scholarly journals Can hunting data be used to estimate unbiased population parameters? A case study on brown bears

2016 ◽  
Vol 12 (6) ◽  
pp. 20160197 ◽  
Author(s):  
Martin Leclerc ◽  
Joanie Van de Walle ◽  
Andreas Zedrosser ◽  
Jon E. Swenson ◽  
Fanie Pelletier
Keyword(s):  
Adult Female ◽  
Ursus Arctos ◽  
Temporal Trends ◽  
Legal Protection ◽  
Brown Bears ◽  
Adult Females ◽  
Fundamental Research ◽  
Management And Conservation

Quantifying temporal changes in harvested populations is critical for applied and fundamental research. Unbiased data are required to detect true changes in phenotypic distribution or population size. Because of the difficulty of collecting detailed individual data from wild populations, data from hunting records are often used. Hunting records, however, may not represent a random sample of a population. We aimed to detect and quantify potential bias in hunting records. We compared data from a long-term monitoring project with hunting records of brown bears ( Ursus arctos ) in Sweden and investigated temporal trends (1996–2013) in the ratio of yearlings to adult females, yearling mass and adult female mass. Data from hunting records underestimated the decline in yearling and adult female mass over time, most likely owing to the legal protection of family groups from hunting, but reflected changes in the ratio of yearlings to adult females more reliably. Although hunting data can be reliable to approximate population abundance in some circumstances, hunting data can represent a biased sample of a population and should be used with caution in management and conservation decisions.

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

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.

The brown bear Ursus arctos population in Lar Wildlife Refuge, northern Iran

Mammalia ◽  
2017 ◽  
Vol 81 (6) ◽  
Author(s):  
Jamshid Parchizadeh
Keyword(s):  
Ursus Arctos ◽  
Brown Bear ◽  
Conservation Strategies ◽  
Animal Population ◽  
Basic Information ◽  
Northern Iran ◽  
Brown Bears ◽  
Wildlife Refuge ◽  
Management And Conservation

AbstractBasic information about an animal population is essential to produce management and conservation strategies. Little is known about the brown bears

scholarly journals Brown bear communication hubs: patterns and correlates of tree rubbing and pedal marking at a long-term marking site

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10447
Author(s):  
Eloy Revilla ◽  
Damián Ramos Fernández ◽  
Alberto Fernández-Gil ◽  
Agnieszka Sergiel ◽  
Nuria Selva ◽  
...  
Keyword(s):  
Chemical Communication ◽  
Ursus Arctos ◽  
Brown Bear ◽  
Population Level ◽  
Adult Males ◽  
Communication Behaviors ◽  
Brown Bears ◽  
Low Frequencies ◽  
A Site

Chemical communication is important for many species of mammals. Male brown bears, Ursus arctos, mark trees with a secretion from glands located on their back. The recent discovery of pedal glands and pedal-marking at a site used for tree-rubbing led us to hypothesize that both types of marking form part of a more complex communication system. We describe the patterns of chemical communication used by different age and sex classes, including differences in the roles of these classes as information providers or receivers over four years at a long-term marking site. Using video recordings from a camera trap, we registered a total of 285 bear-visits and 419 behavioral events associated with chemical communication. Bears visited the site more frequently during the mating season, during which communication behaviors were more frequent. A typical visit by male bears consisted of sniffing the depressions where animals pedal mark, performing pedal-marking, sniffing the tree, and, finally, rubbing against the trunk of the tree. Adult males performed most pedal- and tree-marking (95% and 66% of the cases, respectively). Males pedal-marked and tree-rubbed in 81% and 48% of their visits and sniffed the pedal marks and the tree in 23% and 59% of visits, respectively. Adult females never pedal marked, and juveniles did so at very low frequencies. Females rubbed against the tree in just 9% of their visits; they sniffed the tree and the pedal marks in 51% and 21% of their visits, respectively. All sex and age classes performed pedal- and tree-sniffing. There were significant associations between behaviors indicating that different behaviors tended to occur during the same visit and were more likely if another individual had recently visited. These associations leading to repeated marking of the site can promote the establishment of long-term marking sites. Marking sites defined by trees and the trails leading to them seem to act as communication hubs that brown bears use to share and obtain important information at population level.

scholarly journals Competition between apex predators? Brown bears decrease wolf kill rate on two continents

