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  • 1
    Online Resource
    Online Resource
    Demography of Ferruginous Hawks Breeding in Western Canada
    Wiley ; 2008
    In:  Journal of Wildlife Management Vol. 72, No. 6 ( 2008-08), p. 1352-1360
    Details
    In: Journal of Wildlife Management, Wiley, Vol. 72, No. 6 ( 2008-08), p. 1352-1360
    Type of Medium: Online Resource
    ISSN: 0022-541X , 1937-2817
    URL: Article
    DOI: 10.2193/2007-231
    Language: English
    Publisher: Wiley
    Publication Date: 2008
    detail.hit.zdb_id: 2066663-9
    SSG: 12
    SSG: 23
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  • 2
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    Nested population structure of threatened boreal caribou revealed by network analysis
    Elsevier BV ; 2022
    In:  Global Ecology and Conservation Vol. 40 ( 2022-12), p. e02327-
    Details
    In: Global Ecology and Conservation, Elsevier BV, Vol. 40 ( 2022-12), p. e02327-
    Type of Medium: Online Resource
    ISSN: 2351-9894
    URL: Article
    DOI: 10.1016/j.gecco.2022.e02327
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2022
    detail.hit.zdb_id: 2814786-8
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  • 3
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    Predicting patterns of terrestrial lichen biomass recovery following boreal wildfires
    Wiley ; 2021
    In:  Ecosphere Vol. 12, No. 4 ( 2021-04)
    Details
    In: Ecosphere, Wiley, Vol. 12, No. 4 ( 2021-04)
    Abstract: Increased fire activity due to climate change may impact the successional dynamics of boreal forests, with important consequences for caribou habitat. Early successional forests have been shown to support lower quantities of caribou forage lichens, but geographic variation in, and controls on, the rates of lichen recovery has been largely unexplored. In this study, we sampled across a broad region in northwestern Canada to compare lichen biomass accumulation in ecoprovinces, including the Saskatchewan Boreal Shield, the Northwest Territories Taiga Shield, and Northwest Territories Taiga Plains, divided into North and South. We focused on the most valuable Cladonia species for boreal and barren‐ground caribou: Cladonia mitis and C. arbuscula , C. rangiferina and C. stygia , and C. stellaris and C. uncialis . We developed new allometric equations to estimate lichen biomass from field measurements of lichen cover and height; allometries were consistent among ecoprovinces, suggesting generalizability. We then used estimates of lichen biomass to quantify patterns of lichen recovery in different stand types, ecoprovinces, and with time following stand‐replacing fire. We used a hurdle model to account both for the heterogeneous nature of lichen presence (zero inflation) and for the range of abundance in stands where lichen was present. The first component of the hurdle model, a generalized linear model, identified stand age, stand type, and ecoprovince as significant predictors of lichen presence. With a logistic growth model, a measure of lichen recovery (time to 50% asymptotic value) varied from 28 to 73 yr, dependent on stand type and ecoprovince. The combined predictions of the hurdle model suggest the most rapid recovery of lichen biomass across our study region occurred in jack pine in the Boreal Shield (30 yr), while stands located in the Taiga Plains (North and South) required a longer recovery period (approximately 75 yr). These results provide a basis for estimating future caribou habitat that encompasses some of the large variation in fire effects on lichen abundance and vegetation types across the range of boreal and barren‐ground caribou in North America.
