RELATIONSHIP BETWEEN SPECIES DIVERSITY AND PLANT BIOMASS OF UNDERSTORY FERNS IN HIGH-NITROGEN HABITAT.

The aim of the study was to explore the relationship between species diversity of understory ferns and plant biomass in high-nitrogen habitats in China. Four species Cyrtogonellum fraxinellum, Pteris nipponica, Humata griffithiana and Pteris fauriei were chosen to set up three species richness (1, 2 and 4 species) and a total of 11 species combinations at two nitrogen habitats (control and 10 g N m2 yr-1 ). Plant biomass and soil physical and chemical properties were determined. The study had the following results: (1) Species richness had no significant effect on plant biomass under both nitrogen habitats. (2) Under both nitrogen habitats, species combination had a significant effect on plant biomass. (3) The presence of P. nipponica and P. fauriei significantly increased the plant biomass, and the presence of C. fraxinellum significantly reduced the plant biomass under two nitrogen habitats. (4) Nitrogen addition significantly increased soil nitrogen content, but plant species diversity had no significant effect on soil physical and chemical properties. (5) There was a significantly negative correlation between plant biomass (aboveground, underground, and total) and soil phosphorus content; there was also a significantly negative correlation between plant underground biomass and soil pH. Assembling specific species combinations can improve plant biomass and promote ecological restoration under high nitrogen habitat. [ABSTRACT FROM AUTHOR]