Vital Rates ◽

Isolated Populations ◽

Brown Bears ◽

Female Survival

Identifying mechanisms of population change is fundamental for conserving small and declining populations and determining effective management strategies. Few studies, however, have measured the demographic components of population change for small populations of mammals (<50 individuals). We estimated vital rates and trends in two adjacent but genetically distinct, threatened brown bear (Ursus arctos) populations in British Columbia, Canada, following the cessation of hunting. One population had approximately 45 resident bears but had some genetic and geographic connectivity to neighboring populations, while the other population had <25 individuals and was isolated. We estimated population-specific vital rates by monitoring survival and reproduction of telemetered female bears and their dependent offspring from 2005 to 2018. In the larger, connected population, independent female survival was 1.00 (95% CI: 0.96–1.00) and the survival of cubs in their first year was 0.85 (95% CI: 0.62–0.95). In the smaller, isolated population, independent female survival was 0.81 (95% CI: 0.64–0.93) and first-year cub survival was 0.33 (95% CI: 0.11–0.67). Reproductive rates did not differ between populations. The large differences in age-specific survival estimates resulted in a projected population increase in the larger population (λ = 1.09; 95% CI: 1.04–1.13) and population decrease in the smaller population (λ = 0.84; 95% CI: 0.72–0.95). Low female survival in the smaller population was the result of both continued human-caused mortality and an unusually high rate of natural mortality. Low cub survival may have been due to inbreeding and the loss of genetic diversity common in small populations, or to limited resources. In a systematic literature review, we compared our population trend estimates with those reported for other small populations (<300 individuals) of brown bears. Results suggest that once brown bear populations become small and isolated, populations rarely increase and, even with intensive management, recovery remains challenging.

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Vital rates of two small populations of brown bears in Canada and range-wide relationship between population size and trend

10.26686/wgtn.14607597 ◽

2021 ◽

Author(s):

ML McLellan ◽

BN McLellan ◽

R Sollmann ◽

Heiko Wittmer

Keyword(s):

Population Change ◽

Brown Bear ◽

High Rate ◽

Population Increase ◽

First Year ◽

Small Populations ◽

Vital Rates ◽

Isolated Populations ◽

Brown Bears ◽

Female Survival

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Insights into bear evolution from a Pleistocene polar bear genome

10.1101/2021.12.11.472228 ◽

2021 ◽

Author(s):

Tianying Lan ◽

Kalle Leppala ◽

Crystal Tomlin ◽

Sandra L Talbot ◽

George K Sage ◽

...

Keyword(s):

Climate Change ◽

Polar Bear ◽

Ursus Arctos ◽

Genetic Erosion ◽

Brown Bear ◽

Population History ◽

Polar Bears ◽

Effective Population ◽

Brown Bears ◽

Svalbard Archipelago

The polar bear (Ursus maritimus) has become a symbol of the threat to biodiversity from climate change. Understanding polar bear evolutionary history may provide insights into apex carnivore responses and prospects during periods of extreme environmental perturbations. In recent years, genomic studies have examined bear speciation and population history, including evidence for ancient admixture between polar bears and brown bears (Ursus arctos). Here, we extend our earlier studies of a 130,000-115,000-year-old polar bear from the Svalbard Archipelago using 10X coverage genome sequence and ten new genomes of polar and brown bears from contemporary zones of overlap in northern Alaska. We demonstrate a dramatic decline in effective population size for this ancient polar bear's lineage, followed by a modest increase just before its demise. A slightly higher genetic diversity in the ancient polar bear suggests a severe genetic erosion over a prolonged bottleneck in modern polar bears. Statistical fitting of data to alternative admixture graph scenarios favors at least one ancient introgression event from brown bears into the ancestor of polar bears, possibly dating back over 150,000 years. Gene flow was likely bidirectional, but allelic transfer from brown into polar bear is the strongest detected signal, which contrasts with other published works. These findings have implications for our understanding of climate change impacts: polar bears, a specialist Arctic lineage, may not only have undergone severe genetic bottlenecks, but also been the recipient of generalist, boreal genetic variants from brown bear during critical phases of Northern Hemisphere glacial oscillations.

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La protezione dagli incendi boschivi nelle Alpi centro-occidentali | Forest Fire-Prevention in the Central Eastern Alps

Schweizerische Zeitschrift fur Forstwesen ◽

10.3188/szf.2000.0325 ◽

2000 ◽

Vol 151 (9) ◽

pp. 325-335 ◽

Cited By ~ 4

Author(s):

Giovanni Bovio

Keyword(s):

Forest Fire ◽

Eastern Alps ◽

Fire Prevention ◽

Forest Fire Prevention ◽

Central Eastern

Important forest fire prevention developments of the Lombardy, Piedmont and Aosta Valley regions are highlighted in this study and a certain number of activities considered able to improve the situation are proposed.

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Identifying priority core habitats and corridors for effective conservation of brown bears in Iran

Scientific Reports ◽

10.1038/s41598-020-79970-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

A. Mohammadi ◽

K. Almasieh ◽

D. Nayeri ◽

F. Ataei ◽

A. Khani ◽

...

