Brown bear (Ursus arctos) den site concealment in relation to human activity in Scandinavia

As a hibernating species, the brown bear spend most of the winter months in a den as a strategy to avoid unfavorable conditions. The denning period is a vulnerable time for bears, making them unable to flee disturbances without losing valuable amounts of energy. Brown bears' wariness of humans and a...

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Main Author: Sahlén, Ellinor
Format: M2
Language:Inglés
Swedish
Published: SLU/Dept. of Wildlife, Fish and Environmental Studies 2009
Subjects:
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author Sahlén, Ellinor
author_browse Sahlén, Ellinor
author_facet Sahlén, Ellinor
author_sort Sahlén, Ellinor
collection Epsilon Archive for Student Projects
description As a hibernating species, the brown bear spend most of the winter months in a den as a strategy to avoid unfavorable conditions. The denning period is a vulnerable time for bears, making them unable to flee disturbances without losing valuable amounts of energy. Brown bears' wariness of humans and avoidance of anthropogenic disturbance often steer denning bears away from human infrastructure, and bears thereby avoid possible disturbance and its associated energetic costs. This study was carried out to test the hypothesis that bears denning closer to infrastructure select more covered den sites to compensate for the close distance. Dens from 32 individuals were visited and analyzed in terms of sighting distance (a measurement for den horizontal cover) and habitat ruggedness, in relation to distances to infrastructure. This study showed that bears tended to have more concealed dens and/or dens situated in more rugged terrain closer to roads and settlements with the highest human activity. Expanding human infrastructure might affect bear categories differently, since younger bears were shown to den closer to human activity areas than older bears. Close distance to human activity might therefore alter bears’ natural behavior evolved to endure unfavorable conditions during winter. Undeveloped forest regions are important to decrease anthropogenic effects on bear denning behavior, and presumably also for the spatial distribution concerning different bear categories (e.g. age classes).
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institution Swedish University of Agricultural Sciences
language Inglés
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publishDate 2009
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spelling RepoSLU5502012-04-20T14:10:03Z Brown bear (Ursus arctos) den site concealment in relation to human activity in Scandinavia Brunbjörnars (Ursus arctos) döljande av iden i förhållande till mänsklig aktivitet i Skandinavien Sahlén, Ellinor brown bear den site denning habitat habitat cover concealment rugged terrain human activity infrastructure sighting distance villages roads As a hibernating species, the brown bear spend most of the winter months in a den as a strategy to avoid unfavorable conditions. The denning period is a vulnerable time for bears, making them unable to flee disturbances without losing valuable amounts of energy. Brown bears' wariness of humans and avoidance of anthropogenic disturbance often steer denning bears away from human infrastructure, and bears thereby avoid possible disturbance and its associated energetic costs. This study was carried out to test the hypothesis that bears denning closer to infrastructure select more covered den sites to compensate for the close distance. Dens from 32 individuals were visited and analyzed in terms of sighting distance (a measurement for den horizontal cover) and habitat ruggedness, in relation to distances to infrastructure. This study showed that bears tended to have more concealed dens and/or dens situated in more rugged terrain closer to roads and settlements with the highest human activity. Expanding human infrastructure might affect bear categories differently, since younger bears were shown to den closer to human activity areas than older bears. Close distance to human activity might therefore alter bears’ natural behavior evolved to endure unfavorable conditions during winter. Undeveloped forest regions are important to decrease anthropogenic effects on bear denning behavior, and presumably also for the spatial distribution concerning different bear categories (e.g. age classes). Som en övervintrande art så spenderar brunbjörnar de flesta av vintermånaderna i iden som en strategi för att undvika ogynnsamma förhållanden. Idesperioden är en känslig tid för björnar eftersom de då inte kan undvika störningar utan att därmed förlora värdefull energi. Brunbjörnars undvikande av mänskliga störningar driver björnar och deras idesområden bort från mänsklig infrastruktur och på detta vis undviker björnar möjliga störningar och de energimässiga kostnader som är förenade med dessa. Denna studie utfördes för att testa hypotesen att björnar väljer mer dolda idesplatser i de fall de är belägna närmare mänsklig aktivitet som en kompensation för det nära avståndet. Iden från 32 individer besöktes och analyserades med avseende på ”sighting distance” (ett mått för den horisontella täckhetssgraden) och graden av ojämn terräng, i relation till idenas avstånd från vägar och bebyggelse. Studien visade att björnar har mer dolda iden, och/eller iden belägna i mer ojämn terräng, närmare de bebyggelser och vägar med högst mänsklig aktivitet. Expanderande infrastruktur kan eventuellt påverka olika kategorier av björnar på olika sätt, eftersom yngre björnar i studien hade iden närmare mänsklig aktivitet i större grad än äldre björnar. Ett nära avstånd till mänsklig aktivitet kan därför förändra björnars naturliga beteende som selekterats för att utstå ogynnsamma förhållanden under vinterhalvåret. Obebyggda skogsområden är viktiga för att minska antropogena effekter på björnars beteenden när det gäller val av idesplatser och förmodligen också för den spatiella distributionen av olika björngrupper (t.ex. ålderklasser). SLU/Dept. of Wildlife, Fish and Environmental Studies 2009 M2 eng swe https://stud.epsilon.slu.se/550/
spellingShingle brown bear
den site
denning habitat
habitat
cover
concealment
rugged terrain
human activity
infrastructure
sighting distance
villages
roads
Sahlén, Ellinor
Brown bear (Ursus arctos) den site concealment in relation to human activity in Scandinavia
title Brown bear (Ursus arctos) den site concealment in relation to human activity in Scandinavia
title_full Brown bear (Ursus arctos) den site concealment in relation to human activity in Scandinavia
title_fullStr Brown bear (Ursus arctos) den site concealment in relation to human activity in Scandinavia
title_full_unstemmed Brown bear (Ursus arctos) den site concealment in relation to human activity in Scandinavia
title_short Brown bear (Ursus arctos) den site concealment in relation to human activity in Scandinavia
title_sort brown bear (ursus arctos) den site concealment in relation to human activity in scandinavia
topic brown bear
den site
denning habitat
habitat
cover
concealment
rugged terrain
human activity
infrastructure
sighting distance
villages
roads