The role of familial conflict in home range settlement and fitness of a solitary mammal

Journal of evolutionary biology Blackwell/wileyFamilial conflict, including parenteoffspring conflict (POC) and sibling competition (SC), occurs when an individual maximizes its access to a limiting resource at the expense of a related individual. The role of familial conflict for competition over space as a limited resource remains relatively unexplored. In this study, we examined how familial conflict affects natal dispersal and settlement decisions of a solitary mammal, the brown bear, Ursus arctos, and tested whether these settlement patterns covary with fitness. First, we tested whether the distance settled from the natal range was affected by aspects of POC (litter type: single versus multiple; mother's age; mother's living status) and SC (settled near versus far from the natal home range, body size). We then modelled how distance settled from the natal range influenced three measures of fitness: survival to reproduction, lifetime reproductive success and lifetime survival. In line with POC, we found that daughters settled twice as far from the natal range when their mother was alive than when she was dead. We found strong evidence for SC where in sibling pairs, the ‘near’ sister settled nearly three times closer to the natal range than her sibling. We found contradictory patterns in fitness outcomes based on settlement distance, such that females settling closer to the natal range had higher lifetime survival but were less likely to successfully wean at least one offspring. Despite survival advantages gained by settling closer to the natal range, there was no evidence that settlement distance influenced lifetime reproductive success. Fitness outcomes in this population may be influenced more by factors related to annual hunting than by familial conflict or proximity to the natal range. dispersal fitness parenteoffspring conflict reproductive success sibling competitionpublishedVersio

Landscape of fear or landscape of food? Moose hunting triggers an antipredator response in brown bears

Hunters can affect the behavior of wildlife by inducing a landscape of fear, selecting individuals with specific traits, or altering resource availability across the landscape. Most research investigating the influence of hunting on wildlife resource selection has focused on target species and less attention has been devoted to nontarget species, such as scavengers that can be both attracted or repelled by hunting activities. We used resource selection functions to identify areas where hunters were most likely to kill moose (Alces alces) in southcentral Sweden during the fall. Then, we used step-selection functions to determine whether female brown bears (Ursus arctos) selected or avoided these areas and specific resources during the moose hunting season. We found that, during both day and nighttime, female brown bears avoided areas where hunters were more likely to kill moose. We found evidence that resource selection by brown bears varied substantially during the fall and that some behavioral changes were consistent with disturbance associated with moose hunters. Brown bears were more likely to select concealed locations in young (i.e., regenerating) and coniferous forests and areas further away from roads during the moose hunting season. Our results suggest that brown bears react to both spatial and temporal variations in apparent risk during the fall: moose hunters create a landscape of fear and trigger an antipredator response in a large carnivore even if bears are not specifically targeted during the moose hunting season. Such antipredator responses might lead to indirect habitat loss and lower foraging efficiency and the resulting consequences should be considered when planning hunting seasonsacceptedVersio

The role of familial conflict in home range settlement and fitness of a solitary mammal

Familial conflict, including parent–offspring conflict (POC) and sibling competition (SC), occurs when an individual maximizes its access to a limiting resource at the expense of a related individual. The role of familial conflict for competition over space as a limited resource remains relatively unexplored. In this study, we examined how familial conflict affects natal dispersal and settlement decisions of a solitary mammal, the brown bear, Ursus arctos, and tested whether these settlement patterns covary with fitness. First, we tested whether the distance settled from the natal range was affected by aspects of POC (litter type: single versus multiple; mother's age; mother's living status) and SC (settled near versus far from the natal home range, body size). We then modelled how distance settled from the natal range influenced three measures of fitness: survival to reproduction, lifetime reproductive success and lifetime survival. In line with POC, we found that daughters settled twice as far from the natal range when their mother was alive than when she was dead. We found strong evidence for SC where in sibling pairs, the ‘near’ sister settled nearly three times closer to the natal range than her sibling. We found contradictory patterns in fitness outcomes based on settlement distance, such that females settling closer to the natal range had higher lifetime survival but were less likely to successfully wean at least one offspring. Despite survival advantages gained by settling closer to the natal range, there was no evidence that settlement distance influenced lifetime reproductive success. Fitness outcomes in this population may be influenced more by factors related to annual hunting than by familial conflict or proximity to the natal range

Solutions for archiving data in long-term studies: a reply to Whitlock et al.

