An experiment was carried out in two heathland ecosystems, one dominat
ed by Calluna vulgaris and the other by Molinia caerulea, to analyse t
he effects of soil organic matter accumulation and nutrient mineraliza
tion on plant species dynamics during succession. The experiment inclu
ded one treatment that received nutrient solution and two treatments w
here the rate of soil organic matter accumulation was reduced by remov
ing litter or accelerated by adding litter. In a fourth treatment the
C. vulgaris litter produced in the C. vulgaris-dominated plots was rep
laced by litter of M. caerulea and vice versa. Treatments were applied
over 8 years. Addition of nutrient solution caused C. vulgaris to dec
line, and grass species to increase sharply, compared to the control p
lots. Addition of litter enhanced both N mineralization and the biomas
s of M. caerulea and Deschampsia flexuosa but reduced the biomass of C
. vulgaris. The effects of replacing C. vulgaris litter by M. caerulea
litter, or vice versa, on N mineralization and species dynamics could
not be attributed to differences between the decomposability of the d
ifferent litter materials that were transferred. The results confirm t
he hypothesis that increased litter inputs accelerate the rate of spec
ies replacement during succession.