title: Phenology and cover of plant growth forms predict herbivore habitat selection in a high latitude ecosystem.
abstract: The spatial and temporal distribution of forage quality is among the most central factors affecting herbivore habitat selection. Yet, for high latitude areas, forage quantity has been found to be more important than quality. Studies on large ungulate foraging patterns are faced with methodological challenges in both assessing animal movements at the scale of forage distribution, and in assessing forage quality with relevant metrics. Here we use first-passage time analyses to assess how reindeer movements relate to forage quality and quantity measured as the phenology and cover of growth forms along reindeer tracks. The study was conducted in a high latitude ecosystem dominated by low-palatable growth forms. We found that the scale of reindeer movement was season dependent, with more extensive area use as the summer season advanced. Small-scale movement in the early season was related to selection for younger stages of phenology and for higher abundances of generally phenologically advanced palatable growth forms (grasses and deciduous shrubs). Also there was a clear selection for later phenological stages of the most dominant, yet generally phenologically slow and low-palatable growth form (evergreen shrubs). As the summer season advanced only quantity was important, with selection for higher quantities of one palatable growth form and avoidance of a low palatable growth form. We conclude that both forage quality and quantity are significant predictors to habitat selection by a large herbivore at high latitude. The early season selectivity reflected that among dominating low palatability growth forms there were palatable phenological stages and palatable growth forms available, causing herbivores to be selective in their habitat use. The diminishing selectivity and the increasing scale of movement as the season developed suggest a response by reindeer to homogenized forage availability of low quality.
authors: Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway.
authors: Marianne
authors: M
authors: Iversen
authors: Norwegian Institute for Nature Research (NINA), Department of Arctic Ecology, Fram Centre, Tromsø, Norway.
authors: Per
authors: P
authors: Fauchald
authors: Norwegian Institute for Nature Research (NINA), Department of Arctic Ecology, Fram Centre, Tromsø, Norway.
authors: Knut
authors: K
authors: Langeland
authors: Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway.
authors: Rolf A
authors: RA
authors: Ims
authors: Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway.
authors: Nigel G
authors: NG
authors: Yoccoz
authors: Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway.
authors: Kari Anne
authors: KA
authors: Bråthen
mesh_terms: D025041:Animal Migration; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D017753:Ecosystem; D040362:Geographic Information Systems; D060434:Herbivory; D006109:Poaceae / Q000254:growth & development; D012053:Reindeer; D012621:Seasons