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  • 1
    In: Parasitology, Cambridge University Press (CUP), Vol. 143, No. 8 ( 2016-07), p. 983-997
    Abstract: In wild and domestic animals, gastrointestinal parasites can have significant impacts on host development, condition, health, reproduction and longevity. Improving our understanding of the causes and consequences of individual-level variation in parasite load is therefore of prime interest. Here we investigated the relationship between strongyle fecal egg count (FEC) and body condition in a unique, naturalized population of horses that has never been exposed to anthelmintic drugs (Sable Island, Nova Scotia, Canada). We first quantified variation in FEC and condition for 447 individuals according to intrinsic (sex, age, reproductive status, social status) and extrinsic (group size, location, local density) variables. We then quantified the repeatability of measurements obtained over a field season and tested for covariance between FEC and condition. FECs were high relative to other horse populations (mean eggs per gram ± SD = 1543·28 ± 209·94). FECs generally decreased with age, were higher in lactating vs non-lactating females, and unexpectedly lower in males in some part of the island. FECs and condition were both spatially structured, with patterns depending on age, sex and reproductive status. FECs and condition were both repeatable. Most notably, FECs and condition were negatively correlated, especially in adult females.
    Type of Medium: Online Resource
    ISSN: 0031-1820 , 1469-8161
    RVK:
    Language: English
    Publisher: Cambridge University Press (CUP)
    Publication Date: 2016
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  • 2
    In: Ecology, Wiley, Vol. 97, No. 8 ( 2016-08), p. 1929-1937
    Abstract: Sea‐to‐land nutrient transfers can connect marine food webs to those on land, creating a dependence on marine webs by opportunistic species. We show how nitrogen, imported by gray seals, Halichoerus grypus , and traced through stable isotope (δ 15 N) measurements in marram grass , Ammophila breviligulata , significantly alters foraging behavior of a free‐roaming megaherbivore (feral horses, Equus ferus caballus ) on Sable Island, Canada. Values of δ 15 N correlated with protein content of marram and strongly related to pupping‐seal densities, and positively influenced selective foraging by horses. The latter was density dependent, consistent with optimal foraging theory. We present the first demonstration of how sea‐to‐land nutrient transfers can affect the behavioral process of resource selection (resource use relative to availability) of terrestrial consumers. We hypothesize that persistence of horses on Sable Island is being facilitated by N subsidies. Our results have relevance to advancing theory on trophic dynamics in island biogeography and metaecosystem ecology.
    Type of Medium: Online Resource
    ISSN: 0012-9658 , 1939-9170
    RVK:
    Language: English
    Publisher: Wiley
    Publication Date: 2016
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    detail.hit.zdb_id: 2010140-5
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  • 3
    In: Journal of Animal Ecology, Wiley, Vol. 89, No. 1 ( 2020-01), p. 173-185
    Abstract: Dispersal is a key mechanism enabling species to adjust their geographic range to rapid global change. However, dispersal is costly and environmental modifications are likely to modify the cost–benefit balance of individual dispersal decisions, for example, by decreasing functional connectivity. Dispersal costs occur during departure, transience and settlement, and are levied in terms of energy, risk, time and lost opportunity, potentially influencing individual fitness. However, to the best of our knowledge, no study has yet quantified the energetic costs of dispersal across the dispersal period by comparing dispersing and philopatric individuals in the wild. Here, we employed animal‐borne biologgers on a relatively large sample ( N  = 105) of juvenile roe deer to estimate energy expenditure indexed using the vector of dynamic body acceleration and mobility (distance travelled) in an intensively monitored population in the south‐west of France. We predicted that energy expenditure would be higher in dispersers compared to philopatric individuals. We expected costs to be (a) particularly high during transience, (b) especially high in the more fragmented areas of the landscape and (c) concentrated during the night to avoid disturbance caused by human activity. There were no differences in energy expenditure between dispersers and philopatric individuals during the pre‐dispersal phase. However, dispersers expended around 22% more energy and travelled around 63% further per day than philopatric individuals during transience. Differences in energy expenditure were much less pronounced during the settlement phase. The costs of transience were almost uniquely confined to the dawn period, when dispersers spent 23% more energy and travelled 112% further than philopatric individuals. Finally, the energetic costs of transience per unit time and the total distance travelled to locate a suitable settlement range were higher in areas of high road density. Our results provide strong support for the hypothesis that natal dispersal is energetically costly and indicate that transience is the most costly part of the process, particularly in fragmented landscapes. Further work is required to link dispersal costs with fitness components so as to understand the likely outcome of further environmental modifications on the evolution of dispersal behaviour.
