Ecological descriptor | Type of effect | Parameter related to the NAO | Suggested mechanism | Reference |
UK and US birds | Direct | Timing of egg laying | Alteration of physiological rates (temperature effect) | Crick et al. (1997); *Forchhammer et al. (1998a); McCleery and Perrins (1998); Crick and Sparks (1999); *Forchhammer and Post (2000); Sćther et al. (2000); *Wuethrich (2000) |
UK amphibians | Direct | Timing of spawning | Alteration of physiological rates (temperature effect) | Beebee (1995); *Forchhammer et al. (1998a); *Forchhammer and Post (2000) |
Terrestrial plants | Direct | Timing of blooming/length of production season | Alteration of physiological rates (temperature, precipitation) | Myneni et al. (1997); Menzel and Fabian (1999); *Post and Stenseth (1999) |
African terrestrial plants | Direct | Vegetation productivity | Alteration of physiological rates (precipitation) | *G. Oba et al. (2001) |
Zooplankton (Daphnia), central Europe | Direct | Abundance | Alteration of physiological rates (temperature) | *Straile and Geller (1998); *Straile (2000); Straile and Adrian (2000) |
Barents Sea cod and haddock | Direct | Growth rate in early stages | Alteration of physiological rates in larval and juvenile stages | Loeng et al. (1995); Ottersen and Loeng (2000) |
Sea trout fry, Lake District, UK | Direct | Date of fry emergence | Unknown but linked to temperature | *Elliott et al. (2000) |
Barents Sea cod and haddock | Direct/indirect | Recruitment levels | Regulates inflow of Atlantic water to the Barents Sea, influencing temperature and food availability for the larval and juvenile stages | Ottersen et al. (1994); Ottersen and Sundby (1995); Ottersen (1996) |
UK wheat | Direct/indirect | Quality | Delayed effect through rainfall during August (?) | *Kettlewell et al. (1999) |
North Sea cod and plaice | Direct/indirect | Recruitment levels | Unknown but linked to climate and temperature. Possibly modification of the timing of spawning, and alteration of the bioenergetic balance between metabolic requirements and food availability | Svendsen et al. (1995); *Dippner (1998a, 1998b); Planque and Frédou (1999); C.J. Fox, B. Planque, C.D. Darby, unpublished data |
Marine polychaetes | Direct?/indirect | Abundance | Effect of winter temperature on a predatory polychaete followed by changes in predation rates on two prey polychaete species | Beukema et al. (2000) |
North Sea zooplankton: Calanus species | Indirect | Abundance | Modification of the competition balance through alteration of phytoplankton production and change in sea surface temperature | *Fromentin and Planque (1996) |
North Sea zooplankton: Calanus finmarchicus | Indirect | Abundance | Alteration of the circulation and transport of individuals to the North Sea | Backhaus et al. (1994); *Planque and Taylor (1998); Stephens et al. (1998); Heath et al. (1999) |
European flycatchers (birds) | Indirect | Abundance | Modification of the competition balance between pied and collared flycatchers | *Sćtre et al. (1999) |
UK tits (birds) | Indirect | Abundance | Effect of early spring temperature on population density through juvenile survival rate, possibly related to migration and/or territorial behaviour | Slagsvold (1975) |
UK birds | Indirect | Spatial distribution | Migration northward in response to migration of prey (butterflies) in response to temperature increase | Thomas and Lennon (1999) |
Netherlands birds | Indirect | Timing of egg laying | Phenotypic selection on early-laying birds in response to earlier timing of food availability | Visser et al. (1998) |
Norwegian red deer | Indirect | Growth, breeding, density, and sex ratios | Combination of alteration of physiological rates, changes in the timing and availability of food, delayed effects through density-dependent mechanisms, in utero growth, fecundity | *Post et al. (1997, 1999a, 1999b, 1999c); *Forchhammer et al. (1998b); *Loison et al. (1999); *Post and Stenseth (1999); *Mysterud et al. (2000, in press) |
Soay sheep (Scotland) | Indirect | Abundance | Winter survival combined with density-dependent processes | *Milner et al. (1999); *Post and Stenseth (1999) |
Macrofaunal community | Indirect | Abundance | Effect on surface primary production transferred to the bottom macrofaunal community (Tunberg) or unspecified effect of temperature (Kröncke) | *Kröncke et al. (1998); *Tunberg and Nelson (1998) |
European sardine and herring | Indirect | Abundance | Changes in temperature and wind patterns causing regime shifts. Changes in the pattern of transport of herring in the North Sea | *Alheit and Hagen (1997); *Corten (1999) |
Salmon (rivers, coastal waters, open ocean) | Indirect/integrated | Salmon environment | Various effects on rivers, coastal waters and thermal habitat in oceanic waters (again, little is known about the mechanisms) | Friedland et al. (*1993, 1998); *Dickson and Turrell (1999); *Reid and Planque (1999) |
Canadian lynx | Indirect/ integrated | Population phenology | Uncertain; possibly alteration of trophic interactions | *Stenseth et al. (1999) |
Moose and white-tailed deer | Indirect/ integrated | Population dynamics | Effect on winter survival and density-dependent processes | *Post and Stenseth (1998) |
Wolf predation and moose dynamics | Indirect/cascading | Winter pack size | Increased pack size and deeper snow lead to higher kill rates and declines in moose density | *Post et al. (1999c) |
Southern Norway dipper (Cinclus cinclus) birds | Indirect/integrated | Population dynamics | Population dynamics and carrying capacity respond to temperature | Sćther et al. (2000) |
Phytoplankton (fjord, lake, open ocean) | Indirect/integrated | Abundance and production | Unknown (in Reid et al., the environmental factors which might be responsible are given but no clear mechanism is proposed); mechanism(s) under study | *Reid et al. (1998a, 1998b); *Belgrano et al. (1999); *Weyhenmeyer et al. (1999) |
Benthic foraminifera, Gullmar Fjord, Sweden | Indirect/integrated | Changes in faunal composition | Effects of changes in oxygen concentrations; mechanism(s) not clear | *Nordberg et al. (2000) |
North Sea zooplankton: Calanus finmarchicus | Integrated | Abundance | Reduction in the volume of Norwegian Sea Deep Water where C. finmarchicus overwinters | *Heath et al. (1999) |