    Type of Medium: Online Resource
    ISSN: 2150-8925 , 2150-8925
    URL: Issue
    URL: Article
    DOI: 10.1002/ecs2.v12.4
    DOI: 10.1002/ecs2.3481
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 2572257-8
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  • 4
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    Science to inform policy: Linking population dynamics to habitat for a threatened species in Canada
    Wiley ; 2020
    In:  Journal of Applied Ecology Vol. 57, No. 7 ( 2020-07), p. 1314-1327
    Details
    In: Journal of Applied Ecology, Wiley, Vol. 57, No. 7 ( 2020-07), p. 1314-1327
    Abstract: Boreal forests provide numerous ecological services, including the ability to store large amounts of carbon, and are of significance to global biodiversity. Increases in industrial activities in boreal landscapes since the mid‐20th century have added to concerns over biodiversity loss and climate change. Boreal forests are home to dwindling populations of boreal caribou Rangifer tarandus caribou in Canada, a species at risk that requires large, undisturbed landscapes for persistence. In 2012, the Canadian government defined critical habitat for boreal caribou by relating calf recruitment to disturbances. Some have questioned whether the recruitment relationship can be extrapolated beyond the environmental conditions represented in the analysis. We examined the effects of human disturbances and fire (alone and in combination) on variation in recruitment and adult female survival using data from 58 study areas in Canada. Top models were used in aspatial scenarios of landscape change to evaluate the efficacy of the critical habitat definition in achieving the recovery objectives for boreal caribou in two contrasting landscapes: Little Smoky, dominated by high levels of human disturbances, and the northern boreal shield of Saskatchewan (SK1), dominated by fire. The top recruitment model suggested the negative effect of fire was three to four times smaller than human disturbances. The top adult female survival model included human disturbances only. These results re‐affirm that human disturbances are the primary factor contributing to boreal caribou declines. Our aspatial scenarios suggested that undisturbed habitat would have to increase to ≥68% for Little Smoky to maintain a self‐sustaining population of boreal caribou with some degree of certainty. In contrast, the SK1 population was self‐sustaining with 40% undisturbed habitat when fire disturbance predominates, but could become vulnerable with increases in human disturbances (8%–9%). Policy implications . Boreal caribou are listed as threatened under Canada's Species at Risk Act. Our results suggest that the 65% undisturbed critical habitat designation in Canada's boreal caribou Recovery Strategy may serve as a reasonable proxy for achieving self‐sustaining populations of boreal caribou in landscapes dominated by human disturbances. However, some populations may be less or more vulnerable, as illustrated by the scenarios in a landscape dominated by fire (SK1). Continued population monitoring will be essential to assessing the effectiveness of land management strategies developed for boreal caribou recovery, especially with climate change.
    Type of Medium: Online Resource
    ISSN: 0021-8901 , 1365-2664
    URL: Issue
    URL: Article
    DOI: 10.1111/jpe.v57.7
    DOI: 10.1111/1365-2664.13637
    Language: English
    Publisher: Wiley
    Publication Date: 2020
    detail.hit.zdb_id: 2020408-5
    detail.hit.zdb_id: 410405-5
    SSG: 12
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  • 5
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    Hair Cortisol Concentrations in Feral Horses and the Influence of Physiological and Social Factors
    MDPI AG ; 2023
    In:  Animals Vol. 13, No. 13 ( 2023-06-27), p. 2133-
    Details
    In: Animals, MDPI AG, Vol. 13, No. 13 ( 2023-06-27), p. 2133-
    Abstract: Cortisol is a glucocorticoid hormone produced during activation of the hypothalamic–pituitary–adrenal axis (HPA) in response to psychological or physiological demands. High amounts of circulating cortisol can be found in individuals experiencing energetically demanding physiological events, such as pregnancy, lactation, injury, or starvation, but, also, in individuals who may have less obvious HPA activation from social situations. The feral horse population on Sable Island (Nova Scotia, Canada) provides an opportunity to look at hair cortisol concentration (HCC) as a proxy for circulating cortisol concentration to better understand physiological correlates. The horse’s complex social structure also allows us to look at how the population and group structure may influence HPA activation. Hair samples (n = 282) were analyzed from 113 females and 135 males. Females with dependent offspring (foals) had higher HCC than those females without dependent offspring (p = 0.005). Horses in poor body condition were also more likely to have higher HCC (females: p 〈 0.001, males: p = 0.028); females had greater variation in the body condition index (BCI), which also correlated with foal production. In general, the top-ranked models describing female cortisol levels included age, BCI, presence of a foal, as well as social measures such as harem size and the number of bachelors in the vicinity. The top model describing male cortisol levels included age, BCI, and year of collection only, and the number of bachelors in the home range appeared in subsequent, though still high-ranked, models. Among the variables not of direct interest, we found some significant results relating to hair color and hair texture. Differences in HCC patterns between feral and domestically kept horses (e.g., age and sex) are likely linked to periods of resource limitations, particularly for individuals experiencing energetically demanding processes such as reproduction, illness/parasitism, or related to experiencing the full range of social and reproductive behaviors.
