Shoot increment of Calluna is the most sensitive indicator for N fertilisation.
Cryptogam tissue C:N ratios responded to N inputs ≥5 kg ha−1 yr−1 after 3 years.
Shifts in species cover occurred after 3 years of N inputs ≥10 kg ha−1 yr−1.
C:N ratios of the mineral soil were inappropriate indicators for N inputs.
Dwarf shrub growth suggests ecosystem sensitivity even to low but chronic N inputs.