James A. Mills et al.-- Letter.Peer Reviewe

Lead exposure in brown bears is linked to environmental levels and the distribution of moose kills

Lead (Pb) is heterogeneously distributed in the environment and multiple sources like Pb ammunition and fossil fuel combustion can increase the risk of exposure in wildlife. Brown bears (Ursus arctos) in Sweden have higher blood Pb levels compared to bears from other populations, but the sources and routes of exposure are unknown. The objective of this study was to quantify the contribution of two potential sources of Pb exposure in female brown bears (n = 34 individuals; n = 61 samples). We used multiple linear regressions to determine the contribution of both environmental Pb levels estimated from plant roots and moose (Alces alces) kills to blood Pb concentrations in female brown bears. We found positive relationships between blood Pb concentrations in bears and both the distribution of moose kills by hunters and environmental Pb levels around capture locations. Our results suggest that the consumption of slaughter remains discarded by moose hunters is a likely significant pathway of Pb exposure and this exposure is additive to environmental Pb exposure in female brown bears in Sweden. We suggest that spatially explicit models, incorporating habitat selection analyses of harvest data, may prove useful in predicting Pb exposure in scavengers. Ursus arctos Pb Scavenger Slaughter remain Resource selection functionacceptedVersio

The interplay between hunting rate, hunting selectivity, and reproductive strategies shapes population dynamics of a large carnivore

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in van de Walle, J., Pelletier, F., Zedrosser, A., Swenson, J. E., Jenouvrier, S., & Bischof, R. The interplay between hunting rate, hunting selectivity, and reproductive strategies shapes population dynamics of a large carnivore. Evolutionary Applications, (2021): 1-19, https://doi.org/10.1111/eva.13253.Harvest, through its intensity and regulation, often results in selection on female reproductive traits. Changes in female traits can have demographic consequences, as they are fundamental in shaping population dynamics. It is thus imperative to understand and quantify the demographic consequences of changes in female reproductive traits to better understand and anticipate population trajectories under different harvest intensities and regulations. Here, using a dynamic, frequency-dependent, population model of the intensively hunted brown bear (Ursus arctos) population in Sweden, we quantify and compare population responses to changes in four reproductive traits susceptible to harvest-induced selection: litter size, weaning age, age at first reproduction, and annual probability to reproduce. We did so for different hunting quotas and under four possible hunting regulations: (i) no individuals are protected, (ii) mothers but not dependent offspring are protected, (iii) mothers and dependent offspring of the year (cubs) are protected, and (iv) entire family groups are protected (i.e., mothers and dependent offspring of any age). We found that population growth rate declines sharply with increasing hunting quotas. Increases in litter size and the probability to reproduce have the greatest potential to affect population growth rate. Population growth rate increases the most when mothers are protected. Adding protection on offspring (of any age), however, reduces the availability of bears for hunting, which feeds back to increase hunting pressure on the nonprotected categories of individuals, leading to reduced population growth. Finally, we found that changes in reproductive traits can dampen population declines at very high hunting quotas, but only when protecting mothers. Our results illustrate that changes in female reproductive traits may have context-dependent consequences for demography. Thus, to predict population consequences of harvest-induced selection in wild populations, it is critical to integrate both hunting intensity and regulation, especially if hunting selectivity targets female reproductive strategies.JVdW and FP were funded by the Natural Sciences and Engineering Research Council of Canada. JVdW was also funded by the Fonds de Recherche du Québec—Nature et Technologies. This is scientific paper number 305 from the Scandinavian Brown Bear Research Project, which is funded by the Swedish Environmental Protection Agency, the Norwegian Directorate for Nature Management, and the Austrian Science Fund. This research was funded through the 2015-2016 BiodivERsA COFUND, with the national funders ANR (ANR-16-EBI3-0003), NCN (2016/22/Z/NZ8/00121), DLR-PT (01LC1614A), UEFISCDI (BiodivERsA3-2015-147-BearConnect (96/2016), and RCN (269863 and 286886). SJ acknowledges support of NSF OPP #1840058

The management of brown bears in Sweden, Norway and Finland

There are about 2,700 bears in the central and northern parts of Sweden, about 150 bears in Norway (most of them along the Swedish, Finnish, and Russian borders), and about 2,400 in Finland, mostly in the eastern parts of the country. The conservation status of the brown bear is considered “Near Threatened” in Sweden and Finland and “Endangered” in Norway. All three countries have well-developed population monitoring programs, but the methods used differ widely. However, because these countries share the same population of bears, cross-border collaboration in research, management, and the sharing of information is well established. All three countries have damage compensation systems in place, however, the type of damages vary; in Sweden and Finland they are mainly due to depredation of semi-domestic reindeer in the northern parts of the countries, while damages in Norway are mainly related to the depredation of free-grazing sheep and they are concentrated in the eastern part of the country, along the border with Sweden. Bears in Sweden and Norway are managed at the regional level, while bears in Finland are managed on the national level. Hunting of bears is allowed in all three countries nowadays

