Differences in response of two Sphagnum species to elevated CO2 and nitrogen input

Cushions of Sphagnum fuscum and S. angustifolium were grown in the laboratory in four different CO2 concentrations (350, 700, 1000 and 2000 ppm) and N deposition levels (0, 10, 30 and 100 kg/ha-1 a-1). The same N deposition levels were also applied in the field. CO2 concentration increases both the shoot density and dry mass of S. fuscum but decreased the length increment. There was no net effect on production. For S. angustifolium, shoot density did not alter with elevated CO2 concentration but the CO2 induced increment in dry mass and length caused increased production. S. angustifolium suffered from nutrient deficiency on the 0kg/ha-1 a-1 treatment and S. fuscum had difficulties to survive at heaviest N load. No clear trends in length increment or cover was noticed in the field study during the first year