scholarly journals Long-term trends in food habits of a relict brown bear population in northern Spain: the influence of climate and local factors

2007 ◽  
Vol 34 (1) ◽  
pp. 36-44 ◽  
Author(s):  
C. RODRÍGUEZ ◽  
J. NAVES ◽  
A. FERNÁNDEZ-GIL ◽  
J.R. OBESO ◽  
M. DELIBES
Keyword(s):  
Climate Change ◽  
Food Habits ◽  
Brown Bear ◽  
Local Scale ◽  
Plant Distribution ◽  
Food Sources ◽  
Brown Bears ◽  
Local Factors ◽  
Food Items ◽  
Recent Climate

Relict endangered populations may be especially vulnerable to the effects of climate change. A data series for the period 1974–2003 was used to examine shifts in brown bear Ursus arctos food habits in its south-westernmost European population. This focused on the hyperphagic season, when bears gain the fat that is essential for winter dormancy and reproduction. General climatic indicators were predictors of diet trends. Other variables potentially able to modify brown bear food habits at the local scale were accounted for by considering two areas where local conditions changed in different ways during the study period. General climatic indicators such as temperature and the winter North Atlantic Oscillation index were good predictors of some diet trends, although local factors seemed to modulate the potential response of food habits to recent climate change. Boreal and temperate food items decreasingly contributed to brown bear diet, replaced by increasing contributions of southern foods, which suggested that warmer temperatures might determine the occurrence of some food items in the diet of Cantabrian brown bears through effects on plant distribution and phenology. At the local scale, high cattle density in one of the study areas limited food sources available for brown bears. Important food sources for brown bears, such as heath-like Vaccinium formations and old-growth oak forest in the Cantabrian Mountains, require increased levels of protection.

scholarly journals Autumn food habits of the brown bear Ursus arctos in the Golestan National Park: a pilot study in Iran

Mammalia ◽  
2018 ◽  
Vol 82 (4) ◽  
pp. 338-342 ◽  
Author(s):  
Mahmood Soofi ◽  
Ali Turk Qashqaei ◽  
Achyut Aryal ◽  
Sean C.P. Coogan
Keyword(s):  
Food Habits ◽  
National Park ◽  
Dry Matter ◽  
Ursus Arctos ◽  
Brown Bear ◽  
Minor Importance ◽  
Importance Value ◽  
Food Items ◽  
Hawthorn Fruit ◽  
Food Consumed

Abstract Food consumed by brown bears in the Golestan National Park in Iran was analyzed during autumn 2011. We identified 22 food items in 61 scats, with the most important food items being hawthorn fruit, cherry plum fruit and chestnut-leaved oak hard mast, based on importance value (IV) estimates of 26.4%, 18.1% and 12.9%, respectively. The overall bear diet (percent digestible dry matter) was composed of 77.9% soft mast (i.e. fruit), 21.3% hard mast and small proportions of other vegetation (0.3%) or animal matter (0.4%). One anthropogenic food was identified (vine grape) and was of minor importance (IV=0.2%).

scholarly journals Insights into bear evolution from a Pleistocene polar bear genome

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.

scholarly journals Genomic evidence of globally widespread admixture from polar bears into brown bears during the last ice age

2017 ◽  
Author(s):  
James A. Cahill ◽  
Peter D. Heintzman ◽  
Kelley Harris ◽  
Matthew Teasdale ◽  
Joshua Kapp ◽  
...  
Keyword(s):  
Climate Change ◽  
Polar Bear ◽  
Ursus Arctos ◽  
Brown Bear ◽  
Ice Age ◽  
Evolutionary Significance ◽  
Polar Bears ◽  
Brown Bears ◽  
Last Ice Age ◽  
Genomic Introgression

AbstractRecent genomic analyses have provided substantial evidence for past periods of gene flow from polar bears (Ursus maritimus) into Alaskan brown bears (Ursus arctos), with some analyses suggesting a link between climate change and genomic introgression. However, because it has only been possible to sample bears from the present day, the timing, frequency, and evolutionary significance of this admixture remains unknown. Here, we analyze genomic DNA from three additional and geographically distinct brown bear populations, including two that lived temporally close to the peak of the last ice age. We find evidence of admixture in all three populations, suggesting that admixture between these species has been common in their recent evolutionary history. In addition, analyses of ten fossil bears from the now-extinct Irish population indicate that admixture peaked during the last ice age, when brown bear and polar bear ranges overlapped. Following this peak, the proportion of polar bear ancestry in Irish brown bears declined rapidly until their extinction. Our results support a model in which ice age climate change created geographically widespread conditions conducive to admixture between polar bears and brown bears, as is again occurring today. We postulate that this model will be informative for many admixing species pairs impacted by climate change. Our results highlight the power of paleogenomes to reveal patterns of evolutionary change that are otherwise masked with only contemporary data.

