Figure 1.

(a) Map with the six locations where 128 individual specimens of S. glauca, S. arctica and B. nana were collected. For each location is given latitude and the number of collected individuals. Average length of growth time series was 34.27 ± 1.62 (±s.e.m.) years with a minimum length of 11 years and a maximum length of 116 years. (b) Variations in the average estimated autoregressive coefficients b₁ (direct temporal dependence) and and b₂ (delayed temporal dependence) (equation (2.1)) across locations. (c) Latitudinal variations in the estimated average effect of June sea-ice extent (c₁) and annual growth (G_t) and long-term annual growth equilibrium (G*). Horizontal bars indicate ± s.e.m.