Bryophyte biomass and species richness on the Park Grass Experiment, Rothamsted, UK

The relationships between bryophyte biomass and species richness and soil p H, nutrient applications and vascular plant biomass and species richness we re analyzed for the Park Grass Experiment (Rothamsted, UK). The study exami ned the abundance of bryophytes in relation to long-term fertilizer and lim e application and to fertilizer treatments recently being ceased on some pl ots. The probability of bryophytes being present on a plot increased with i ncreasing soil pH, and on plots at soil pH 3.3-4.5, the lowest values in th is experiment, there were virtually no mosses present. Total bryophyte biom ass decreased with increasing vascular plant biomass and vascular plant ric hness. Both bryophyte biomass and species richness showed a curvilinear res ponse to soil pH. Bryophyte biomass was markedly increased on plots where n itrogen (N) fertilization had recently been ceased. The abundance of the co mmon bryophyte species showed individualistic responses to treatments. N ha d a negative effect on the abundance of Brachythecium rutabulum. Increasing soil pH, and the application of phosphorus (P) and potassium (K) fertilize r together, had a positive effect on Eurhynchium praelongum. This species w as also negatively affected by N, but tolerated larger amounts of it (100-1 50 kg ha(-1) N) than B. rutabulum. An ephemeral moss, Bryum subapiculatum, had a unimodal response to soil pH but showed no response to N, P, K or oth er explanatory variables.