    Type of Medium: Online Resource
    ISSN: 0021-8790 , 1365-2656
    URL: Issue
    RVK:
    Language: English
    Publisher: Wiley
    Publication Date: 2020
    detail.hit.zdb_id: 2006616-8
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  • 4
    In: Journal of Animal Ecology, Wiley, Vol. 81, No. 6 ( 2012-11), p. 1327-1327
    Type of Medium: Online Resource
    ISSN: 0021-8790
    RVK:
    Language: English
    Publisher: Wiley
    Publication Date: 2012
    detail.hit.zdb_id: 2006616-8
    SSG: 12
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  • 5
    In: Ecosphere, Wiley, Vol. 8, No. 12 ( 2017-12)
    Abstract: Partial migration is common in a large variety of taxa in seasonally variable environments. Understanding the mechanisms underlying migration is important, as migration affects individual fitness. Migratory herbivores benefit from delayed forage maturation and hence higher food quality during migration and at their summer range, termed the forage maturation hypothesis ( FMH ). The link between diet quality and rumination time allows migrants eating a higher quality diet to spend less time on rumination, and they can thus allocate more time to additional feeding. However, such an argument implicitly assumes that deer are energy maximizers, while studies have reported also time minimization strategies under risk of predation. Male and female distributions are limited by different factors linked to both body size differences and reproductive strategies, but there is no study investigating differences in activity pattern according to the individual migratory patterns for male and female deer. We here unify the FMH with the hypotheses predicting sex‐specific time allocation strategies. To test predictions of sex‐specific activity of resident and migratory red deer ( Cervus elaphus ), we analyzed activity data of 286 individuals that were fitted with GPS collars from a population in western Norway. While migrants were more active during the migration itself, we found no differences in activity pattern between migrant and resident deer during the main growth season, neither in terms of proportion of daily time active nor in terms of daily mean movement speed, thus rejecting that deer were energy maximizers. Overall, we found that females were more active during the main growth season even after controlling for body size differences. These patterns are consistent with patterns predicted from sexual segregation theory linked to the reproductive strategy hypothesis. Our study highlights how the understanding of migration can be advanced by considering it in the context of different reproductive strategies of males and females.
    Type of Medium: Online Resource
    ISSN: 2150-8925 , 2150-8925
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2017
    detail.hit.zdb_id: 2572257-8
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  • 6
    In: Oikos, Wiley, Vol. 125, No. 12 ( 2016-12), p. 1790-1801
    Abstract: Dispersal is a key life‐history trait governing the response of individuals, populations and species to changing environmental conditions. In the context of global change, it is therefore essential to better understand the respective role of condition‐, phenotype‐ and genetic‐dependent drivers of dispersal behaviour. Although the importance of immune function and pathogen infestation in determining patterns of dispersal is increasingly recognised, no study to our knowledge has yet investigated the influence of immune gene variability on dispersal behaviour. Here, we filled this knowledge gap by assessing whether individual heterozygosity at five immune gene loci (one from the Major histocompatibility complex and four from encoding Toll‐like receptors) influences roe deer natal dispersal. We found that dispersal propensity was affected by immune gene diversity, suggesting potential pathogen‐mediated selection through over‐dominance. However, the direction of this effect differed between high and low quality individuals, suggesting that dispersal propensity is driven by two different mechanisms. In support of the condition‐dependent dispersal hypothesis, dispersal propensity increased with increasing body mass and, among high quality individuals only (standardized body mass 〉 18 kg), with increasing immune gene diversity. However, among poor quality individuals, we observed the opposite pattern such that dispersal propensity was higher for individuals with lower immune gene diversity. We suggest that these poor quality individuals expressed an emergency dispersal tactic in an attempt to escape a heavily infested environment associated with poor fitness prospects. Our results have potentially important consequences in terms of population genetics and demography, as well as host–pathogen evolution.
