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How spatial variation in areal extent and configuration of labile vegetation states affect the riparian bird community in Arctic Tundra
(Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
The Arctic tundra is currently experiencing an unprecedented combination of climate change, change in grazing pressure by large herbivores and growing human activity. Thickets of tall shrubs represent a conspicuous vegetation state in northern and temperate ecosystems, where it serves important ecological functions, including habitat for wildlife. Thickets are however labile, as tall shrubs respond ...
Shedding new light on the diet of Norwegian lemmings: DNA metabarcoding of stomach content
(Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
Lemmings are key herbivores in many arctic food webs, and their population dynamics have major impacts on the functioning of tundra systems. However, current knowledge of lemming diet is limited, hampering evaluation of lemming–vegetation interactions. This lack of knowledge is mainly due to methodological challenges, as previously used microhistological methods result in large proportions of poorly ...
Local and regional determinants of colonisation-extinction dynamics of a riparian mainland-island root vole metapopulation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
The role of local habitat geometry (habitat area and isolation) in predicting species distribution has become an increasingly
more important issue, because habitat loss and fragmentation cause species range contraction and extinction. However, it
has also become clear that other factors, in particular regional factors (environmental stochasticity and regional population
dynamics), should be taken ...
How rapidly do invasive birch forest geometrids recruit larval parasitoids? Insights from comparison with a sympatric native geometrid
(Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
Two related issues in studies of biological invasions are how quickly the enemy complexes of invasive species become as species-rich and efficient as those of native species and how important enemy release is for the establishment and spread of invaders. We addressed these issues for the geometrid moths Operophtera brumata and Agriopis aurantiaria, who invaded the coastal mountain birch forest ...
Outbreaks by canopy-feeding geometrid moth cause state-dependent shifts in understorey plant communities
(Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
The increased spread of insect outbreaks is
among the most severe impacts of climate warming predicted
for northern boreal forest ecosystems. Compound
disturbances by insect herbivores can cause sharp transitions
between vegetation states with implications for ecosystem
productivity and climate feedbacks. By analysing
vegetation plots prior to and immediately after a severe and
widespread ...
Arctic Small Rodents Have Diverse Diets and Flexible Food Selection
(Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
The ecology of small rodent food selection is poorly understood, as mammalian herbivore food selection theory has mainly been developed by studying ungulates. Especially, the effect of food availability on food selection in natural habitats where a range of food items are available is unknown. We studied diets and selectivity of grey-sided voles (Myodes rufocanus) and tundra voles (Microtus oeconomus), ...
Indirect food web interactions mediated by rodent cycles: Relative roles of lemmings and voles
(Journal article; Tidsskriftartikkel; Peer reviewed, 2013-12-23)
Production cycles in birds are proposed as prime cases of indirect interactions
in food webs. They are thought to be driven by predators switching from
rodents to bird nests in the crash phase of rodent population cycles. Although
rodent cycles are geographically widespread and found in different rodent
taxa, bird production cycles appear to be most profound in the high Arctic
where lemmings ...