Keyword(s):

Protected Areas ◽

Brown Bear ◽

Population Connectivity ◽

Habitat Associations ◽

Area Network ◽

Zagros Mountains ◽

Range Limit ◽

Brown Bears ◽

Core Areas ◽

Effective Conservation

AbstractIran lies at the southernmost range limit of brown bears globally. Therefore, understanding the habitat associations and patterns of population connectivity for brown bears in Iran is relevant for the species’ conservation. We applied species distribution modeling to predict habitat suitability and connectivity modeling to identify population core areas and corridors. Our results showed that forest density, topographical roughness, NDVI and human footprint were the most influential variables in predicting brown bear distribution. The most crucial core areas and corridor networks for brown bear are concentrated in the Alborz and Zagros Mountains. These two core areas were predicted to be fragmented into a total of fifteen isolated patches if dispersal of brown bear across the landscape is limited to 50,000 cost units, and aggregates into two isolated habitat patches if the species is capable of dispersing 400,000 cost units. We found low overlap between corridors, and core habitats with protected areas, suggesting that the existing protected area network may not be adequate for the conservation of brown bear in Iran. Our results suggest that effective conservation of brown bears in Iran requires protection of both core habitats and the corridors between them, especially outside Iran’s network of protected areas.

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Small population size and low genomic diversity have no effect on fitness in experimental translocations of a wild fish

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2019.1989 ◽

2019 ◽

Vol 286 (1916) ◽

pp. 20191989 ◽

Cited By ~ 1

Author(s):

M. C. Yates ◽

E. Bowles ◽

D. J. Fraser

Keyword(s):

Genetic Diversity ◽

Body Size ◽

Population Size ◽

Brook Trout ◽

Habitat Degradation ◽

Species Conservation ◽

Empirical Work ◽

Genomic Diversity ◽

Effective Population ◽

Isolated Populations

Little empirical work in nature has quantified how wild populations with varying effective population sizes and genetic diversity perform when exposed to a gradient of ecologically important environmental conditions. To achieve this, juvenile brook trout from 12 isolated populations or closed metapopulations that differ substantially in population size and genetic diversity were transplanted to previously fishless ponds spanning a wide gradient of ecologically important variables. We evaluated the effect of genome-wide variation, effective population size ( N e ), pond habitat, and initial body size on two fitness correlates (survival and growth). Genetic variables had no effect on either fitness correlate, which was determined primarily by habitat (pond temperature, depth, and pH) and initial body size. These results suggest that some vertebrate populations with low genomic diversity, low N e , and long-term isolation can represent important sources of variation and are capable of maintaining fitness in, and ultimately persisting and adapting to, changing environments. Our results also reinforce the paramount importance of improving available habitat and slowing habitat degradation for species conservation.

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Tectonometamorphic Evolution of the Austroalpine Nappe Complex in the Central Eastern Alps—Consequences for the Eo-Alpine Evolution of the Eastern Alps

International Geology Review ◽

10.2747/0020-6814.45.12.1100 ◽

2003 ◽

Vol 45 (12) ◽

pp. 1100-1127 ◽

Cited By ~ 19

Author(s):

Walter Kurz ◽

Harald Fritz

Keyword(s):

Eastern Alps ◽

Nappe Complex ◽

Central Eastern

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The smell of success: Reproductive success related to rub behavior in brown bears

PLoS ONE ◽

10.1371/journal.pone.0247964 ◽

2021 ◽

Vol 16 (3) ◽

pp. e0247964

Author(s):

Andrea T. Morehouse ◽

Anne E. Loosen ◽

Tabitha A. Graves ◽

Mark S. Boyce

Keyword(s):

Reproductive Success ◽

Ursus Arctos ◽

Scent Marking ◽

Brown Bear ◽

Parentage Analysis ◽

Fitness Component ◽

Brown Bears ◽

Male And Female ◽

Rubbing Behavior ◽

Insight Into

Several species of bears are known to rub deliberately against trees and other objects, but little is known about why bears rub. Patterns in rubbing behavior of male and female brown bears (Ursus arctos) suggest that scent marking via rubbing functions to communicate among potential mates or competitors. Using DNA from bear hairs collected from rub objects in southwestern Alberta from 2011–2014 and existing DNA datasets from Montana and southeastern British Columbia, we determined sex and individual identity of each bear detected. Using these data, we completed a parentage analysis. From the parentage analysis and detection data, we determined the number of offspring, mates, unique rub objects where an individual was detected, and sampling occasions during which an individual was detected for each brown bear identified through our sampling methods. Using a Poisson regression, we found a positive relationship between bear rubbing behavior and reproductive success; both male and female bears with a greater number of mates and a greater number of offspring were detected at more rub objects and during more occasions. Our results suggest a fitness component to bear rubbing, indicate that rubbing is adaptive, and provide insight into a poorly understood behaviour.

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