Blar i Institutt for natur, helse og miljø på forfatter "Heggenes, Jan"
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Are trampling effects by wild tundra reindeer understudied?
Heggenes, Jan; Odland, Arvid; Bjerketvedt, Dag (Journal article; Peer reviewed, 2018)Grazing and trampling by the wide-ranging wild tundra reindeer may have major top down landscape effects by causing vegetation changes. Grazing, as the collective effect of eating, trampling, defecation, and urination, has ... -
Colonizing the high arctic: Mitochondrial DNA reveals common origin of Eurasian archipelagic reindeer (Rangifer tarandus)
Kvie, Kjersti; Heggenes, Jan; Anderson, David G.; Kholodova, Marina V.; Sipko, Taras; Mizin, Ivan; Røed, Knut H. (Journal article; Peer reviewed, 2016)In light of current debates on global climate change it has become important to know more on how large, roaming species have responded to environmental change in the past. Using the highly variable mitochondrial control ... -
Herbivore grazing—or trampling? Trampling effects by a large ungulate in cold high- latitude ecosystems
Heggenes, Jan; Odland, Arvid; Chevalier, Tomas; Ahlberg, Jörgen; Berg, Amanda; Larsson, Håkan; Bjerketvedt, Dag (Journal article; Peer reviewed, 2017)Mammalian herbivores have important top-down effects on ecological processes and landscapes by generating vegetation changes through grazing and trampling. For free-ranging herbivores on large landscapes, trampling is an ... -
Hydropower‐driven thermal changes, biological responses and mitigating measures in northern river systems
Heggenes, Jan; Stickler, Morten; Alfredsen, Knut; Brittain, John Edward; Adeva Bustos, Ana; Huusko, Ari (Peer reviewed; Journal article, 2021)Water temperatures control life histories and diversity of aquatic species. Hydropower regulation, particularly in high head systems, alters natural water temperature regimes, which may have profound and long‐term impacts ... -
Landscape genetics of northern crested newt Triturus cristatus populations in a contrasting natural and human-impacted boreal forest
Haugen, Hanne; Linløkken, Arne; Østbye, Kjartan; Heggenes, Jan (Peer reviewed; Journal article, 2020)Among vertebrates, amphibians currently have the highest proportion of threatened species worldwide, mainly through loss of habitat, leading to increased population isolation. Smaller amphibian populations may lose more ... -
Life histories and ecotype conservation in an adaptive vertebrate: Genetic constitution of piscivorous brown trout covaries with habitat stability
Wollebæk, Jens; Heggenes, Jan; Røed, Knut H. (Journal article; Peer reviewed, 2018)Ecotype variation in species exhibiting different life history strategies may reflect heritable adaptations to optimize reproductive success, and potential for speciation.Traditionally, ecotypes have, however, been defined ... -
Merging and comparing three mitochondrial markers for phylogenetic studies of Eurasian reindeer (Rangifer tarandus)
Kvie, Kjersti; Heggenes, Jan; Røed, Knut H. (Journal article; Peer reviewed, 2016)Phylogenetic analyses provide information that can be useful in the conservation of genetic variation by identifying intraspecific genetic structure. Reconstruction of phylogenetic relationships requires the use of markers ... -
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 William; Bjerketvedt, Dag Kjartan; Odland, Arvid; Heggenes, Jan (Journal article; Peer reviewed, 2021)Optimal foraging models predict that individual animals will optimize net energy gain by intensifying forage activity and/or reducing forage energy cost. Then, the free distribution model predicts an animal's distribution ... -
Population connectivity: dam migration mitigations and contemporary site fidelity in arctic char
Wollebæk, Jens; Heggenes, Jan; Røed, Knut H. (Journal article; Peer reviewed, 2011-07-14)BACKGROUND: Animal feeding and spawning migrations may be limited by physical barriers and behavioral interactions. Dam constructions (e.g. hydropower) commonly include gateways for fish migrations to sustain ecological ... -
Predicting Habitat Properties Using Remote Sensing Data: Soil pH and Moisture, and Ground Vegetation Cover
Haugen, Hanne; Devineau, Olivier; Heggenes, Jan; Østbye, Kjartan; Linløkken, Arne N. (Peer reviewed; Journal article, 2022)Remote sensing data comprise a valuable information source for many ecological landscape studies that may be under-utilized because of an overwhelming amount of processing methods and derived variables. These complexities, ... -
Predicting Habitat Properties Using Remote Sensing Data: Soil pH and Moisture, and Ground Vegetation Cover
Haugen, Hanne; Devineau, Olivier; Heggenes, Jan; Østbye, Kjartan; Linløkken, Arne N. (Journal article; Peer reviewed, 2022)Remote sensing data comprise a valuable information source for many ecological landscape studies that may be under-utilized because of an overwhelming amount of processing methods and derived variables. These complexities, ... -
Soft resilience: moisture-dependent lichen elasticity buffer herbivore trampling in cold alpine-tundra ecosystems
Heggenes, Jan; Fagertun, Christian; Odland, Arvid; Bjerketvedt, Dag K. (Peer reviewed; Journal article, 2020)Herbivores may have extensive top-down effects in open grazing ecosystems, generating vegetation changes by grazing and trampling. Trampling effects are understudied, but may be a major ecological factor. In cold alpine-Arctic ...