    Type of Medium: Online Resource
    ISSN: 0030-1299 , 1600-0706
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2016
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  • 7
    Online Resource
    Online Resource
    Oxford University Press (OUP) ; 2015
    In:  Behavioral Ecology Vol. 26, No. 6 ( 2015), p. 1476-1485
    In: Behavioral Ecology, Oxford University Press (OUP), Vol. 26, No. 6 ( 2015), p. 1476-1485
    Type of Medium: Online Resource
    ISSN: 1045-2249 , 1465-7279
    RVK:
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2015
    detail.hit.zdb_id: 1496189-1
    SSG: 12
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  • 8
    In: Ecological Applications, Wiley, Vol. 32, No. 7 ( 2022-10)
    Abstract: Animals perceive human activities as risky and generally respond with fear‐induced proactive behaviors to buffer the circadian patterns of lethal and nonlethal disturbances, such as diel migrations (DMs) between risky places during safe nighttime and safer places during risky daytime. However, such responses potentially incur costs through movement or reduced foraging time, so individuals should adjust their tolerance when human activities are harmless, through habituation. Yet this is a challenging cognitive task when lethal and nonlethal risks co‐occur, forming complex landscapes of fear. The consequences of this human‐induced complexity have, however, rarely been assessed. We studied the individual DM dynamics of chamois ( Rupicapra rupicapra rupicapra ), 89 GPS‐tracked individual‐years, from/to trails in the French Alps in areas with co‐occurring lethal (hunting) and nonlethal (hiking and skiing) disturbances, with different intensities across seasons. We developed a conceptual framework relying on the risk‐disturbance hypothesis and habituation to predict tolerance adjustments of chamois under various disturbance contexts and across contrasted seasonal periods. Based on spatial and statistical analyses combining periodograms and multinomial logistic models, we found that DM in relation to distance to a trail was a consistent response by chamois (~85% of individuals) to avoid human disturbance during daytime, especially during the hiking and hunting periods. Such behavior revealed a low tolerance of most chamois to human activities, although there was considerable interindividual heterogeneity in DM. Interestingly, there was an increased tolerance among the most disturbed diel migrants, potentially through habituation, with chamois performing shorter DMs in areas highly disturbed by hikers. Crucially, chamois that were most human‐habituated during the hiking period remained more tolerant in the subsequent harvesting period, which could increase their risk of being harvested. In contrast, individuals less tolerant to hiking performed longer DMs when hunting risk increased, and compared to hiking, hunting exacerbated the threshold distance to trails triggering DMs. No carryover effect of hunting beyond the hunting period was observed. In conclusion, complex human‐induced landscapes of fear with co‐occurring disturbances by nature‐based tourism and hunting may shape unexpected patterns of tolerance to human activities, whereby animal tolerance could become potentially deleterious for individual survival.
    Type of Medium: Online Resource
    ISSN: 1051-0761 , 1939-5582
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2022
    detail.hit.zdb_id: 2010123-5
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  • 9
    In: Behavioural Processes, Elsevier BV, Vol. 132 ( 2016-11), p. 22-28
    Type of Medium: Online Resource
    ISSN: 0376-6357
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2016
    detail.hit.zdb_id: 1499897-X
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  • 10
    In: Global Change Biology, Wiley, Vol. 29, No. 20 ( 2023-10), p. 5788-5801
    Abstract: Human activity and associated landscape modifications alter the movements of animals with consequences for populations and ecosystems worldwide. Species performing long‐distance movements are thought to be particularly sensitive to human impact. Despite the increasing anthropogenic pressure, it remains challenging to understand and predict animals' responses to human activity. Here we address this knowledge gap using 1206 Global Positioning System movement trajectories of 815 individuals from 14 red deer ( Cervus elaphus ) and 14 elk ( Cervus canadensis ) populations spanning wide environmental gradients, namely the latitudinal range from the Alps to Scandinavia in Europe, and the Greater Yellowstone Ecosystem in North America. We measured individual‐level movements relative to the environmental context, or movement expression, using the standardized metric Intensity of Use, reflecting both the directionality and extent of movements. We expected movement expression to be affected by resource (Normalized Difference Vegetation Index, NDVI) predictability and topography, but those factors to be superseded by human impact. Red deer and elk movement expression varied along a continuum, from highly segmented trajectories over relatively small areas (high intensity of use), to directed transitions through restricted corridors (low intensity of use). Human activity (Human Footprint Index, HFI) was the strongest driver of movement expression, with a steep increase in Intensity of Use as HFI increased, but only until a threshold was reached. After exceeding this level of impact, the Intensity of Use remained unchanged. These results indicate the overall sensitivity of Cervus movement expression to human activity and suggest a limitation of plastic responses under high human pressure, despite the species also occurring in human‐dominated landscapes. Our work represents the first comparison of metric‐based movement expression across widely distributed populations of a deer genus, contributing to the understanding and prediction of animals' responses to human activity.
    Type of Medium: Online Resource
    ISSN: 1354-1013 , 1365-2486
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2023
    detail.hit.zdb_id: 2020313-5
    SSG: 12
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