Movement and habitat selection of a large carnivore in response to human infrastructure differs by life stage

BackgroundThe movement extent of mammals is influenced by human-modified areas, which can affect population demographics. Understanding how human infrastructure influences movement at different life stages is important for wildlife management. This is true especially for large carnivores, due to their substantial space requirements and potential for conflict with humans.MethodsWe investigated human impact on movement and habitat selection by GPS-collared male brown bears (Ursus arctos) in two life stages (residents and dispersers) in central Sweden. We identified dispersers visually based on their GPS locations and used hidden Markov models to delineate dispersal events. We used integrated step selection analysis (iSSA) to infer movement and habitat selection at a local scale (availability defined by hourly relocations), and resource selection functions (RSFs) to infer habitat selection at a landscape scale (availability defined by the study area extent).ResultsMovement of residents on a local scale was facilitated by small forestry roads as they moved faster and selected areas closer to forestry roads, and they avoided areas closer to larger public roads and buildings on both scales. Dispersers were more ambivalent in their response to human infrastructure. Dispersers increased their speed closer to small forestry roads and larger public roads, did not exhibit selection for or against any road class, and avoided areas closer to buildings only at local scale. Dispersers did not select for any features on the landscape, which is likely explained by the novelty of the landscape or their naivety towards it.ConclusionOur results show that movement in male brown bears is life stage-dependent and indicate that connectivity maps derived from movement data of dispersing animals may provide more numerous and more realistic pathways than those derived from resident animal data alone. This suggests that data from dispersing animals provide more realistic models for reconnecting populations and maintaining connectivity than if data were derived from resident animals alone

Correcting for enzyme immunoassay changes in long term monitoring studies

Enzyme immunoassays (EIAs) are a common tool for measuring steroid hormones in wildlife due to their low cost, commercial availability, and rapid results. Testing technologies improve continuously, sometimes requiring changes in protocols or crucial assay components. Antibody replacement between EIA kits can cause differences in EIA sensitivity, which can hinder monitoring hormone concentration over time. The antibody in a common cortisol EIA kit used for long-term monitoring of stress in wildlife was replaced in 2014, causing differences in cross reactivity and standard curve concentrations. Therefore, the objective of this study was to develop a method to standardize results following changes in EIA sensitivity. We validated this method using cortisol concentrations measured in the hair of brown bears (Ursus arctos). • We used a simple linear regression to model the relationship between cortisol concentrations using kit 1 and kit 2. • We found a linear relationship between the two kits (R2 = 0.85) and used the regression equation (kit2 = (0.98 × kit1) + 1.65) to predict cortisol concentrations in re-measured samples. • Mean predicted percent error was 16% and 72% of samples had a predicted percent error <20%, suggesting that this method is well-suited for correcting changes in EIA sensitivity.publishedVersio

The eVects of primiparity on reproductive performance in the brown bear

Abstract We studied the eVects of primiparity on litter size, oVspring size, and cub loss in brown bears (Ursus arctos) in two study areas (north, south) in Sweden from 1987 to 2006. Sexually selected infanticide (SSI) has been suggested previously as a mortality factor in our study populations. Females in the south became primiparous earlier than females in the north. Primiparous females had signiWcantly smaller litters of cubs than multiparous females. We found no evidence that primiparity was costly in terms of the interlitter interval. Primiparous mothers had a higher probability of cub loss than multiparous mothers. The probability of cub loss was analyzed separately for the premating and the mating season. The probability of cub loss by primiparous females in the pre-mating season increased with both increasing population density and deteriorating food conditions, whereas the probability of cub loss during the mating season decreased with increasing age of primiparity and increased with male turnover (a variable predicting SSI). The temporal patterns of cub loss by primiparous females suggested that the critical times for reproductive success by primiparous females were the pre-mating season (from birth to shortly after leaving the den) and the mating season. Cub loss in these periods was independent and caused by diVerent factors. Cub loss before the mating season seemed to be most inXuenced by food conditions, whereas that during the mating season appeared to be caused by SSI