Behavioral reactions of brown bears to approaching humans in Fennoscandia

Human disturbance causes behavioral responses in wildlife, including large carnivores. Previous research in Scandinavia has documented that brown bears (Ursus arctos) show a variety of behavioral reactions to different human activities. We investigated how proximity to human settlements and roads, as proxies of human influence, affected brown bears' reactions to encountering humans. We analyzed experimental approaches to GPS collared bears, 18 males and 23 single females, in Sweden (n = 148 approaches) and Finland (n = 33), conducted between 2004 and 2012. The bears in Finland inhabited areas with higher human density compared to Sweden. However, the proportion of bears staying or moving when approached and the flight initiation distances were similar in both countries. In Sweden, the flight responses were not dependent on human densities or roads inside the bears' home ranges or the distances from the bears to roads and settlements. Brown bears in Fennoscandia live in areas with relatively low human population densities, but in many areas with high forestry road densities. Our results show that bears' flight reactions were consistent between areas, which is an important message for management, reinforcing previous studies that have documented human avoidance by bears at different spatial and temporal scales.Peer reviewe

Behaviour of Solitary Adult Scandinavian Brown Bears (Ursus arctos) when Approached by Humans on Foot

Successful management has brought the Scandinavian brown bear (Ursus arctos L.) back from the brink of extinction, but as the population grows and expands the probability of bear-human encounters increases. More people express concerns about spending time in the forest, because of the possibility of encountering bears, and acceptance for the bear is decreasing. In this context, reliable information about the bear's normal behaviour during bear-human encounters is important. Here we describe the behaviour of brown bears when encountering humans on foot. During 2006–2009, we approached 30 adult (21 females, 9 males) GPS-collared bears 169 times during midday, using 1-minute positioning before, during and after the approach. Observer movements were registered with a handheld GPS. The approaches started 869±348 m from the bears, with the wind towards the bear when passing it at approximately 50 m. The bears were detected in 15% of the approaches, and none of the bears displayed any aggressive behaviour. Most bears (80%) left the initial site during the approach, going away from the observers, whereas some remained at the initial site after being approached (20%). Young bears left more often than older bears, possibly due to differences in experience, but the difference between ages decreased during the berry season compared to the pre-berry season. The flight initiation distance was longer for active bears (115±94 m) than passive bears (69±47 m), and was further affected by horizontal vegetation cover and the bear's age. Our findings show that bears try to avoid confrontations with humans on foot, and support the conclusions of earlier studies that the Scandinavian brown bear is normally not aggressive during encounters with humans

Flight initiation distance (FID) in relation to age of the bear.

<p>Distribution of flight initiation distance (FID) for passive (circles and full line) and active (triangles and broken line) Scandinavian brown bears approached by humans on foot in central Sweden in 2006–2009 (n = 78), in relation to the age of the bear.</p

Flight initiation distance (FID) in relation to sighting distance at the initial site.

<p>Distribution of flight initiation distance (FID) for passive (circles and full line) and active (triangles and broken line) Scandinavian brown bears approached by humans on foot in central Sweden in 2006–2009 (n = 78), in relation to sighting distance at the initial site (shorter sighting distance indicates more horizontal vegetation cover).</p

Results from the generalised linear mixed model for remaining or leaving the initial site.

<p>Results from the generalised linear mixed model (binomial link function) explaining whether brown bears remained (0) or left (1) their initial site when approached by humans on foot in central Sweden in 2006–2009 (n = 148). Test statistics are given for the model with the lowest value of AIC. The parameter <i>β</i> is the slope, SE denotes the standard error, Z denotes the z-value, and P denotes the p-value for the test.</p

Results from the linear mixed model for flight initiation distance (FID).

<p>Results from the linear mixed model (Gaussian link function) explaining the flight initiation distance (FID) for brown bears when approached by humans on foot in central Sweden in 2006–2009 (n = 78). Test statistics are given for the model with the lowest value of AIC. The parameter <i>β</i> is the slope, SE denotes the standard error and T denotes the t-value.</p