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| Throughout the Northern Hemisphere, changes in local and regional climate
conditions are coupled to the recurring and persistent large-scale patterns of
pressure and circulation anomalies spanning vast geographical areas, the
so-called teleconnection patterns. Indeed, the atmospheric fluctuations
described by the North Atlantic Oscillation (NAO) are closely associated
with the last four decades of inter-annual variability in local snow and ice
conditions observed in the Arctic. Since the NAO has also been connected with changes in the global climate, the behaviour of species, communities and
other ecosystem elements at Zackenberg in relation to the NAO enables us to
view these in circumpolar and global contexts.
Large-scale systems like the NAO constitute the link between the global
change and local climate variability to which ecosystem components respond.
Here, we place selected ecosystem elements from the monitoring programme
Zackenberg Basic presented in previous chapters in a circumpolar context
related to NAO-mediated climatic changes. We begin by linking the local
variability in winter weather conditions at Zackenberg to fluctuations in the
NAO. We then proceed by linking the observed intra- and inter-annual behaviour
of selected ecosystem elements to changes in the NAO. The functional
ecosystemcharacteristics in focus are landscape gas exchange dynamics phenological
patterns at diVerent trophic levels, consumer–resource dynamics and
community stability. The influence of the NAO is presented and discussed in a
broader perspective based on information obtained fromother arctic localities.
The relation between the NAO and the Zackenberg winter weather is nonlinear,
reflecting diVerential eVects of the NAO as the index moves between
high and low phases. The inverse hyperbolic relationship found between the
NAOand the amount ofwinter snowwas also evident as non-linear response in
organisms and systems to inter-annual changes in the NAO. Responses investigated
included growth and reproduction in plants and animals, population
dynamics and synchrony, inter-trophic interactions and community stability
together with system feedback dynamics | |
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