Risk Assessment of Sulphite Exposure through Foods Among Adolescents of Delhi (India)

2019 ◽  
Vol 15 (7) ◽  
pp. 685-693
Author(s):  
Arushi Jain ◽  
Pulkit Mathur
Keyword(s):  
Risk Assessment ◽  
Food Intake ◽  
Daily Intake ◽  
Food Sources ◽  
Acceptable Daily Intake ◽  
Food Record ◽  
Government Schools ◽  
Adverse Health Effects ◽  
Food Items ◽  
Permissible Levels

Background: Sulphites added as preservatives in food have been associated with adverse health effects in humans. Objective: The present study was designed with an objective of assessing the risk of sulphite exposure through food in adolescents (12-16 years old) of Delhi, India. Methods: A total of 1030 adolescents selected from four private and four government schools of Delhi, were asked to record their food intake using a 24 hour food record, repeated on three days, for assessing exposure to sulphites. The risk was assessed using six different scenarios of exposure. Results: The actual intake for sulphites for average consumers was 0.15 ± 0.13 mg / kg b.w. / day which was 21.4% of acceptable daily intake (ADI). For high consumers (P95), it was 65% of the ADI. However, for 2 respondents, the actual intake exceeded the ADI. The major food contributors to sulphite intake were beverage concentrates (46%), ready to serve beverages (22%) followed by miscellaneous food items (16%), mainly ice creams and snowballs. Estimation of sulphite intake using different exposure scenarios revealed that for certain scenarios where the highest reported sulphite level or maximum permissible levels were considered for calculation, the high consumers exceeded the ADI, though, for average consumers, intake was well below the ADI. Conclusion: Actual intake of sulphite for average consumers was well below the ADI but for high consumers was approaching the ADI. People with sulphite sensitivity need to be aware of hidden food sources of sulphites.

Evaluation of simulated recent climate change in Australia

2015 ◽  
Vol 65 (1) ◽  
pp. 4-18 ◽  
Author(s):  
Jonas Bhend ◽  
Penny Whetton
Keyword(s):  
Climate Change ◽  
Recent Climate Change ◽  
Recent Climate

DEATH ASSEMBLAGES AS RECORDERS OF RECENT CLIMATE CHANGE ON THE CONTINENTAL SHELF

2017 ◽  
Author(s):  
Eric N. Powell ◽  
◽  
Kelsey Kuykendall ◽  
Paula Moreno ◽  
Sara Pace
Keyword(s):  
Climate Change ◽  
Continental Shelf ◽  
Recent Climate Change ◽  
Recent Climate ◽  
Death Assemblages

scholarly journals Effects of climate change and industrialization on Lake Bolshoe Toko, eastern Siberia

2021 ◽  
Vol 65 (3) ◽  
pp. 335-352
Author(s):  
Boris K. Biskaborn ◽  
Biljana Narancic ◽  
Kathleen R. Stoof-Leichsenring ◽  
Lyudmila A. Pestryakova ◽  
Peter G. Appleby ◽  
...  
Keyword(s):  
Climate Change ◽  
Nineteenth Century ◽  
Deep Water ◽  
Boreal Lakes ◽  
Lake Ecosystem ◽  
Intermediate Water ◽  
Eastern Siberia ◽  
Natural Ecosystems ◽  
Planktonic Diatoms ◽  
Recent Climate

AbstractIndustrialization in the Northern Hemisphere has led to warming and pollution of natural ecosystems. We used paleolimnological methods to explore whether recent climate change and/or pollution had affected a very remote lake ecosystem, i.e. one without nearby direct human influence. We compared sediment samples that date from before and after the onset of industrialization in the mid-nineteenth century, from four short cores taken at water depths between 12.1 and 68.3 m in Lake Bolshoe Toko, eastern Siberia. We analyzed diatom assemblage changes, including diversity estimates, in all four cores and geochemical changes (mercury, nitrogen, organic carbon) from one core taken at an intermediate water depth. Chronologies for two cores were established using 210Pb and 137Cs. Sedimentation rates were 0.018 and 0.033 cm year−1 at the shallow- and deep-water sites, respectively. We discovered an increase in light planktonic diatoms (Cyclotella) and a decrease in heavily silicified euplanktonic Aulacoseira through time at deep-water sites, related to more recent warmer air temperatures and shorter periods of lake-ice cover, which led to pronounced thermal stratification. Diatom beta diversity in shallow-water communities changed significantly because of the development of new habitats associated with macrophyte growth. Mercury concentrations increased by a factor of 1.6 since the mid-nineteenth century as a result of atmospheric fallout. Recent increases in the chrysophyte Mallomonas in all cores suggested an acidification trend. We conclude that even remote boreal lakes are susceptible to the effects of climate change and human-induced pollution.

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