Optimal foraging by a large ungulate in an extreme environment: Wild mountain reindeer select snow‐free feeding habitats in winter

Romtveit, Lena; Strand, Olav; Mossing, Anders; Kastdalen, Leif; Hjeltnes, Arne W.; Bjerketvedt, Dag; Odland, Arvid; Heggenes, Jan

doi:10.1002/ece3.7843

Cited by 4 publications

(3 citation statements)

References 77 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As such, snow-free habitats, irrespective of their lichen cover, likely provide energy-efficient foraging habitats. This hypothesis was indirectly supported by remote sensing data (Romtveit et al 2021), suggesting that wild Mountain reindeer were located on or close to snowfree patches much more frequently than expected from a 'random walk'. Therefore, we predict direct observations of reindeer foraging behaviours will document that Mountain reindeer preferably feed on snow-free patches, and primarily walk when on snow.…”

Section: Introductionmentioning

confidence: 81%

“…We suggest forage availability may be best predicted via amounts of vegetated snow-free patches in alpine areas, and not restricted to lichen resources only. Snow-free patches also have the considerable benefit of being estimable via remote sensing data (Romtveit et al 2021).…”

Section: Discussionmentioning

confidence: 99%

“…Snow cover (thickness and duration) and snow melt may vary across years, but snow-free areas tend to be similar across winters for topographic and wind reasons (Kohler et al 2006;Odland et al 2018), and the corresponding snow melt patterns remain remarkably consistent among microsites (Gjaerevoll 1956;Billings and Bliss 1959). Modelling of snow cover based on remote sensing data (Romtveit et al 2021), indicated snow melt starting to accelerate during the last week of May in all three areas and in both study years (2012,2017).…”

Section: Videos and Behavioural Datamentioning

confidence: 99%

See 2 more Smart Citations

Wild Mountain reindeer Rangifer tarandus tarandus winter foraging: snow-free areas a key resource for feeding

Holtan,

Strand,

Kastdalen

et al. 2023

Polar Biol

Self Cite

View full text Add to dashboard Cite

In a landscape with patchily distributed forage resources, an animal’s distribution may reflect the distribution of the resources if the population is forage-limited in time or space. This may be particularly explicit in climatically extreme and seasonally variable environments, notably alpine and polar environments during winter. Sustainable management considers the amount of available alpine ground lichen in winter as a predictor of carrying capacity for the last remaining populations of wild European Mountain reindeer Rangifer tarandus tarandus in alpine environments in South Norway. Ground lichen growth is constrained to elevated, wind-blown, snow-free ridges. However, wild Mountain reindeer also persist in areas providing little lichen resources. Our alternative functional hypothesis is that the critical resource is the amount of snow-free feeding areas during winter, which provide direct access to forage, likely to be energy-profitable regardless of the type of vegetation. We sampled animal-borne videos from wild Mountain reindeer during maximum accumulation of snow in late winter/spring, in three contrasting areas providing variable amounts of ground lichen and alternative vegetation resources. Direct observations of reindeer foraging via videos document an active selection and strong preference for feeding on snow-free patches, regardless of type of vegetation. Active ‘cratering’ in snow was not observed. In contrast, walking behaviours occurred much more frequently across snow-covered areas. Remote sensing data and analyses corroborated these observations. In the sustainable management of wild Mountain reindeer amounts of vegetated snow-free areas is an important functional predictor of winter carrying capacity.

show abstract

Section: Introductionmentioning

confidence: 81%

Section: Discussionmentioning

confidence: 99%

Section: Videos and Behavioural Datamentioning

confidence: 99%

See 1 more Smart Citation

Wild Mountain reindeer Rangifer tarandus tarandus winter foraging: snow-free areas a key resource for feeding

Holtan,

Strand,

Kastdalen

et al. 2023

Polar Biol

Self Cite

View full text Add to dashboard Cite

show abstract

Trade‐Offs Between Forage Availability, Accessibility, and Predation Risk on Winter Foraging Strategies of Wood Bison (Bison bison athabascae)

Rawleigh,

Edwards,

Epperson

et al. 2024

Ecology and Evolution

View full text Add to dashboard Cite

Optimal foraging theory (OFT) and the energy maximization hypothesis (EMH) have long been essential when examining wildlife habitat selection. At high latitudes and altitudes, animals in winter face greater limitations in availability and accessibility of forage. Here we explore the foraging behavior of wood bison (Bison bison athabascae) during winter within the Ronald Lake bison herd in northeastern Alberta, Canada, and examine the trade‐offs they face due to limitations in forage abundance and availability (snow conditions), as well as the need to minimize predation risk. We used Global Positioning System (GPS) location data collected from 70 female wood bison to identify winter foraging sites and craters selected by bison to access forage beneath the snow. Within wetlands used by bison we selected 190 pairs of used (foraged) and random (available) sites to test eight a priori hypotheses explaining how bison traded‐off between forage availability, accessibility, and minimizing predation risk. We found with matched‐paired logistic regression that Carex atherodes was 1.21‐times more likely to be selected per unit increase in ground cover, compared to 1.17‐times per unit ground cover for C. aquatilis and C. utriculata. However, all Carex species showed an increase in selection when cover was > 50% cover within individual craters. While the importance of Carex was clear, forage site selection was still inversely related to snow depth. There is also a neutralizing combined effect of snow depth and Carex species ground cover which suggests that bison maximized their energy return by avoiding areas with deep snow (> 30 cm) that demanded intensive cratering, even when highly selected forage was accessible beneath. Avoidance of forage areas with deep snow demonstrates that wood bison employed a foraging strategy that considers both forage availability and environmental conditions, with snow depth being a limiting factor. We highlight the relationship between optimal foraging based on food availability and the trade‐offs within an energy restrictive winter season, furthering the understanding of how large herbivores forage strategically to maximize energy intake in northern environments.

show abstract

Dietary differences in males and females of a strongly sexually dimorphic ungulate

Brambilla,

Bal,

Lusetti

et al. 2024

Eur J Wildl Res

View full text Add to dashboard Cite

Detailed knowledge of dietary preferences in wild species are important both for understanding evolutionary processes as well as for their conservation. By means of DNA metabarcoding analysis of faecal samples, we investigated the diet of Alpine ibex (Capra ibex), a mountain ungulate characterised by strong sexual dimorphism and segregation, and analysed differences between male and female diet. Despite a low level of selectivity, we found differences in the diet of males and females that consumed different plant in different quantities. Differences were maintained during both spring and summer. Males tended to feed more on plants richer in fibres (i.e., grasses and sedges) and showed stronger seasonal differences while females consumed more digestible plant families (i.e., forbs). Differences in diet between male and female Alpine ibex are compatible with the strong sexual dimorphism and segregation typical of the species and with female reproductive constraints. These results also show that conservation actions have to take into account different ecological needs of males and females in species characterized by sexual dimorphism and segregation.

show abstract

Optimal foraging by a large ungulate in an extreme environment: Wild mountain reindeer select snow‐free feeding habitats in winter

Abstract: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Cited by 4 publications

References 77 publications

Wild Mountain reindeer Rangifer tarandus tarandus winter foraging: snow-free areas a key resource for feeding

Wild Mountain reindeer Rangifer tarandus tarandus winter foraging: snow-free areas a key resource for feeding

Trade‐Offs Between Forage Availability, Accessibility, and Predation Risk on Winter Foraging Strategies of Wood Bison (Bison bison athabascae)

Dietary differences in males and females of a strongly sexually dimorphic ungulate

Contact Info

Product

Resources

About