    Type of Medium: Online Resource
    ISSN: 2076-2615
    URL: Article
    DOI: 10.3390/ani13132133
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2606558-7
    SSG: 23
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  • 6
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    Island tameness and the repeatability of flight initiation distance in a large herbivore
    Canadian Science Publishing ; 2017
    In:  Canadian Journal of Zoology Vol. 95, No. 10 ( 2017-10), p. 771-778
    Details
    In: Canadian Journal of Zoology, Canadian Science Publishing, Vol. 95, No. 10 ( 2017-10), p. 771-778
    Abstract: Antipredator behaviours can be lost relatively quickly in populations that are relieved of predation, as is known for several species inhabiting islands. Flight initiation distance (FID) is often studied in the context of island tameness; however, little is known about the factors that influence and maintain FID variation in predation-free populations. Here, we studied FID in foals of an isolated predator-free population of feral horses (Equus caballus L., 1758) on Sable Island, Canada, to determine if FID could be used for research on consistent individual differences in risk aversion and island tameness. In addition to testing for temporal, spatial, and sex effects on FID, we compared repeatability estimates at two temporal scales (within and among days). Similar FID for measurements obtained on the same day and for males and females indicated an absence of short-term desensitization and sex effects. In contrast, FID decreased for measurements made on subsequent days and from east to west, which could reflect habituation to human presence and (or) other temporal and spatial processes. Repeatability was high (0.42 ± 0.06), but tended to decrease with increasing time intervals. This study highlights the potential of FID for individual-based research on the ecology and evolutionary dynamics of risk aversion in predation-free populations.
    Type of Medium: Online Resource
    ISSN: 0008-4301 , 1480-3283
    URL: Article
    DOI: 10.1139/cjz-2016-0305
    RVK:
    WA 15000
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2017
    detail.hit.zdb_id: 1490831-1
    SSG: 12
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  • 7
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    Overcoming radiotelemetry bias in habitat-selection studies
    Canadian Science Publishing ; 1999
    In:  Canadian Journal of Zoology Vol. 77, No. 8 ( 1999-11-01), p. 1175-1184
    Details
    In: Canadian Journal of Zoology, Canadian Science Publishing, Vol. 77, No. 8 ( 1999-11-01), p. 1175-1184
    Abstract: For many species, determination of habitat selection is based on habitat-use data obtained through radiotelemetry. Recent papers pertaining to study techniques have largely ignored the effect of habitat-dependent bias in the performance of radiotelemetry systems. Such biases cannot be overcome by increasing radiotelemetry precision, excluding data, or increasing sample sizes, as the biases are centred around data that are missing or that contain habitat-dependent errors in location. The problem is best addressed at the data-analysis stage through the use of geographic information systems. We used Monte Carlo simulations to assess the effect of habitat-dependent bias in radiotelemetry studies on the assessment of habitat selection. We looked at the effects of habitat-patch size, level of telemetry signal inhibition, level of habitat co-occurrence, and selection pattern. We demonstrated that regarding use as the composition of habitat types within a circular area around each telemetry location can help to overcome the inaccurate assessment of habitat-selection patterns that biased data produce. The size of the circular area best able to overcome the bias is related to habitat patch size and to the level of association between two or more habitat types. Furthermore, we argue that the characteristics of habitat mosaics selected by animals can and should be studied in this way.
    Type of Medium: Online Resource
    ISSN: 0008-4301 , 1480-3283
    URL: Article
    DOI: 10.1139/z99-079
    RVK:
    WA 15000
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 1999
    detail.hit.zdb_id: 1490831-1
    SSG: 12
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  • 8
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    Climatic conditions cause spatially dynamic polygyny thresholds in a large mammal
    Wiley ; 2017
    In:  Journal of Animal Ecology Vol. 86, No. 2 ( 2017-03), p. 296-304
    Details
    In: Journal of Animal Ecology, Wiley, Vol. 86, No. 2 ( 2017-03), p. 296-304
    Abstract: The polygyny threshold ( PT ) is a critical transition point in the sexual selection process for many organisms in natural populations, characterizing when females choose to mate with an already mated male over an unmated one to improve fitness. Understanding its causes and consequences is therefore of high interest. While both theoretical and empirical work suggest that the degree of polygyny within a species is plastic and a function of male inequality, the functional relationship between underlying availability of resources occupied by breeding males under variable climatic conditions and the dynamics of PT s across space and time has received less attention. Here, we use a standardized measure of male mating inequality as the culmination of female mate choices to analyse how spatially dynamic PT s in a naturally regulated feral horse ( Equus ferus caballus ) population emerge along a geographic gradient in a known, limiting resource (freshwater) each year from variable climatic conditions. Polygyny threshold distance from permanent freshwater increased with increasing precipitation during the breeding season of each year, suggesting a relationship between annual resource availability and female mate choice. The mechanism by which climatic conditions underpin the spatial dynamics of PT s was likely through precipitation providing ephemeral freshwater sources across the study area that effectively weakened the gradient in availability of permanent freshwater, thereby providing mating males that occupied home ranges far from permanent water with access to this limiting resource and enabling them to attract and retain females. Increased precipitation also coincided with a decreased proportion of males in the population that experienced sexual selection pressure attributed to female mate choice in relation to the acquisition and/or defence of freshwater sources. Climatic conditions caused spatial shifts in PT s annually along the geographic gradient in resource availability. Our findings reveal that such environmental gradients may either buffer or amplify impacts of climatic variation on selection pressure operating in natural populations, and emphasize the importance of integrating spatially explicit PT s with atmospheric fluctuations when predicting the effect of climatic change on selection processes within populations that occupy environmental gradients.
