The influence of nitrogen in stemflow and precipitation on epiphyticbryophytes, Isothecium myosuroides Brd., Dicranum scoparium Hewd. and Thuidium tamariscinum (Hewd) Schimp of Atlantic oakwoods.

The spatial relationship between the concentration and deposition of the major ions in precipitation and stemflow and their influence on the tissue nitrogen concentration of 3 epiphytic bryophytes on Quercus petraea and Q. robur was investigated at 7 UK Atlantic oak woodland sites with a range of total N deposition of 55-250 mmole m-2. The main driver of change in tissue N concentrations of 3 epiphytic bryophytes (Isothecium myosuroides Brid. (Eurhynchium myosuroides (Brid.) Schp.), Dicranum scoparium (Hedw.) and Thuidium tamariscinum (Hedw.) was total N deposition in stemflow, dominated by ammonium deposition. The 3 epiphytic species also showed strong relationships between tissue N concentration and total N deposition in rainfall but a poor correlation with total N ion concentration in rainfall. This study shows that epiphytic bryophytes utilise stemflow N and thus increase their risk from inputs of total N deposition compared to terricolous species at the same site.