2017 ◽  
Vol 284 (1848) ◽  
pp. 20162368 ◽  
Author(s):  
Aimee Tallian ◽  
Andrés Ordiz ◽  
Matthew C. Metz ◽  
Cyril Milleret ◽  
Camilla Wikenros ◽  
...  
Keyword(s):  
Opposite Effect ◽  
Ursus Arctos ◽  
Brown Bear ◽  
Trophic Levels ◽  
Apex Predators ◽  
Brown Bears ◽  
Common Assumption ◽  
The Common ◽  
Kill Rate

Trophic interactions are a fundamental topic in ecology, but we know little about how competition between apex predators affects predation, the mechanism driving top-down forcing in ecosystems. We used long-term datasets from Scandinavia (Europe) and Yellowstone National Park (North America) to evaluate how grey wolf ( Canis lupus ) kill rate was affected by a sympatric apex predator, the brown bear ( Ursus arctos ). We used kill interval (i.e. the number of days between consecutive ungulate kills) as a proxy of kill rate. Although brown bears can monopolize wolf kills, we found no support in either study system for the common assumption that they cause wolves to kill more often. On the contrary, our results showed the opposite effect. In Scandinavia, wolf packs sympatric with brown bears killed less often than allopatric packs during both spring (after bear den emergence) and summer. Similarly, the presence of bears at wolf-killed ungulates was associated with wolves killing less often during summer in Yellowstone. The consistency in results between the two systems suggests that brown bear presence actually reduces wolf kill rate. Our results suggest that the influence of predation on lower trophic levels may depend on the composition of predator communities.

scholarly journals Ain't Nothing Like Family - Brown Bears Share their Home Range with Relatives

2021 ◽  
Author(s):  
Astrid Olejarz ◽  
Jouni Aspi ◽  
Ilpo Kojola ◽  
Vesa Nivala ◽  
Alina Niskanen ◽  
...  
Keyword(s):  
Home Range ◽  
Spatial Data ◽  
Ursus Arctos ◽  
Home Ranges ◽  
Brown Bears ◽  
Adult Females ◽  
Animal Populations ◽  
Centroid Distance ◽  
Range Overlap ◽  
Eastern Finland

Sociality in animal populations is a continuum, and interactions between conspecifics are meaningful for all vertebrates. Ignorance of social structures can lead to misunderstanding their ecology and, consequently, to unsuccessful species management. Here, we combined genetic and spatial data on radio-collated brown bears (Ursus arctos) to investigate kin-related home range overlap and kin-related centroid distance within central and eastern Finland. We found that the extent of overlap of home ranges was positively linked with relatedness among adult females. A similar positive correlation could be detected between home range centroid distance and relatedness among adult females. Moreover, there were significant differences between the two studied regions: female brown bears in central Finland were more closely related to each other, and the sizes of their home ranges were larger than those in eastern Finland. The smaller home ranges and lower degree of relatedness among bears in eastern Finland might be a result of the substantially higher hunting pressure in the area, combined with immigration of new unrelated individuals from Russia.

scholarly journals First successful hand-rearing and release to the wild of two orphan brown bear cubs in Greece

2018 ◽  
Vol 67 (3) ◽  
pp. 163
Author(s):  
A. Th. KOMNENOU ◽  
A. A. KARAMANLIDIS ◽  
G. M. KAZAKOS ◽  
A. P. KYRIAZIS ◽  
M. AVGERINOU ◽  
...  
Keyword(s):  
Ursus Arctos ◽  
Brown Bear ◽  
Rehabilitation Centre ◽  
Brown Bears ◽  
Rehabilitation Process ◽  
In The Wild ◽  
Northwestern Greece ◽  
First Time ◽  
Management And Conservation ◽  
Conservation And Management

The rehabilitation and release of orphan brown bears (Ursus arctos) to the wild is of increasing importance in the conservation and management of the species. In April 2011 two orphan male brown bears were found and rehabilitated for the first time at a dedicated Bear Rehabilitation Centre in Greece. In this case report we describe in detail the veterinary procedures and the feeding regime followed during the 9-month rehabilitation process. For the release on the 23rd of January 2012 the two bears were anaesthetized with a combination of xylazine and ketamine, and satellite collars were placed on them for post-release monitoring. Eight hours later the bears were anaesthetized with the same mixture for a second time, transported and placed into an artificial den in the wild; recovery from anaesthesia took place without complications. Three months later the bears left the den and started moving in the wider area of northwestern Greece. We conclude that rehabilitation and release of orphan bears is an important tool in the management and conservation of this endangered species in Greece.

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