A human-induced landscape of fear influences foraging behavior of brown bears

Animals adapt their foraging behavior to variations in food availability and predation risk. In Sweden, brown bears (Ursus arctos) depend on a nearly continuous intake of berries, especially bilberries (Vaccinium myrtillus) during late summer and early autumn to fatten up prior to hibernation. This overlaps with the bear hunting season that starts on 21 August. Bilberry occurrence varies across space, as does human-induced mortality risk. Here, we hypothesize that brown bears select for areas with a high probability of bilberry occurrence across a boreal forest ecosystem in Sweden (H1), and that human-induced mortality risk reduces bear selection for bilberries (H2). In addition, we hypothesized that bears that survived the hunting season avoided bilberry areas associated with high risk, whereas bears that were later killed selected more strongly for berries and less against risk prior to the hunting season (H3). To evaluate our hypotheses, we used resource selection functions to contrast bear GPS relocation data (N = 35, 2012–2015) and random positions within the bearś home range with generalized linear mixed effect models against two focal variables: a map predicting bilberry occurrence and a map predicting human-induced mortality risk. We found that bears selected for areas with a high probability of bilberry occurrence (supporting H1), but avoided these areas if they were associated with and high risk of hunting mortality (supporting H2). The killed and surviving bears did not differ in their selection for bilberries, but they did differ in their selection against risk (partially supporting H3). Surviving bears strongly avoided high risk areas, whereas killed bears responded less to risk and selected for high-risk areas with a low probability of bilberry occurrence. This suggests that killed bears selected for other food sources than berries in high risk areas, which exposed them to human hunters. We conclude that bears respond to a landscape of fear during the berry season and that different foraging strategies may have a direct impact on individual mortality during the hunting season.acceptedVersio

Risky berry business? : brown bear (Ursus arctos) foraging behaviour in a landscape of fear

Mobile animals are expected to optimize their diet and foraging strategies, and balance the cost of resource gain with the perceived predation risk, and therefore trade-off risky areas for safer areas with fewer resources. Large carnivores have few natural enemies and their mortality, forage behaviour, and response to risk are mostly related to human induced disturbances. Scandinavian brown bears feed exclusively on berries during late summer and autumn to gain sufficient carbohydrates to survive hibernation. The purpose of this thesis was to predict spatiotemporal berry availability and whether berry availability created a temporal “blue/red wave” across the berry season. I analysed how bear selection for berries was influenced by various anthropogenic structures and whether bears treaded-off good berry areas for poor berry areas further away from anthropogenic structures. Both bilberries and lingonberries were included in the analysis.M-ECO

