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Populasjonssykluser hos hare – drevet av rovdyr og spesielt gaupe
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-27)
Snøskohare – og gaupesyklusene i det boreale Nord-Amerika er et av de best kjente eksempler på populasjonssykluser. Sammenlignet med andre sykliske arter har denne syklusen en relativ konstant periode på 9–10 år. Haretettheten varierer typisk 20–30 ganger mellom topp- og bunnår. Mye økologisk forskning har ved hjelp av forskjellige metoder forsøkt å avdekke årsakene til snøskoharesyklusene, også med ...
Deepened winter snow significantly influences the availability and forms of nitrogen taken up by plants in High Arctic tundra
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-13)
Climate change may alter nutrient cycling in Arctic soils and plants. Deeper snow during winter, as well as summer warming, could increase soil temperatures and thereby the availability of otherwise limiting nutrients such as nitrogen (N). We used fences to manipulate snow depths in Svalbard for 9 consecutive years, resulting in three snow regimes: 1) <i>Ambient</i> with a maximum snow depth of ...
Comparison of budburst phenology trends and precision among participants in a citizen science program
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-01)
Quantifying shifts in plant phenology in response to climate change represents an ongoing challenge, particularly in mountain ecosystems. Because climate change and phenological responses vary in space and time, we need long-term observations collected at a broad spatial scale. While data collection by volunteers is a promising approach to achieve this goal, one major concern with citizen science ...
Temporal trend of mercury in relation to feeding habits and food availability in arctic foxes (Vulpes lagopus) from Svalbard, Norway
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-20)
We investigated the temporal trend of mercury (Hg) in arctic foxes from Svalbard, Norway sampled in the period 1997–2014 (<i>n</i> = 109, from 11 trapping seasons). We used linear models to investigate the effect of trapping season, feeding habits (δ<sup>13</sup>C), food availability from marine and terrestrial ecosystems (reindeer carcasses and sea ice cover), sex, age and body condition on liver ...
Identifying key needs for the integration of social-ecological outcomes in arctic wildlife monitoring
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-24)
For effective monitoring in social–ecological systems to meet needs for biodiversity, science, and humans, desired outcomes must be clearly defined and routes from direct to derived outcomes understood. The Arctic is undergoing rapid climatic, ecological, social, and economic changes and requires effective wildlife monitoring to meet diverse stakeholder needs. To identify stakeholder priorities ...
Sources of variation in small rodent trophic niche: New insights from DNA metabarcoding and stable isotope analysis
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014-05-15)
Quantifying individual heterogeneity and its influence on life-history trajectories: different methods for different questions and contexts
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-09-25)
Heterogeneity among individuals influences the life‐history trajectories we observe at the population level because viability selection, selective immigration and emigration processes, and ontogeny change the proportion of individuals with specific trait values with increasing age. Here, we review the two main approaches that have been proposed to account for these processes in life‐history trajectories, ...
Gatekeepers to the effects of climate warming? Niche construction restricts plant community changes along a temperature gradient
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-20)
Organisms that modify the environment (niche constructors) are likely candidates to mediate the effects of climate warming. Here we assess tundra plant community changes
along a temperature gradient and how these are modified in the presence of the common
allelopathic dwarf shrub Empetrum nigrum and the large herbivore Rangifer tarandus.
2
We developed a structural equation model based on data ...
Not only mosses: lemming winter diets as described by DNA metabarcoding
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-01)
The temporal dynamics of most tundra food webs are shaped by the cyclic population
dynamics of lemmings. While processes during winter may be behind the recent disruptions
of lemming cycles, lemming winter ecology is poorly known. We present here the first DNA metabarcoding data on the winter diet of Norwegian lemmings (Lemmus lemmus), based on feces collected after a winter of population ...
Earlier colony arrival but no trend in hatching timing in two congeneric seabirds (Uria spp.) across the North Atlantic
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-23)
A global analysis recently showed that seabird breeding phenology (as the timing of egg-laying and hatching) does not, on average, respond to temperature changes or advance with time (Keogan <i>et al.</i> 2018 <i>Nat. Clim. Change</i> <b>8</b>,
313–318). This group, the most threatened of all birds, is therefore prone to spatio-temporal mismatches with their food resources. Yet, other aspects of ...