Organisms use changes in photoperiod to anticipate and exploit favourable conditions in a seasonal environment. While species living at temperate latitudes receive day length information as a year-round input, species living in the Arctic may spend as much as two-thirds of the year without experiencing dawn or dusk. This suggests that specialised mechanisms may be required to maintain seasonal ...

Successional processes can be observed for many organisms and resources, but most studies of succession have focused on plants. A general framework has been proposed, advocating that successional patterns in species turnover are predominantly driven by competition, dispersal or abiotic limitation, and that the patterning of species accumulation over time gives clues to which process is most influential ...

Nutrient supply to the surface ocean is a key factor regulating primary production in the Arctic Ocean under current conditions and with ongoing warming and sea ice losses. Here we present seasonal nitrate concentration and hydrographic data from two oceanographic moorings on the northern Barents shelf between autumn 2017 and summer 2018. The eastern mooring was sea ice-covered to varying degrees ...

To optimally time reproduction, seasonal mammals use a photoperiodic neuroendocrine system (PNES) that measures photoperiod and subsequently drives reproduction. To adapt to late spring arrival at northern latitudes, a lower photoperiodic sensitivity and therefore a higher critical photoperiod for reproductive onset is necessary in northern species to arrest reproductive development until spring ...

Polar regions are currently warming at a rate above the global average. One issue of concern is the consequences on biodiversity in relation to the Northward latitudinal shift in distribution of temperate species. In the present study, lasting almost two years, we examined two phenological traits, i.e. the shell growth and behavioural rhythm of a recently re-established species in the high Arctic, ...

Many terrestrial endotherm food webs constitute three trophic level cascades. Others have two trophic level dynamics (food limited herbivores; plants adapted to tackle intense herbivory) or one trophic level dynamic (herbivorous endotherms absent, thus plants compete for the few places where they can survive and grow). According to the Exploitation Ecosystems Hypothesis (EEH), these contrasting ...

Tap av dyr er en utfordring og et sentralt tema i norsk tamreindrift. Dette kunnskapsgrunnlaget beskriver status for hva vi vet om tapsomfang, tapsårsaker og tapsammenhenger innen områdene tap av rein til rovvilt, sykdom, klimarelatert tap, påkjørsler og grunnet kumulative effekter. Videre setter den fokus på forebyggende tiltak og hvilke felt man trenger ytterligere kunnskapsbygging på. Gjennomgående ...

Skogens helsetilstand påvirkes i stor grad av klima og værforhold, enten direkte ved tørke, frost og vind, eller indirekte ved at klimaet påvirker omfanget av soppsykdommer og insektangrep. Klimaendringene og den forventede økningen i klimarelaterte skogskader gir store utfordringer for forvaltningen av framtidas skogressurser. Det samme gjør invaderende skadegjørere, både allerede etablerte arter ...

Diatoms tend to dominate the Arctic spring phytoplankton bloom, a key event in the ecosystem including a rapid decline in surface-water <i>p</i>CO₂. While a mass sedimentation event of diatoms at the bloom terminus is commonly observed, there are few reports on the status of diatoms' health during Arctic blooms and its possible role on sedimentary fluxes. Thus, we examine the idea that ...