Friluftslivet og ulven. Markabrukeres meninger om ulvene i Østmarka

Dette er den andre rapporten fra prosjektet «Vill ulv i urban skog» som handler om hvordan brukere av Østmarka ser på ulveflokken som har slått seg ned der. Målsettingen har i bred for-stand vært å studere hva folk som bruker marka, mener om ulven; hvilken kunnskap de har, meningsnyanser og meningsammenhenger. Og å vurdere i hvilken grad ulvene påvirker infor-mantenes friluftsliv i dette populære friluftsområdet. Rapporten er basert på kvalitative intervjuer av 48 informanter som bedriver ulike friluftsaktiviteter i Østmarka, og er delt i to deler. Den første delen omhandler informantenes bruk av marka, kunnskap om ulvene, ulvenes plass i marka og hvordan ulvene fremstilles i media, historier og rykter. Del to beskriver informantenes oppfatning av ulvekonflikter, deres meninger om opphavet til slike konflikter og oppfatninger av hvordan ulvekonflikter bør håndteres. Østmarka ligger i Akershus fylke og omfatter kommunene Oslo, Lørenskog, Rælingen, Enebakk og Ski. Marka byr på varierte naturopplevelser og friluftsaktiviteter året rundt og er et svært po-pulært friluftsområde med mer enn 110 000 friluftslivsutøvere årlig. I 2012 slo et ulvepar seg ned i Østmarka og har siden reprodusert og dannet en ulveflokk. Informantene i undersøkelsen er regelmessige brukere av Østmarka og alle uttrykker at marka er svært viktig for dem. De bruker marka på måter som både engasjerer dem og gir dem ulik kunnskap om naturen. Basert på dette kan informantene deles inn i to grupper; hardcore-frilufts-liv og friluftsliv-light. Informanter blant begge friluftslivsgruppene uttrykker et positivt syn på ulv ut fra en opplevelse om at ulvene hører til i naturen og har rett til å være i Østmarka. Blant hardcore-friluftsliv argumenteres det likevel med at Østmarka er økologisk uegnet for ulv på grunn av den begrensede størrelsen og reduserte bestander av hjortevilt. De deler en oppfatning om at ulvene snart vil vandre ut av området, men er i prinsippet ikke negative til ulv til tross for potensiell negativ innvirkning på deres eget friluftsliv. Friluftsliv-light mener i større grad at Øst-marka er velegnet økologisk sett siden ulvene allerede har etablert seg, og forventer derfor at ulvene blir værende. Mange av disse informantene synes ulvene er et spennende og eksotisk innslag i marka, og at ulvene ikke påvirker deres eget friluftsliv i særlig grad. Noen av friluftsliv-light informantene opplever likevel Østmarka som uegnet basert på en menneskesentrert argu-mentasjon der området først og fremst er et friluftsområde, og ulvene kan komme i konflikt med friluftsliv og husdyrhold i marka. Informantene vi kaller hardcore-friluftsliv har gjerne mye kunnskap om ulvene og produserer selv kunnskap ved å observere spor av ulvene i Østmarka. Noen av disse markabrukerne er skep-tiske til kunnskap presentert av både forskere og historier fortalt av andre markabrukere. Frilufts-liv-light har typisk langt mindre kunnskap om ulvene, og flere har en holdning om at dette ikke angår dem i særlig grad. De har likevel i større grad tillit til kunnskap presentert fra offisielt hold, og til en viss grad også tillit til historier som blir fortalt av andre markabrukere. Selv om media er en av hovedkildene til informasjon om ulvene blant friluftsliv-light gruppen, blir media også kriti-sert av begge grupper for å fremstille ulvedebatten i Norge som svært polarisert og konfliktfylt. Østmarka, ulv, friluftsliv, meninger, kvalitative intervjuer, wolves, outdoor recreation, opinions, qualitative interview

Bears and berries: species-specific selective foraging on a patchily distributed food resource in a human-altered landscape

When animals are faced with extraordinary energyconsuming events, like hibernation, finding abundant, energy-rich food resources becomes particularly important. The profitability of food resources can vary spatially, depending on occurrence, quality, and local abundance. Here, we used the brown bear (Ursus arctos) as a model species to quantify selective foraging on berries in different habitats during hyperphagia in autumn prior to hibernation. During the peak berry season in August and September, we sampled berry occurrence, abundance, and sugar content, a proxy for quality, at locations selected by bears for foraging and at random locations in the landscape. The factors determining selection of berries were species specific across the different habitats. Compared to random locations, bears selected locations with a higher probability of occurrence and higher abundance of bilberries (Vaccinium myrtillus) and a higher probability of occurrence, but not abundance, of lingonberries (Vaccinium vitis-idaea). Crowberries (Empetrum hermaphroditum) were least available and least used. Sugar content affected the selection of lingonberries, but not of bilberries. Abundance of bilberries at random locations decreased and abundance of lingonberries increased during fall, but bears did not adjust their foraging strategy by increasing selection for lingonberries. Forestry practices had a large effect on berry occurrence and abundance, and brown bears responded by foraging most selectively in mature forests and on clearcuts. This study shows that bears are successful in navigating human-shaped forest landscapes by using areas of higher than average berry abundance in a period when abundant food intake is particularly important to increase body mass prior to hibernation. Significance statement Food resources heterogeneity, caused by spatial and temporal variation of specific foods, poses a challenge to foragers, particularly when faced with extraordinary energy-demanding events, like hibernation. Brown bears in Sweden inhabit a landscape shaped by forestry practices. Bilberries and lingonberries, the bears’ main food resources in autumn prior to hibernation, show different temporal and habitat-specific ripening patterns. We quantified the bears’ selective foraging on these berry species on clearcuts, bogs, young, and mature forests compared to random locations. Despite a temporal decline of ripe bilberries, bears used locations with a greater occurrence and abundance of bilberries, but not lingonberries. We conclude that bears successfully navigated in this heavily human-shaped landscape by selectively foraging in highreturn habitats for bilberries, but did not compensate for the decline in bilberries by eating more lingonberries.Bilberry . Brown bear . Lingonberry . Movement trajectories . Optimal foraging . Sugar contentpublishedVersio

