Role of brown bears ( Ursus arctos ) in the flow of marine nitrogen into a terrestrial ecosystem

Oecologia ◽  
1999 ◽  
Vol 121 (4) ◽  
pp. 546-550 ◽  
Author(s):  
G. V. Hilderbrand ◽  
Thomas A. Hanley ◽  
Charles T. Robbins ◽  
C. C. Schwartz
Keyword(s):  
Ursus Arctos ◽  
Terrestrial Ecosystem ◽  
Brown Bears

Salmon consumption by Kodiak brown bears (Ursus arctos middendorffi) with ecosystem management implications

2013 ◽  
Vol 91 (3) ◽  
pp. 164-174 ◽  
Author(s):  
M.B. Van Daele ◽  
C.T. Robbins ◽  
B.X. Semmens ◽  
E.J. Ward ◽  
L.J. Van Daele ◽  
...  
Keyword(s):  
Total Mass ◽  
Ursus Arctos ◽  
Adult Males ◽  
Management Implications ◽  
Brown Bears ◽  
Adult Females ◽  
Commercial Harvest ◽  
Maximum Sustained Yield ◽  
Large Predators

The ecological role of large predators in North America continues to spark heated public debate. Although brown bears (Ursus arctos L., 1758) and the salmon (genus Oncorhynchus Suckley, 1861) they feed on have declined in many areas, the Kodiak archipelago is famous for large brown bears and abundant salmon. Salmon have generally been managed for maximum sustained yield in a fisheries sense, but those levels may be well below what is necessary for maximum ecosystem productivity. Consequently, we used stable isotopes and mercury accumulated in hair to estimate intake of salmon by Kodiak brown bears (Ursus arctos middendorffi Merriam, 1896). Salmon intake increased from subadult males (592 ± 325 kg·bear−1·year−1) to adult males (2788 ± 1929 kg·bear−1·year−1) and from subadult females (566 ± 360 kg·bear−1·year−1) to adult females (1364 ± 1261 kg·bear−1·year−1). Intake within each group increased 62% ± 23% as salmon escapement increased from ∼1 500 to ∼14 000 kg·bear−1·year−1. The estimated population of 2300 subadult and adult bears consumed 3.77 ± 0.16 million kg of salmon annually, a mass equal to ∼6% of the combined escapement and commercial harvest (57.6 million kg). Although bears consume a small portion of the total mass of adult salmon, perpetuation of dense populations of large bears requires ecosystem-based management of the meat resources and environments that produce such bears.

scholarly journals The role of the brown bear Ursus arctos as a legitimate megafaunal seed disperser

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alberto García-Rodríguez ◽  
Jörg Albrecht ◽  
Sylwia Szczutkowska ◽  
Alfredo Valido ◽  
Nina Farwig ◽  
...  
Keyword(s):  
Plant Regeneration ◽  
Seed Dispersal ◽  
Plant Species ◽  
Ursus Arctos ◽  
Mediterranean Forests ◽  
Brown Bears ◽  
Fleshy Fruits ◽  
Seed Dispersers ◽  
Regeneration Processes

AbstractMegafaunal frugivores can consume large amounts of fruits whose seeds may be dispersed over long distances, thus, affecting plant regeneration processes and ecosystem functioning. We investigated the role of brown bears (Ursus arctos) as legitimate megafaunal seed dispersers. We assessed the quantity component of seed dispersal by brown bears across its entire distribution based on information about both the relative frequency of occurrence and species composition of fleshy fruits in the diet of brown bears extracted from the literature. We assessed the quality component of seed dispersal based on germination experiments for 11 fleshy-fruited plant species common in temperate and boreal regions and frequently eaten by brown bears. Across its distribution, fleshy fruits, on average, represented 24% of the bear food items and 26% of the total volume consumed. Brown bears consumed seeds from at least 101 fleshy-fruited plant species belonging to 24 families and 42 genera, of which Rubus (Rosaceae) and Vaccinium (Ericaceae) were most commonly eaten. Brown bears inhabiting Mediterranean forests relied the most on fleshy fruits and consumed the largest number of species per study area. Seeds ingested by bears germinated at higher percentages than those from whole fruits, and at similar percentages than manually depulped seeds. We conclude that brown bears are legitimate seed dispersers as they consume large quantities of seeds that remain viable after gut passage. The decline of these megafaunal frugivores may compromise seed dispersal services and plant regeneration processes.