    Type of Medium: Online Resource
    ISSN: 0021-8790 , 1365-2656
    URL: Issue
    URL: Article
    DOI: 10.1111/jane.2017.86.issue-2
    DOI: 10.1111/1365-2656.12608
    RVK:
    WA 15000
    Language: English
    Publisher: Wiley
    Publication Date: 2017
    detail.hit.zdb_id: 2006616-8
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  • 9
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    Relative Contributions of Sampling Error in Initial Population Size and Vital Rates to Outcomes of Population Viability Analysis : Sampling Error in PVA
    Wiley ; 2004
    In:  Conservation Biology Vol. 18, No. 6 ( 2004-12), p. 1665-1669
    Details
    In: Conservation Biology, Wiley, Vol. 18, No. 6 ( 2004-12), p. 1665-1669
    Type of Medium: Online Resource
    ISSN: 0888-8892
    URL: Article
    DOI: 10.1111/j.1523-1739.2004.00500.x
    Language: English
    Publisher: Wiley
    Publication Date: 2004
    detail.hit.zdb_id: 2020041-9
    SSG: 12
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  • 10
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    Local density and group size interacts with age and sex to determine direction and rate of social dispersal in a polygynous mammal
    Wiley ; 2013
    In:  Ecology and Evolution Vol. 3, No. 9 ( 2013-09), p. 3073-3082
    Details
    In: Ecology and Evolution, Wiley, Vol. 3, No. 9 ( 2013-09), p. 3073-3082
    Abstract: Movement away from an area or social group in response to increasing density (density‐dependent dispersal) is known for most species; why it evolves is fundamental to our understanding of ecology and evolution. However, we have yet to fully appreciate how individuals of varying conditions (e.g., age and sex) might differently consider effects of density (quorum) when deciding to disperse or not, and scale dependence in their sense of quorum. We tracked movements of all individuals of a naturalized population of feral horses ( Equus ferus caballus ; Sable Island National Park Reserve, Nova Scotia, Canada) during a period of rapid population growth ( N increased from 375 to 484 horses from 2008 to 2010). Permanent dispersal from breeding groups (bands) was positively density dependent for all age and sex categories with respect to local density (horses/km 2 , bounded by the 99th percentile of individual movements [8000 m]), but was negatively and positively density dependent for males and females, respectively, in relation to group (band) size. Dispersal was generally female biased, with the exception of foals which moved with their mothers (no sex effect), and for yearlings and subadults when band sizes were smaller than average, in which case males dispersed at higher rates than females. Dispersal distance was positively related to local density. We conclude that dispersal rate can be both positively and negatively density dependent for feral horses, contingent on the state of individuals and the scale at which quorum with respect to choosing to disperse or not is assessed. Scale effects and interactions of density‐dependent and sex‐ and age‐biased dispersal may have both ecological and evolutionary consequences through effects on resource and mate competition.
    Type of Medium: Online Resource
    ISSN: 2045-7758 , 2045-7758
    URL: Issue
    URL: Article
    DOI: 10.1002/ece3.2013.3.issue-9
    DOI: 10.1002/ece3.694
    Language: English
    Publisher: Wiley
    Publication Date: 2013
    detail.hit.zdb_id: 2635675-2
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