A human-induced landscape of fear influences foraging behavior of brown bears

Animals adapt their foraging behavior to variations in food availability and predation risk. In Sweden, brown bears (Ursus arctos) depend on a nearly continuous intake of berries, especially bilberries (Vaccinium myrtillus) during late summer and early autumn to fatten up prior to hibernation. This overlaps with the bear hunting season that starts on 21 August. Bilberry occurrence varies across space, as does human-induced mortality risk. Here, we hypothesize that brown bears select for areas with a high probability of bilberry occurrence across a boreal forest ecosystem in Sweden (H1), and that human-induced mortality risk reduces bear selection for bilberries (H2). In addition, we hypothesized that bears that survived the hunting season avoided bilberry areas associated with high risk, whereas bears that were later killed selected more strongly for berries and less against risk prior to the hunting season (H3). To evaluate our hypotheses, we used resource selection functions to contrast bear GPS relocation data (N = 35, 2012–2015) and random positions within the bearś home range with generalized linear mixed effect models against two focal variables: a map predicting bilberry occurrence and a map predicting human-induced mortality risk. We found that bears selected for areas with a high probability of bilberry occurrence (supporting H1), but avoided these areas if they were associated with and high risk of hunting mortality (supporting H2). The killed and surviving bears did not differ in their selection for bilberries, but they did differ in their selection against risk (partially supporting H3). Surviving bears strongly avoided high risk areas, whereas killed bears responded less to risk and selected for high-risk areas with a low probability of bilberry occurrence. This suggests that killed bears selected for other food sources than berries in high risk areas, which exposed them to human hunters. We conclude that bears respond to a landscape of fear during the berry season and that different foraging strategies may have a direct impact on individual mortality during the hunting season

A human-induced landscape of fear influences foraging behavior of brown bears

Animals adapt their foraging behavior to variations in food availability and predation risk. In Sweden, brown bears (Ursus arctos) depend on a nearly continuous intake of berries, especially bilberries (Vaccinium myrtillus) during late summer and early autumn to fatten up prior to hibernation. This overlaps with the bear hunting season that starts on 21 August. Bilberry occurrence varies across space, as does human-induced mortality risk. Here, we hypothesize that brown bears select for areas with a high probability of bilberry occurrence across a boreal forest ecosystem in Sweden (H1), and that human-induced mortality risk reduces bear selection for bilberries (H2). In addition, we hypothesized that bears that survived the hunting season avoided bilberry areas associated with high risk, whereas bears that were later killed selected more strongly for berries and less against risk prior to the hunting season (H3). To evaluate our hypotheses, we used resource selection functions to contrast bear GPS relocation data (N = 35, 2012–2015) and random positions within the bearś home range with generalized linear mixed effect models against two focal variables: a map predicting bilberry occurrence and a map predicting human-induced mortality risk. We found that bears selected for areas with a high probability of bilberry occurrence (supporting H1), but avoided these areas if they were associated with and high risk of hunting mortality (supporting H2). The killed and surviving bears did not differ in their selection for bilberries, but they did differ in their selection against risk (partially supporting H3). Surviving bears strongly avoided high risk areas, whereas killed bears responded less to risk and selected for high-risk areas with a low probability of bilberry occurrence. This suggests that killed bears selected for other food sources than berries in high risk areas, which exposed them to human hunters. We conclude that bears respond to a landscape of fear during the berry season and that different foraging strategies may have a direct impact on individual mortality during the hunting season