scholarly journals Seed Dispersal by Brown Bears, Ursus arctos, in Southeastern Alaska

2004 ◽  
Vol 118 (4) ◽  
pp. 499 ◽  
Author(s):  
Mary F. Willson ◽  
Scott M. Gende
Keyword(s):  
Seed Dispersal ◽  
Plant Species ◽  
Ursus Arctos ◽  
Forest Understory ◽  
Habitat Distribution ◽  
Brown Bears ◽  
Fleshy Fruits ◽  
Scat Analyses

Mammals often consume fleshy fruits and disperse significant quantities of the enclosed seeds. In southeastern Alaska, Brown Bears (Ursus arctos) are among the most important dispersers of seeds for the numerous plant species producing fleshy fruits, because these bears are abundant, often eat large quantities of fruit, and commonly excrete seeds in germinable condition. Scat analyses showed that Brown Bears on Chichagof Island ate increasing quantities of fruit through summer and fall. Scats commonly contained several thousand seeds, often of two or more species. Four kinds of seeds of fleshyfruited plants that normally grow in forest understory germinated at similar levels when experimentally deposited (in bear scats) in the two most common habitats (forest and muskeg), suggesting that habitat distribution of these plants is not determined simply by germination patterns. Although seed passage through bear digestive tracts and the composition of scats are known to affect germination rates to some degree, the most important role of bears in seed dispersal is probably transport.

Molecular identification of Taenia spp. in wolves (Canis lupus), brown bears (Ursus arctos) and cervids from North Europe and Alaska

2011 ◽  
Vol 60 (3) ◽  
pp. 289-295 ◽  
Author(s):  
Antti Lavikainen ◽  
Sauli Laaksonen ◽  
Kimberlee Beckmen ◽  
Antti Oksanen ◽  
Marja Isomursu ◽  
...  
Keyword(s):  
Molecular Identification ◽  
Canis Lupus ◽  
Ursus Arctos ◽  
Brown Bears

scholarly journals Long-Term Safety of Intraperitoneal Radio Transmitter Implants in Brown Bears (Ursus arctos)

2018 ◽  
Vol 5 ◽  
Author(s):  
Jon M. Arnemo ◽  
Bjørnar Ytrehus ◽  
Knut Madslien ◽  
Jonas Malmsten ◽  
Sven Brunberg ◽  
...  
Keyword(s):  
Ursus Arctos ◽  
Brown Bears ◽  
Radio Transmitter

Sexing free-ranging brown bears Ursus arctos using hairs found in the field

1993 ◽  
Vol 2 (6) ◽  
pp. 399-403 ◽  
Author(s):  
P. TABERLET ◽  
H. MATTOCK ◽  
C. DUBOIS-PAGANON ◽  
J. BOUVET
Keyword(s):  
Ursus Arctos ◽  
Brown Bears ◽  
Free Ranging

Serologic Evidence of Leptospira spp. Serovars in Brown Bears (Ursus arctos) from Croatia

2010 ◽  
Vol 46 (1) ◽  
pp. 251-256 ◽  
Author(s):  
Alen Slavica ◽  
Dean Konjević ◽  
Đuro Huber ◽  
Zoran Milas ◽  
Nenad Turk ◽  
...  
Keyword(s):  
Ursus Arctos ◽  
Brown Bears ◽  
Leptospira Spp ◽  
Serologic Evidence

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

PLoS ONE ◽  
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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